German-built mini-rover for Japanese Phobos mission shipped to Japan

A German-built mini-rover, dubbed Idefix, has now been shipped to Japan to intergrate it as a secondary payload on that country’s MMX mission to the Martian moon Phobos.

The rover itself weighs 25 kilograms (55 pounds), is 51 centimeters long (20 inches), and is designed to explore up to 100 meters of Phobos’ surface. During one of MMX’s closest approaches to Phobos, the rover will be released at an altitude between 40 and 100 meters above the surface and touch down on Phobos. The drop utilizes the low gravity of Phobos, which will allow IDEFIX to just fall onto the surface, roll, and then raise itself to prepare for the roughly three-month-long mission. The gravity of Phobos is only roughly 1/1000th of the gravity of Earth, which can be attributed to the moon’s small size. Phobos only has a diameter of approximately 27 kilometers.

“Thanks to the low gravity, IDEFIX will need between 60 to 80 seconds from release to the touchdown on Phobos. The impact will be with less than one meter per second,” explained Professor Markus Grebenstein, who is DLR’s project lead for IDEFIX, in an interview with NSF.

If all goes right, the rover’s mission will last at least 100 days. MMX itself it scheduled to reach Phobos in 2029.

Meanwhile, scientists used one of the Perseverance’s high resolution cameras to capture another partial eclipse of the Sun by Phobos. This is not the first such Phobos eclipse that Perseverance has photographed (see for example here and here), but it is neat nonetheless.

Perseverance spots Phobos

Phobos, as seen by Perseverance on Mars
Click for full image.

Cool image time! The photo to the right, cropped to post here, was taken on January 12, 2022 by one of the high resolution cameras on the Mars rover Perseverance, and shows the Martian moon Phobos.

As noted in an update today by Claire Newman, one of the members of the science team,

This provides a measurement, using visible light, of the amount of dust in the nighttime atmosphere, which can be compared to similar measurements made by looking at the sun during the daytime, and to nighttime measurements of dust abundance made in the infrared by MEDA [another Perseverance instrument].

There have been three attempts to land on Phobos, all by the Russians, all of which failed. At present a Japanese mission to Phobos, dubbed Mars Moons eXploration or MMX, is scheduled to launch in 2024. This is a planned sample return mission, and will also include a rover.

China releases one photo of Phobos taken by its Tianwen-1 Mars orbiter

Phobos as seen by Tianwen-1
Click to see original photo.

China today released a single photo of the Martian moon Phobos, taken by its Tianwen-1 Mars orbiter, to mark the second anniversary of the orbiter’s launch.

The English press release at the link conveniently did not provide the image to the non=Chinese world, but the Chinese language release did. That picture is to the right, reduced slightly to post here. Considering its disinterest in making it easy to find this photo for English speakers, it is intriguing that China included the English language name Opik for one crater.

Moreover, this single picture release illustrates the paucity of Tianwen-1 photos made available to the public by China. Very few have been released, and though eventually China has been making its raw data available, it has not been doing so in a manner that makes it easy for outsiders to access it.

Nonetheless, this is one of the best pictures of Phobos I have yet seen.

Perseverance captures solar eclipse by Phobos

Phobos eclipse the Sun
Click for full image.

Cool movie time! The photo to the right, cropped to post here, shows the Sun partly blocked by the Mars’ moon Phobos, taken by the high resolution camera on Perseverance on the surface of Mars. Below I have embedded the full movie compiled from the images taken as Phobos moved across the Sun’s face. From the caption:

It’s long been known that Phobos is drifting toward the Martian surface year by year; tens of millions of years from now, it is expected to crash into the planet or fragment into chunks that will impact the planet. Studying Phobos’ orbit also allows scientists to refine predictions of when the doomed moon will crash into Mars.

Unfortunately, the website does not say when this solar eclipse occurred. The spots on the lower left of the Sun’s face are sunspots.
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Japan to attempt sample return mission to Martian moon

Japan’s space agency JAXA today announced that it will launch in ’24 an unmanned probe to the Martian moon Phobos that will return a sample to Earth in ’29.

The plan is to bring back about 10 grams of material.

If launched as planned, Japan will beat everyone in getting the first samples back from Martian space. China says it hopes to grab samples from Mars itself by 2030, while the U.S. and Europe hope to launch a mission to return the Perseverance cached samples sometime in the 2030s.

The temperature on Phobos

The temperature on Phobos
Click for full image.

The Mars Odyssey science team today released false color images of the Martian Moon Phobos showing the temperature range that the spacecraft has detected, shown above in a reduced form.

The April 24, 2019 image is the first time Mars Odyssey had gotten a full moon look at the Moon. Not surprisingly, the hottest spots on the surface are at the center, at noon, with it getting cooler as one gets to the outer edges near dawn and dusk and at the poles.

