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Host: Fraser Cain (@fcain)
Guests:
Jolene Creighton (@jolene723 / fromquarkstoquasars.com)
Brian Koberlein (@briankoberlein / briankoberlein.com)
Dave Dickinson (@astroguyz / www.astroguyz.com)
Morgan Rehnberg (cosmicchatter.org / @MorganRehnberg )
Alessondra Springmann (@sondy)
Continue reading “Weekly Space Hangout – May 15, 2015: Finding, Studying and Visiting Other Worlds!”
What fate awaits Phobos, one of the moons of Mars?
“All these worlds are yours except Europa, attempt no landing there.”
As much as I love Arthur C. Clarke and his books, I’ve got to disagree with his judgement on which moons we should be avoiding. Europa is awesome. It’s probably got a vast liquid ocean underneath its icy surface. There might even be life swimming down there, ready to be discovered. Giant freaky Europa whales or some kind of alien sharknado. Oh man, I just had the BEST idea for a movie.
So yea, Europa’s fine. The place we should really be avoiding is the Martian Moon Phobos. Why? What’s wrong with Phobos? Have I become some kind of Phobo…phobe? Is there any good reason to avoid this place?
Well first, its name tells us all we need to know. Phobos is named for the Greek god of Horror, and I don’t mean like the usual gods of horror as in Clive Barker, John Carpenter or Wes Craven, I mean that Phobos is the actual personification of Fear… possibly with a freaky lion’s head. And… there’s also the fact that Phobos is doomed.
Literally doomed. Living on borrowed time. Its days are numbered. It’s been poisoned and there’s no antidote. It’s got metal shards in its heart and the battery on it’s electro-magnet is starting to brown out. More specifically, in a few million years, the asteroid-like rock is going to get torn apart by the Martian gravity and then get smashed onto the planet.
It all comes down to tidal forces. Our Moon takes about 27 days to complete an orbit, and our planet takes around 24 hours to complete one rotation on its axis. Our Moon is pulling unevenly on the Earth and slowing its rotation down.
To compensate, the Moon is slowly drifting away from us. We did a whole episode about this which we’ll link at the end of the episode. On Mars, Phobos only takes 8 hours to complete an orbit around the planet. While the planet takes almost 25 hours to complete one rotation on its axis. So Phobos travels three times around the planet for every Martian day. And this is a problem.
It’s actually speeding up Mars’ rotation. And in exchange, it’s getting closer and closer to Mars with every orbit. The current deadpool gives the best odds on Phobos taking 30 to 50 million years to finally crash into the planet. The orbit will get lower and lower until it reaches a level known as the Roche Limit. This is the point where the tidal forces between the near and far sides of the moon are so different that it gets torn apart. Then Mars will have a bunch of teeny moons from the former Phobos.
And then good news! Those adorable moonlets will get further pulverized until Mars has a ring. But then bad news… that ring will crash onto the planet in a cascade of destruction to be described as “the least fun balloon drop of all time”. So, you probably wouldn’t want to live on Mars then either.
Count yourself lucky. What were the chances that we would exist in the Solar System at a time that Phobos was a thing, and not a string of impacts on the surface of Mars.
Enjoy Phobos while you can, but remember that real estate there is temporary. Might I suggest somewhere in the alien sharknado infested waters of Europa instead?
What do you think. Did Arthur C Clarke have it wrong? Should we explore Europa?
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NASA’s Curiosity Rover spends most of its time staring at the ground, but like humans, it looks up once in a while too. As reported earlier, NASA ground controllers pointed the rover’s Mast Camera (mastcam) skyward to shoot a series of photos of Comet Siding Spring when it passed closest to the Red Planet on October 19th. Until recently, noise-speckled pictures available on the raw image site confounded interpretation. Was the comet there or wasn’t it? In these recently released versions, the fuzzy intruder is plain to see, tracking from right to left across the field of view.
