by Paul Gilster | Jun 8, 2017 | Exoplanetary Science |
I seem to be reminded every day of how many discoveries are lurking in our archives. On the question of red dwarf stars and the flare activity that could compromise the habitability of planets around them, the ten year dataset from GALEX is proving invaluable. The Galaxy Explorer Evolution spacecraft was launched in 2003 and operated until 2012. Bear in mind that it was designed to study the evolution of galaxies at ultraviolet wavelengths. But now this valuable mission’s archives are helping us track the study of nearby habitable planets.
Led by first author Chase Million (Million Concepts, State College PA), a project dubbed gPhoton has set about reprocessing more than 100 terabytes of GALEX data now at the Mikulski Archive for Space Telescopes (MAST), which is maintained at the Space Telescope Science Institute in Baltimore. Million worked with STScI’s Clara Brasseur to develop custom software that could tease out the signature of flares for several hundred red dwarf stars. Dozens have been detected so far, with the prospect of far more in the GALEX archive.
Image: Artist’s illustration of a red dwarf star orbited by a hypothetical exoplanet. Red dwarfs tend to be magnetically active, displaying gigantic arcing prominences and a wealth of dark sunspots. Red dwarfs also erupt with intense flares that could strip a nearby planet’s atmosphere over time, or make the surface inhospitable to life as we know it. Credit: NASA, ESA, and G. Bacon (STScI).
The software behind this project is significant because it can measure flare events that are much less energetic than previously detected from red dwarfs, reminding us that while major flares get our attention, persistent lower-strength flare activity could have the more dangerous cumulative effect on a closely orbiting planet. A significant amount of a flare’s total energy is released in the ultraviolet wavelengths GALEX observed, while the stars themselves are relatively dim at these wavelengths, offering contrast that made these results possible. The team was able to trace stellar variations lasting as little as a few seconds in the data.
“We have found dwarf star flares in the whole range that we expected GALEX to be sensitive to, from itty bitty baby flares that last a few seconds, to monster flares that make a star hundreds of times brighter for a few minutes,” said Million.
Many of the flares detected in the GALEX observations are similar to those that occur on our own Sun. But bear in mind that any planet in the habitable zone of a cool, dim red dwarf is going to be much closer to its host, making it subject to more of the flare’s energy than the Earth. Flares of large enough energy could play a role in stripping a planet of its atmosphere, while strong ultraviolet light from persistent flaring could damage living organisms.
The work was presented at the 230th meeting of the American Astronomical Society in Austin in early June. But the study is far from over. Clara Brasseur and team member Rachel Osten are now looking at stars that were observed both by GALEX and the Kepler mission, trying to track down similar flare activity. Hundreds of thousands of flares may be hidden in the data.
“These results show the value of a survey mission like GALEX, which was instigated to study the evolution of galaxies across cosmic time and is now having an impact on the study of nearby habitable planets,” said Don Neill, research scientist at Caltech in Pasadena, who was part of the GALEX collaboration. “We did not anticipate that GALEX would be used for exoplanets when the mission was designed.”
So we keep factors like these in mind as we assess the possible habitability of planets around stars like Proxima Centauri, LHS 1140 and TRAPPIST-1. While we’re learning that Earth-sized planets may be plentiful around red dwarfs, and that many may occur in the zone where liquid water could occur on the surface, the question of habitability is far from resolved.
by Paul Gilster | Jun 7, 2017 | Uncategorized |
Alex Tolley mentioned Ray Bradbury’s story “The Golden Apples of the Sun” in connection with my first article on the Parker Solar Probe, and it’s a short tale worth remembering in connection with a mission flying so remarkably close to our star. First published in 1953 in a Doubleday collection of the same name, the tale is a short, mythic take on dangerous questing, with its main character, the unnamed captain, a figure something like Melville’s Captain Ahab. His goal is to fly to the Sun’s surface and retrieve some of its fire:
The captain stared from the huge dark-lensed port, and there indeed was the sun, and to go to that sun and touch it and steal part of it forever away was his quiet and single idea. In this ship were combined the coolly delicate and the coldly practical. Through corridors of ice and milk-frost, ammoniated winter and storming snowflakes blew. Any spark from that vast hearth burning out there beyond the callous hull of this ship, any small fire-breath that might seep through would find winter, slumbering here like all the coldest hours of February.
