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Remembering the Early Robotic Explorers

Reflecting back on the history of robotic space missions, Larry Klaes offers a look at the early missions to Venus and Mars, harbingers of the far more complex probes we would later send into the Solar System. The Pioneers, Veneras and Mariners were, in their day, on the forefront of planetary research, blazing the trail most recently followed by Curiosity on Mars. As a site focused on deep space issues, we often return to Voyager and Pioneer, but let’s not forget how planetary exploration got its start.

By Larry Klaes

Once upon a time, our Solar System was a very lively place.

In past centuries, most if not all of the known planets and their moons, along with the even smaller members of our celestial neighborhood, were imagined to have native life forms as numerous and diverse as those found on Earth. Otherwise, it seemed pointless for whole worlds to exist without any inhabitants.

Then along came the Twentieth Century. Improved knowledge about the Sol system caused the majority of contemporary astronomers and other scientists to realize that most of these distant bodies were just too hot or too cold or too airless to support complex organisms, especially intelligent ones capable of building civilizations.

There were some holdouts, however.

The fourth world from the Sun, the planet Mars, retained enough of its Earth-like characteristics to convince scientists that plant life and perhaps even some lower animal forms dwelled in the harsh environment. It was also considered that while the canal-building beings of the Red Planet were probably figments of the Nineteenth Century imagination of Percival Lowell and his followers, astronomers could not entirely rule out the possibility that an advanced society once did exist in the Martian past, when that alien globe was warmer and wetter. The crumbling ruins of their civilization might be awaiting discovery, buried by ages of unchecked planet-wide dust storms.

Image: A once enigmatic planet, Mars began to yield its secrets to our early probes. This HST image shows the Valles Marineris region (centered on roughly 60 degrees longitude). Credit: NASA/NSSDC.

Moving in the direction of our yellow dwarf star past Earth, the planet Venus was even more of an enigma than Mars. The primary mystery of our other celestial neighbor came from its being sheathed in an unbroken cover of vaguely yellowish clouds.

The rather high limitations on factual information about the second world from the Sun due to its global atmospheric conditions did very little to stem some rather high levels of speculation about what was going on far beneath the Venusian cloud deck.

Some assumed that because Venus was perpetually shrouded with clouds, it must be raining there everywhere all the time. Toss in the fact that Venus is closer to the Sun than every other planet but Mercury and it became easy to conclude that the whole world was a very tropical place bathed in a perpetual twilight. Perhaps Venus was reminiscent of the Carboniferous Period on Earth, with alien swamps full of strange plants and reptilian creatures crawling through the dankness.

Even when astronomers were able to do more than just stare at the nearly blank visage of Venus with their optical telescopes, conflicting data ruled the day. As a result, some scientists theorized that the planet was covered in a global ocean of either boiling oil or seltzer. Others concluded that Venus was a desert world where fast, hot winds whipped across the utterly dry surface and the clouds were made not of water droplets but of constantly elevated dust.

Image: Venus’ hidden surface would not be understood until Soviet and American probes confirmed its extreme temperatures and pressures. Credit: NASA/NSSDC.

Nor could the scientists come to an agreement on the average surface temperature of Venus: Some thought their measurements meant that the face of the planet was very hot, many hundreds of degrees warmer than on Earth; any water present would be turned to vapor and any known forms of native life would be out of the question. The other camp said the high temperatures came not from the planet’s surface but its surrounding ionosphere. Perhaps Venus was just hospitable enough to keep water in a liquid state, thus preserving the Venusian ferns and dinosaurs – at least in theory.

Enter the Space Age

Two major events of the Twentieth Century played important roles in helping science to discover the true nature of the planet Venus: World War Two and the subsequent Cold War. Both international conflicts provided the technology, engineering, and motivation to bring about the Space Age, which officially began in the fall of 1957.

On October 4, the Soviet Union lofted into Earth orbit a silvery sphere named Sputnik 1, its four swept-back whip antennae transmitting to the world far below a deceptively simple signal of its existence, along with the wider implications of what had been and could be achieved in this new era. Then, just one month later, the Soviets sent a dog named Laika into space aboard Sputnik 2, the first living creature to circle the globe.

In response to this geopolitical challenge and potential military threat, the United States ramped up its own space efforts, quickly turning the Space Age into the Space Race. Both superpowers began to use the rest of the Universe as a generally non-destructive means to show the rest of humanity that its capabilities, resources, and especially its ideologies were the best.

Science and the expansion of human knowledge into the Cosmos were often touted as the first and foremost reason for lofting these new machines into space: One of the goals of the International Geophysical Year (IGY) of 1957-1958 was to achieve the orbiting of an artificial satellite. While not a fabrication, it was clear to anyone who looked beyond the rhetoric and propaganda that without the swiftly growing military-industrial complex of both sides, most space science and exploration plans would have remained largely science fiction for many more years if not decades into the future.

The early years of the Space Age/Race were dominated by achieving a series of firsts in the Final Frontier. Once low Earth orbit, or LEO, had been reached (and won in the political sense by the USSR), the next obvious goals were the nearest worlds to Earth: Our celestial home’s singular natural satellite, the Moon, and the two closest planets in the Solar System, Venus and Mars.

By the end of the 1950s, the geopolitical winner in the robotic race to the Moon was again the Soviet Union. After several launch failures by both superpowers in 1958, the next year witnessed the USSR’s aptly named Luna series sending one probe past the Moon (and subsequently becoming the first artificial satellite to orbit the Sun), a second vessel impacting on the lunar surface, and a third robot revealing to humanity with its onboard cameras the face of the mysterious lunar farside.

The next obvious goal in this celestial competition was Venus. With a closest approach to Earth of 26 million miles during its 224.7-day dance around the Sun, an unmanned probe could reach that world in less than four months with the most ideal launch window. This relatively short trip time was a most important factor, for the environment of the inner Sol system held many potentially hazardous unknowns for an exploring spacecraft.

Another key milestone to conquer was the endurance of the prevailing space technology itself. If a vessel survived the initial launch and escape from its Earth parking orbit – for numerous rockets during that pioneering era had an alarming frequency of exploding or otherwise malfunctioning – the probe then had to last long enough to communicate its scientific findings to Earth across many millions of miles of near vacuum.

The farthest any vessel had reached into that celestial region at the time was the American probe named Pioneer 5. Originally intended to be part of an ambitious double mission to flyby and orbit Venus, the goals were scaled back until Pioneer 5’s primary focus became the interplanetary space between Venus and Earth. The probe spent over three months in 1960 returning precious scientific data and was tracked out to a distance of 22.5 million miles from home. Pioneer 5 paved the way for the flotilla of Venus probes that were soon to follow.

As with Mars in 1960, the Soviets were the first nation to attempt sending automated spacecraft to the second world from the Sun. Two probes were launched from their primary space center in a remote region of Kazakhstan just over one week apart in February of 1961.

The first machine never left Earth orbit due to a technical issue with one of its rocket stages. The second probe, later to be known as Venera 1 (the Russian word for Venus), was successfully injected into deep space but ceased communicating with its controllers before the month was out. Attempts were made to detect and resume contact with Venera 1 through its predicted arrival at Venus in May of 1961, but the probe was never heard from again.

Years later, the West learned that the Soviets had intended to place simple instrumented capsules on the surface of Venus with these 1961 missions and not just fly by the planet as originally thought, just as they had tried and failed with Mars one year earlier. As a number of the Soviet scientists had sided with the Venus model that included some kind of liquid ocean covering the planet, the capsules were designed to float.

The Soviets’ confidence in a watery Venus was demonstrated by the fact that the landers were not equipped with any mechanical means to touch down softly on the planet. Instead the capsules would have to rely on the thick Venusian atmosphere along with its presumed alien ocean for cushioning, which the Soviets estimated to be five times denser than on the surface of Earth.

The Mariners of a Vaster Sea

When the next launch window to Venus opened up in the late summer of 1962, the United States was finally ready to join the Soviets in sending robotic representatives to that alien world.

The first American Venus explorer, named Mariner, was based on the Ranger series of lunar probes made by the Jet Propulsion Laboratory (JPL). Designed to image the lunar surface until impact and place on the Moon a seismometer wrapped in a protective sphere of balsa wood to record any quakes, the Ranger craft were not performing as planned. Various technical issues kept the three Rangers launched throughout 1962 from returning any images or data about Earth’s natural satellite. National prestige took some small comfort when Ranger 4 impacted on the lunar farside, becoming the first American probe to touch the Moon.

The Soviets attempted to trump the planned American deep space efforts by sending three rather sophisticated probes toward Venus between August 25 and September 12 of that year. One vessel would conduct a photographic flyby of the planet, while its two siblings would place landers on the surface, analyzing the thick and cloudy atmosphere during their descents.

Unfortunately for Soviet prestige and planetary science, none of the three unnamed Venus explorers were able to get any further than temporary Earth orbits at best due to technical failures with their launch rockets. The Soviet Union officially downplayed the loss of their newest Venus probes. This was standard procedure for many of their space efforts, failed and otherwise depending on the mission, during the Cold War.

An Oil Rig to Venus

At first glance, the design of the first two planetary Mariners bears some resemblance to an old fashioned oil rig, albeit one with two rectangular wing-like solar panels and a parabolic high-gain antenna attached to its hexagonal base where the basic computer, electronics, batteries, and attitude control devices were stored. The lattice-work mast held the majority of the probes’ forty pounds of scientific instruments and was capped off by a cylindrical omni-directional antenna.

Of all the scientific devices on the Mariners, perhaps the most important ones were the microwave and infrared radiometers. They would determine the actual overall temperature of the planet’s surface and the makeup of the obscuring cloud deck, scanning Venus across its day and night hemispheres. The rest of the instruments would search for any magnetic and radiation fields generated from the planet, along with detecting high-energy cosmic radiation, interplanetary dust, and charged particles streaming from the Sun, also known as the solar wind.

Small sensors spread about the Mariners would constantly measure the state and health of the space probes while in flight. They would alert mission controllers to any technical problems during the long and potentially hazardous trek to Venus and provide the space agency with vital data for improving future vessels on interplanetary journeys.

