Tag Archives: phobos

Mars’ two moons used to be a single moon, says new research

Today, the red planet boasts two moons — Phobos and Deimos. Although we discovered them almost two centuries ago, their story was still a mystery. Both moons are very small and rough-shaped, which just isn’t very moon-y. A new paper suggests this is due to the fact that they aren’t really moons, but the remnants of a one.

An image of Phobos taken by Mars Express HRSC during a close flyby, April 30, 2017. Image credits ESA / DLR / FU Berlin /J. Cowart.

Phobos, at only 22 kilometers in diameter, is really small — around 160 times smaller than our moon. Deimos is even tinier, with a diameter of only 12 kilometers. Furthermore, while the Moon is pretty much spherical, both of Mars’ are shaped very irregularly. You could describe them as potato-shaped quite accurately. In order to understand why, a team of researchers at the Institute of Geophysics at ETH Zurich used computer simulations to track the moons’ orbits back through time.

At one point, these simulations revealed, the two were likely a single body.

A cosmic breakup

“Our moon is essentially spherical, while the moons of Mars are very irregularly shaped—like potatoes,” says Amirhossein Bagheri, a doctoral student at the Institute of Geophysics at ETH Zurich.

“Phobos and Deimos look more like asteroids than natural moons.”

The first theory the team started working with is that the two are in fact asteroids that were captured by Mars’ gravity field sometime in the past. Still, this didn’t really pan out. Captured objects should, as far as we know, have eccentric orbits at random inclinations around their capturer — but neither Phobos nor Deimos does. They actually have almost circular orbits on the equatorial plane of Mars.

So they set out to simulate how their orbits changed over time, hopeful to get to the bottom of things. The simulation showed that if we go back in time far enough, Phobos and Deimos come to share the same orbit. This, the team says, likely means they’re both pieces of a larger, original body. In Greek mythology, Phobos (fear) and Deimos (terror) are the twin sons of Ares, the god of war. Given that the planet was named after the Roman equivalent of Ares — Mars, — this origin story seems quite fitting.

Still, I have massively simplified the work needed to reach these results. The team had to improve on what we know of the interactions between Mars, Phobos, and Deimos. Khan explains that these bodies all exert tidal forces on one another, leading to “a form of energy conversion known as dissipation, the scale of which depends on the bodies’ size, their interior composition and not least the distances between them”.

Luckily, NASA’s InSight mission is hard at work around Mars, and ETH Zurich supplied the electronics for the mission’s seismometer. With the data it supplied, the team refined our interior models of Mars, which in turn allowed them to improve on the equations describing this process of dissipation.

Data obtained from other instruments on other Martian craft also suggested that both moons were made of a very porous (and thus, lightweight) material. The team explains that this is true — their average densities, both at under 2 grams per cubic centimeter, are around half that of Earth (5,5 grams per cubic centimeter, on average).

“There are a lot of cavities inside Phobos, which might contain water ice,” says Amir Khan, a Senior Scientist at the Physics Institute of the University of Zurich and the Institute of Geophysics at ETH Zurich and co-author of the paper, “and that’s where the tides are causing a lot of energy to dissipate.”

Armed with this data and their findings on tidal interactions, they refined the models underpinning the simulations — then ran them a few hundred times for good measure. Depending on the exact parameters fed into the simulation, it shows that Phobos and Deimos were ‘born’ between 1 and 2.7 billion years ago. Until we know exactly what the moons’ physical properties are — especially porosity and water content — this timeframe will have to be our best estimate. A Japanese mission aimed for launch in 2025 will explore Phobos and return samples to Earth, so we might have a much better estimate in a few years.

As far as the original moon is concerned, the team says it orbited Mars at a greater distance than Phobos today. Deimos, owing to its smaller mass, has remained roughly at the distance this original moon was orbiting on. The more massive Phobos, however, has been drawn closer by tidal forces, and this process is still ongoing. The team’s simulations show that Deimos will keep drifting away from Mars (much like Earth’s Moon is doing), while Phobos will keep inching towards the surface. They estimate either an impact taking place in the next 40 million years or so, or for Phobos to break down under the strain of Mars’ gravity as it comes nearer.

The paper “Dynamical evidence for Phobos and Deimos as remnants of a disrupted common progenitor” has been published in the journal Nature.

Saturn rings

Cassini is no more, but it left us one of the most memorable photos of Saturn

After twenty years in space, thirteen of which orbiting Saturn and its moons, the enduring Cassini spacecraft finally met its end on September 15, 2017. The trove of images and scientific data it beamed back, however, will keep scientists busy and the general public entertaining for many more years to come. For instance, NASA spoils us with this amazing shot of Saturn and its icy rings — one of the most spectacular we’ve seen so far.

