Ceres, Pluto: Looking Toward the Next New Year

by Paul Gilster on January 2, 2014

Over the New Year transition I saw a number of tweets to the effect that as of January 1, the first flyby of Pluto was going to occur next year, a notable thought when I ponder how fast this long journey has seemed to move. Was it really way back in 2006 that New Horizons launched? We can only wonder what surprises the Pluto/Charon system has in store for us in 2015. The same can be said for Ceres, a body which, as of December 27, is now closer to the Dawn spacecraft than Vesta, the asteroid around which it orbited so many interesting times.

Christopher Russell (UCLA) is Dawn’s principal investigator, a man whose thoughts on the mission naturally carry weight:

“This transition makes us eager to see what secrets Ceres will reveal to us when we get up close to this ancient, giant, icy body. While Ceres is a lot bigger than the candidate asteroids that NASA is working on sending humans to, many of these smaller bodies are produced by collisions with larger asteroids such as Ceres and Vesta. It is of much interest to determine the nature of small asteroids produced in collisions with Ceres. These might be quite different from the small rocky asteroids associated with Vesta collisions.”

The departure from Vesta occurred in September of 2012 — Dawn spent almost fourteen months there. Both Vesta and Ceres are considered ‘protoplanets,’ bodies that came close to becoming planets of their own, and the lessons learned in the mission should be useful in firming up our ideas on planet formation in the earliest days of the system. We’re also learning about a doughty spacecraft that will now attempt something that has never been done before, to orbit not just one but two destinations beyond the Earth.

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Image: This graphic shows the planned trek of NASA’s Dawn spacecraft from its launch in 2007 through its arrival at the dwarf planet Ceres in early 2015. When it gets into orbit around Ceres, Dawn will be the first spacecraft to go into orbit around two destinations in our solar system beyond Earth. Its journey involved a gravity assist at Mars and a nearly 14-month-long visit to Vesta. Credit: NASA/JPL.

We have a year to go before the Dawn controllers begin approach operations, and not long after that we’ll be getting imagery from Ceres that will be useful both for science and for navigation. Arrival at the diminutive world will occur some time in late March of 2015. The first full study of Ceres is slated for April at an altitude of 13,500 kilometers, after which the spacecraft will spiral down to an altitude of 4,430 kilometers for its survey science orbit. Continued lower spirals will culminate in a closest orbit approaching to within 375 kilometers in late November.

This NASA news release describes the ‘hybrid’ mode — a combination of reaction wheels and thrusters — that controllers will use to point the spacecraft during this close, low-altitude mapping orbit. Dawn has been using hydrazine thruster jets for orientation and pointing, but using two of the spacecraft’s reaction wheels, which are gyroscope-like devices that can be spun up on demand, will help to conserve hydrazine. Bear in mind that two of the four reaction wheels aboard the spacecraft failed after Dawn left Vesta in 2012, but the hybrid mode using just two of the reaction wheels has now been thoroughly tested.

As we continue the long journey to Ceres, you’ll want to keep an eye on Dawn chief engineer Marc Rayman’s Dawn Journal, which offers regular updates on the mission’s progress. Here’s Rayman’s take on Dawn’s early imaging of Ceres, beginning just over a year from now:

Starting in early February 2015, Dawn will suspend thrusting occasionally to point its camera at Ceres. The first time will be on Feb. 2, when they are 260,000 miles (420,000 kilometers) apart. To the camera’s eye, designed principally for mapping from a close orbit and not for long-range observations, Ceres will appear quite small, only about 24 pixels across. But these pictures of a fuzzy little patch will be invaluable for our celestial navigators. Such “optical navigation” images will show the location of Ceres with respect to background stars, thereby helping to pin down where it and the approaching robot are relative to each other. This provides a powerful enhancement to the navigation, which generally relies on radio signals exchanged between Dawn and Earth. Each of the 10 times Dawn observes Ceres during the approach phase will help navigators refine the probe’s course, so they can update the ion thrust profile to pilot the ship smoothly to its intended orbit.

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Image: NASA’s Hubble Space Telescope color image of Ceres, the largest object in the asteroid belt. Astronomers optimized spatial resolution to about 18 km per pixel, enhancing the contrast in these images to bring out features on Ceres’ surface, that are both brighter and darker than the average which absorbs 91% of sunlight falling on it. Credit: NASA, ESA, J. Parker (Southwest Research Institute), P. Thomas (Cornell University), and L. McFadden (University of Maryland, College Park).

Dawn’s view of Ceres by February 11 should be marginally better, says Rayman, than the sharpest views we’ve captured from the Hubble instrument, as seen above. Soon after that we’ll be seeing numerous features we’ve never known about before, including the possibility of small moons. Yet another indistinct sphere in the night sky will have been resolved into a sharply imaged object, while New Horizons continues its approach to Pluto/Charon. Even as we begin 2014 we can say with confidence that its successor will be an extremely interesting year.