The ship and crew, fighting malfunctioning equipment, fall in their cryogenic ship “like a snowflake into the lap of June, warm July, and the sweltering dog-mad days of August.” It’s Bradbury in full poetic mode, not one of his best tales but one that does capture a bit of the natural human awe at stellar immensity. As for the Parker Solar Probe and the European Space Agency’s Solar Orbiter mission, neither will ‘touch the Sun,’ though the former will close to about 6.2 million kilometers, with the Solar Orbiter at 42 million kilometers.
Image: The dustjacket of the first edition of Bradbury’s collection The Golden Apples of the Sun. The title comes from the lush Yeats lyric The Song of Wandering Aengus. In an interview late in his life, Bradbury recalled: “Maggie [his wife] introduced me to romantic poetry when we were dating, and I loved it. I loved that line in the poem, and it was a metaphor for my story, about taking a cup full of fire from the sun.”
These missions are framed so as to study the near-Sun environment from different perspectives. Both are scheduled for launch in 2018, the Solar Orbiter in October and the Parker Solar Probe in July. What I’m seeing here are two complementary ventures, both examining the interaction between the Sun’s atmospheric gases and its magnetic field. Comparing the datasets should give us our best understanding yet of the inner heliosphere.
The key issues for the Solar Orbiter are listed on this European Space Agency page:
- What drives the solar wind and where does the coronal magnetic field originate from?
- How do solar transients drive heliospheric variability?
- How do solar eruptions produce energetic particle radiation that fills the heliosphere?
- How does the solar dynamo work and drive connections between the Sun and the heliosphere?
Image: Payload accommodation onboard Solar Orbiter. In this rendering, one side wall has been removed to expose the remote-sensing instruments mounted on the payload panel. The SPICE [Spectral Imaging of the Coronal Environment} instrument (not visible) is mounted to the top panel from below. Credit: ESA.
What Solar Orbiter brings to the mix is an orbit that will allow us to get close-up views of the Sun’s polar regions, with images from latitudes higher than 25 degrees. We should be able to see solar storms building up over an extended period from the same vantage point, because when traveling at the highest velocity along its orbit, Solar Orbiter will come close to matching the speed of the Sun’s rotation on its axis. We will be able to track solar storms for days.
Remember that many of the Sun’s jets originate in the areas around the poles, meaning we need more data about the magnetic field and plasma flows there to delve more fully into the process. These are not regions that are visible to us from Earth.
Understanding the solar wind also helps us consider the feasibility of future propulsion concepts using magnetic sail technologies to ride the solar wind. Meanwhile, the thermal issues a photon-driven sundiver mission will encounter will take center stage as we weigh the performance of the instrument packages on both these spacecraft. A sundiver would pass as close as possible to the Sun before unfurling a solar sail for maximum acceleration. We gain information from the upcoming solar missions that benefits both types of sail technology.
Solar Orbiter will carry a suite of 10 instruments to observe solar activity, 8 of them provided by ESA member states, while the other two are being developed by a European-led consortium and NASA respectively. A three and a half year approach to the operational orbit will include close flybys of Earth and Venus to insert the craft into a highly elliptical orbit. The instruments will measure solar wind plasma, fields, wave and energetic particles close to the Sun, while we can also expect images of solar features at the highest resolution ever seen.
So we’re going to have in situ measurements of the Sun’s extended corona from the Parker Solar Probe along with high-resolution studies of the inner heliosphere and the Sun itself from Solar Orbiter. Which takes me back to Bradbury’s captain, who has now ‘touched’ the Sun and is contemplating what is next:
“Well,” said the captain, sitting, eyes shut, sighing. “Well, where do we go now, eh, where are we going?” He felt his men sitting or standing all about him, the terror dead in them, their breathing quiet. “When you’ve gone a long, long way down to the sun and touched it and lingered and jumped around and streaked away from it, where are you going then? When you go away from the heat and the noonday light and the laziness, where do you go?”
We know where a sundiver sail mission would go: Outward, fast and far…
by Paul Gilster | Jun 6, 2017 | Sail Concepts |
No spacecraft has ever flown as close to the Sun as the Parker Solar Probe will. The spacecraft will penetrate the outer solar atmosphere — the corona — where its measurements should help us understand the origin and characteristics of the solar wind. To put this in perspective, consider that Mercury is at 0.39 AU. The Helios-B spacecraft, launched in 1976, closed to within 43 million kilometers of the Sun (0.29 AU), the current record for a close pass. The Parker Solar Probe will fly seven times closer, moving within ten solar radii.