An optical imaging system was not included among the scientific equipment of these pioneering robotic explorers, partly because it was felt there would be little or nothing to witness beyond the bland, yellowish cloud cover. Earth-based astronomers sometimes reported and photographed diffuse darker patches on the clouds of Venus (and a strange luminous glow on the night side called the Ashen Light) and even cloud breaks through the turgid atmosphere straight to the surface, but the last claims were always questionable at best.

One last item placed aboard each Mariner was neither a scientific instrument nor a sensor: A small American flag was sandwiched between some layers of thermal material at the top of the probes. The Soviets also placed commemorative mementos aboard their Venus explorers. Their tributes consisted of small metal Earth globes designed to survive the plunge to the planet’s surface with their Venera landers. Inside the hollow spheres were medallions with the Soviet Coat of Arms engraved on one side. The other face of the metallic disk displayed a diagram of the inner Sol system depicting the space probe’s (planned) journey from Earth to Venus.

Donald Mitchell offers a very nice collection of images of the Soviet space medallions and pendants which now rest on Venus and several other nearby worlds.

First Try

The first of the twin 447-pound robotic probes to be aimed for the second world from the Sun was naturally named Mariner 1. Encased atop an Atlas-Agena B launch vehicle, the vessel was sent on its way from Launch Complex 12 at Cape Canaveral in Florida into the predawn skies of July 22, 1962.

Oran W. Nicks, who was the Director of Lunar and Planetary Programs for NASA and present at the launch of Mariner 1, poignantly described what happened next in his wonderfully written book Far Travelers: The Exploring Machines (NASA SP-480, 1985):

“Our friend died violently at 4:26 A M. on a hot July night. Her finish was spectacular; she was trapped amid the flaming wreckage of an explosion that lit the night sky. Four of us watched helplessly, standing together at a site that gave us a perfect view. We had come there with a common interest in her adventuresome goal, though we came from different backgrounds, and each of us brought a different perspective and commitment to her tragic performance.

“We were soon to learn that she had been blown up intentionally by a man with no firsthand knowledge of her ability and promise. My emotion changed from disappointment to bitterness when I learned that she was destroyed barely seconds before flying beyond his reach [just six seconds, to be exact]. We had witnessed the first launch from Cape Canaveral of a spacecraft that was directed toward another planet. The target was Venus, and the spacecraft blown up by a range safety officer was Mariner 1, fated to ride aboard an Atlas/Agena that wobbled astray, potentially endangering shipping lanes and human lives.”

Guidance equipment for the rocket carrying Mariner 1 had become faulty, sending the entire vehicle off course. The Range Safety Officer (RSO) at Cape Canaveral sent a destruct signal to explosive devices on the booster to keep it from potentially causing harm or worse to people and property in the vicinity. Falling from the sky with the shattered remains of its rocket, Mariner 1 continued to transmit right until it slammed into the Atlantic Ocean. The first American attempt at Earth’s nearest planetary neighbor joined the ranks of the Soviet Venera probes which never left their home world.

Second Time’s the Charm

Since the early days of robotic planetary exploration, NASA’s plans for a typical deep space probe mission often included constructing at least three versions of a space probe: The primary craft that would be sent to the target world, an identical or sometimes improved backup probe, and a full-scale engineering model that stays home. This third version allows the mission team members to directly test the probe and to recreate and (hopefully) resolve any technical issues the flight version may have while enroute to and at the planet.

With the sudden loss of Mariner 1, the wisdom of having built more than one version of the same probe became all too apparent. America would still have a chance to explore Venus thanks to the existing backup vessel, which became known as Mariner 2. However, with the 1962 launch window to Venus closing rapidly, the mission team would need to complete their preparations sooner than normal.

Just over one month after Mariner 1 had found itself at the bottom of the Atlantic rather than on its way to Venus, Mariner 2 found itself rising into the sky above Cape Canaveral on August 27 aboard another Atlas-Agena B launch vehicle. Several times on its way to an Earth parking orbit, the booster behaved erratically, but thankfully the situations corrected themselves before any drastic action had to be taken.

Within two hours after launch, Mariner 2 found itself in open space with its two solar panels fully extended and on its way for a four-month journey to an alien world. The solar cells were found to be generating a bit more power than expected, so on August 29 the mission team activated the craft’s science cruise experiments that would let them know what the probe was finding out there and experiencing on its way to Venus.

The interplanetary voyage for Mariner 2 across millions of miles of space was anything but calm and routine, and not just because it was something rather new for NASA JPL.

The first major technical problem for Mariner 2 arose on September 8 when the probe suddenly lost its attitude control. Three gyroscopes automatically restored stability to the vessel just three minutes later. A possible strike by a stray meteoroid was suspected but never confirmed.

Even before the official Space Age, meteoroids were a particular concern to space engineers, as no one knew to any high degree just how much cosmic debris roamed the Sol system and how much damage they could do to a spacecraft. One of the staples of early science fiction involving spaceflight often had the intrepid crew of a silvery V-2 style rocket ship being threatened by whole storms of meteoroids as they bravely explored the Universe.

Had Mariner 2 been unable to realign itself, the probe could have begun tumbling, eventually resulting in a loss of contact with Earth and a serious loss of power due to the probe being unable to keep its solar panels focused on the Sun.

The next serious threat to the health of Mariner 2 while in deep space took place right on Halloween. One of the probe’s two solar panels began to malfunction by short circuiting. Concerned that Mariner might not have enough onboard energy to examine Venus and transmit back to Earth the priceless data on that planet, the mission team turned off the science cruise instruments to conserve power.

One week later, the errant solar panel appeared to have healed itself, so the Mariner team reactivated the cruise devices. The panel’s revival was short-lived, though: By mid-November, the panel had permanently broken down, leaving Mariner 2 with just one solar panel for collecting energy, along with its short-term batteries.

Thankfully for the mission, the probe was now close enough to the Sun that it could survive on the energy from just one panel all the way to Venus. There was, of course, a down side to being much nearer to our yellow dwarf star: An increase in solar heating.

Anyone seriously putting together a satellite to operate in open space plans for the craft to deal with extremes of heat and cold among other factors in the harsh environment beyond our planet’s relatively comfortable lithosphere. In the essentially airless void of space, the outer skin of a spacecraft facing away from the Sun can be hundreds of degrees below freezing, while the sunlight side is above the boiling point of water.

Not only did Mariner 2 have to contend with these same incredible temperature variations as other spacecraft have done before and since, but the probe was also approaching 26 million miles closer to the Sun than when its journey began back in August. The scientific instruments were starting to encounter temperatures much higher than they were nominally designed for. The Mariner team became increasingly worried that their robot emissary to Venus might succumb to the equivalent of a mechanical fever before it could arrive.

Then, just two days before Mariner 2 would encounter Venus, the onboard computer failed to give what was called a “cyclic calibrate pulse” which normally took place every 16.6 hours. The team worried this error meant that when the probe came upon the planet, the computer would fail to initiate the critical final encounter sequence that would activate the science instruments to examine the planet and return all that precious information to Earth.

Venus Day

On December 14, 1962, just six hours before much of the sky would be filled with the looming presence of the planet Venus from the perspective of the Mariner probe, the mission team discovered that their fears about the vessel’s mechanical “brain” were true: The computer had not told the probe to switch to encounter mode. Mariner 2 was in danger of flying past Venus without conducting a single scientific scan of the planet.

A command was radioed from the Goldstone tracking facility in California to Mariner 2, which was 36 million miles from Earth at that moment, father than any operating spacecraft had ever been before. Traveling at the speed of light, the command was received and replied to by the probe 6.5 minutes later, which took another 6.5 minutes to let the humans conducting the mission know that all their efforts were not in vain.

Approaching the planet’s darkened hemisphere at 39,000 miles per hour, Mariner 2 flew by Venus at a distance of 21,648 miles from its surface. If the probe had possessed electronic eyes, it would have seen that cloudy world appearing 900 times larger than the full phase Moon does in Earth’s skies. For the first time in history, a space vessel had reached another planet intact and functioning well enough to return scientific information about such a world. This was a mere five years after Sputnik 1 had been sent beeping into Earth orbit.

For 35 minutes, Mariner 2’s two radiometers scanned across the planet from its night side into the daylight hemisphere. The resulting data that streamed across interplanetary space back to the eagerly waiting scientists at a mere 8.33 bits each second confirmed that the high temperatures astronomers had previously detected were coming from the very surface of the planet and not its ionosphere.

Not only was Venus a very hot world, averaging 800 degrees Fahrenheit, but that temperature remained constant across the entire globe; not just from its equator to the poles, but also both in the day and night hemispheres. Clearly the planet retained its heat through the “greenhouse effect”, allowing solar energy to penetrate its cloud layers and thick air, but not to escape back into space. No other terrestrial world approached the surface temperatures Mariner 2 found at Venus, not even Mercury.

Gone almost instantly were the humid swamps of strange plants and even stranger animals. Gone too were the seas of oil, seltzer, and especially liquid water, for not even a single drop could survive there except to become a very temporary vapor. On the planet revealed by the American robot probe, even bars made of zinc and lead would melt into puddles, and no human being exposed on the surface would last beyond mere seconds.

Image: This 1961 photo shows Dr. William H. Pickering, (center) JPL Director, presenting a Mariner spacecraft model to President John F. Kennedy. NASA Administrator James Webb is standing directly behind the Mariner model.

As for native life, anything that had ever lived on Venus or could exist there as Mariner 2 slipped by their world would be nothing like organisms from Earth. Those who envisioned the second planet from the Sun as a scorching, desolate desert had been closest to the truth.

Readings from the other science instruments aboard Mariner 2 gave further evidence that about the only aspects Venus had left in common with Earth were its size and mass. Neither a magnetic field nor a radiation belt could be found around the planet, at least to the detection limits of the probe’s magnetometer. Venus appeared to be rotating very slowly and in the direction opposite to that of our planet. If a person standing on Venus could somehow observe the Sun rising at morning, our star would appear to come up from the western horizon, crawl across the sky, and then slowly set in the east several hundred terrestrial days later.