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{ 11 comments… read them below or add one }

Alex Tolley January 2, 2014 at 15:08

The massaged Hubble image of Ceres must be giving a very false impression of the surface. If the Wikipedia data is correct, Ceres is much darker than Vesta. The icy surface must be covered in very dark material. Is the orange hue in the image indicative of the true colors, possibly indicating tholins?

In 2015 we may get our best views of a body that will become one of the most important in space exploitation – the Saudi Arabia of accessible water for propellant and life support in the inner system.

Ronald January 2, 2014 at 15:21

Happy and successful new year to all! And in particular to Paul, who maintains one of the most awesome and visionary websites.

Who knows what the new year will bring?
Hopefully some good news from Kepler. And/or from HARPS?

c howard January 2, 2014 at 17:32

speaking of robots …

Early Mars rovers had little more intelligence than a fancy remote-controlled car. NASA’s Curiosity rover is somewhat more evolved: It can navigate around simple obstacles and spot a dust devil on its own.

Much more brainpower would be required for a robotic exploration of Saturn’s moon Titan. Home to one of the solar system’s liveliest environments outside of Earth, Titan has tidal seas of methane, a stormy atmosphere and perhaps ice volcanoes. In 2005, the European Space Agency’s Huygens probe landed on a beach in Titan and transmitted data about its surroundings for 90 minutes; ever since, scientists have been eager to send another probe with more staying power. But because communications from Earth to Titan take hours, the robot would have to solve problems on its own. If it has been floating in a methane sea for months and finally approaches shore, it must begin taking pictures of newly visible land. If a methane-dwelling octopus swims by, engineer Trey Smith of NASA’s Intelligent Robotics Group says, it must notice. He’s only mostly joking.

With the aim of building a robot smart enough for Titan, Smith and a team of other engineers and scientists spent three weeks this month at a remote lake in the high Chilean Andes. They were field-testing the Planetary Lake Lander, an early prototype of a floating space probe that could, among other things, notice an octopus swimming past.

Since no hydrocarbon seas are available on Earth, the researchers, from NASA Ames Research Center and the Search for Extraterrestrial Intelligence (SETI) Institute in Mountain View, Calif., chose to test their probe on a lake under the disappearing Echaurren glacier, an ideal setting for technology that must notice both abrupt and subtle environmental changes.

View a slide show of the Chilean Andes test side for the Titan lander prototype

The robot has been exploring the lake with increasing astuteness since 2011, with periodic visits and upgrades from its makers. In August the team endowed the robot with the ability to collect and communicate meteorological data. Since then the team has received six emails from the Lake Lander, each accurately announcing a storm on the lake. In one case, the accompanying photograph sent by the robot showed its camera buried in snow.

“My colleague posted on Facebook that he had just sent Curiosity its instructions for the day and I wrote, ‘My robot is smarter than yours—he’s the one sending me emails!’” says Principal Investigator Nathalie Cabrol of the SETI Institute. “We will stop it short of writing our papers.”

The Lake Lander has a long way to go before it can write scientific studies, but it is already mastering some adaptive science techniques. It has learned to notice irregularities in its environment and focus its instruments on those anomalies. It conducts simple data analysis and sends only the most interesting information to scientists.

Selectivity in transmitting data is crucial for a robot on Titan. It takes about a joule of energy to send one bit of information from Titan to Earth, says NASA roboticist Liam Pedersen. At that rate, sending a single black-and-white compressed image would require the energy equivalent of a D-cell battery. A probe on Titan must therefore be stingy about what it sends and must compress information intelligently based on what it has learned about its environment, Smith says.

These technologies have applications on Earth as well. Selective data capturing and transmission could be used, for example, by probes that monitor ocean chemistry or by telescopes that scan the skies and send alerts when they spot pulsars, quasars, supernova or asteroids.

“I don’t know if we are smarter than the dinosaurs, but we have more technology than they did,” Cabrol says. “If we want to continue surviving on this planet, we’re going to have to get better at monitoring our environment.”

As it lays the groundwork for a future Titan mission, the Planetary Lake Lander’s technology is also monitoring the rapid decline of Echaurren glacier, a victim of climate change whose remnants frost a toothy ridge 1,000 feet above the lake. For the team’s recent visit, burros carried in equipment from a nearby dirt road. Thunder frequently emanated from a cloud-clotted volcano nearby, momentarily drowning out the assemblage of small generators that buzzed the camp to life. Otherwise the only visible mark of humankind was the canary yellow robot reflected in the cobalt lake.

In November the NASA Astrobiology Science and Technology for Exploring Planets program notified Cabrol’s team that the Lake Lander project had been extended for another year. The scientists plan to use the time to advance the adaptive science system. Yet whatever progress they make, the window will soon close for a robotic visit to Titan’s largest seas.

