NASA and the European Space Agency (ESA) today unveiled the final architecture of their ambitious program to return samples of Martian rock and soil back to Earth. One big change: Instead of sending a new ESA-built “retrieval rover” to help collect the material in the 2030s, the Mars Sample Return mission will plan a direct delivery from NASA’s existing Perseverance rover, which has been at the planet since the start 2021. As a backup, the lander designed to send the samples home will carry two small helicopters — based on the successful Ingenuity currently making Mars flights — that could collect samples in case Perseverance fails.
“The reliability and life expectancy of Perseverance … means we are confident it will be able to deliver samples to the ascent vehicle in 2030,” said Jeff Gramling, Mars Sample Return program director, in a briefing today. Confidence that Perseverance will be up to the task is bolstered by the performance of its larger sibling, Curiosity. This rover is approaching its 10th anniversary on Mars and is still going strong.
Planners are now optimistic that the helicopters are a reliable backup for the sample return mission. NASA sent the Ingenuity helicopter to Mars with Perseverance as a technology demonstration, and it made 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 adding a fetch rover would make NASA’s 2030 lander too heavy to land safely. So the rover will have to be sent in a separate spacecraft with its own landing system. That would increase the cost of the mission, originally estimated at about $7 billion. “One lander is cheaper than two,” Gramling said.
Aside from the increased role for Perseverance and added helicopters, the mission is otherwise as previously announced. “The return of samples from Mars is happening as we speak,” says Zurbuchen, noting that Perseverance has already collected samples of 11 different rock types from Jezero Crater. Each sample was divided into two flashlight-sized tubes. One will stay with the rover, the other will be deposited in a depot on Earth as an “insurance policy,” Zurbuchen says. The rover will continue to collect samples until it reaches about 30, the total number that can be brought back to Earth.
In 2030, if all goes according to plan, NASA’s lander will land near where Perseverance operates. The rover will reach the lander and an ESA-built robotic arm will remove the tubes one by one and place them in a spherical container about the size of a basketball. In early 2031, a lander rocket will lift the container into Mars orbit, where an ESA-built reentry craft will trap it, enclose it in several layers of safety shielding, and then head home . In 2033, a saucer-shaped descent capsule will carry the samples to the Utah desert.
If Perseverance runs into trouble during its 9-year wait for the company, controllers can instruct it to drop its cargo of sample tubes on Earth, creating a second depot. If that happens, the helicopters spring into action: they can fly up to 700 meters, land next to a sample tube – each weighing up to 150 grams – and, with wheels on the bottom of their legs, roll over the tube and pick it up with grapple. On returning to the drop module, they will drop the tubes to the ground for the arm to pick up.
If Perseverance fails completely and is unable to eject its payload — “the worst-case scenario,” says Richard Cook of NASA’s Jet Propulsion Laboratory — the lander will descend near the first depot in Jezero Crater and return with those samples.