Seven hours after its historic encounter with Venus, the mission team sent another command to the Mariner to switch the probe back into science cruise mode. Along with its invaluable and startling revelations at Venus, Mariner 2 also reported several important discoveries about the interplanetary environment to which the terrestrial worlds of the inner Sol system are immersed.

Scientists were surprised to learn that the charged particles streaming from the Sun, known as the solar plasma or solar wind, were always present and constant in deep space. Mariner 2 also revealed it had received far fewer hits from cosmic dust than expected, though at least one jarring meteoroid impact was suspected during its journey through the interplanetary realm. All of this data would do much for better preparing future deep space missions.

The Last Days of Mariner

Though Venus would soon be well behind Mariner 2 as it plunged even closer to the vicinity of the Sun, its overall mission was hardly at an end. The probe continued to send back a stream of data about existence just beyond its metal skin, none of which had ever been examined directly before.

However, as Mariner 2 made its closest approach to the Sun two days after Christmas of 1962 at 65.5 million miles, the temperatures inside and outside the probe continued to rise.

On January 3, 1963, Mariner 2 had transmitted thirty minutes of real-time telemetry data to the monitoring station in Johannesburg, South Africa. The probe appeared to be functioning as well as it often had during most of the 129 days it had spent in deep space since leaving Florida the previous August. Mariner’s home planet was almost 54 million miles distant, while Venus was reduced to a brilliant white point of light in the perpetual night sky 5.7 million miles away.

Then Mariner 2 was heard from no more.

NASA JPL attempted to find the probe via its radio signal through August of 1963, but without success. In addition to its already vaunted legacy in the history of space exploration, Mariner 2 had transmitted over eleven million measurements while traversing 223.7 million miles of deep space during its known functional lifetime, a record not to be broken until the United States and Soviet Union began sending probes to the planet Mars in the next several years. Mariner 2 now orbits the Sun inside Earth’s solar circuit once every 345.9 days – silent, inoperative, and presumably largely intact.

Image: Mariner 2 celebrated at the Tournament of Roses Parade.

Oran W. Nicks, a man most personally invested in the early Mariner missions, eulogized the space probe in his work, The Far Travelers, thusly:

“Thus ended the saga of Mariner 2 – A robot, designed and directed by men, given a mission to extend the search for knowledge beyond the limited reach of Homo sapiens. Though it accomplished a voyage that was clearly “superhuman”, Mariner was a simple exploring machine, with only a very modest capability to perform on its own. A total of 11 real-time commands and a spare were possible, along with a stored set of 3 onboard commands which could be modified. Other functions, such as updating antenna position and adjusting thermal control louvers, were provided, but in every sense it was a simple robot with the capability for only a small amount of human interaction.

“From the meager information returned by telemetry, we know that Mariner 2 endured significant stress, but how many meteorite impacts it received and why it developed an ultimately fatal fever will forever remain a mystery. Perhaps in its passage from Earth to Venus and its transfer from orbit to orbit, it had other experiences which we will better understand when man repeats the voyage in person, with his own sensors and the additional capabilities that will exist at the time.”

The Legacy of Mariner 2

It is not an exaggeration to state that what Mariner 2 accomplished at Venus on December 14, 1962 changed the course of the American and Soviet space programs. When the intrepid probe reported back to humanity that what lay beneath the clouds of our neighboring world was anything but neighborly to all known forms of terrestrial life, the United States turned its planetary focus towards Earth’s other celestial neighbor, Mars.

Though almost no professional scientist of the early Space Age still looked upon the Red Planet as a haven for an alien civilization, many members of the relevant sciences did seriously think that Mars supported some form of simple plant life or perhaps even more complex creatures, albeit not highly intelligent. In addition, Mars looked much easier to land and maintain machines and astronauts upon compared to Venus. Now while NASA did not intend to stop exploring Venus altogether, being closer to Earth than any other planet in the Sol system was no longer good enough to devote a substantial amount of the space agency’s time, resources, and funds to that shrouded inferno. It was Mars that appeared to offer the best planetary return on their investment in terms of finding extraterrestrial life and founding permanent colonies.

Soviet space scientists had a decidedly different reaction to the findings of Mariner 2. Already invested in the concept of a Venus with a surface covered in some form of liquid, plus the indignity of being scientifically and politically trumped at once by their chief Cold War rival, the Soviet space agency was determined to learn the true nature of Venus for themselves. After all, Mariner 2 actually opened more key questions about the planet than it had answered, among them being: Exactly how dense was the atmosphere of Venus? What were the main constituents of the air? What did the surface of Venus really look like? In addition, the Soviets were far ahead of the United States when it came to developing and launching planetary landers, even if none had yet made it to the second planet from the Sun.

The years 1964 and 1965 saw America fling its next two Mariner probes away from the Sun towards the Red Planet. In the same time period, the Soviets hurled three more flyby probes and three more landing vehicles at Venus. While none of them achieved their intended scientific goals, suffering either from launch failures or overheating in space enroute, the Soviets were at least able to glean another planetary first in the Space Race from these efforts, specifically the first craft to land on another planet with Venera 3. Although the probe had stopped transmitting to Earth by the time it reached Venus in March of 1966, Venera 3 may have been functioning when it impacted on the night side of that world. Despite this technical achievement, the scientific questions about Venus left by Mariner 2 were still wide open.

Mariner 5: The Sequel

By the late 1960s, NASA was prepared to solve some of those critical questions about the second world from the Sun left open by the second Mariner. Taking leftover parts from the two 1964 Mariners they built for exploring Mars, JPL put together a single deep space probe they named Mariner 5.

Modified to survive in the much warmer vicinity of Venus, the fifth member of the Mariner probe series was lofted upwards on the night of June 14, 1967 from the same launch complex with the same kind of rocket configuration that its trailblazing predecessor had used almost five years earlier.

Meanwhile, just two days earlier on the other side of the globe, the Soviet Union had launched their latest effort to reach not just Venus but the very surface of the planet itself.

Named Venera 4 – once the probe had successfully escaped its Earth parking orbit – the nearly spherical landing capsule it carried strongly reflected the Soviet view of a liquid-covered planet: Not only could the one yard-wide capsule float, the probe’s makers also included with it a protective lock composed of sugar. Upon being dunked in the alien sea, the sugar lock would dissolve and release the probe’s transmitter antennae, which would send home the incredible news that Earth was no longer the only known world able to keep water in a liquid state on its surface. That was the expectation, at least.

As Venera 4 descended towards whatever fate awaited it on that distant realm dangling beneath a large parachute, the vessel’s scientific instruments would perform the first direct readings of Venus’ dense atmosphere. While some of the elements and molecules making up the planet’s air were already know to astronomers, exactly how much of each constituent was present and if any other kinds were waiting to be discovered remained a mystery as Venera 4 plunged through interplanetary space to Venus, with the American Mariner 5 probe following close behind.

Having been launched first, Venera 4 arrived at Venus one day ahead of its American counterpart on October 18, 1967. The entire probe sailed right into the planet’s night side. The main bus carrying the lander capsule conducted several scientific measurements of its own before its demise as an undoubtedly brilliant meteor far above the cloud deck.

In agreement with Mariner 2, the Soviet probe bus could find no evidence for either a magnetic field or radiation belts around Venus. What Venera 4 did discover was a weak corona of hydrogen particles sixteen thousand miles above the planet.

The automated capsule, operating on batteries with a 100-minute lifetime and drifting slowly downwards beneath a successive series of braking parachutes, began letting the scientists back on Earth know exactly what the Venusian air is made of: To their surprise, at least 93 percent of the planet’s atmosphere was composed of carbon dioxide, with nitrogen following at around seven percent and just traces of oxygen and water vapor. Many assumed nitrogen would have been the dominating element of that alien air as it is with Earth, but the reverse was true.

Venera 4 ceased transmitting 93 minutes into its mission. The last atmospheric pressure reading the probe reported was about 18.5 times what is experienced at sea level on Earth’s surface, not far from what the capsule was designed to tolerate. Since about 25 Earth atmospheres are what most contemporary scientists estimated about the density of Venus’s air, it was logical (and politically expedient) for the Soviets to conclude that Venera 4 had reached the surface of the planet while still transmitting data – yet another space first.

The next day, October 19, Venus received the other mechanical emissary of 1967 from the inhabitants of the third world from the Sun. Although Mariner 5 carried neither an imaging system nor its own lander capsule (the latter was considered but never implemented, as the probe was under tight budget and time constraints), the vessel would use its radio signal to greatly refine the then current information about the atmosphere of Venus. This revised data would also let the scientists on both sides learn if Venera 4 did indeed survive intact and functioning to the planet’s surface – or not.

Flying past the veiled planet much closer than Mariner 2 did at a distance of just 2,480 miles, Mariner 5 spent 26 minutes behind Venus as seen from Earth. As the robotic explorer was being eclipsed by the bulk of the planet, Mariner’s radio signals cut through Venus’ atmosphere on their way to Earth, revealing new details on that planet’s mantle of air.

The atmospheric pressure of Venus at its very bottom was much higher than the majority of scientists expected, ranging from 75 to 100 Earth atmospheres. There appeared to be two different cloud layers over Venus, one approximately 37 miles above the surface and the other at 31 miles in altitude. The global ground temperature was even higher than recorded by Mariner 2, approaching up to 981 degrees Fahrenheit. Tracking Mariner 5 also helped to refine the planet’s mass at 81.5 percent that of Earth’s. This meant that an object weighing one hundred pounds on Earth would weigh just nine pounds less on Venus.

Over the next two years, American and Soviet scientists met formally several times to discuss the data results from their indirectly joint space mission to Venus. The Soviets initially argued that Venera 4 could have landed on a very high mountain or plateau to account for their readings, but the Mariner evidence and later Earth-based radar observations showed Venus’ crust to be relatively flat overall. The conclusion was that Venera 4 had been crushed into radio silence by the increasing air pressure just sixteen miles above surface. Eventually the capsule would have landed on the face of Venus in any event, just not in working order.

