WASHINGTON — A key official for Europe’s ExoMars mission believes the rover’s launch will be pushed back until at least 2028 to accommodate changes after cooperation with Russia ends.
ExoMars was to be launched in September on a Proton rocket thanks to a partnership between Roscosmos and the European Space Agency. Roscosmos also provided the landing pad for the ESA-built Rosalind Franklin rover.
However, ESA announced on March 17 that it was suspending cooperation with Russia on ExoMars in response to the Russian invasion of Ukraine. This forces ESA to not only find a new launch for the mission, but also to replace the landing platform. That meant pushing the launch back to at least 2026, ESA Director General Josef Aschbacher said at the time, adding that “even that is very difficult”.
Speaking at a May 3 meeting of NASA’s Mars Exploration Program Analysis Group (MEPAG), ESA ExoMars project scientist Jorge Vago said he doubted that a new lander could be ready by 2026. “It’s theoretically possible, but in practice we think it would be very difficult to reconfigure ourselves and produce our own lander for 2026,” he said. “In reality, we would be looking at a launch in 2028.”
Launching in 2028 could pose technical challenges for ExoMars. One trajectory would get the rover to Mars fairly quickly, but would have it arrive just a month before the start of dust storm season at the preferred landing site. An alternate trajectory would require traveling for more than two years to each Mars, but getting the rover there six months before the dust storms start.
“We tried very hard to convince the engineering team that dust storm season is not death,” Vago said. “We should focus on making the rover more robust and able to withstand a dust storm.”
A launch in 2028, he added, would require help from NASA. Specifically, he said the ESA would need descent engines similar to those produced by Aerojet Rocketdyne for NASA’s Mars missions like Curiosity and Perseverance, because there are no European models the right size for. ExoMars.
A second item is radioisotope heating units, or RHUs, which use the heat produced by the radioactive decay of plutonium to keep the rover warm. Russia had supplied RHUs for the rover, and there is no European replacement. Using US RHUs would likely also require launching ExoMars from the US, he said.
Aschbacher said in an April 6 interview that ESA was working with NASA on potential cooperation with ExoMars while considering replacing Russian components of the mission with European alternatives. This will lead to a decision in July on the way forward for ExoMars, which would likely require additional funding to be requested at the next ESA Ministerial meeting at the end of this year.
A delay to 2028 would mean that ExoMars would be launched at the same time as the two landers for the revised Mars Sample Return (MSR) campaign that NASA and ESA are jointly conducting. ESA’s contributions include a rover that would go to one of the landers to retrieve samples cached by Perseverance, placing them in a rocket on the other lander that would place the samples in Mars orbit to be retrieved and returned to Earth by an ESA orbiter. .
This led to speculation in the Mars exploration community that the Rosalind Franklin rover could be repurposed to support the Mars sample return effort. Vago said he expected some sort of “quid pro quo” arrangement between NASA and ESA if NASA helped ESA on ExoMars. That could mean, he said, “looking at both MSR and ExoMars holistically, if you like, and seeing if we can find solutions that work for both missions.”
A unique aspect of the Rosalind Franklin rover is a drill that can take samples up to two meters below the surface. A similar exercise is proposed for Mars Life Explorer, a Mars lander concept approved by the recent 10-Year Survey of Planetary Science for launch no earlier than the mid-2030s to search for signs of life in ice deposits. underground. During the MEPAG discussions on May 2, some suggested that a drill mounted on a rover, like the one on ExoMars, would be more efficient than a drill mounted on a stationary lander.
Vago confirmed that the ExoMars drill can handle ice as well as rock, although he said the mixture of ice and rock could complicate sample processing.