The Martian Moons eXploration (MMX) mission is JAXA’s lead mission that plans to survey and discover Mars’ two moons, Phobos and Deimos. Whereas the Japanese company will construct the principle payload, the German House Company (DLR) and the Nationwide Centre for House Research (CNES) will contribute to the mission. “IDEFIX,” a small secondary payload, will experience with MMX and is deliberate to the touch down on the floor of Phobos in 2029.
IDEFIX lately completed development, and DLR and CNES are set to ship the rover to JAXA for integration with the MMX mission.
The IDEFIX rover
IDEFIX is known as after the canine from the comics “The Adventures of Asterix.” The title refers back to the wordplay “Idée Fixe,” which roughly interprets to an obsession or a ardour that someone fixates on.
The rover itself weighs 25 kilograms, is 51 centimeters lengthy, and is designed to discover as much as 100 meters of Phobos’ floor. Throughout one in every of MMX’s closest approaches to Phobos, the rover will probably be launched at an altitude between 40 and 100 meters above the floor and contact down on Phobos.
The drop makes use of the low gravity of Phobos, which is able to permit IDEFIX to only fall onto the floor, roll, after which elevate itself to arrange for the roughly three-month-long mission. The gravity of Phobos is just roughly 1/one thousandth of the gravity of Earth, which may be attributed to the moon’s small measurement. Phobos solely has a diameter of roughly 27 kilometers.
IDEFIX rover throughout development. (Credit score: DLR)
“Because of the low gravity, IDEFIX will want between 60 to 80 seconds from launch to the landing on Phobos. The affect will probably be with lower than one meter per second,” defined Professor Markus Grebenstein, who’s DLR’s venture lead for IDEFIX, in an interview with NSF.
IDEFIX’s mission length will probably be round 100 days and is restricted by the truth that the principle MMX mission will finally transfer away from Phobos. The MMX spacecraft will probably be used as a relay for IDEFIX, so with out the spacecraft orbiting close to Phobos, IDEFIX will not have the ability to talk and function on the floor. Along with contemplating MMX’s place round Phobos through the IDEFIX mission, the workforce additionally needed to think about Martian eclipses to make sure they have been maximizing photo voltaic publicity and minimizing Phobos nights.
Quantity and weight have been a predominant consideration when constructing IDEFIX, because the rover needed to be as light-weight and small as attainable in an effort to match as a secondary payload on MMX. After landing, the sequence to boost itself is important and automatic. If the rover fails to boost itself, it won’t be able to generate sufficient solar energy to proceed its mission. With out sufficient solar energy, IDEFIX’s devices could be unable to function, and different rover methods could be unable to warmth themselves — which might be a significant difficulty on condition that Phobos’ floor can get as chilly as -112 levels Celsius.
“What motivates us are a number of elements. In fact, one in every of them is trying the primary landing on the floor of Phobos. It can even be the primary time that we try to land on a celestial physique with such low gravity, and naturally, being the primary to gather floor probes from Phobos motivated us. It´s a once-in-a-lifetime likelihood,” stated Professor Grebenstein
IDEFIX’s development was accomplished in July 2023, with testing starting quickly after. Testing included a number of drop checks, the place DLR and CNES tried to simulate all of the completely different potential methods the rover might hit the floor and roll on the bottom.
In regards to the landing sequence, Grabenstein stated, “The Rover is designed to all the time carry out the identical sequence as soon as it touches down. Irrespective of how we land, the sequence ought to all the time result in the rover getting on its wheels. This makes the entire course of far more redundant in opposition to potential malfunctions.”
IDEFIX earlier than supply to Japan. (Credit score: DLR)
The rover’s wheels are additionally designed in a particular approach. “The primary problem is the low contact strain, because of the low gravity. However a second problem can also be the truth that we don’t precisely know the properties of the bottom. […] There’s a potential that the bottom is extra like powder snow, which is the explanation for this paddle wheel-like design,” Professor Grebenstein stated.
IDEFIX’s lead scientist, Dr. Stephan Ulamec, provides, “You noticed the out there footage now we have from Phobos. They’re pretty low-resolution. It appears to be like prefer it may very well be a regolith space, which it almost certainly is, but it surely is also a rubble floor. We are going to simply get to know this as soon as we’re there.”
The motors which can be wanted to show the rover are akin to different motors DLR already makes use of for the finger motion of robotic arms at its science middle, with particular modifications made to optimize for working in Phobos’ low gravity setting. Grabenstein stated, “We already used these motors for our hand-arm robotics system, medical robotics, and even for an in-space robotic arm.”
The science of IDEFIX
Phobos is the innermost and largest of the 2 moons of Mars, the opposite being Deimos. It’s an irregularly formed moon with a radius of 11 kilometers and an orbital altitude of 6,000 kilometers above the Martian floor. In reality, Phobos orbits nearer to its planet than another moon within the photo voltaic system. For comparability, Earth’s moon orbits at an altitude of roughly 384, 399 kilometers from Earth’s floor, or about 64 occasions farther than Phobos.
One of the vital urgent questions in all of planetary and photo voltaic system science is Phobos’ (and Deimos’) origin. Each moons look just like C-type asteroids, which means that Phobos and Deimos might really be two asteroids that occurred to move too near Mars and have been captured by the planet’s gravity. Nevertheless, scientists have questioned Mars’ potential to seize an object like Phobos so near its ambiance.
Phobos as imaged by the Mars Reconnaaissance Orbiter. (Credit score: NASA/JPL)
“One factor it is possible for you to to look at when trying nearer at Phobos is 2 completely different supplies. You will notice the extra purple background and the extra blue-ish floor. This isn’t absolutely understood but,” stated Dr. Ulamec.
“Taking a look at Phobos, it jogs my memory of a sure class of asteroids. These sorts of asteroids are wealthy in carbon and are potential culprits for delivering matter to develop life. […] Nevertheless, one downside with this concept is the orbital dynamics of capturing such objects. There are theoretical situations the place a possible double asteroid constellation might end in such a state of affairs. This works nice on paper however sounds extra unlikely with two moons of Mars,” Dr. Ulamec defined.
One other concept that’s attainable is the idea of a heavy affect at Mars that helped type these moons. Concerning the idea, Ulamec says, ”These theories additionally work very properly on paper. Nevertheless, this doesn’t clarify the spectrum and colours of the moons.”
IDEFIX will probably be geared up with 4 predominant devices, which is able to assist to grasp the origin and actual sediment particulars of Phobos. The primary is a NavCam, which is a CNES-provided instrument for optical-stereo navigation. The second is RAX, a Raman-spectrometer, which was developed by DLR, JAXA, and the Spanish house company INTA. RAX will probably be used to generate a structural fingerprint of Phobos.
Subsequent is WheelCams, that are two optical sensors at two wheels that can analysis the interplay between IDEFIX’s wheels and Phobos’ floor materials. The WheelCams have been developed by CNES. The ultimate instrument is MiniRad, a DLR-developed infrared radiometer, which was developed across the design of the MARA instrument on the MASCOT-lander.
Dr. Ulamec defined, “In fact, the principle objectives of IDEFIX and MMX will probably be to uncover the actual historical past behind the origin of Phobos and in addition perceive the context of the entire Mars system higher.”
The flight plan of MMX. (Credit score: JAXA)
MMX is ready to launch no sooner than December 2026 on a Japanese H3-24 rocket. The full mission plans to land a few times on Phobos, accumulate 10 grams of samples, after which carry out a number of flybys of Deimos earlier than returning to Earth.
(Lead Picture: Artist’s depiction of IDEFIX on Phobos. Credit score: DLR/CNES/JAXA)