We need to learn a lot more about this region as we consider various mission concepts for the future. The Parker Solar Probe uses an 11.43 cm carbon-composite shield designed to keep its instrument package at room temperature, or close to it, despite outside temperatures well over 1350° Celsius. The sundiver concept we talked about yesterday — sometimes called a ‘fry-by’ — has the advantage of maximizing the effect of solar photons by unfurling a sail in close proximity to the Sun. To fly such a mission, we need to understand this environment.
Image: The Parker Solar Probe spacecraft leaving Earth, after separating from its launch vehicle and booster rocket, bound for the inner solar system and an unprecedented study of the Sun. Credit: JHU/APL.
And let’s compare the Parker Solar Probe with the two Helios spacecraft in one other regard. Helios-B set the current speed record for spacecraft at 70.22 kilometers per second. The Parker Solar Probe should reach 194 km/sec. The goal of a future sundiver mission would be to turn solar photon pressure into maximum departure velocity out to deep space. Just how fast an outward-bound sail could fly will depend upon how close it can approach the Sun and what kind of materials it is made of, issues about which we have much to learn.
Conditions this close to the Sun are obviously going to be treacherous, and highly variable. The solar wind of electrons, protons and ionized helium nuclei flowing from the Sun can reach velocities as high as 800 kilometers per second. Unfortunately, the plasma flow is also highly variable, fluctuating over periods short and long. While we speak of ‘solar sailing’ by way of photon pressure on a sail, a truer analog to sailing is the use of a magnetic sail riding the solar wind. In the latter case, we have a highly variable ‘wind’ like mariners face on Earth, with all the attendant issues raised by its fluctuations. The study of both types of sailing should be enhanced by the data we retrieve from the Parker Solar Probe.
In Solar Sails: A Novel Approach to Interplanetary Travel (Springer, 2014), authors Giovanni Vulpetti, Les Johnson and Greg Matloff consider the positive electric charge that can emerge on a sail as ultraviolet solar photons knock electrons free from sail atoms. The problem here is that interactions with high-energy electrons can degrade sail reflectivity. A possible strategy is to deploy an electrically charged grid in front of the sail or use layers of protective plastic that evaporate rather than becoming ionized by solar ultraviolet light.
But every time we add mass to the sail, we reduce the spacecraft’s velocity outbound, meaning we’re probably going to be better served by designing solar sails that are more resistant to UV. It’s clear that we have a lot of work ahead on the interactions between spacecraft and the near-Sun environment, the subject of the Parker Solar Probe’s investigations. Of course, the upcoming probe is also set to investigate the interactions between the solar wind and the Earth’s magnetic field that produce so-called ‘space weather.’ Learning how to predict this kind of weather can protect space assets much closer to home.
A Mechanism for Solar Eruptions
We also need to consider solar activity, for flying any kind of mission within 10 solar radii is going to be dangerous if we have to contend with solar flares or coronal mass ejections. We can do our best to predict the occurrence of such dangers to the spacecraft, but CMEs appear to be random enough that the unexpected appearance of one could quickly end a mission.
On that score, a new paper in Nature looks at a single mechanism that can explain solar eruptions from small jets to coronal mass ejections, working with 3D computer simulations to reveal the underlying process at work. Peter Wyper (Durham University, UK), lead author of the study, notes that filaments — long, dark structures above the surface of the Sun consisting of dense and colder solar material — are associated with the onset of CMEs. We’re now learning that solar jets have filament-like structures as well before their eruption.
“In CMEs, filaments are large, and when they become unstable, they erupt,” said Wyper. “Recent observations have shown the same thing may be happening in smaller events such as coronal jets. Our theoretical model shows the jet can essentially be described as a mini-CME.”
Image: A long filament erupted on the sun on Aug. 31, 2012, shown here in imagery captured by NASA’s Solar Dynamics Observatory. Credit: NASA’s Goddard Space Flight Center/SDO.
The researchers at Durham University and at NASA have produced a ‘breakout model’ showing how stressed filaments break through magnetic restraints in both solar jets and CMEs. In this model, the process at work is magnetic reconnection, in which magnetic field lines come together and realign into a new configuration. The event is powerful enough that the energy stored in the filament breaks out from the surface and is ejected into space.