Saturn rings

Credit: NASA/JPL-Caltech/Space Science Institute.


The photo was taken just a month before the spacecraft made a suicide plunge into Saturn’s atmosphere. At the time, Cassini was a staggering 600,000 km away from the planet, which, even so, still looks enormous.

Saturn has four main groups of rings and three fainter, narrower ring groups, separated by gaps called divisions. Each ring group is made up of thousands of smaller rings made of ice and debris, in some places no thicker than a few meters. In between Saturn’s cloud tops and the innermost D ring, the spacecraft passed through 22 times before it ended its mission. Before Cassini’s plunges were routed, scientists spent countless hours analyzing such images in search for debris that might prove hazardous to the spacecraft.

Remarkably, besides Saturn and some of its ring groups, the image also features an outlier: Saturn’s moon Pandora. Discovered in October 1980 by Voyager 1, the potato-shaped moon has 25.3 miles (40.7 km) mean radius. In this particular image, seen in the top-right corner, it barely measures more than a single pixel.

The image was taken in  with the spacecraft’s wide-angle camera. To increase visibility, Pandora was brightened by a factor of 2.

Cassini's best close-up view of Saturn's F ring shepherd moon, Pandora, taken in December 2016. Credit: NASA.

Cassini’s best close-up view of Saturn’s F ring shepherd moon, Pandora, taken in December 2016. Credit: NASA.

Over the course of its long mission, Cassini’s achievements were legion. Besides landing a probe on Titan, a methane-filled world similar to the early days of Earth before life evolved, Cassini made the most planetary flybys of any spacecraft — over 100. Before arriving in Saturn’s orbit, Cassini circled Earth, Venus, and Jupiter.

Curiosity rover snaps a video of Martian moonrise

The otherwordly new video features one of the two Martian moons – Phobos, as it rises on the sky. Even though the movie only has 32 seconds, the action actually took place over the course of 27 minutes.

Mars has two moons: Phobos (which is just 22 km wide on average), and Deimos, which is even smaller. They are believed to be asteroids trapped a long time ago by the Martian gravitational field.

This video isn’t the first from Curiosity to represent Phobos – just five weeks after it landed on Mars, it sed its workhorse MastCam camera to photograph the moon as it crossed the face of the sun, covering a small fraction of the star.

The Curiosity rover landed inside a geological feature called Gale Crater last August, kicking off a planned two-year surface mission to find out if the Red Planet was ever able to support (microbial) life. So far, the mission was a great success, as the rover already showed that a site called Yellowknife Bay was indeed habitable billions of years ago.


Via WikiCommons

Phobos transit over sun. (c) NASA

Partial solar eclipse on Mars as seen from Curiosity [PHOTO]

Phobos transit over sun. (c) NASA

Phobos transit over sun. (c) NASA

As once can see above, Curiosity recently caught glimpse of a partial solar eclipse from the surface of Mars and wired back some eye candy for us Earthlings to rejoice. You might find the fact that there’s only a small black dot partially covering the sun a bit disappointing. Instead, maybe we should look at our moon in more appreciative light.

During partial or total solar eclipses, our moon which is 2,160 miles across, is big enough to block the sun when perfectly aligned, allowing for a marvelous spectacle. In the shot from above, the small black dot on the sun is Mars’ tiny moon Phobos which is a mere 14 miles across, albeit much closer to the surface of the red planet than our moon is to Earth. Mars’ other moon, Deimos, is even tinier. In fact, scientists believe both moons were once flyby asteroids which ended up captured into Mars’ orbit by its gravity.

The Curiosity rover is already six weeks into its mission, albeit its first month was stationary, time in which critical system checks were made to ensure everything is in order for the actual mission. Currently, the rover is on the move towards a site called Glenelg, where three different types of Martian terrain come together in one place. It’s a while a short stop, however, until it reaches its main destination – Mount Sharp, the 3.4-mile-high (5.5 km) mountain that rises from Gale’s center. In the meantime, Curiosity is sure to broadcast some more interesting facts from Mars. Stay tuned!

Artist impression of the Phobos-Grunt probe bursting into flames as it enters Earth's atmosphere. (c) Michael Caroll

Russia gives up on Phobos failed mission, scientist apologizes

Artist impression of the Phobos-Grunt probe bursting into flames as it enters Earth's atmosphere. (c) Michael Caroll

Artist impression of the Phobos-Grunt probe bursting into flames as it enters Earth's atmosphere. (c) Michael Caroll

After what can only be described has a frustrating, sleepless month for the Russian scientists involved in the Phobos grunt mission, which failed just after it escaped Earth’s atmosphere and became stranded into low-orbit, officials have announced that they have finally lost all hope and have abandoned any future efforts of re-salvaging the probe.