Ten exposures of 25 seconds each were taken between 4:33 p.m. and 5:54 p.m. CDT on October 19th to create the animation. The few specks you see are electronic noise, but the sharp, bright streaks are stars that trailed during the time exposure. Curiosity’s Mastcam camera system has dual lenses – a 100mm f/10 lens with a 5.1° square field of view and a 34mm, f/8 lens with a 15° square field of view. NASA didn’t include the information about which camera was used to make the photos, but if I had to guess, the faster, wide-angle view would be my choice. Siding Spring was moving relatively quickly across the Martian sky at closest approach.
Prowling through the Curiosity raw image files, I came across this photo of the Sun on November 10th. Three dark spots at the left are immediately obvious and a dead-ringer for Active Region 2192, now re-named 2209 as it rounds the Sun for Act II. You’ll recall this was the sunspot group that nearly stole the show during the October 23rd partial solar eclipse. From Mars’ perspective, which currently allows Curiosity to see further around the solar “backside”, AR 2209 showed up a few days before it was visible from Earth.
Although it’s slimmed down in size, the region is still large enough to view with the naked eye through a safe solar filter. More importantly, it possesses a complex beta-gamma-delta magnetic field where magnetic north and south poles are in close proximity and ripe for reconnection and production of M-class and X-class flares. Already, the region’s crackled with three moderate M-class flares over the past two days. In no mood to take a back seat, AR 2209 continues to dominate solar activity even during round two.
Mars possesses two small moons, Deimos and Phobos. Curiosity has photographed them both before including an occultation Deimos (9 miles/15 km) by the larger Phobos (13.5 miles/22 km). Phobos orbits closer to Mars than any other moon does to its primary in the Solar System, just 3,700 miles (6,000 km). As a result, it moves too fast for Mars’ rotation to overtake it the way Earth’s rotation overtakes the slower-moving Moon, causing it to set in the west overnight. Contrarian Phobos rises in the western sky and sets in the east just 4 hours 15 minutes later. When nearest the horizon and farthest from an observer, it’s apparent size is just 0.14º. At the zenith it grows to 0.20º of 1/3 the diameter of the Moon.
One longish observing session on the planet would cover a complete rise-set cycle during which Phobos would first appear as a crescent and finish up a full moon a few hours later. All this talk about Phobos is only meant to direct you to the picture above taken by Curiosity on October 20, 2014 when the moon was a thick crescent. As on Earth, where Earthshine fills out the remainder of the crescent Moon, so too does Mars-shine provide enough illumination to see the full outline of Phobos.
Curiosity has also photographed Earth, sunsets and transits of Phobos across the Sun while rambling across the dusty red landscape since August 2012. Before we depart, it seems only fair to aim our gaze Mars-ward again to see what’s up. Or down. The rover’s been doing a geological “Walkabout” in the Pahrump Hills outcrop at the base of Mt. Sharp in Gale Crater since September. Earlier this fall it drilled and sampled rock there containing more hematite than at any of its previous stops. Hematite is an iron oxide that’s often associated with water.
The mission may spend weeks or months at the outcrop looking for and drilling new target rocks before moving further up the geological layer cake better known as Mt. Sharp.
Ask any space enthusiast, and almost anyone will say humankind’s ultimate destination is Mars. But NASA is currently gearing up to go to an asteroid. While the space agency says its Asteroid Initiative will help in the eventual goal of putting people on Mars, what if instead of going to an asteroid, we went to Mars’ moon Phobos?
Three prominent planetary scientists have joined forces in a new paper in the journal Planetary and Space Science to explain the case for a mission to the moons of Mars, particularly Phobos.
“Phobos occupies a unique position physically, scientifically, and programmatically on the road to exploration of the solar system,” say the scientists. In addition, the moons may possibly be a source of in situ resources that could support future human exploration in circum-Mars space or on the Martian surface. But a sample return mission first could provide details on the moons’ origins and makeup.
The Martian moons are riddles, wrapped in a mystery, inside an enigma. Phobos and its sibling Deimos seem like just two asteroids which were captured by the planet Mars, and they remain the last objects of the inner solar system not yet studied with a dedicated mission. But should the moons be explored with flybys or sample-return? Should we consider “boots or bots”?