The Parker Solar Probe gives us another way to obtain high-resolution observations of the magnetic field and plasma flows in the solar atmosphere. We can expect similar help from the European Space Agency’s Solar Orbiter mission, scheduled for a launch in the fall of 2018. Unlike the Parker Solar Probe, the Solar Orbiter will go into an inclined orbit that allows better imaging of the areas around the Sun’s poles. Both missions obviously deepen our resources for sundiver mission planning as we contemplate fast departures into the outer system.
Tomorrow I’ll take a look at ESA’s Solar Orbiter in the context of our continuing efforts to understand the nearest star. The paper on solar eruptions is Wyper et al., “A universal model for solar eruptions,” Nature 544 (27 April 2017), 452-455 (abstract).
by Paul Gilster | Jun 5, 2017 | Sail Concepts |
We’re going to be keeping a close eye on what is now called the Parker Solar Probe as work continues toward a July 2018 launch. This is a mission with serious interstellar implications because it takes us into the realm of so-called ‘sundiver’ maneuvers in which a solar sail could be brought as close as possible to the Sun (perhaps behind a protective occulter) and then unfurled to get maximum effect. Velocities well beyond Voyager’s can grow from this.
Throw in the prospect of beamed propulsion and such sails could receive an additional boost. To be sure, the Parker Solar Probe is not a solar sail but an unmanned, instrumented probe designed to explore a region as close as 10 solar radii from the Sun’s surface, where temperatures can be expected to reach about 1375° Celsius. But the sundiver implications are there, and we’ll gain priceless data about operations in this extreme environment.
Why a sundiver? Voyager 1 is exiting the neighborhood of the Solar System at 17.1 kilometers per second. And while New Horizons left Earth breaking all speed records for spacecraft launched into interplanetary space, it’s worth remembering that its velocity during the Pluto/Charon encounter had fallen to about 14 kilometers per second, a consequence of the long climb out of the gravity well. So finding ways to get spacecraft to two or three times this velocity is an obvious objective as we explore ways of moving faster still.
Image: Artist’s impression of NASA’s Solar Probe Plus spacecraft on approach to the sun. Set to launch in 2018, Solar Probe Plus will use Venus’ gravity during seven flybys over nearly seven years to gradually bring its orbit closer to the sun. The spacecraft will fly through the Sun’s atmosphere as close as 6.2 million kilometers to our star’s surface, well within the orbit of Mercury and more than seven times closer than any spacecraft has come before. Credit: NASA/Johns Hopkins University Applied Physics Laboratory.
The first use of the word ‘sundiver’ in a scientific paper that I am aware of is Greg and Jim Benford’s “Near-Term Beamed Sail Propulsion Missions: Cosmos-1 and Sun-Diver” (Beamed Energy Propulsion, AIP Conf. Proc. 664, pg. 358, A. Pakhomov, ed., 2003), though the word’s history goes back a bit further to David Brin’s 1980 novel Sundiver, which turned out to be the first book in his Uplift Trilogy. Greg Benford worked with Brin on some of the novel’s concepts, discussions that he recalled in a column in Fantasy & Science Fiction:
I called this craft the Sundiver. The term is old—I gave it to David Brin when he first came to see me, back when he was struggling with his first novel. (As he now recounts, I asked him how his craft that literally plunges into the Sun could survive. He answered that he would throw in some jargon, techtalk, whatever. I disdainfully replied, “Oh—magic.” So David went home and found a physically possible way to do it, confounding me.)
I read Sundiver not long after it came out and don’t recall anything like a close solar pass mission — instead (as Benford says above), Brin was looking for a way to actually get a craft into the Sun by way of exploring the novel’s unusual lifeforms, creatures that lived off magnetic fields in the chromosphere. But the Benford paper mentioned above (available here) discusses sail concepts using a close solar pass as well as desorption of heated embedded molecules from the hot side of the sail that can deliver a second propulsive ‘burn.’
Let’s pause on desorption, which turned out to be interesting because in their laboratory work at JPL pushing an ultra-light carbon sail with a microwave beam, the Benfords found that the beam alone could not account for the acceleration they observed. Subsequent investigation showed that embedded molecules — CO2, hydrocarbons and hydrogen that had been incorporated in the sail material lattice when it was made — could be ejected under high enough temperatures. The original sail material was left unharmed by this propulsive effect.