Russia’s Phobos- Grunt did indeed manage to communicate with ESA ground station a few weeks ago, albeit briefly back then, shinning a ray of hope for a possible re-boot, however it was all just a fluke, apparently. Subsequent efforts to re-establish contact with the probe failed miserably, despite worldwide efforts signaling it from behalf of any station capable enough were in vain.

The  $170 million Phobos-Grunt mission was set to land on Mars’ moon Phobos, collect samples and then return to Earth with them. The mission summed up Russia’s interplanetary ambitions, which hasn’t been able to achieve such a feat for more than 25 years.

In a recent press conference, Roscosmos and the Russian defense department announced that they have abandoned the project and are now preparing for a forced re-entry of the probe, which carries 7.5 tons of fuel and a small amount of radioactive cobalt. The announcement came just recently after a top Russian scientists directly involved in the project openly apologized.  Curiously enough, two weeks ago the Russian president threatened the scientists involved in Phobos mission with criminal charges, though I personally haven’t heard any more updates on this.

“Despite people being at work 24/7 since the launch, all these attempts have not yield[ed] any satisfactory results,” wrote Lev Zelenyi, director of the Space Research Institute in Moscow.

Zelenyi added, “We are working nevertheless on the issue of re-entry and [the] probability of where and which fragments may hit the ground (if any).”

In his letter, Zelenyi urges his fellow scientists not to give up hope and to try again on another mission when the next window to Phobos opens in 26 months. Concerning the Phobos re-entry,  Roscosmos expects the probe to plunge back to Earth around Jan. 9. Its location will be pinpointed with great accuracy, so chances of any human casualties occurring will be almost nil.

Artist impression of the Phobos-Grunt craft in orbit around Mars. Alas...

Russia’s Phobos probe is alive! Contact established with the failed Russian craft

Artist impression of the Phobos-Grunt craft in orbit around Mars. Alas...

Artist impression of the Phobos-Grunt craft in orbit around Mars. Alas...

Two weeks ago, panic engulfed the Russian space agency after one of its dearest project, the  $170 million Phobos-Grunt mission, which was set to land on Mars’ moon Phobos, collect samples and then return to moon, got stranded in orbit, completely blocked off from any kind of communication. Valiant efforts were made to restore the craft, but in vain. However, just recently, an Australian ground station has managed to establish contact with the probe, fueling hope for a possible salvaging.

Before the disastrous Nov. 9 launch from Russia’s favorite pad site, the Baikonur Cosmodrome in Kazakhstan, the Phobos probe was herald as a symbol of the nation’s interplanetery ambitions. When the probe eventually reached Earth’s orbit, however, engineers couldn’t fire its engines which should’ve propelled the craft in its months long voyage towards the red planet – they couldn’t even establish a com-link for that matter. Along with the Phobos craft, was China’s first interplanetary probe, Yinghuo 1, which piggy-bagged along with the Russian drone for a supposed drop off in Martian orbit – it too, of course, failed.

A glimmer of hope has risen recently after ESA’s tracking station in Perth, Australia, made contact with the probe late Tuesday. Before this event, Vitaly Davydov,  Russia’s deputy space chief, was quoted as saying  “chances to accomplish the mission are very slim.” Expect to add at least a notch to those chances, now.

Currently, the Russian space agency is hard at work trying to kick-start the probe again, in cooperation with ESA and NASA, and have been doing so for the past two weeks, for that matter. To problem is, even with a firm re-establishment of contact with the Phobos-Grunt, its engineers can only do so much. If the problem is indeed related to a software issue, they might have a chance, however some experts believe the the failure was rooted in the hardware, which in space is impossible to fix.

Davydov said that if engineers can’t take control of the spacecraft, it could crash to Earth sometime between late December and late February. It’s trajectory can’t be calculated earlier than a day in advance. People should not worry, though, says Davydov, who claims the probability of the probe hitting a human being is virtually nil. This person was part of the 0.000001%.

There is one good thing that might come off this disaster – a tighter international collaboration for missions in the future. Seems like this huge setback for the Russian interplanetary program could motivate the country to accept the issued invitation to join U.S.-European space missions to Mars. The ExoMars Trace Gas Orbiter mission will launched in 2016 for a scheduled arrival at Mars nine months later. The mission will test out the technology necessary for entry, descent and landing for future, possibly manned, missions to Mars.

More updates on the events following the Phobos probe will be posted as soon as they reach our ears. 

Russia struggles to fix Grunt Phobos mission

The drama continues for the Russian Grunt mission, which had the purpose of going to Phobos and extracting samples.

Russian Federal Space Agency

The mission was supposed to launch, go to Mars, orbit it for a few months, then land on Phobos, extract samples of soil and rocks, then lift back up and return to Earth. However, the mission, as well as the Russian space program’s pride, suffered a significant blow, as the shuttle suffered an engine failure in our planet’s orbit.