The publications and mission concepts for Phobos and Deimos are numerous and go back decades. The authors of “The Value of a Phobos Sample Return,” Murchie, Britt, and Pieters, explore the full breadth of questions of why and how to explore Phobos and Deimos.
Dr. Murchie is the principal investigator of the Mars Reconnaissance Orbiter’s CRISM instrument, a visible/infrared imaging spectrometer. He is a planetary scientist from John Hopkins’ Applied Physics Lab (APL) which has been at the forefront of efforts to develop a Phobos mission. Likewise, authors Dr. Britt, from the University of Central Florida, and Dr. Pieters, from Brown University, have partnered with APL and JPL in Phobos/Deimos mission proposals.
APL scientists are not the only ones interested in Phobos or Deimos. The Jet Propulsion Laboratory, Ames Research Center and the SETI Institute have also proposed several missions to the small moons. Every NASA center has been involved at some level.
But the only mission to actually get off the ground is the Russian Space Agency’s Phobos-GRUNT[ref]. The Russian mission was launched November 9, 2011, and two months later took a bath in the Pacific Ocean. The propulsion system failed to execute the burns necessary to escape the Earth’s gravity and instead, its orbit decayed despite weeks of attempts to activate the spacecraft. But that’s a whole other story.
“The Value of a Phobos Sample Return” first discusses the origins of the moons of Mars. There is no certainty. There is a strong consensus that Earth’s Moon was born from the collision of a Mars-sized object with Earth not long after Earth’s formation. This is just one possibility for the Martian moons. Murchie explains that the impacts that created the large basins and craters on Mars could have spawned Phobos and Deimos: ejecta that achieved orbit, formed a ring and then coalesced into the small bodies. Alternative theories claim that the moons were captured by Mars from either the inner or outer solar system. Or they could have co-accreted with Mars from the Solar Nebula. Murchie and the co-authors describe the difficulties and implications of each scenario. For example, if captured by Mars, then it is difficult to explain how their orbits came to be “near-circular and near-equatorial with synchronous rotational periods.”
To answer the question of origins, the paper turns to the questions of their nature. Murchie explains that the limited compositional knowledge leaves several possibilities for their origins. They seem like D-type asteroids of the outer asteroid belt. However, the moons of Mars are very dry, void of water, at least on their surfaces as the paper discusses in detail. The flybys of Phobos and Deimos by NASA and ESA spacecraft are simply insufficient for drawing any clear picture of their composition or structure, let alone their origins, Murchie and co-authors explain.
If the moons were captured then they have compositions different from Mars; however if they accreted with or from Mars, then they share similar compositions with the early Mars when forming, or from Martian crustal material, respectively.
The paper describes in some detail the problem that billions of years of Martian dust accumulation presents. Every time Mars has been hit by a large asteroid, a cloud of debris is launched into space. Some falls back to the planet but much ends up in orbit. Each time, some of the debris collided with Phobos and Deimos; Murchie uses the term “Witness plate” to describe what the two moons are to Mars. There is an accumulation of Martian material and also material from the impactors covering the surfaces of the moons. Flyby images of Phobos show a reddish surface similar to Mars, and numerous tracks along the surface as if passing objects struck, plowed or rolled along. However, the reddish hue could be weathering from Solar flux over billions of years.
The paper continues with questions of the composition and how rendezvous missions could go further to understanding the moons makeup and origins, however, it is sample return that would deliver, the pay dirt. Despite how well NASA and ESA engineers have worked to shrink and lighten the instruments that fly, orbit, and land on Mars, returning a sample of Phobos to labs on Earth would permit far more detailed analysis.
Science Fiction writers and mission designers have imagined Phobos, in particular, as a starting point for the human exploration and colonization of Mars. A notable contemporary work is “Red Mars” by Kim Stanley Robinson; however, the story line is dated due to the retirement of the Space Shuttle and the external tanks Robinson clustered to form the colonization vessel. While this paper by Murchie et al. is purely scientific, fiction writers have used the understanding that Phobos is far easier to reach from Earth than is the surface of Mars (see Delta-V chart below).