The Soviets would eventually succeed in reaching Venus with a functioning lander and refine the planet’s air pressure and temperature even further. Venera 7 touched down on December 15, 1970 in the southwestern section of what would one day be called Tinatin Planitia. There the instrumented capsule spent the 23 remaining minutes of its working life letting scientists know that the temperature of its landing site averaged 887 degrees Fahrenheit, while about ninety Earth atmospheres of pressure weighed down upon its hull (the Soviets had designed Venera 7 to withstand double that amount, just to be safe). One would have to dive over three thousand feet beneath the oceans to find an equivalent natural pressure on Earth. Any lingering thoughts of a cool and watery Venus brimming with life were finally crushed with Venera 7, the first probe to transmit from another planet.

Venus Exploration Heats Up

The robotic exploration of Venus reached its peak in the 1970s and 1980s, thanks largely to Soviet efforts but also with several notable American missions in those same decades.

Between 1972 and 1985, the Soviet space program succeeded in landing eight more probes on our celestial neighbor. These technologically superior Veneras, while lasting no more than a few hours in the very harsh conditions of the planet, returned the first (and so far only) optical images of Venus’ rocky surface and the first data on the composition of the crust.

These Veneras revealed that much of Venus is covered in various types of basalt, a mineral produced by volcanic lava. The surface readings and images, along with other data returned by that generation of Soviet probes, gave a pretty clear indication that most of the face of the second planet has been long shaped by intense volcanic activity, past and very likely present. The images also showed that daytime on Venus is not as gloomily dim as thought and that atmospheric refraction turns the sky bright orange in color, compared to Earth’s blue skies and the salmon pink ones of Mars.

Image: Color images of Venus, first obtained by Venera 13 and 14.

The last two space probes in the Venera series remained in orbit about Venus upon their arrival in 1983 and conducted the most sophisticated radar mapping of the planet until the American Magellan probe arrived there seven years later. The Soviets also succeeded in placing two instrumented balloons into the atmosphere of Venus with the twin Vega missions in 1985. These balloons spent two days traveling over five thousand miles among the thick and turbulent cloud layers.

While not quite as ambitious as the Soviets, the United States did send several more space probes to Venus, among them the last of the robot vessels officially part of the Mariner series.

Although its primary goal was to become the first probe to flyby the planet Mercury, Mariner 10 utilized Venus for a historic first gravity assist to reach the world closest to the Sun. Launched from Cape Canaveral in Florida in November of 1973, the probe flew by Venus on February 5, 1974. Equipped with an imaging system, Mariner 10 proved that scientists could see physical features in the planet’s clouds, especially in the ultraviolet range of the spectrum. The visiting probe revealed that hurricane-level winds whipped the Venusian clouds around the planet in just four Earth days, much faster than the global rotation rate of over 243 days, which is longer than it takes for Venus to go once around the Sun!

Four years later, the United States lofted its own armada of Venus explorers towards the planet as the last official members of the Pioneer family of deep space probes. While one spacecraft would circle the planet and return the first radar map of its surface made from orbit, the other member of the fleet would drop four small probes onto the planet itself. They would directly examine the atmosphere from four different regions over Venus until impact with the ground.

Along with determining that Venus has three distinct cloud layers instead of two as indicated by Mariner 5 eleven years earlier, the Pioneer Venus Multiprobes greatly added to the planet’s reputation as a hellish place when it was realized they were plunging through an atmosphere saturated with droplets of sulfuric acid!

Although none of these drop probes were designed or expected to survive their encounters with the surface, one called Day did manage to keep functioning after its rough landing. The vessel transmitted for 67 minutes before being overcome by the intense heat of its surroundings. The Pioneer Venus Multiprobes were the first American craft to land on the veiled world and remain the only ones to do so to this day.

A Mariner Called Magellan

The last American robotic probe mission dedicated to the exploration of Venus was a spacecraft named Magellan. Other later deep space machines built and launched by NASA such as Galileo, Cassini, and MESSENGER would fly by and aim their scientific instruments at the second planet from the Sun in the 1990s and 2000s, but their ultimate goals lay elsewhere in the Sol system. For them, Venus was primarily a gravity boost to save on fuel and costs. Magellan’s focus was Venus, namely to radar map its entire surface in unprecedented detail.

Although Magellan was never officially listed as a member of the Mariner family of space probes, the automated craft did more than just emulate the spirit of the Mariners that went to Venus: Magellan was actually put together from the spare parts of previous space probes, including Mariners and their kin.

The main body of Magellan came from a spare bus of the Voyager probes, which famously explored the outer Sol system from 1979 to 1989 and are expected to keep returning data from the fringes of our planetary neighborhood until 2025. The twin Voyager craft were originally going to be known as the eleventh and twelfth Mariners until NASA officials wanted them to have what they considered to be a more dynamic nomenclature. Despite the change of labels, if one looks at the structural design of Voyager 1 and 2, it is not hard to see their Mariner family heritage going all the way back to the first two Mariner probes to Venus.

Other features that Magellan literally shared with the Mariner probes were the large white high-gain antenna that also came from the Voyager mission and a medium-gain antenna that was originally a spare for the Mariner 9 probe that became the first spacecraft to orbit Mars back in 1971.

Whether anyone considered Magellan to be an actual part of the Mariner family or not, the craft did honor to that historic legacy by revealing the face of Venus as never before from 1990 until its demise in the planet’s atmosphere in 1994.

Many thousands of volcanoes of wondrous variety cover the surface of that planet, an unknown number of which may be active at present. Lava channels thousands of miles long snake across the landscape. By contrast, no impact craters smaller than a few miles wide exist due to the very thick atmosphere preventing all but the largest planetoids and comets from getting through to the ground.

Image: Color information from the Soviet Venera landers and radar data from the Magellan spacecraft were used to construct this striking perspective view of the Venusian landscape. (In this computer generated image, the vertical scale has been exagerated.) In the foreground is the edge of a rift valley created by faulting in the crust of Venus. The valley runs all the way to the base of Gula Mons, a 2 mile high volcano seen here on the right, some 450 miles in the distance. On the left is another volcano, Sif Mons. Using radar to pierce the dense clouds continuously shrouding the Face of Venus, Magellan was able to explore over 98% of the Venusian surface, revealing a a diverse and tantalizing topography. Credit: The Magellan Project, JPL, and NASA.

The Magellan radar data also seems to indicate that the face of Venus is about 800 million years old – rather young in geological terms for a planet created about 4.6 billion years ago. While there seems to be no evidence for plate tectonics, the planet’s interior may erupt in massive lava flows onto the surface, completely reshaping it over and over. Scientists also wonder if Venus has a rotating iron core, a lack of which would explain the very weak magnetic field that was later discovered by probes with much more sensitive detectors than the early Mariners.

Venus Now and in the Future

Other nations have since gotten into exploring Venus with their own robotic probes. The European Space Agency (ESA) built their first Venus craft called Venus Express, which they based on the Mars Express probe design, equipped with seven scientific instruments and launched on a Russian rocket in November of 2005 to go into polar orbit around the planet the following April. The primary goal of Venus Express is to monitor the atmosphere for a long time period, at least through the end of 2014. Scientists also hope to use what they learn about the climate of Venus to better explain Earth’s atmosphere and climate and ensure that what happened to our neighbor does not happen to our world.

One interesting finding from Venus Express is that the second planet may have slowed down its rotation rate by over one minute since Magellan measured this activity in the early 1990s. Scientists think if this is a real phenomenon, then the high winds and other harsh conditions of Venus turgid atmosphere may make an important contribution to this relatively pronounced rotational slowing.

Japan is another nation with a long and vibrant space program which has attempted to send their first probe to Venus, which they call Akatsuki, the Japanese word for “dawn”.

Launched from Japan in May of 2010, Akatsuki was supposed to go into orbit about Venus that December, where among other things the probe would attempt to learn if the planet has lightning storms and if any of its many volcanoes are active. Unfortunately, something went wrong with the critical braking burn when the probe arrived at Venus and Akatsuki and its mission team found themselves adrift in solar orbit. The hope is that when Akatsuki comes into the vicinity of Venus in 2015, it can be placed into orbit around the shrouded world using a different set of rockets on the probe.

Image: Launch of the Akatsuki Venus Probe. Credit: JAXA.

Not all was lost with Akatsuki. Riding along with Japan’s first Venus orbiter was a satellite named IKAROS, which stands for Interplanetary Kite-craft Accelerated by Radiation Of the Sun. When IKAROS arrived at Venus just one day after Akatsuki’s less than triumphant attempt to orbit the planet on December 8, 2010, the sail craft successfully flew 80,000 miles past Venus and demonstrated the feasibility of solar sailing in interplanetary space.

Talk of future plans for Venus include balloon probes and landers with methods to extend their life on the planet into months instead of just days. Other talk includes nuclear-powered rovers, gondolas, and aircraft on and just above Venus. Even a surface sample return mission has been considered. When and if these and other missions come to pass in the next few years and decades is up to those in charge of humanity’s future in space.

Scientists have even shown some confidence in the last few years that life might exist on the hellish world of Venus after all. Certain layers in the Venusian atmosphere are rather mild in comparison to other layers of air above that planet. It is considered possible that colonies of microbes may live up there in the more biologically friendly zones, floating, eating, and reproducing on the winds. Others think that just below the roasting and crushing realm that is the Venusian surface, the temperature remains milder and fairly constant, a better place for native organisms. Perhaps certain space agencies will be intrigued and encouraged enough to test these theories by sending missions to Venus equipped to answer the questions about life on or maybe under that world.

As for future humans living on Venus, the planet would have to undergo some pretty sophisticated terraforming to make conditions comfortable enough for people to live on Venus without protective gear. One possible method for making Venus more like Earth is to strategically slam comets into the planet. They may be able to provide the water and other elements necessary to cool Venus down and thin out its acidic and roasting atmosphere. Properly directed comet impacts may also speed up Venus’ rotation rate, which at the moment is painfully slow. Genetic engineering and other future technologies may provide life forms that will hasten Venus’ transformation into a place terrestrial organisms could call home one day.