Russians declared they have three days to solve the problem, but one has already passed, with no clear signs of progress on the horizon.

“So far all efforts to communicate with the craft have been unsuccessful,” lead mission scientist Alexander Zakharov of Moscow’s Space Research Institute told Reuters. “They are trying everything including visual methods to try to assess what is wrong with it, but of course the situation doesn’t inspire much hope.”

Experts say the problems originated when the computer onboard the craft failed to fire two engine burns to send it on its trajectory toward Mars; as a result, there is now only a small chance to fix it.

“In my opinion Phobos-Grunt is lost,” Vladimir Uvarov, a former chief Russian military expert on space, told the state-run Rossiiskaya Gazeta.

China is also a little disappointed, after trusting the Russians with their first Mars satellite, in a piggyback ride. Phobos-Grunt was also carrying bacteria, plant seeds and tiny animals known as water bears to see if they could survive outside Earth.

The Mars curse strikes again: Russian Phobos mission gets stuck on Earth’s orbit

Just yesterday I was telling you about an extremely ambitious and admirable mission planned by the Russian, which has the purpose of extracting samples from Phobos, a moon of Mars. However, the mission seems to face some serious problems right after launch.

According to Russian officials, the probe is currently stuck in orbit and engineers have three days to solve this problem before its £105-million batteries run out. The probe successfully launched from the Baikonur Cosmodrome in Kazakhstan on 9 November (Moscow time), and separated from its Zenit-2 booster rocket some 11 minutes later. But immediately after that, everything took a turn for the worse, resulting in an engine failure.

The plan was for it to reach Mars, orbit it for a couple of months, then land on Phobos, where it would extract up to a few hundred grams of samples of dust and rocks. The mission was then supposed to heroically land in Russia, where it would be acclaimed and mark the start of a new era for Russian space flight, as well as end two decades of failed missions towards Mars.

That’s right, Russia seems to be suffering from a Mars: in 1988 Phobos 1 lost its way en-route to Mars after a faulty command sequence caused it to basically shut down. They tried again in ’96 with Mars 96, but the shuttle crashed into the shuttle immediately after launch. Phobos 2 managed to reach planet and even send a few pictures back, but engineers lost contact with the ship before it could land.

However, not all is lost, and there is a good chance engineers could fix the engine failure in the remaining three days; if this would happen, and nothing else would intervene, then the Grunt mission would reach Mars in September 2012 and resume plans as expected. Meanwhile, there’s going to be a couple of sleepless nights for engineers and astronomers in Russia.

Via Wired

Russia believes Phobos mission will bring them in back in the spatial spotlight

In these past few decades, the US space program seemed to have significantly overcome the Russian one, with all sort of missions and studies, but more recently, the balance seems to have turned once again, as NASA is undergoing numerous problems, while the Russians are planning an ambitious mission which is aimed at the Mars moon Phobos. This will be their first interplanetary mission in over 15 years !

Artist depiction of an extracting mission

The Phobos-Grunt mission is set to blast off from Kazakhstan’s Baikonur cosmodrome at 3:16 p.m. EST today with the purpose of extracting and bringing back some samples from the red planet’s moon (‘grunt’ means ‘dirt’ in Russian). If successful, it would shed some new light on the early days of the planet, and give some indication about the mechanisms which take place on Phobos. Furthermore, it would be a great morale and image boost for the Russian space agency, which has surpassed the cone of shadow in which it lay for years.

“If Phobos-Grunt fully carries out its mission, then this will be a world-class achievement,” Igor Lisov, editor-in-chief of the journal Novosti Kosmonavtiki (Space News), told Agence France-Presse. “The problem with Russian space exploration has been that people have forgotten the taste of victory. The task of this mission is to restore confidence in our abilities and the importance of the task.”

If everything goes according to plan, the $163 million mission will arive near Phobos in Autumn 2012, and drop its lander on the moon in the following months. The moon is most likely a potato shaped asteroid that was trapped by Mars’ gravity. After this, the lander will then return to the probe which will start its journey back to our planet, where it should arrive sometime in 2014, depending on the conditions and encountered problems.

Scientists are just boiling to get their hands on some samples; if it is indeed an asteroid, then it would be even more interesting, because these asteroids are leftovers from the solar system’s early days, primeval pieces that didn’t get absorbed by any planets. Also, some dust from Phobos could actually originate on Mars, from where it was brought as a result of a meteorite impact.

“This is really a very difficult project, if not the most difficult interplanetary one to date,” Phobos-Grunt lead scientist Alexander Zakharov told Reuters. “We haven’t had a successful interplanetary expedition for over 15 years. In that time, the people, the technology, everything has changed. It’s all new for us; in many ways, we are working from scratch.”