Incorporating that phenomenon into a sundiver mission, we get this: The sail approaches the Sun turned edge-on to minimize solar flux that would push against it. The spacecraft then turns at perihelion to get the full effect of both photons and related sail desorption, gaining velocity even as (because of the loss of some of the molecules in its fibers) it loses a bit of mass. When desorption is complete, the sail operates like any other solar sail, though one now moving fast enough to explore the outer Solar System in far less time than it took Voyager.
On the way to a sundiver, what the Parker Solar Probe gives us, among other things, is the ability to investigate the high energy particle environment that any future sundiver mission would have to cope with. An 11.43 cm carbon-composite shield will be used to protect the craft. We’ll learn much about the solar wind, findings that will also prove useful as we contemplate future magsail possibilities, in which a spacecraft might use the highly variable plasma flow to reach high velocities. More about that possibility tomorrow, when we’ll take a closer look at the conditions the Parker Solar Probe will face and ponder the insights it is certain to provide.
by Paul Gilster | Jun 2, 2017 | Culture and Society |
I always keep an eye on what’s going on at the NASA Innovative Advanced Concepts office, which is where I ran into Jeff Nosanov’s Phase I study for a solar sail called Solar System Escape Architecture for Revolutionary Science. At the Jet Propulsion Laboratory, Jeff managed flight mission proposals and supported the radio isotope power program. He now lives in Washington DC, a technology entrepreneur whose fascination with spacecraft design has never diminished. In the essay below, Jeff explains the background of his first NIAC award (a second, PERIapsis Subsurface Cave Optical Explorer, would lead to Phase I and Phase II grants), and gives us an idea of the ins and outs of making ideas into reality at NIAC and JPL. For more, the website nosanov.com is about to go online, and Jeff’s new podcast debuts today.
By Jeff Nosanov
It’s an honor and a privilege to be asked to write about my near-interstellar mission work for the Tau Zero Foundation. Marc’s book and Paul’s writing were very inspiring to me as I began working at JPL and dove into the interstellar mission community. This article will describe my journey to JPL, the process of proposing the mission concept, and the experience of managing the project. The mission concept itself can be read about here.
In summary, SSEARS (Solar System Escape Architecture for Revolutionary Science) is a solar sail-based mission to return to the heliopause (the edge of the solar system) to continue the Voyager science. The driving goal was to determine the fastest possible propulsion method to return to the outer solar system. We concluded that it was possible to get there in about 18 years (half the time it took Voyager) using a very large solar sail system. How did we get to this point? I’ll start at the beginning.
A Child’s View
One of my favorite childhood photos was taken at the Griffith Observatory in Los Angeles. I don’t quite remember this event, but I do strongly remember a later one, my visit at age 5 in 1987 around the time of the Voyager 2 Neptune encounter. My dad took me there to look through the big telescope at Neptune, and told me of the spacecraft that was nearing the ice giant planet.
I distinctly remember the “mind blown” moment of realization that such things were possible. I also learned that day about JPL, the NASA lab just a few dozen miles from the Griffith Observatory where the Voyagers, and so many other spacecraft, were built. I didn’t know it until much later but that event turned me into a space guy. I also recall a conversation with my dad from around that time in which he told me that we can visit other planets, but not other stars. That stuck with me.
Image: Photo of Jeff as a baby being held by his mother at Griffith Observatory.
As a child it is easy to have a fairly distorted view of what NASA actually is, and what it does. It’s tempting to imagine something out of Star Trek, with wild and amazing technologies in development all around. In reality, only a small part of NASA, the NASA Innovative Advanced Concepts Program (NIAC), embodies that exciting vision, as I discovered as an adult.
Working at JPL
About 22 years later I started working at JPL on January 4th, 2010. Suddenly the greatest deep space exploration playground was opened to me. I was extremely eager, giddy even, to learn about this work and discover how I could contribute. I began to learn everything I could about everything I could access. I spent many hours reading books in the library (especially Frontiers of Propulsion Science) and talking to as many people, especially senior people, as possible. I especially stalked the Voyager program people.
My general knowledge about how NASA missions are developed, selected, funded, built, and operated grew. I began to pay attention to RFPs (Requests for Proposals) and BAAs (Broad Agency Announcements) that came through the daily emails. I eventually pieced together the realization that anyone could propose concepts (at nearly any stage of development) to various programs within NASA. But how to possibly find the right combination of ambition, team, capability, vision, most importantly a receptive NASA program?