For those who want to see an actual rendition of the probe that started it all for deep space exploration, the Smithsonian National Air and Space Museum in Washington, D.C. has a full-scale model of Mariner 2 hanging from its ceiling, as shown in the image below:

The spacecraft on display was constructed from test components by engineers from NASA’s Jet Propulsion Laboratory. Until the day that someone goes out into interplanetary space and recovers the original Mariner 2, this replica made of actual test components will have to suffice for now.

No matter how far we eventually go into space, or what forms our space vessels may take as they evolve to handle the new and strange celestial environments they will encounter, they will all owe their existence and success to a rather primitive and ungainly probe named Mariner 2 that was first to succeed in exploring another world fifty years ago. And humanity will continue to be grateful for the vast amounts of knowledge that Mariner 2 and all its mechanical descendants have delivered to us about the amazing Universe we live in.


Comments on this entry are closed.

  • Abelard Lindsey August 29, 2012, 12:37

    I think microwave and radio telescope measurements made of Venus in the mid to late 50’s made clear it was way too hot for liquid water and any kind of Earth-like life. Venera 2 only confirmed these measurements.

    The notion of Venus being a steamy tropical rainforest was more of a 1940’s concept. Unlike Venus, Mars was believed to be somewhat Earth-like right up to the Mariner 4 flyby in summer of ’65. The Mars depicted in Arthur Clarke’s “Sand of Mars” was the scientific consensus until the Mariner 4 flyby.

  • ljk August 29, 2012, 13:49

    Abelard, if you reread my article, while some groups thought their pre-Space Age measurements indicated a very hot surface on Venus, others – especially the Soviets – thought the high temperatures came from the ionosphere.

    Even after Mariner 2 sent back data indicating surface temperatures of 800 degrees Fahrenheit, the Soviets were still sending probes with ability to land on a liquid surface until after the indirect joint mission of Mariner 5 and Venera 4 in 1967, when it was finally established that Venus was way too hot on the ground for liquid water or much else.

    If you can ever get ahold of the Time-Life Science Series book titled Planets, which Carl Sagan was the science advisor of when it was first published in 1966, there is a section on the historical perceptions of Venus complete with excellent artwork representing each new idea on the subject.

  • FrankH August 29, 2012, 15:50

    Farewell, Fantastic Venus! is an anthology of short stories about the pre-space age Venus. It’s long out of print, but I found a copy at a used bookstore.
    Here’s the description from Wikipedia:


    ljk – I remember that Time-Life book; iirc, some of the artwork included a desert Venus and a carbonated ocean Venus.

    There’s also the classic “Mr. Smith goes to Venus” with artwork by Chesley Bonestell:


    I wish Mars and Venus had traded places in our solar system!

  • NS August 29, 2012, 19:09

    Just wanted to note that the Donald Mitchell site has a great deal of info about Soviet Venus (and other) probes:


  • Interstellar Bill August 29, 2012, 22:30

    Minor correction concerning Mariner 2 closest approach to Venus:
    Venus would subtend about 30 degrees, which is 60 full moons.
    After all, 450 full moons would be 225 degrees,
    though nothing can subtend more than 180.

  • David August 29, 2012, 22:34

    Carl Sagan was also inspired to warn of a greehouse effect on Earth after he studied Venus. The century before 1970 was amazing in science and technology and certainly leaves me disappointed over the 1970-2020 period.
    These accounts by AA and Larry are amazing to hear now. I was in my childhood in the 60s and followed all this on TV and book series like the Life Science Library

  • mike shupp August 30, 2012, 0:50

    Oh man, it’s a great yarn! even though it’s true and I hope they teach this stuff to beginning planetary scientists for the next thousand years.

  • James Jason Wentworth August 30, 2012, 7:24

    FrankH wrote (in part):

    [There’s also the classic “Mr. Smith goes to Venus” with artwork by Chesley Bonestell:


    I wish Mars and Venus had traded places in our solar system!]

    That story (complete with the “Jurassic Park”-style Venusian zoo) could conceivably come true by the date of A.D. 2500 that was mentioned in the article, although the dinosaurs would, of course, have to be genetically engineered. If we started seeding Venus’ clouds with algae now, in 500 years the planet’s climate might be more inviting for future tourists like the Smiths.

  • ljk August 30, 2012, 11:18

    mike shupp said on August 30, 2012 at 0:50:

    “Oh man, it’s a great yarn! even though it’s true and I hope they teach this stuff to beginning planetary scientists for the next thousand years.”

    LJK replies:

    I wrote this article primarily to commemorate the fiftieth anniversary of Mariner 2, the first successful space probe mission to examine another planet. There were several Soviet and American robotic attempts to reach Venus and Mars before Mariner 2, but none of them made it to their target worlds in functioning (or at least transmitting) order. Of course a number of probes had reached the Moon intact by 1959, but that is a natural satellite, not a planet. :^)

    I also wanted to share the history of an aspect of human exploration via our mechanical extensions that is often neglected by the overall historical story of our civilization and by most historians in general. I think much of this comes from the fact that many historians are neither familiar nor comfortable with the sciences and technology, especially space science. Please note I am not saying this is the case with every historian, I am just pointing out the general trend. C. P. Snow’s Two Cultures is still well in play in our education systems as well as our general culture as far as I can tell.

    They and as a result our various school systems tend to focus on a select number of the early explorers who sailed across the seas in wooden vessels, often for political and monetary gain. The missions both terrestrial and off-world which had as a focus to bring back scientific knowledge and advance our technology either get set aside or receive brief mentions in the general history books – especially if they were accomplished without any human crews aboard.

    If you had only a standard American history school text with which to learn human events upon, when it comes to space exploration you might find out about Sputnik 1, Neil Armstrong, and maybe Yuri Gagarin, but all the other missions and the reasons they even happened would remain a mystery. This needs to change, especially as we head towards becoming a species permanently embedded beyond our home planet.

    The children of those future eras living in the Sol system and beyond will want to know how they got there. Teaching our current generations, especially those for whom Sputnik 1, Vostok 1, Mariner 2, and Apollo 11 are nothing but history and not first-hand experience, will also help to inspire them to make that kind of future happen. This must include our robotic path makers, whose descendants will be our primary vanguards into the Milky Way galaxy and beyond for ages to come.

  • Eniac August 30, 2012, 23:54

    I would like to second NS in recommending the Donald Mitchell site: http://www.mentallandscape.com/V_Venus.htm
    LJK wrote a great story, and mentions Venera fairly, but in my perception his exposition still demonstrates a fair amount of America-centrism. The above link goes a long way to balance that, for those interested in balance.

  • ljk August 31, 2012, 10:31

    Eniac said on August 30, 2012 at 23:54:

    “LJK wrote a great story, and mentions Venera fairly, but in my perception his exposition still demonstrates a fair amount of America-centrism. The above link goes a long way to balance that, for those interested in balance.”

    LJK replies:

    That is because my article is primarily a tribute to Mariner 2 on its golden jubilee. I would never ignore the Soviet contributions to Venus exploration and science, but I did not want to get too far off the main focus. I even threw in a bit on Mariner 5 and its indirect joint mission with Venera 4 on the 45th anniversary of their historic and important adventure to the shrouded world.

    If you want to read an earlier article I wrote which does focus on all the space probe missions to Venus (though new information has come in on some of them since), check out my three-part work in the magazine Quest: The History of Spaceflight from 2000.


    I also wrote an article on the Soviet missions to Mars in the August, 1990 issue of Spaceflight magazine published by the BIS, but we have learned a lot more about those probes since then. I wrote this piece at a time when it seemed like the Soviet Union (yep, the USSR hadn’t even dissolved yet) was getting ready to send a manned mission to the Red Planet and I felt it was a good idea to examine their past robotic efforts to see what the chances were of that happening. Plus, as with this latest article on Mariner 2, I felt that the space probes and those who work on them did not always get the proper recognition they deserve in the history of human exploration and science.

  • Mark Schnitzius September 3, 2012, 1:06

    Great read, but I still vote that we take all the Magellan-generated landscape images of Venus with an “exaggerated scale” and throw them in the bit bucket. Why someone thought it necessary to do that, I’ll never understand. They should show us how it really looks without the mathematical hyperbole.

  • ljk September 3, 2012, 2:00

    Another perception about Venus that became popular in the latter half of the Nineteenth Century was the idea that the planet had gigantic mountains on its surface. Some of them were believed to reach forty miles high! Mount Everest on Earth, by comparison, is a measely five or so miles tall.

    Since another aspect of Venus that could not be seen was its rotation rate, astronomers guessed it was everything from 24 hours like Earth to the time the planet took to orbit the Sun once, 227 days, due to being tidally locked to our star. They thought that the solar-facing side of Venus was a roasting desert and the side was lush and alive.

    The really tall mountains of Venus last into the Space Age. When Mariner 2 flew by Venus in December of 1962, it found a spot that was 20 degrees F cooler than the rest of the surface. Some assumed that it was a very high mountain rising into cooler regions of the planet’s atmosphere. Other astronomers said the flattening of Venus at its south pole was an indication of a tall mountain poking up into the clouds.

    When Venera 4 stopped transmitting during its plunge into the planet’s thich air, some Soviet scientists argued that the probe had landed on one of those very high mountains.

    There is an amusing story in Carl Sagan’s 1973 book The Cosmic Connection that when he thought the odds of this happening were slim and that Venus’ air was probably much denser than believed, a Soviet scientist asked Sagan what were the odds that the first Axis bomb to fall on the city of Leningrad during World War 2 would kill the only elephant in the city’s zoo. Apparently this did happen despite the odds, but it still turned out that Venera 4 had been crushed by the rising atmosphere pressure before it could reach the surface, where the air pressure was 90 times that of Earth’s.

    See this blog post by The Planetary Society on Mariner 2 as well:


  • ljk September 4, 2012, 9:20


    Experimental Reconstruction of Lomonosov’s Discovery of Venus’s Atmosphere with Antique Refractors During the 2012 Transit of Venus

    Authors: Alexandre Koukarine, Igor Nesterenko, Yuri Petrunin, Vladimir Shiltsev

    (Submitted on 27 Aug 2012)

    Abstract: In 1761, the Russian polymath Mikhail Vasilievich Lomonosov (1711-1765) discovered the atmosphere of Venus during its transit over the Sun’s disc.

