Details are being refined for arguably the most ambitious space mission since Apollo. Although they are not ready to send humans to another world, NASA and the European Space Agency (ESA) hope to take custody of the samples Perseverance has been patiently collecting and return them safely to Earth, and they'll need the help of two more helicopters.

For all the instruments aboard the Martian rovers, they're still far behind the analytical capacity available on Earth, and that's not going to change soon. If we really want to know what is in the Martian rocks and soil and even atmosphere, we're going to need to return samples to Earth, preferably with more protection against contamination than via meteorite. 

Whatever Elon Musk tells you, humans visiting Mars and bringing back some samples remains a long way off. Instead, NASA and the ESA are collaborating on putting a lander on Mars that is capable of taking off again and making a rendezvous with an orbiter which will then bring the cargo back to Earth. Rather than collect its own samples, the return mission will take over those collected by Perseverance, and the biggest change to the plans lies in how that transfer will occur.

The project has not got funding yet but the space agencies are refining their plans. In a quest for the backing they need new details have been announced, along with a return date – 2033 – only slightly further off than 1969 was when Kennedy promised a Moon landing “before this decade is out”.

The idea of a Mars sample return has been such an important goal that it was designed into Perseverance. Equipped with 43 sample tubes, Perseverance has lived up to its name after an initial sampling failure, filling one with gas from the atmosphere, and 10 others with particularly interesting rocks or soil. How and when the return mission would take place was not decided when Perseverance launched, or even landed, however. The new announcement fills in some details.

Previously the Sample Return Lander was planned to carry a Sample Fetch Rover and its associated second lander. Instead, NASA and the ESA are now proposing to equip the lander with two helicopters based on the phenomenally successful Ingenuity. They will be able to traverse the gap between the Mars Ascent Vehicle and where Perseverance left them much more quickly and having two offers redundancy if one fails. There's also a possibility that Perseverance could deliver the samples directly to the Mars Ascent Vehicle if it is still operating when the ascent vehicle lands.

“ESA is continuing at full speed the development of both the Earth Return Orbiter that will make the historic round-trip from Earth to Mars and back again; and the Sample Transfer Arm that will robotically place the sample tubes aboard the Orbiting Sample Container before its launch from the surface of the Red Planet,” said ESA's David Parker.

If everything goes to plan the Earth Return Orbiter and Sample Retrieval Lander will launch in 2027 and 2028 respectively. Although delays are common for space missions, the fact Ingenuity has continued to operate – and even set records for its flights – well beyond its anticipated mission time has increased the sample return team's optimism.