Phobos, orbiting at 9,400 kilometers (5,840 miles), and Deimos, at 23,500 km (14,600 miles), above Mars avoids the need for the 7-odd minutes of EDL terror – Entry, Descent, and Landing — and pulling oneself out of the Martian gravity well to return to Earth. Furthermore, there is the interest in using Phobos as a material resource – water, material for rocket fuel or building materials. “The Value of a Phobos Sample Return” discusses the potential of Phobos as a resource for space travelers – “In Situ Resource Utilization” (ISRU), in the context of its composition, how the solar flux may have purged the moons of water or how Martian impact debris covers materials of greater interest and value to explorers.
With so many questions and interests, what missions have been proposed and explored? The Murchie paper describes a half dozen missions but there are several others that have been conceived and proposed to some level over several decades.
At present, there is at least one mission actively pursuing funds. The SETI and Ames proposed “Phobos and Deimos & Mars Environment” (PADME) mission led by Dr. Pascal Lee is competing for Discovery program funding. Such projects must limit cost to $425 million or less and be capable of launching in less than 3 years. They are proposing a launch date of 2018 on a SpaceX Falcon 9. The PADME mission design would reuse Ames LADEE hardware and expertise, however, it does not go so far as what Murchie and co-authors argue – returning a sample from Phobos. PADME would maintain in a synchronized orbit with Phobos and then Deimos foe repeated flybys. The mission is likely to cost in the range of $300 million. Stardust, a relevant mission due to its sample return capsule, launched in 1999 and had costs which likely reached a similar level by end of mission in 2012.
The Russian Space Agency is attempting to gain funding for Phobos-Grunt 2 but possible launch dates continue to be moved back – 2020, 2022, and now possibly 2024.
Additionally, each of this papers’ authors has mission proposals described. Dr. Pieters, JPL, and Lockheed-Martin proposed the Aladdin mission; Dr. Britt at APL, also with Lockheed-Martin, proposed the mission Gulliver; both would re-use the Stardust sample-return capsule (photo, above). Dr. Murchie also describes his APL/JPL mission concept called MERLIN (Mars–Moon Exploration, Reconnaissance and Landed Investigation).
Phobos and Deimos are the last two of what one would call major objects of the inner Solar System that have not had dedicated missions of exploration. Several bodies of the Asteroid Belt have been targeted with flybys and Dawn is nearing its second target, the largest of the Asteroids, Ceres.
So sooner rather than later, a spacecraft from some nation (not necessarily the United States) will target the moons of Mars. Targeted Phobos/Deimos missions are also likely to include both flyby missions and one or more sample-return missions. A US-led mission with sample-return in the Discovery program will be strained to meet both criteria – $425 million cost cap and 3 year development period.
Those utilizing the Lockheed-Martin (LM) Stardust design have a proven return capsule and spacecraft buses (structure, mechanisms and avionics) for re-use for cost and time savings. This includes five generations of the LM flight software that holds an incredible legacy of mission successes starting with Mars Odyssey/Genesis/Spitzer to now Maven.
All three proposals by this paper’s authors could be re-vamped and proposed again and compete against each other. All three could use Lockheed-Martin past designs. Cooperation in writing this paper may be an indicator that they will join forces, combine concepts, and share investigator positions on a single NASA-led project. The struggle for federal dollars remains a tough, tight battle and with the human spaceflight program struggling to gain a new footing after Space Shuttle, dollars for inter-planetary missions are likely to remain very competitive. However, it appears a Phobos-Deimos mission is likely within the next ten years.
Further reading:
“The Value of a Phobos Sample Return”, Scott L. Murchie, Daniel T. Britt, Carle M. Pieters, Planetary and Space Science, 1 November 2014
The US Naval Observatory, Great 26″ Refractor Telescope
Past Universe Today story, “Finding Phobos: Discovery of a Martian Moon”
A moon rocket thundering from a pad in Florida. Two moons discovered around Mars. Space tourism. These are all things that are part of history today — and which were also predicted in literature years or decades before the event actually happened.
