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.
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.”
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.
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.
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.)
It’s always interesting to consider the astronomical goings-on that occur under alien skies.
On August 17th, Curiosity wowed us once again, catching the above sequence of images of the Martian moon Phobos transiting the Sun.
Such phenomena have been captured by the Curiosity, Opportunity and Spirit rovers before, as the twin Martian moons of Deimos & Phobos cross the face of the Sun. But these recent images taken by Curiosity’s right Mastcam pair are some of the sharpest yet.
Orbiting only an average of 6,000 kilometres above the surface of Mars, Phobos is the closest to its primary of any moon in the solar system. It appears about 11 arc minutes in size when directly overhead, about 3 times smaller than our own Moon does from the Earth.
“This event occurred near noon at Curiosity’s location, which put Phobos at its closest point to the rover, appearing larger against the Sun than it would at other times of the day,” Said co-investigator Mark Lemmon of Texas A&M University in a recent press release. “This is the closest to a total eclipse that you can have on Mars.”
Phobos is 40% more distant from an observer standing on the surface of Mars when it is rising above the local horizon than when it is overhead. The Sun is about 20’ arc minutes across as seen from Mars, 66% of its diameter as seen from the Earth.
The sequence above spans only six seconds in duration. You would easily note the apparent motion of Phobos as it drifted by! Also, since Phobos orbits Mars once every 7.7 hours, it actually rises in the west and sets in the east. The Martian day is over three times this span, at 24.6 hours long. Deimos has a more sedate orbit of 30.4 hours in duration.
The twin Moons of Deimos and Phobos were discovered this month back during the opposition of 1877 by Asaph Hall using the United States Naval Observatory’s newly installed 65 centimetre refractor. The moons are just within the grasp of eagle-eyed amateurs near opposition. You’ve got another opportunity to cross these elusive moons off of your life list coming up in the Spring of 2014.
It’s especially captivating that you can make out the irregular “potato shape” of Phobos in the above images. With low orbital inclinations relative to the equator of Mars of 1.1 degrees for Phobos and 0.9 degrees for Deimos, solar transits are not an uncommon occurrence, transpiring somewhere along the Martian surface with every orbit. If Phobos were twice as close to Mars, it would completely cover the Sun in a total solar eclipse. What Curiosity gave us this month is more akin to an annular eclipse with a ragged central shadow. An annular eclipse occurs when the occulting body is too distant to cover the Sun, leaving a bright, shining ring, or annulus.
On the Earth, we live in an epoch where annular eclipses are slightly more common than total solar eclipses, as the Moon currently recedes from us to the tune of 3.8 centimetres a year. About 1.4 billion years from now, the last total solar eclipse will be seen from the Earth. The next purely annular eclipse as seen from Earth occurs on April 29th, 2014 across Australia and the Antarctic.
Conversely, Phobos is in a “death spiral,” meaning that it will one day crash into Mars about 30-50 million years from now. This also means that in about half that time, it will also be large enough to visually cover the Sun when crossing it near local noon. For a brief time far in the future, jagged total solar eclipses will be visible from Mars. That is, if the gravitational field of Mars doesn’t rip Phobos apart before that!
But beyond just aesthetics, these observations serve a scientific purpose as well. These phenomena serve to refine our understanding of the precise positions of Phobos and Deimos and their orbits.
“This one is by far the most detailed image of any Martian lunar transit ever taken, and it is especially useful because it is annular. It was taken closer to the Sun’s center than predicted, so we learned something.”
The track during the August 17th observation was off by about 2-3 kilometres, allowing for a surprise central transit of the Sun as seen from Curiosity’s location.
Both Phobos and Deimos are captured asteroids only 22.2 & 12.6 kilometres across, respectively. Both must be subject to occasional bombardment from meteorites blasted off of the surface of nearby Mars. Sample return missions to Phobos have been proposed. Russia’s ill-fated Phobos-Grunt mission would’ve done just that.
Will humans ever stand on the surface of the Red Planet and witness an annular eclipse of the Sun by Phobos in person? Well, if we make it there by November 10th, 2084, observers placed on the slopes of Elysium Mons will witness just such an event… with a rare transit of Earth and the Moon to boot!:
Arthur C. Clarke wrote of a transit of Earth from Mars that occurred in 1984 in his science fiction short story Transit of Earth.
