WASHINGTON – A key official for the European ExoMars mission believes the rover’s launch will be postponed until at least 2028 to accommodate changes after cooperation with Russia ends.
ExoMars was to be launched in September on a Proton rocket through a partnership between Roscosmos and the European Space Agency. Roscosmos also supplied the landing pad for ESA’s Rosalind Franklin rover.
However, ESA announced on March 17 that it would suspend cooperation with Russia on ExoMars in response to the Russian invasion of Ukraine. This requires ESA to not only find a new launch for the mission, but also to replace the landing pad. That meant postponing the launch until at least 2026, ESA Director General Josef Aschbacher said at the time, adding that “this is also very challenging”.
Speaking at a May 3 meeting of NASA’s Mars Exploration Program Analysis Group (MEPAG), Jorge Vago, ESA’s ExoMars project scientist, said he doubted 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 lander for 2026, ”he said. “Realistically, we would be looking for a launch in 2028”.
Launching in 2028 could pose technical challenges for ExoMars. A trajectory would take the rover to Mars relatively quickly, but it would only get it a month before the start of the dust storm season at its preferred landing site. An alternate trajectory would require traveling more than two years to each Mars, but taking the rover there six months before the sandstorms start.
“We have made an effort to convince the engineering team that sandstorm season is not death,” said Vago. “We should focus on making the rover more robust and able to withstand a dust storm.”
A launch in 2028, he added, would require NASA assistance. In particular, he said that ESA would need descent engines similar to those produced by the Aerojet Rocketdyne for NASA’s Mars missions such as Curiosity and Perseverance, because there are no European models of the right size for ExoMars.
A second element 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 RHU for the rover and there is no European substitute. Using American RHUs would likely also require ExoMars to be launched from the US, he said.
Aschbacher said in an April 6 interview that ESA was working with NASA on a potential cooperation with ExoMars, also seeking to replace Russian components of the mission with European alternatives. This will lead to a decision in July on a path to follow for ExoMars, which would likely require additional funding that would have been requested at ESA’s next ministerial meeting later this year.
A delay to 2028 would mean ExoMars will launch at the same time as the two landers for the revised Mars Sample Return (MSR) campaign that NASA and ESA are jointly conducting. ESA contributions include a rover that would go to one of the landers to collect Perseverance cached samples, placing them in a rocket on the other lander that would place the samples in Mars orbit to be collected and returned to Earth by an orbiter. of ESA.
This has led to some 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” agreement between NASA and ESA if NASA assisted ESA on ExoMars. That could mean, she said, “looking at both MSR and ExoMars in a holistic sort of way, if you like, and see if we can find solutions that work for both missions.”
A unique aspect of the Rosalind Franklin rover is a drill capable of collecting samples up to two meters below the surface. A similar exercise is being proposed for Mars Life Explorer, a Mars lander concept approved by the recent decade-long survey of planetary science to launch no earlier than the mid-2030s to look for signs of life in underground ice deposits. During MEPAG discussions on May 2, some suggested that a rover-mounted drill, such as the one for ExoMars, would be more effective than a drill mounted on a stationary lander.
Vago confirmed that the ExoMars drill can handle both ice and rock, although he said the mixture of ice and rock could complicate sample processing.