I spent many hours with program managers, scientists and engineers learning about the current challenges and capabilities in deep space exploration. I was extremely grateful at the time, but in retrospect I have even greater appreciation for the time spent with me. It was only through the kind support of managers, engineers, scientists and many others that I developed the general background knowledge to attempt the work that became my project.
Eventually I came to learn about the NIAC program. That program exists to fund revolutionary concepts that significantly increase exploration capability. This is distinct from the majority of NASA projects, which largely seek to minimize technological risk. The NIAC program exists as a way to ensure that investments in promising, ambitious technology get made, and to reduce technological stagnation as the risk-minimizing forcing functions of most other NASA programs run their course.
Stalking Voyager
I knew I wanted to make a dent in interstellar flight, so I spent a lot of time with people from the Voyager program. I tried to learn everything I could about the mission to develop a mission concept that would be worth doing scientifically. Around this time NASA had been planning to fund a technology demonstration mission for a concept called SunJammer. This was to be a solar sail mission to a Lagrange point, using the sail for propulsion and station-keeping. I decided that a NIAC-worthy proposal would be to start with just how large we could reasonably build a solar sail, and then see how fast such a system could reach the heliopause with a scientifically valuable payload.
I approached Ed Stone at Caltech with child-like reverence. Stone was project scientist for Voyager and a former director of JPL itself. I wanted to ask him what he would do to follow Voyager if he had a limitless budget. To my surprise he accepted my meeting request, and we had several meetings in which he outlined a scientific payload designed entirely for the heliopause region. This became the “mission” that the hypothetical giant solar sail propulsion system would uniquely enable.
Writing the Proposal
JPL has several systems in place to help people write successful proposals. Each proposal opportunity announcement from NASA results in a mentoring and guidance resource from the responsible JPL program office. I took great advantage of this resource for the first few proposals of my career and it has made a world of difference.
The theme across many proposals for many agencies in my experience is the importance of genuine, exciting storytelling. Thinking back, that was all I had for my first effort! The process of writing the proposal exposed me to a great many inner workings of JPL including program management, costing, and even obtaining submission authority. I doggedly, perhaps obsessively, followed the process to ensure that all the rules were followed and I felt a deep sense of relief and excitement once the proposal was fully submitted. However, I did not have any way of estimating my chances for success due to my lack of experience. I moved on with my regular work and hoped.
Months later I got a most unexpected phone call telling me that my proposal had been selected! I was over the moon, and I felt something very powerful for the first time: My ideas are good and are worth pursuing. I felt a change in responsibility. The proposal development process was partly for my own personal satisfaction and growth. It was a wonderful experience. Now, having been selected, I had the privilege of having the responsibility of discovering something new about the universe and our place in it.
Outcome
One of the important lessons I learned is to keep the long term goal in mind. In our case, this specifically meant figuring out the fastest possible way back to the heliopause with a science payload worth taking there. It turned out that we could get there in 18 years with a 250m x 250m solar sail and a “Voyager on steroids” payload.
This rendering shows our vision for the spacecraft, and a small part of the solar sail behind it.
Towards the end of the study I made another appointment with Ed Stone. I told him what we had learned. He looked me in the eye and said “Wow.” I’d like to imagine that in that one moment he was the 5 year old looking at the sky, his mind bursting with possibilities, instead of me.
Impact
We ultimately submitted a proposal for Phase 2. Unfortunately intervening events ended the possibility in the foreseeable future for significant progress on our work. We had relied upon the NASA excitement in the SunJammer program to chart the course for solar sail work. That program was cancelled and so we did not have a path forward to advance the technology, and without that potential synergy it seemed that a NIAC phase 2 award was unlikely.
Still, I was satisfied and inspired by our results. I must conclude that the relative impact, in the grand scheme of things, of our study was small, perhaps incremental. However the experience drastically changed my goals and ambition. Ultimately my study is one of many that attempted to explore the limits of what human ingenuity and curiosity can achieve.
Conclusion
I became a father on May 4, 2012 in the middle of the study period. This event fundamentally changed the way I think about space exploration and my own role in it. I enjoyed bringing my son to the Griffith Observatory for many reasons. During the Griffith Observatory visit in which this photo of my son was taken I recalled my dad’s statement that we can travel to other planets but not other stars. As of June 2nd, 2017 now that is still true…
… but we’re working on it.