Hey, I’m marking my calendar for the 2084 event… assuming, of course, my android body is ready by then!
Mars moon Phobos (above, center) rising in the night time Martian sky shortly after sunset in this still image from a movie taken by NASA’s Mars rover Curiosity on Sol 317, June 28, 2013. The apparent ring is an imaging artifact. Credit: NASA/JPL-Caltech See the complete ‘Phobos Rising’ movie below [/caption]
Every once in a while when the time is just right and no one is looking, Curiosity’s Earthly handlers allow her some night time Martian delights.
In this case a pair of rising and setting celestial events bookend another magnificent week in humankinds exploration of the Red Planet – courtesy of NASA.
This past week NASA’s Curiosity rover captured esthetically stunning imagery of Phobos rising and Our Sun setting on Mars.
Phobos is the larger of Mars pair of tiny moons. The other being Diemos.
On June 28, (Sol 317) Curiosity aimed her navigation camera straight overhead to captured a breathtaking series of 86 images as Phobos was ascending in the alien evening sky shortly after sunset.
NASA combined these raw images taken over about 27 minutes into a short movie clip, sped up from real time.
Video Caption: ‘Phobos Rising’ – This movie clip shows Phobos, the larger of the two moons of Mars, passing overhead, as observed by NASA’s Mars rover Curiosity in a series of images centered straight overhead starting shortly after sunset. Phobos first appears near the lower center of the view and moves toward the top of the view. The images were taken on June 28, 2013. The apparent ring is an imaging artifact. Credit: NASA/JPL-Caltech
The pockmarked and potato shaped moon measures about 26.8 × 22.4 × 18.4 kilometers.
Mars’ moon Phobos is captured in a daytime image by Curiosity (NASA/JPL-Caltech/MSSS)
A raw image taken on September 21 by Curiosity’s right Mastcam shows a daytime view of the Martian sky with a crescent-lit Phobos in the frame… barely visible, yes, but most certainly there. Very cool!
The image above is a crop of the original, contrast-enhanced and sharpened to bring out as much detail as possible.
The 13-km-wide Phobos has been spotted several times before by Mars rovers, most recently during a solar transit on September 13 (sol 37) but I’m not sure if it’s ever been clearly captured on camera during the day before (i.e., not passing in front of the Sun.) If not, this will be a first!
See the latest news from the Curiosity mission here.
Added 9/28: According to Universe Today publisher Fraser Cain, this is “the most dramatic space picture of the year”… whether you agree or not, hear what he had to say on this and other recent news during the September 27 episode of the Weekly Space Hangout.
Once again, it’s time for the Weekly Space Hangout – our round up of all the big space news stories that you should be aware of. This week we talked about the following interesting stories in space and astronomy:
Yes, Mars gets eclipses too! This brief animation, made from ten raw subframe images acquired with Curiosity’s Mastcam on September 13 — the 37th Sol of the mission — show the silhouette of Mars’ moon Phobos as it slipped in front of the Sun’s limb.
The entire animation spans a real time of about 2 minutes.
As a moon Phobos really is an oddity. In addition to its small size – only 8 miles (13 km) across at its widest – and irregular shape, it also orbits its parent planet at a very low altitude, only 5,840 miles (9,400 km) and thus needs to travel at a relatively high velocity in order to even stay in orbit. Phobos actually orbits Mars over three times faster than Mars rotates, appearing to rise in Mars’ western sky. And its orbit is so low that it can’t even be seen from the polar regions!
Since Phobos, and its even more petite sibling Deimos, are so small, the Mars rovers won’t ever see a total solar eclipse. In fact these events are often referred to as transits rather than actual eclipses.
This isn’t the first time an eclipse was captured by a Mars Exploration Rover; Opportunity witnessed a similar partial eclipse of the Sun by Phobos in December 2010, and Spirit caught a lunar (or “Phobal?”) eclipse on camera back in 2005, when the moon passed into the shadow of Mars.
Curiosity’s find was no accident, either, as mission engineers had the Mastcam already positioned to capture the event. Preparation really pays off!
See the latest images and news from the MSL mission here.
Images: NASA/JPL-Caltech/Malin Space Science Systems. Animation by Jason Major. Inset image: Phobos as seen by Mars Express ESA/DLR/FU Berlin (G. Neukum)
UPDATE 9/19/12: See a close-up animation of the eclipse event here.