    In this paper we report on experimental reenactments of Lomonosov’s discovery with antique refractors during the transit of Venus June 5-6, 2012.

    We conclude that Lomonosov’s telescope was fully adequate to the task of detecting the arc of light around Venus off the Sun’s disc during ingress or egress if proper experimental techniques as described by Lomonosov in his 1761 report are employed.

    Comments: 14 pages, 9 figures

    Subjects: History and Philosophy of Physics (physics.hist-ph); Earth and Planetary Astrophysics (astro-ph.EP)

    Cite as: arXiv:1208.5286v1 [physics.hist-ph]

    Submission history

    From: Vladimir Shiltsev [view email]

    [v1] Mon, 27 Aug 2012 03:35:21 GMT (724kb)


  • Doug M. September 6, 2012, 13:49

    ljk, I have to make a minor correction here. As early as the 1930s, it was noted that Venus showed no detectable equatorial bulge. This placed a clear upper limit on Venus’ rotational speed. Long before Mariner arrived, the scientific consensus that Venus’ rotation had to be at least an order of magnitude slower than Earth’s.

    Doug M.

  • ljk September 6, 2012, 22:55

    Doug M., yes, you are correct. The astronomers who thought Venus might have a 24-hour rotation rate go back to the Nineteenth Century and earlier.

    The pattern of knowledge about Venus is not cut and dried. There were people long before Mariner and Venera came along who suspected, based on the available evidence of their day, that the planet was a roasting desert. But as with Mars, the hope of there being life won out (not to mention that a dead world tends not to be the best place for science fiction stories) and thus the support of oceans and jungles right up until Mariner 5 and Venera 4 arrived in 1967. Just like Mariner 4 did with Mars a mere two years earlier, their data sealed the deal on any major life forms for what used to be the two most popular extraterrestrial planets for that trait.

    Since this is a presidential election year and a thread on an article about Venus, I just wanted to add one of my favorite historical explanations for an aspect of the second planet from Sol, the Ashen Light.

    Bavarian astronomer Franz von Gruithuisen (1774-1852) believed that the faint glow seen on the dark hemisphere of Venus was from the fires from celebration of a new Venusian emperor. He later concluded that it was the inhabitants burning vegetation to make room for farmland. He assumed that since Venus was closer to our star than Earth, that their jungles grew faster.

    On the plus side for Gruithuisen, he was one of the first astronomers to think that lunar craters were caused by celestial impacts. Then again, he also thought he saw cities on Luna which were refuted by other astronomers of the day with larger telescopes.

  • Doug M. September 8, 2012, 8:01

    Actually, radar observations of Venus during the opposition of 1961 produced the first correct estimate of its rotation: about 250 days, retrograde. Americans and Soviets came up with different numbers, with the Soviets claiming evidence for a much faster rotation (<50 days). So both sides went back again and bounced more radar off Venus in 1962, right on the eve of Mariner. The Americans got two estimates using two different methods: 250 days retrograde and 265 days retrograde. The Soviets got "between 200 and 300 days" retrograde. (See, e.g., _Astron. J. 69, 1964.)

    So, by the time Mariner flew past Venus, the international scientific community was very close to certain that Venus' rotation was retrograde and very slow. In fact, final confirmation of Venus' rotation came, not from satellites, but from additional radar observations in the middle 1960s.

    Doug M.

  • ljk September 9, 2012, 0:46

    Interesting side note about the 1962 radar efforts at Venus:

    Quoting from here:


    The Morse Message (1962)

    From Wikipedia, the free encyclopedia

    In 1962, a radio message in Morse code was transmitted from Evpatoria Planetary Radar (EPR) and directed to planet Venus.[1][2] The word “MIR” (Russian: Мир, it means both “peace” and “world”) was transmitted from the EPR on November 19, 1962, and the words “LENIN” (Russian: Ленин) and “SSSR” (Russian: СССР, acronym for the Soviet Union (Союз Советских Социалистических Республик)) on November 24, 1962, respectively.

    All three words were sent using the Morse code.[3] In Russian, this letter is called Radio Message “MIR, LENIN, SSSR”.

    This message is the first radio broadcast for extraterrestrial civilizations in the history of mankind,[1] it was also used as a test for the radar station (but was not used for measuring the distance to Venus because for distance measurements the EPR uses coherent waveform with frequency manipulation): The signal reflected from surface of Venus and was received 4 minutes 32.7 seconds (Nov 19) and 4 minutes 44.7 seconds (Nov 24) later.

    Now this radio message is flying to the star HD131336 in the Libra constellation (the famous star Gliese 581, the addressee of A Message From Earth and Hello From Earth, is also located in the Libra).

  • ljk September 11, 2012, 13:47

    Preserve your memories of the 2012 Transit of Venus in the Transit of Venus Time Keg!


  • ljk September 12, 2012, 12:47

    IKAROS, the Japanese solar sail mission that flew by Venus in 2010, is still alive!


  • ljk October 3, 2012, 1:03

    Surprise! Hot Venus has a Cold Upper Atmosphere

    by Nancy Atkinson on October 1, 2012

    The hottest planet in the Solar System has a surprisingly cold region high in the planet’s atmosphere, according to new findings by the Venus Express spacecraft. While surface temperatures on this hot and hostile planet tops out at 735 Kelvin, or 462 degrees Celsius, ESA scientists say that a layer in the atmosphere about 125 km up has temperatures of around –175 degrees C, and may be cold enough for carbon dioxide to freeze out as ice or snow.

    This means this curious cold layer is much colder than any part of Earth’s atmosphere even though Venus is known for its dense, blistering atmosphere and is much closer to the Sun. Additionally, the cold layer appears to be affected by the transitioning between day and night on Venus.

    Full article here:


  • ljk October 3, 2012, 12:57

    Evidence from a Soviet space book for children from 1962 that they still assumed a swampy and dinosaur-laden Venus:


  • ljk October 11, 2012, 22:49

    Should we terraform Venus first?

    George Dvorsky

    As a future terraforming species, we take it for granted that Mars will be our first megaproject. But while transforming the Red Planet into something more hospitable for life seems the most logical — if not easiest — first step towards colonizing the solar system, it may actually make more sense to tackle our sister planet first.

    Because some scientists warn of a runaway greenhouse effect here on Earth, it may be prudent for us to terraform Venus first — a planet that has already undergone a carbon dioxide-induced apocalypse. And by doing so, we may learn how to prevent or reverse a similar catastrophe here on Earth.

    Full article here:


  • ljk December 3, 2012, 10:00


    For decades, planetary scientists have debated whether Venus possesses active volcanoes. The latest twist to the tale is provided by data sent back from ESA’s Venus Express orbiter, revealing unexplained major changes in the amount of sulphur dioxide gas above the planet’s dense cloud layer.


  • ljk December 13, 2012, 10:26


    NASA Celebrates 50 Years of Planetary Exploration

    Jet Propulsion Laboratory

    December 12, 2012

    PASADENA, Calif. — Fifty years ago on a mid-December day, NASA’s
    Mariner 2 spacecraft sailed close to the shrouded planet Venus, marking
    the first time any spacecraft had ever successfully made a close-up
    study of another planet. The flyby, 36 million miles (58 million
    kilometers) away from Earth, gave America its first bona fide space
    “first” after five years in which the Soviet Union led with several
    space exploration milestones. Designed and built by NASA’s Jet
    Propulsion Laboratory in Pasadena, Calif., the successful Mariner 2
    spacecraft ushered in a new era of solar system exploration.

    “JPL has always attempted to do mighty things on behalf of NASA and our
    nation,” said JPL director Charles Elachi. “Achieving America’s first
    ‘first in space’ is among the lab’s proudest achievements.”

    In celebration of the anniversary, an interactive presentation
    highlighting 50 years of planetary exploration is available online at:


    The first Mariners were designed and built on an extremely demanding
    schedule. JPL had to ready three probes – two to fly to Venus and one
    spare — in less than a year, with strict weight limits.

    Getting to Venus was no easy feat. The Soviet Union suffered several
    failures in their attempts to get to Venus in 1961. And the rocket
    carrying NASA’s first attempt, Mariner 1, began to fishtail shortly
    after launch. The range safety officer pushed the self-destruct button
    four minutes and 53 seconds into flight.

    Mariner 2 was launched Aug. 27, 1962, from Cape Canaveral. Shortly after
    liftoff, the rocket began to roll, making it unable to respond to
    guidance commands. In the first of a series of Mariner “miracles,” the
    electrical short causing the issue mysteriously healed itself after
    about a minute.

    En route to Venus, Mariner 2 encountered many problems that nearly ended
    its mission. Among these were a solar panel that twice stopped working,
    a balky sensor designed to locate Earth and gyros that mysteriously
    misbehaved. Most troubling of all, temperatures on the spacecraft
    climbed to alarming levels as Mariner 2 drew closer to Venus. Mission
    controllers worried the spacecraft might cook itself before reaching its

    But on Dec. 14, 1962, Mariner 2 hit its expected mark, gliding within
    21,564 miles (13,399 kilometers) of our closest planetary neighbor.
    Machines at JPL spit out rolls of paper tape with microwave, infrared,
    radiation and magnetic fields data.

    The encounter produced the first close-up measurements of Venus’s
    scorching surface temperature, helping to confirm scientists’ hypotheses
    of a runaway “greenhouse” effect that trapped heat from the sun under an
    atmospheric blanket. The spacecraft’s precision tracking also enabled
    navigators to use radio signals to measure the effect of Venus’s gravity
    on the spacecraft and calculate the most precise figure ever of the
    planet’s mass.

    The mission also made scientific discoveries beyond Venus. During
    Mariner 2’s cruise phase, it was the first to confirm the existence of
    the solar wind, the stream of charged particles flowing outward from the
    sun. Its data also enabled scientists to refine the value for an
    astronomical unit, the average distance between Earth and the sun.
    Mariner 2 also showed that micrometeorites and the radiation environment
    were not significant threats in that part of the solar system.