In 2012 a proposal to drop a probe into Titan’s Ligeia Mare narrowly lost a NASA funding bid to a 2016 Mars lander mission. The Titan Mare Explorer is still seeking funding, but if it does not come through this year, it will be too late—the robot must launch in 2016 if it wishes to arrive on Titan before the polar area loses direct communications with Earth in 2025. It will not regain contact until 2040.

Waiting 15 more years to explore Titan’s seas would be a shame, since they could host life, Cabrol says. She concedes that life may not exist in a methane-drenched world, but you never know. “Methane has its problems for life, but that being said, it could just be that our intellect is limited,” she says. “And if I had to bet, I would bet on that.”

Wojciech J January 2, 2014 at 18:53

Ceres for me always represented the one of the best choices for space colonization with its vast reserves of water and low gravity. I can’t to see it up close!

Alex Tolley January 2, 2014 at 19:25

Since no hydrocarbon seas are available on Earth

Oil reservoirs are a possible proxy, and we know they harbor microbes that live off the hydrocarbons. I don’t think the hydrocarbons are the problem, it’s the extreme cold on Titan’s surface that will stop life. Now if the world’s temperature profile below the surface gets to close to 0 degrees C, then there is a possible viable environment for life.

Michael January 3, 2014 at 3:01

A nice thing about Ceres is the low escape velocity, half that of a modern day rifle bullet. That low velocity and no atmosphere to speak of would make a sample return mission a distict possibility. A rover would also work well due to the low gravity and high rotation rate allowing more sunlight time to illuminate solar cells (lowers battery need). I also believe Ceres offers a habitate for organisms with all that water and mineral material that life would find useful and is more likely to be friendly to the panspermia mode of life spreading.

EricSECT January 3, 2014 at 7:42

I’d like to see a Curiosity-ish rover on Ceres. Start mass producing them and land them on Io, Europa, Ganymede, Callisto, Titan… Enceladus etc.

Tom January 3, 2014 at 14:17

I used to be bummed about how manned spaceflight has fizzled down from Lunar landings to LEO. But despite the ’2001′ classic view of human spaceflight being this shrunk, we actually sailed ahead with these very clever robotic missions.
Average people (and politicians) still suffer from sticker shock when contemplating manned deep space exploration. Like there is some magical kid who will invent a rocket engine that will run off of ‘banana peels & empty beer cans’ and take astronauts to Pluto at lightspeed?
The asteroids & dwarf planets are fair game for a manned mission;sickly if all you had to risk was human life with only a 99% chance of survival, we’d still have people complaining!
If it was a 99% chance, I’d send 100 spaceworkers.
We have sufficient data, our technical readiness is very impressive and we have enough solutions with alternatives to make this happen.
It would be ideal to ‘privately’ fund this. And the only thing we need is to ‘cut away’ the red tape.. not in case of success, but failure.
The big aerospace companies love those government contracts… well, let’s turn tables to public advantage? Any group that can pull this off, NASA will bankroll if you can beat their price by X%!
Tired of sitting on the fence waiting for the next step, its time to close the loop and get to space before our children die of old age.

Michael January 4, 2014 at 13:54

@Tom January 3, 2014 at 14:17

‘If it was a 99% chance, I’d send 100 spaceworkers.’

Would you be one of them to take that chance as I have noticed that you would send THEM? strangely I would want to be one of them.

@EricSECT

NASA have made these rovers before so there should not be that great an issue for building them in a mass production mode as you suggest. Maybe private enterprises could buy the rovers off NASA and use them for their activities lowering NASA costs into the bargain.

Here is some information about Ceres and rovers

http://www.astrobio.net/exclusive/5648/dwarf-planet-ceres-%E2%80%93-a-game-changer-in-the-solar-system

Maybe when an Astrium probe is sent to Europa some penetrators could be dropped off onto Ceres to ascertain the layering of the Dwarf planet.

http://www.youtube.com/watch?v=JgnSIPKCIrU

Lionel Ward January 6, 2014 at 9:31

@Alex Tolley
“the Saudi Arabia of accessible water for propellant and life support in the inner system.”

Absolutely!
Could Ceres be our first huge interplanetary “gold rush” with corporations or countries battling it out for ownership of all that space resource?

ljk February 25, 2014 at 13:39

Predicting Pluto’s moons and moondust

Posted by Emily Lakdawalla

2014/02/19 01:39 CST

A reader comment on an old blog post about the discovery of Pluto’s moons made me wonder about the timing of their discovery. Giant Charon was discovered in 1978, but the much smaller moons required the Hubble Space Telescope to be seen. Nix and Hydra were found in images from May 2005, and Kerberos and Styx in 2011 and 2012.

Given the fact that Hubble has been taking great space photos since 1994, why did it take so long for Pluto’s moons to be discovered, especially with serious interest in a Pluto mission in the form of Pluto Kuiper Express (New Horizons’ predecessor) before 2000?

Full article here:

http://www.planetary.org/blogs/emily-lakdawalla/2014/02191127-predicting-plutos-moons-and-moondust.html

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