Curiosity films partial solar eclipses by both Phobos and Deimos

Phobos partial eclipse of Sun

Last week Curiosity successfully captured partial solar eclipses by both Phobos and Deimos as the Martian moons crossed the face of the Sun.

The movie on the right shows Phobos eclipsing the Sun. The speed is ten times faster than real time.

The press release can be seen here. It notes how these observations, of which 8 in total have been made since Curiosity arrived on Mars, have helped pin down the orbits of both moons.

Escape velocity on Phobos changes a lot depending on location

A new computer analysis of the shape of the gravitational field of the Martian moon Phobos suggests that the escape velocity varies significantly, depending on where you are on the moon’s surface.

Phobos is an odd duck among our solar system’s moons. It’s tiny (a fraction of a percent the size of our own moon) and is shaped like a potato; that weird shape draws gravity to different places, depending on where you are.

All these features make Phobos a challenge to travel on, researchers report in Advances in Space Research. In some places, moving any faster than 5 kilometers per hour would be enough to free you from the moon’s meager gravitational pull, sending you off into space where you’d likely be captured by Mars’s gravity and end up orbiting the Red Planet. The fastest you could travel anywhere on Phobos would be about 36 kilometers per hour, or a little faster than a golf cart, the team finds.

Obviously, this must be recognized for any mission trying to land and explore the moon.

Mars Odyssey makes its first observations of Phobos

Sixteen years after entering Mars orbit Mars Odyssey finally made its first observations of the Martian moon Phobos last week.

Since Odyssey began orbiting the Red Planet in 2001, THEMIS has provided compositional and thermal-properties information from all over Mars, but never before imaged either Martian moon. The Sept. 29 observation was completed to validate that the spacecraft could safely do so, as the start of a possible series of observations of Phobos and Deimos in coming months.

In normal operating mode, Odyssey keeps the THEMIS camera pointed straight down as the spacecraft orbits Mars. In 2014, the spacecraft team at Lockheed Martin Space Systems, Denver; and NASA’s Jet Propulsion Laboratory, Pasadena, California; and the THEMIS team at Arizona State University, Tempe, developed procedures to rotate the spacecraft for upward-looking imaging of a comet passing near Mars. The teams have adapted those procedures for imaging the Martian moons.

The data from this particular observation is less significant than the fact that the spacecraft can now do it. Expect some new results about the Martian moons in the coming months.

Hubble shoots movie of Phobos

Phobos over Mars

Cool image time! By taking a quick series of thirteen images, the Hubble Space Telescope was able to shoot a short movie of the rotation of Phobos above the surface of Mars. The gif animation on the right is the smaller of the two animations released today. Be sure and view the full resolution version.

What is even cooler is that movie was apparently unplanned. From the link:

Over the course of 22 minutes, Hubble took 13 separate exposures, allowing astronomers to create a time-lapse video showing the diminutive moon’s orbital path. The Hubble observations were intended to photograph Mars, and the moon’s cameo appearance was a bonus.

In terms of science this movie has a somewhat limited value. In terms of space engineering it is triumph, and once again illustrates the unprecedented value of having an optical telescope in space. Woe to us all when Hubble finally dies, as we have no plans to replace it.

ExoMars’ Trace Gas Orbiter images Phobos

As part of its checkout, Europe’s ExoMars’ Trace Gas Orbiter has taken test images of the Martian moon Phobos.

The camera imaged the moon on 26 November from a distance of 7700 km, during the closest part of the spacecraft’s orbit around Mars. TGO’s elliptical orbit currently takes it to within 230–310 km of the surface at its closest point and around 98 000 km at its furthest every 4.2 days. A colour composite has been created from several individual images taken through several filters. The camera’s filters are optimised to reveal differences in mineralogical composition, seen as ‘bluer’ or ‘redder’ colours in the processed image. An anaglyph created from a stereo pair of images captured is also presented, and can be viewed using red–blue 3D glasses.

The images were done to test the spacecraft’s operation, and have apparently shown that it is functioning well.

Mars Express will do an extremely close flyby of the martian moon Phobos on December 29.

Mars Express will do an extremely close flyby of the martian moon Phobos on December 29.

Late this month, ESA’s Mars Express will make the closest flyby yet of the Red Planet’s largest moon Phobos, skimming past at only 45 km [28 miles] above its surface. 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.

Russia heads for Mars

Russia heads for Mars: a detailed look at the Phobos/Grunt sample return mission, set to launch on November 8.

I really wish the Russians good luck with this project. Not only would it herald their return to planetary science since the fall of the Soviet Union, success here would break their long string of failures to the red planet. Though their unmanned planetary program had some remarkable achievements during the Soviet era, of the 19 missions they flew to Mars in the 1960s, 1970s, and 1980s, all were failures, producing almost no useful data.