    Mariner 2 was a thrilling success during the early, uncertain days of
    space exploration. As Mariner 2’s project manager Jack James of JPL
    reflected before his death in 2001, “There will be other missions to
    Venus, but there will never be another first mission to Venus.”

    Six other successful Mariner missions to Venus, Mars and Mercury
    followed. And in the ensuing decades, NASA sent spacecraft to all the
    planets, as well as comets, asteroids and other unfamiliar worlds in our
    solar system.

    For a fuller history of Mariner 2’s visit of Venus visit:


    JPL is managed for NASA by the California Institute of Technology, Pasadena.

    Jia-Rui C. Cook 818-354-0850
    Jet Propulsion Laboratory, Pasadena, Calif.


  • ljk December 20, 2012, 18:27

    History’s rhymes

    A recent conference about the fifty-year history of NASA’s planetary exploration program became something of a forum to deliberate and worry about that program’s future.

    Dwayne Day argues that looking back at that history shows how the program has evolved, and for the better.

    Monday, December 17, 2012


  • ljk December 26, 2012, 22:42

    ** This is an excerpt from a longer release; items unrelated to astronomy have been omitted. {RTF} **

    26 December 2012

    ** Contact information appears below. **


    Observations from NASA’s Pioneer Venus orbiter, which reached Venus in 1978, suggested that Venus’s ionosphere had two states: a magnetized state with a large- scale horizontal magnetic field and an unmagnetized state with no large-scale magnetic field but with numerous small-scale thin magnetic structures known as flux ropes. Venus’s ionosphere was observed to be in the unmagnetized state most of the time, but strong solar wind pressure shifted it to the magnetized state.

    Now, using magnetic field observations made in 2008 and 2009 from the European Space Agency’s Venus Express, Zhang et al. report a third state: a magnetized state with giant flux ropes. The giant flux ropes, which form quite often, have strong magnetic fields and diameters of hundreds of kilometers. They are considerably larger and have stronger magnetic fields than the flux ropes that were seen during the unmagnetized state. Although giant flux ropes have previously been seen in Venus’s magnetotail, the authors believe this is the first observation of the phenomenon in Venus’s ionosphere. It is not yet known how the giant flux ropes form.


    Geophysical Research Letters, doi:10.1029/2012GL054236, 2012


    “Giant Flux Ropes Observed in the Magnetized Ionosphere at Venus”


    T. L. Zhang: CAS Key Laboratory of Geospace Environment, University of Science and Technology of China, Hefei, China, and Space Research Institute, Austrian Academy of Sciences, Graz, Austria; W. Baumjohann, W. L. Teh, and R. Nakamura: Space Research Institute, Austrian Academy of Sciences, Graz, Austria; C. T. Russell and H. Y. Wei: IGPP, University of California, Los Angeles, California, USA; J. G. Luhmann: Space Sciences Laboratory, University of California, Berkeley, California, USA; K. H. Glassmeier: IGEP, Technischen Universität Braunschweig, Braunschweig, Germany; E. Dubinin: Max-Planck-Institute for solar system Research, Katlenburg-Lindau, Germany; A. M. Du: Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China; Q. M. Lu and S. Wang: CAS Key Laboratory of Geospace Environment, University of Science and Technology of China, Hefei, China; M. Balikhin: University of Sheffield, Sheffield, UK.


    Mary Catherine Adams
    +1 202 777 7530

  • ljk January 3, 2013, 10:10

    Two recent papers on the history of the transits of Venus:



  • ljk January 3, 2013, 18:11
  • ljk January 8, 2013, 10:04

    Drawing Mars in Greenwich: recreating an experiment for Stargazing Live

    Tuesday’s episode of Stargazing Live focuses on Mars – it was the perfect excuse to film a recreation of a key moment in the early 20th-century campaign against Martian canals.

    This week sees the return of the BBC’s highly successful Stargazing Live. It starts on Tuesday, in an episode that follows last year’s biggest astronomy story by focusing on Mars.

    In thinking about the search for possible life on Mars, the programme will include some of the historical observations and debates that I discussed in a previous post. I’m delighted that the programme gave us at the Royal Observatory a chance to recreate a key Greenwich contribution to the story.

    This was the 1903 experiment carried out by E. Walter Maunder, an assistant at the Observatory, exploring perception at the limits of vision. It was one element in his campaign against the then-dominant view that the Martian surface was covered with immensely long, wide and straight “canals”, thought by many to the work of an advanced civilisation.

    Maunder was not alone, being joined by Eugène Michel Antoniadi and William Campbell, together described in Michael J. Crowe’s The Extraterrestrial Life Debate as “the leaders of a wrecking crew” that demolished the Martian canals.

    Maunder, with the assistance of the headmaster of the Royal Hospital School in Greenwich, asked a number of the school’s pupils to draw from different depictions of Mars, placed on a board at the front of the room. His results suggested that, particularly at certain distances, the eye tended to resolve indistinct waves and dots into straight lines, suggesting that the “canals” were an optical illusion rather than real surface features.

    Ever since I heard about this experiment, I have wanted to recreate it. Asking people to undertake an exercise like this is a wonderful way to understand the problems and contingencies surrounding astronomical observation and recording (imagine not only peering at this small image, but it flickering in an unsteady atmosphere, and having to keep taking your eyes away in order to represent it on paper). I also wondered if it really worked as Maunder described.

    Full article here:


  • ljk January 12, 2013, 13:58

    Publication of my Edited Work: Exploring the Solar System: The History and Science of Planetary Exploration

    by launiusr

    I am pleased to note that this week Palgrave Macmillan released my edited work, Exploring the Solar System: The History and Science of Planetary Exploration.

    This book has been years in the making, and includes essays on a broad selection of topics by a diverse set of authors. It was only possible because of a generous grant from the National Aeronautics and Space Administration’s Science Mission Directorate.

    Full article here:


  • ljk January 14, 2013, 21:55


    The Ranger series of space probes finally succeeded — on the seventh try.

    By George C. Larson

    Air & Space magazine, January 2013

    Anniversaries usually celebrate successes, but for a change of pace, we’ll celebrate a series of failures, which sometimes are better teachers.

    The Ranger series of space probes, launched 51 years ago at what would seem to be a straightforward target—the moon—failed six times to perform their mission before finally succeeding on the seventh try. That record caught the attention of Congress, resulted in a sweeping reorganization of the newly created National Aeronautics and Space Administration, and reformed spacecraft design and preparation for flight.

    The moon became an early target for space scientists doodling on their calendars because it was the closest and most obvious target as well as the simplest mission to another celestial body to achieve. But when President John F. Kennedy’s 1962 speech made a human landing on the moon before the decade’s end a national goal, the doodles got serious. For one thing, the problem of landing astronauts safely required a thorough scouring of the moon’s rugged surface to find a suitable spot. Earthbound telescopes took pretty pictures, but this would require a much closer look. And that meant a spacecraft.

    Full article here:


  • ljk January 14, 2013, 23:51

    December 14, 2012

    The First Planetary Explorers

    Fifty years ago today, we became interplanetary explorers. NASA’s 447-pound Mariner 2 probe zipped past Venus at a distance of 21,564 miles, sending back data on temperature and magnetic fields — the first successful visit to another planet.

    In December 1962 that was quite an engineering triumph, and the spacecraft — modeled after the then-disaster-prone Ranger lunar probes — barely survived its ordeal at Venus. In fact, it’s still amazing that a small team at the Jet Propulsion Laboratory in Pasadena, who had never done any of this stuff before, was able to design, build, launch, and execute a successful planetary flyby, almost from scratch, in just a few months.

    The project manager for Mariner 2 was Jack James, a Texas-born electrical engineer who had previously worked on missile programs at JPL. James wrote a memoir before he died in 2001; the following anecdotes from the Mariner 2 chapter are used here by permission of his son, Jack James.

    In the rush to carry out the crash effort, errors were made. An error I actually enjoyed had to do with the quick rewriting of the Air Force contracts with [its launch contractors]. The young Air Force lieutenant who rewrote, negotiated, and had the contracts signed had been given verbal instructions. He apparently wasn’t too clear on the ultimate destination of this new mission. He had listed in the objectives of the contracts that they were to carry out a mission to Venice.

    Full article here:


  • ljk January 29, 2013, 10:15

    29 January 2013

    ** Contacts are listed below. **

    Text & Images:




    ESA’s Venus Express has made unique observations of Venus during a period of reduced solar wind pressure, discovering that the planet’s ionosphere balloons out like a comet’s tail on its nightside.

    The ionosphere is a region of weakly electrically charged gas high above the main body of a planet’s atmosphere. Its shape and density are partly controlled by the internal magnetic field of the planet.

    For Earth, which has a strong magnetic field, the ionosphere is relatively stable under a range of solar wind conditions. By comparison, Venus does not have its own internal magnetic field and relies instead on interactions with the solar wind to shape its ionosphere.

    The extent to which this shaping depends on the strength of the solar wind has been controversial, but new results from Venus Express reveal for the first time the effect of a very low solar wind pressure on the ionosphere of an unmagnetized planet.

    The observations were made in August 2010 when NASA’s Stereo-B spacecraft measured a drop in solar wind density to 0.1 particle per cubic centimeter, around 50 times lower than normally observed; this persisted for about 18 hours.

    As this significantly reduced solar wind hit Venus, Venus Express saw the planet’s ionosphere balloon outwards on the planet’s ‘downwind’ nightside, much like the shape of the ion tail seen streaming from a comet under similar conditions.

    “The teardrop-shaped ionosphere began forming within 30-60 minutes after the normal high pressure solar wind diminished. Over two Earth days, it had stretched to at least two Venus radii into space,” says Yong Wei of the Max Planck Institute for Solar System Research in Germany, lead author of the new findings.

    The new observations settle a debate about how the strength of the solar wind affects the way in which ionospheric plasma is transported from the dayside to the nightside of Venus.

