WASHINGTON – A key official from Europe’s ExoMars mission believes the rover’s launch will be delayed until at least 2028 to accommodate changes after cooperation with Russia ends.
ExoMars would launch in September on a Proton rocket through 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 would suspend cooperation with Russia on ExoMars in response to the Russian invasion of Ukraine. That requires ESA to find not only a new launch for the mission, but also a replacement landing pad. That meant delaying the launch to at least 2026, ESA Director General Josef Aschbacher said at the time, adding “even that is a big challenge.”
Speaking at a May 3 meeting of NASA’s Mars Exploration Program Analysis Group (MEPAG), Jorge Vago, ExoMars project scientist at ESA, said he doubted a new lander could be ready by 2026. “It is theoretically possible, but in practice we think it is possible.” it would be very difficult to reconfigure and produce our own lander by 2026,” he said. “Realistically, we would be looking at a launch in 2028.”
Launch in 2028 could pose technical challenges for ExoMars. One trajectory would get the rover to Mars relatively quickly, but would arrive only a month before dust storm season begins at the preferred landing site. An alternative 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’ve worked 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 weather a dust storm.”
A launch in 2028, he added, would require assistance from NASA. Specifically, he said ESA would need descent engines similar to those produced by Aerojet Rocketdyne for NASA Mars missions like Curiosity and Perseverance, because there are no European models of the right size for ExoMars.
A second element is the radioisotope heating units, or RHUs, which use the heat produced by the radioactive decay of plutonium to keep the rover warm. Russia had provided RHU for the rover and there is no European replacement. Using US RHUs would also likely require ExoMars to be launched from the United States, he said.
Aschbacher said in an April 6 interview that ESA was working with NASA on possible cooperation with ExoMars as it sought to replace the mission’s Russian components with European alternatives. That will lead to a decision in July on the way forward for ExoMars, which will likely require additional funding to be requested at the next ESA ministerial meeting later this year.
A delay to 2028 would mean that ExoMars would launch at the same time as the two landers for the revised Mars Sample Return (MSR) campaign that NASA and ESA are running jointly. ESA’s contributions include a rover that would go on one of the landers to collect samples cached by Perseverance, placing them on a rocket on the other lander that would place the samples in Mars orbit for a Mars orbiter to carry. ESA pick them up and return them to Earth. .
That 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 that he hoped for some sort of “quid pro quo” agreement between NASA and ESA if NASA helped ESA on ExoMars. That could mean, she said, “looking at both MSR and ExoMars in a holistic way, if you like, and seeing if we can come up with solutions that work for both missions.”
A unique aspect of the Rosalind Franklin rover is a drill that can collect samples from up to two meters below the surface. A similar drill is proposed for the Mars Life Explorer, a Mars landing concept supported by the recent Decadal Survey of Planetary Science for launch no earlier than the mid-2030s to search for signs of life in subsurface ice deposits. During the MEPAG discussions on May 2, some suggested that a drill mounted on a rover, like the one on 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, though he said mixing ice and rock could complicate sample processing.