This fun infographic (embedded below) shows a series of fiction books that were curiously prescient about our future, ranging from From The Earth to the Moon to 2001: A Space Odyssey. Submarines, rocket ships and other pieces of technology were all imagined long before they were reality, so what inspired these authors?
“Many writers of the past have predicted the facts of our present society with a level of detail that seems impossibly accurate,” wrote Printerinks, a print and toner shop that produced the graphic.
“Some of them were even derided in their times for what were called outlandish and unbelievable fictions. Yet their imaginations were in reality painting portraits that would eventually be mirrored by history books a century later. Which seems to beg the question, Where does inspiration come from? So to decide for yourself whether these writers were seers or just plain lucky, explore our History of Books that Predicted the Future.”
You can click on the graphic for a larger version. Is it missing anything? Let us know in the comments.
(h/t It’s Okay To Be Smart)
NASA’s Curiosity Mars rover has caught the first image of asteroids taken from the surface of Mars on April 20, 2014. The image includes two asteroids, Ceres and Vesta. This version includes Mars’ moon Deimos in a circular, exposure-adjusted inset and square insets at left from other observations the same night. Credit: NASA/JPL-Caltech/MSSS/Texas A&M
More night sky views and surface mosaics below[/caption]
The Curiosity rover has captured the first images of asteroids even taken by a Human probe from the alien surface of the Red Planet during night sky imaging.
And it’s not just one asteroid, but two asteroids caught in the same night time pointing on the Red Planet. Namely, asteroids Ceres and Vesta.
The stupendous image – seen above – was snapped by Curiosity’s high resolution Mastcam camera earlier this week on Sunday, April 20, 2014, Sol 606, whilst she was scanning about during daylight for her next drilling target at “The Kimberley” waypoint she pulled into at the start of this month.
Ceres and Vesta appear as streaks since the Mastcam image was taken as a 12 second time exposure.
“This imaging was part of an experiment checking the opacity of the atmosphere at night in Curiosity’s location on Mars, where water-ice clouds and hazes develop during this season,” said camera team member Mark Lemmon of Texas A&M University, College Station, in a statement.
“The two Martian moons were the main targets that night, but we chose a time when one of the moons was near Ceres and Vesta in the sky.”
View our “Kimberley” region photo mosiacs below to see exactly from where the six wheeled robot took the asteroid image shown above, while driving around the base of “Mount Remarkable”.
And those two asteroids are extra special because not only are they the two most massive objects in the Main asteroid belt between Mars and Jupiter, but they are also the destinations of another superlative NASA unmanned mission – Dawn.
The exotic Dawn probe, propelled by a stream of ions, orbited Vesta for a year in 2011 and is now approaching Ceres for an exciting orbital mission in 2015.
Ceres, the largest asteroid, is about 590 miles (950 kilometers) in diameter. Vesta is the third-largest object in the main belt and measures about 350 miles (563 kilometers) wide.
And as if Curiosity’s mouthwatering and heavenly double asteroid gaze wasn’t already spectacular enough, the tinier of Mars’ moons, Deimos, was also caught in that same image.
A trio of star trails is also seen, again due to the 12 second time exposure time.
Furthermore, Mars largest moon Phobos as well as massive planets Jupiter and Saturn were also visible that same Martian evening, albeit in a different pointing.
These celestial objects are all combined in the composite image above.
“The background is detector noise, limiting what we can see to magnitude 6 or 7, much like normal human eyesight. The two asteroids and three stars would be visible to someone of normal eyesight standing on Mars. Specks are effects of cosmic rays striking the camera’s light detector,” says NASA.
An unannotated image is seen below.
Curiosity’s makers back on Earth are nowhere to be seen. But check out the Curiosity’s earlier photo below of the Earth and Moon from my prior article – here.
To date, Curiosity’s odometer totals 3.8 miles (6.1 kilometers) since landing inside Gale Crater on Mars in August 2012. She has taken over 143,000 images.