    Usually, this material flows along a thin channel in the ionosphere, but scientists were unsure what happens under low solar wind conditions. Does the flow of plasma particles increase as the channel widens due to the reduced confining pressure, or does it decrease because less force is available to push plasma through the channel?

    “We now finally know that the first effect outweighs the second, and that the ionosphere expands significantly during low solar wind density conditions,” says Markus Fraenz, also of the Max Planck Institute and co-author on the paper.

    A similar effect is also expected to occur around Mars, the other non-magnetized planet in our inner solar system.

    “We often talk about the effects of solar wind interaction with planetary atmospheres during periods of intense solar activity, but Venus Express has shown us that even when there is a reduced solar wind, the Sun can still significantly influence the environment of our planetary neighbors,” adds Hï¿œkan Svedhem, ESA’s Venus Express project scientist.

    Media Contact:

    Markus Bauer
    ESA Science and Robotic Exploration Communication Officer
    +31 71 565 6799, cell: +31 61 594 3 954

    Science Contacts:

    Yong Wei
    Max Planck Institute for Solar System Research

    Markus Fraenz
    Max Planck Institute for Solar System Research
    +49 555 6979 441

    Hï¿œkan Svedhem
    Venus Express Project Scientist
    +31 71 565 3370

    “A teardrop-shaped ionosphere at Venus in tenuous solar wind,” by Y. Wei et al., is published in Planetary and Space Science 73, 2012:


  • ljk April 11, 2013, 14:24

    11 April 2013

    ** Contact information appears below. **

    Text & Images:



    Hardware from a spacecraft that the Soviet Union landed on Mars in 1971 might appear in images from NASA’s Mars Reconnaissance Orbiter.

    While following news about Mars and NASA’s Curiosity rover, Russian citizen enthusiasts found four features in a five-year-old image from Mars Reconnaissance Orbiter that resemble four pieces of hardware from the Soviet Mars 3 mission: the parachute, heat shield, terminal retrorocket and lander. A follow-up image by the orbiter from last month shows the same features.

    The Mars 3 lander transmitted for several seconds after landing on Dec. 2, 1971, the first spacecraft to survive a Mars landing long enough to transmit anything.

    Images of the possible Mars 3 features, taken by the High Resolution Imaging Science Experiment (HiRISE) camera on Mars Reconnaissance Orbiter:



    “Together, this set of features and their layout on the ground provide a remarkable match to what is expected from the Mars 3 landing, but alternative explanations for the features cannot be ruled out,” said HiRISE Principal Investigator Alfred McEwen of the University of Arizona, Tucson. “Further analysis of the data and future images to better understand the three-dimensional shapes may help to confirm this interpretation.”

    In 1971, the former Soviet Union launched the Mars 2 and Mars 3 missions to Mars. Each consisted of an orbiter plus a lander. Both orbiter missions succeeded, although the surface of Mars was obscured by a planet-encircling dust storm. The Mars 2 lander crashed. Mars 3 became the first successful soft landing on the Red Planet, but stopped transmitting after just 14.5 seconds for unknown reasons.

    The predicted landing site was at latitude 45 degrees south, longitude 202 degrees east, in Ptolemaeus Crater. HiRISE acquired a large image at this location in November 2007. This image contains 1.8 billion pixels of data, so about 2,500 typical computer screens would be needed to view the entire image at full resolution. Promising candidates for the hardware from Mars 3 were found on Dec. 31, 2012.

    Vitali Egorov from St. Petersburg, Russia, heads the largest Russian Internet community about Curiosity (http://vk.com/curiosity_live). His subscribers did the preliminary search for Mars 3 via crowdsourcing. Egorov modeled what Mars 3 hardware pieces should look like in a HiRISE image, and the group carefully searched the many small features in this large image, finding what appear to be viable candidates in the southern part of the scene. Each candidate has a size and shape consistent with the expected hardware, and they are arranged on the surface as expected from the entry, descent and landing sequence.

    “I wanted to attract people’s attention to the fact that Mars exploration today is available to practically anyone,” Egorov said. “At the same time we were able to connect with the history of our country, which we were reminded of after many years through the images from the Mars Reconnaissance Orbiter.”

    An advisor to the group, Alexander Basilevsky, of Vernadsky Institute of Geochemistry and Analytical Chemistry, Moscow, contacted McEwen suggesting a follow-up image. HiRISE acquired the follow-up on March 10, 2013. This image was targeted to cover some of the hardware candidates in color and to get a second look with different illumination angles. Meanwhile, Basilevsky and Egorov contacted Russian engineers and scientists who worked on Mars 3 for more information.

    The candidate parachute is the most distinctive feature in the images. It is an especially bright spot for this region, about 8.2 yards (7.5 meters) in diameter. The parachute would have a diameter of 12 yards (11 meters) if fully spread out over the surface, so this is consistent. In the second HiRISE image, the parachute appears to have brightened over much of its surface, probably due to its better illumination over the sloping surface, but it is also possible that the parachute brightened in the intervening years because dust was removed.

    The descent module, or retrorocket, was attached to the lander container by a chain, and the candidate feature has the right size and even shows a linear extension that could be a chain. Near the candidate descent module is a feature with the right size and shape to be the actual lander, with four open petals. The image of the candidate heat shield matches a shield-shaped object with the right size if partly buried.

    Philip J. Stooke from the University of West Ontario, Canada, suggested the direction of search and offered helpful advice. Arnold Selivanov (one of the creators of Mars 3) and Vladimir Molodtsov (an engineer at NPO Lavochkin, Moscow) helped with access to data archives.


    Guy Webster
    Jet Propulsion Laboratory, Pasadena, Calif.
    +1 818-354-6278

    HiRISE is operated by the University of Arizona, Tucson. The instrument was built by Ball Aerospace & Technologies Corp., Boulder, Colo. The Mars Reconnaissance Orbiter Project and Curiosity are managed by NASA’s Jet Propulsion Laboratory, Pasadena, Calif., for NASA’s Science Mission Directorate, Washington. JPL is a division of the California Institute of Technology in Pasadena.

    More information about the Mars Reconnaissance Orbiter, which has been studying Mars from orbit since 2006: http://www.nasa.gov/mro

  • ljk April 12, 2013, 22:37

    Russia’s Mars 3 lander maybe found by Russian amateurs

    Posted By Emily Lakdawalla

    The Planetary Society

    2013/04/12 01:22 CDT

    Topics: pretty pictures, explaining image processing, spacecraft, amateur image processing, pics of spacecraft in space, Mars, Russian Mars missions, Mars Reconnaissance Orbiter

    It’s fitting, on the anniversary of Yuri Gagarin’s pioneering flight into orbit, to be writing about the possible discovery of Russian space hardware on the surface of Mars. The fact that it may have been found by Russian space enthusiasts is just icing on the cake. Much of the following text is translated from a blog entry by the Russian amateur, Vitaliy Egorov, who located specks on a Mars Reconnaissance Orbiter image that just might be the Mars 3 lander.

    Vitaliy didn’t discover what could be Mars 3 without help; as he explains below, he had help from other amateurs participating in the search in a group on Vkontakt, the Russian Facebook. And the dot that may be Mars 3’s parachute was actually found by another searcher, who goes by the name Imxotep on another forum, novosti-kosmonavtiki.

    But as you’ll see below, it’s Vitaliy’s persistence (and the fact that he listened to skeptical experts who required that he strengthen the case) that resulted in yesterday’s announcement. The reason that this story is different from those of the countless people who have emailed me informing that they have discovered crashed hardware on Mars is because of Vitaliy’s methodical approach to making a strong case. And that he admits that for all that it is a good circumstantial case, and that he wants to shout from the rooftops the fact that he discovered Mars 3, it could still just be a suggestive shadow.

    Most of the below is from a blog entry that Vitaliy posted here. I ran it through Google translate and did my best to edit it into grammatical English, working with Vitaliy to make sure the sense was correct. I provide some extra context and commentary in [brackets and italics].


  • ljk April 25, 2013, 9:24

    Wednesday’s Book Review:

    Geographies of Mars: Seeing and Knowing the Red Planet

    by launiusr

    Geographies of Mars: Seeing and Knowing the Red Planet. By K. Maria D. Lane. Chicago: University of Chicago Press, 2011. Illustrations, acknowledgments, notes, bibliography, index. 266 pages. Hardcover with dust jacket. ISBN: 978-0-226-47078-8. $45.00.

    Mars has long held a special fascination for humans who pondered the planets of the solar system-partly because of the possibility that life might either presently exist or at some time in the past might have existed ï¿œthere. Italian astronomer Giovanni Schiaparelli published a work in 1877 that laid the foundation for the belief in canals on Mars. His map of Mars showed a system of what he called canali, in Italian this meant “channel” and carried no connotation of being an artificial feature. Even so, the word was commonly translated into English as “canal” and began the speculation that Mars held life that were changing the planet’s features for their own purposes.

    American astronomer Percival Lowell became interested in Mars during the latter part of the nineteenth century, and built what became the Lowell Observatory near Flagstaff, Arizona, to study the red planet. His research advanced the argument that Mars had once been a watery planet and that the topographical features known as canals had been built by intelligent beings.

    Over the course of the first forty years of the twentieth century others used Lowell’s observations of Mars as a foundation for their arguments. The idea of intelligent life on Mars stayed in the popular imagination for a long time, and it was only with the scientific data returned from probes to the planet since the beginning of the space age that this began to change.

    Begun as a dissertation written at the University of Chicago, Geographies of Mars: Seeing and Knowing the Red Planet offers a fascinating analysis of the phenomenon of canals on Mars and the personality of Lowell and his detractors in arguing about these astronomical observations. K. Maria D. Lane, now on the faculty of the University of New Mexico, provides six succinct chapters that explore the Percival Lowell arguments about an inhabited Mars and his speculations on the nature of its society.

    Lane comments that in part because of the efforts of astronomers like Lowell the people living between about 1880 and 1910 had a “functionally dominant (if not universal) understanding of Martian geography as arid, inhabited, and irrigated” (p. 13). In Lane’s estimation this perception came because of the emphasis on geographical knowledge, especially cartography, in shape public perceptions in the United States.

    Full review here: