NASA exploring two lower-cost options to go forward with Mars Sample Return mission

NASA announced Tuesday that it's exploring two landing options to move forward with its mission to retrieve environmental samples from Mars at a lower cost.

The goal of the Mars Sample Return Program, which is being planned jointly with the European Space Agency (ESA), is to retrieve samples of rock, gas and loose surface material that were collected by NASA's Perseverance rover and deliver them back to Earth.

Last year, the agency said it was revising plans for the mission due to the estimated cost and long wait time for the samples' return journey to Earth.

At the time, NASA Administrator Bill Nelson said independent reviews estimated the project would cost between $8 billion and $11 billion and that the samples may not return until 2040, which was “unacceptable.”

During Tuesday’s press conference, Nelson presented the two options being considered to help the Sample Retrieval Lander touch down on Mars.

The first option would be the "sky crane" landing method, which would use a heat shield and parachute for the initial descent and then employ retrorockets to lower the vehicle to the surface. The method was previously used for the Perseverance and Curiosity missions.

The second option would be to use a commercially provided mass delivery system with commercial partners such as SpaceX or Blue Origin.

“Either of these two options are creating a much more simplified, faster and less expensive version than the original plan,” Nelson said. He added that the decision regarding which option to use will come in 2026.

The sky crane option is estimated to cost between $6.6 billion and $7.7 billion, while the commercial heavy lift vehicle option carries an estimated cost of between $5.8 billion and $7.1 billion. Both options would likely return the samples to Earth between 2035 and 2029.

Nelson said both options involve cleaning Martian dust from the tubes on the planet surface instead of on the return vehicle, and using one of the spare arms on the Mars Perseverance rover to transfer the samples to the Sample Retrieval Lander.

NASA has previously said the samples will help scientists understand the geological history of Mars and the evolution of its climate, and could answer the question of if life ever existed on the Red Planet.

The agency also says the samples could be studied by future generations “using techniques yet to be invented.”

Perseverance, which landed in February 2021, has been collecting and storing samples in specially designed sealed titanium tubes that are roughly the size of a cigar. Nelson said on Tuesday that by the time the sample collection ends, Perseverance will have collected 30 samples.

The mission's next steps would be the launch of the Sample Retrieval Lander to Mars, carrying with it a rocket and two helicopters to assist in the retrieval.

Perseverance would carry the samples to the lander and attach them to the rocket, which would then launch from Mars – the first rocket ever to launch from the surface of another planet – to rendezvous with an Earth Return Orbiter, provided by the ESA.

The orbiter would capture the capsule containing the samples, propel itself out of Mars’ orbit and carry the sample the rest of the way to Earth, according to NASA.

The helicopters would be used as backups in case Perseverance is unable to carry the sample tubes to the lander, or to retrieve sample tubes that Perseverance might fail to return to the lander.