The sedimentary foothills of Mount Sharp, which reaches 3.4 miles (5.5 km) into the Martian sky, is the 1 ton robots ultimate destination inside Gale Crater because it holds caches of water altered minerals. Such minerals could possibly indicate locations that sustained potential Martian life forms, past or present, if they ever existed.
Curiosity has some 4 kilometers to go to reach the base of Mount Sharp sometime later this year.
Stay tuned here for Ken’s continuing Curiosity, Opportunity, Chang’e-3, SpaceX, Orbital Sciences, LADEE, MAVEN, MOM, Mars and more planetary and human spaceflight news.
There won’t be any pictures out of this close encounter, but the animations sure were spectacular. The European Space Agency’s Mars Express spacecraft skimmed just 45 kilometers (28 miles) above the surface of the moon Phobos yesterday, and through these various videos you can see what the orbital trajectory would have looked like during that time.
“The flyby on 29 December will be so close and fast that Mars Express will not be able to take any images, but instead it will yield the most accurate details yet of the moon’s gravitational field and, in turn, provide new details of its internal structure,” ESA wrote in a press release last week.
“As the spacecraft passes close to Phobos, it will be pulled slightly off course by the moon’s gravity, changing the spacecraft’s velocity by no more than a few centimetres per second. These small deviations will be reflected in the spacecraft’s radio signals as they are beamed back to Earth, and scientists can then translate them into measurements of the mass and density structure inside the moon.”
The goal is to learn more about the structure of Phobos with the aim of figuring out where the moon came from. There are competing theories about the origin of Phobos and the other Martian moon, Deimos. Perhaps they were captured asteroids, or perhaps they were made up of debris made up from huge collisions from the Martian surface.
“Earlier flybys, including the previous closest approach of 67 km in March 2010, have already suggested that the moon could be between a quarter and a third empty space – essentially a rubble pile with large spaces between the rocky blocks that make up the moon’s interior,” ESA added.
Check out the rest of the videos below.
Source: ESA
After seeing Phobos imaged from the surface of the Red Planet by Mars Curiosity, now we’re lucky to get a close-up treat: here’s a video showing Mars Express images of the Martian moon over the last 10 years. The images reveal mysterious grooves running through the small moon, which is 13.5-miles (22 kilometers) in diameter, and scientists still aren’t sure what’s going on.
“The moon’s parallel sets of grooves are perhaps the most striking feature, along with the giant 9 km-wide Stickney impact crater that dominates one face,” the European Space Agency wrote.
“The origin of the moon’s grooves is a subject of much debate. One idea assumes that the crater chains are associated with impact events on the moon itself. Another idea suggests they result from Phobos moving through streams of debris thrown up from impacts 6000 km away on the surface of Mars, with each ‘family’ of grooves corresponding to a different impact event.”
For more about amazing discoveries from Mars Express, check out our top 10 list from the summer!
OTTAWA, CANADA – Humans would spend more than a year orbiting and bouncing on the Martian moon Phobos under a mission concept developed by students at the International Space University.
The very theoretical MARS-X mission — presented more as a concept than a firm plan — would see technology development taking place from 2018 to 2022, with communications satellites and rovers winging their way to the planet to be used by astronauts.
In 2023 to 2024, the spacecraft would be built in low-Earth orbit, requiring several launches to accomplish the massive task. Astronauts would then depart in 2024, spending eight months in transit before arriving at Phobos. There, the mission would last 495 days, and the astronauts would take five months to get home.
While NASA and Lockheed Martin helped sponsor the students who created the plan as part of their academic work, the concept itself is not yet funded beyond the students’ initial development.
But Piotr Murzionak, a member of the ISU team, said the proposal is one way that could help fuel interest in space exploration, if it was to be executed..
“It paves the way to Mars. It will be the initial step towards the landing mission on the Martian surface, but without the extra risk involved in order to land directly to Mars,” Murzionak said.
The Mars Exploration Vehicle (as the crew vehicle would be called) would use nuclear propulsion and liquid hydrogen to bring two habitats along with it. One of those would (along with several fuel tanks) be used on Phobos for up to 40 days of surface operations.
