NASA and the European Space Agency (ESA) revealed today the final architecture of their ambitious program to bring samples of martian rock and soil back to Earth. One big change: instead of sending a new, ESA-built “fetch rover” to help collect the material in 2030, the Mars Sample Return mission will plan on a direct delivery from NASA’s existing Perseverance rover, which has been on the planet since early 2021. As a backup, the lander designed to send the samples home will carry two small helicopters—based on the successful Ingenuity currently making martian sorties—that could collect samples in case Perseverance fails.
“Perseverance’s reliability and life expectancy … means we are confident it will be able to deliver samples to the ascent vehicle in 2030,” Jeff Gramling, Mars Sample Return program director, said at a briefing today. Confidence that Perseverance will be ready for the task has been bolstered by the performance of its older sibling, Curiosity. That rover is approaching its 10th anniversary on Mars and is still going strong.
Planners are also now bullish that helicopters are a dependable backup for the sample return mission. NASA sent the Ingenuity helicopter to Mars with Perseverance as a technology demonstration, and it has performed 29 flights and lasted more than a year longer than expected. Using helicopters as a tool “has moved into the realm of the possible,” says NASA science chief Thomas Zurbuchen. “That’s why we do tech demos.”
This new plan gets NASA and ESA out of a technical hole. Feasibility studies earlier this year suggested that the addition of the fetch rover would make the 2030 NASA lander too heavy to land safely. So the rover would have to be sent in a separate spacecraft with its own landing system. That would have increased the mission’s cost, originally estimated at about $7 billion. “One lander is less expensive than two,” Gramling said.
Apart from the enhanced role for Perseverance and the added choppers, the mission is otherwise as previously advertised. “Mars Sample Return is happening as we speak,” Zurbuchen says, referring to Perseverance having already collected samples of 11 different rock types from Jezero crater. Each sample has been split into two tubes the size of a penlight. One will stay with the rover, the other will be deposited into a depot on the ground as “an insurance policy,” Zurbuchen says. The rover will continue to collect samples until it has about 30, the total number that can be carried back to Earth.
In 2030, if all goes as planned, the NASA lander will touch down near where Perseverance is working. The rover will drive over to the lander, and an ESA-built robot arm will extract the tubes one by one and place them inside a spherical container the size of a basketball. In early 2031, a rocket on the lander will loft the container into Mars orbit, where a return craft built by ESA will snare it, enclose it in several layers of shielding for safety, and then head for home. In 2033, a saucer-shaped descent pod will carry the samples down to the Utah desert.
If Perseverance gets into difficulties during its 9-year wait for company, controllers can instruct it to drop its cargo of sample tubes onto the ground, creating a second depot. If that happens, the helicopters come into play: they can fly up to 700 meters, land next to a sample tube—each weighs up to 150 grams—and, with wheels on the bottom their feet, roll over the tube and pick it up with a grabber. On returning to the lander, they will drop the tubes on the ground for the arm to pick up.
If Perseverance fails completely and cannot drop its cargo—the “worst case scenario,” says Richard Cooke of NASA’s Jet Propulsion Laboratory—the lander will put down near the first depot in Jezero crater and return with those samples.