Story and Crash Zone Map updated 1 p.m. EST Jan 16
Today (Jan. 15) was the last day of life for Russia’s ambitious Phobos-Grunt mission to Mars after a desperate two month race against time and all out attempts to save the daring spaceship by firing up a malfunctioning thruster essential to putting the stranded probe on a trajectory to the Red Planet, failed.
According to the Russian news agency Ria Novosti, the doomed Phobos-Grunt spacecraft apparently plunged into the southern Pacific Ocean today, (Jan. 15) at about 12:45 p.m. EST, 21:45 Moscow time [17:45 GMT] after a fiery re-entry into the Earth’s atmosphere.
“Phobos-Grunt fragments have crashed down in the Pacific Ocean,” Russia’s Defense Ministry official Alexei Zolotukhin told RIA Novosti. He added that the fragments fell 1,250 kilometers to the west of the Chilean island of Wellington.
Universe Today will monitor the developing situation and update this story as warranted. On Jan. 16 Roscosmos confirmed the demise of Phobos-Grunt at 12:45 p.m. EST in the Pacific Ocean – during its last orbit; #1097.
The demise of the Phobos-Grunt spacecraft was expected sometime today, (Jan 15) after a fiery and destructive fall back to Earth, said Roscosmos, the Russian Federal Space Agency, in an official statement released early today before the crash.
Since the re-entry was uncontrolled, the exact time and location could not be precisely calculated beforehand.
The actual crash time of the 13,500 kg space probe was slightly earlier than predicted.
Roscosmos head Vladimir Popovkin had previously stated that perhaps 20 to 30 fragments weighing perhaps 400 pounds (180 kg) might survive and would fall harmlessly to Earth.
The spacecraft burst into a large quantity of pieces as it hit the atmosphere, heated up and broke apart. But the actual outcome of any possible fragments is not known at this time.
Shortly after launching from the Baikonur Cosmodrome on Nov. 9, 2011, the probe became stuck in low Earth orbit after its MDU upper stage engines repeatedly failed to ignite and send the ship on a bold sample return mission to the tiny Martian Moon Phobos.
Phobos-Grunt was loaded with over 11,000 kg of toxic propellants, including dimethylhydrazine and dinitrogen tetroxide, that went unused due to the thruster malfunction and that were expected to be incinerated during the plunge to Earth.
Frictional drag forces from the Earth’s atmosphere had gradually lowered the ship’s orbit in the past two months to the point of no return after all attempts to fire the thrusters and raise the orbit utterly failed.
The audacious goal of Phobos-Grunt was to carry out history’s first ever landing on Phobos, retrieve 200 grams of soil and bring the treasured samples back to Earth for high powered analysis that could help unlock secrets to the formation of Mars, Phobos and the Solar System.
The Holy Grail of planetary science is to retrieve Martian soil samples – and scientists speculated that bits of the Red Planet could be intermixed with the soil of its mini moon Phobos, barely 15 miles in diameter.
The science return from Phobos-Grunt would have been first rate and outstanding.
It’s a sad end to Russia’s attempts to restart their long dormant interplanetary space science program.
The $165 mission was Russia’s first Mars launch in more than 15 years.
Roscosmos had stated that the Atlantic Ocean – to the west of Africa – was at the center of the predicted crash zone. But nothing was certain and the probe had the possibility to crash sooner, perhaps over the Pacific Ocean or South America or later over Africa, Europe or Russia.
Roscosmos had predicted the time of the plunge to Earth to be from 12:50 p.m. EST and 1:34 p.m. EST (1750 to 1834 GMT) or 21:50 to 22: 34 Moscow time on January 15. The last orbit carried the probe over the Pacific Ocean towards South America on a northeasterly heading.
Russia enlisted assistance from ESA and the US in a bid to establish contact with the probe to reorient itself and fire up its engines for a belated journey to the Red Planet. Other than extremely brief signals the efforts proved futile and today’s Pacific plunge is the unfortunate end result.
Hopefully the Russians will not give up in despair, but rather fix the flaws and launch an exciting new Mars mission.
NASA has had better luck with their Mars mission this season.
The Curiosity Mars Science Lab rover is precisely on course to the Red Planet following the Jan 11 firing of the cruise stage thrusters for the first of up to 6 Trajectory Correction Maneuvers – read the details here