It would travel during solar maximum in 2024 to reduce the effects of cosmic radiation from outside the solar system, since the sun’s activity would blow the radiation further away. Further, the crew would be protected from solar flares with high-density polyethylene, as well as a temporary solar storm protection chamber lined with 50 centimeters of water.
The habitat would be spun at 4.4 revolutions per minute, with a habitat of 0.38 to 0.53 the force of gravity — about equivalent to what is on Mars. (This would take 2.5 metric tonnes of fuel to do.)
The students estimate this would cost about $20 billion, but it could go to at least double this due to factors such as “the volatility of political systems and the large amount of bureaucracy involved in any such endeavor,” they write in their final report, which is available here.
Murzionak presented the mission concept at the Canadian Space Society annual conference today (Nov. 14) in Ottawa, Canada.
More information: http://www.project-marsx.com/
After the tragic failure of the first Phobos-Grunt mission to even make it out of low-Earth orbit, the Russian space agency (Roscosmos) is hoping to give it another go at Mars’ largest moon with the Phobos-Grunt 2 mission in 2020. This new-and-improved version of the spacecraft will also feature a lander and return stage, and, if successful, may not only end up sending back pieces of Phobos but of Mars as well.
The origins of Phobos have long been a topic of planetary science debate. Did it form with Mars as a planet? Is it a wayward asteroid that ventured too closely to Mars? Or is it a chunk of the Red Planet blasted up into orbit from an ancient impact event? Only in-depth examination of its surface material will allow scientists to determine which scenario is most likely (or if the correct answer is really “none of the above”) and Russia’s ambitious Phobos-Grunt mission attempted to become the first ever to not only land on the 16-mile-wide moon but also send samples back to Earth.
Unfortunately it wasn’t in the cards. After launching on Nov. 9, 2011, Phobos-Grunt’s upper stage failed to ignite, stranding it in low-Earth orbit. After all attempts to re-establish communication and control of the ill-fated spacecraft failed, Phobos-Grunt crashed back to Earth on Jan. 15, impacting in the southern Pacific off the coast of Chile.
But with a decade of development already invested in the mission, Roscosmos is willing to try again. “Ad astra per aspera,” as it’s said, and Phobos-Grunt 2 will attempt to overcome all hardships in 2020 to do what its predecessor couldn’t.
Read more: Russia to Try Again for Phobos-Grunt?
And, according to participating researchers James Head and Kenneth Ramsley from Brown University in Providence, Rhode Island, the sample mission could end up being a “twofer.”
Orbiting at an altitude of only 5,840 miles (9,400 km) Phobos has been passing through plumes material periodically blown off of Mars by impact events. Its surface soil very likely contains a good amount of Mars itself, scooped up over the millennia.
“When an impactor hits Mars, only a certain of proportion of ejecta will have enough velocity to reach the altitude of Phobos, and Phobos’ orbital path intersects only a certain proportion of that,” said Ramsley, a visiting researcher in Brown’s planetary geosciences group. “So we can crunch those numbers and find out what proportion of material on the surface of Phobos comes from Mars.”
Determining that ratio would then help figure out where Phobos was in Mars orbit millions of years ago, which in turn could point at its origins.
“Only recently — in the last several 100 million years or so — has Phobos orbited so close to Mars,” Ramsley said. “In the distant past it orbited much higher up. So that’s why you’re going to see probably 10 to 100 times higher concentration in the upper regolith as opposed to deeper down.”
In addition, having an actual sample of Phobos (along with stowaway bits of Mars) in hand on Earth, as well as all the data acquired during the mission itself, would give scientists invaluable insight to the moon’s as-yet-unknown internal composition.
“Phobos has really low density,” said Head, professor of geological sciences at Brown and an author on the study. “Is that low density due to ice in its interior or is it due to Phobos being completely fragmented, like a loose rubble pile? We don’t know.”
The study was published in Volume 87 of Space and Planetary Science (Mars impact ejecta in the regolith of Phobos: Bulk concentration and distribution.)
Source: Brown University news release and RussianSpaceWeb.com.
See more images of Phobos here.