NASA will review the mission that returns samples from Mars – here’s why it must and will continue

By John Bridges for The Conversation

Leicester: NASA recently announced that it is looking for new ways to complete the return to Earth of rock cores drilled by the Perseverance Rover in Mars’ Jezero Crater.

This has caused some concern among space scientists, who view the Mars Sample Return (MSR) mission as a cornerstone of plans to explore the solar system.

But considering what’s at stake, scientifically and politically, it seems very likely that NASA will continue with the mission to make it a success.

A key conclusion from the NASA investigation is that MSR was set up with unrealistic budgets and schedules. It now expects a cost of $8 billion to $11 billion (GBP6.5 billion to $8.9 billion), compared to its original estimate of $5.3 billion.

That does not include the investment made by the European Space Agency (Esa), which is likely to be in the order of €2 billion (GBP1.7 billion).

There are also concerns that the timeline for returning cores to Earth could shift in the 2040s, supporting the even more ambitious vision for human missions to Mars.

Despite these obstacles, NASA remains committed to MSR as one of its highest science priorities. In fact, it remains the agency’s top priority of the decade for planetary science.

NASA places great emphasis on delivering what its decade-long community surveys propose – and it would be loath to override the recommendations. It is also unlikely that ESA wants to lose the scientific investment it has already made in MSR.

Great scientific importance

So why does the space science community view MSR as so important? Partly because the technologies provide a springboard for future human exploration. For example, the mission needs an ascent vehicle to deliver the samples into orbit so they can be captured by another spacecraft.

Perseverance is already engaged in the first major phase of this mission: drilling in the Jezero crater. This is phase one of four.

The next two phases will collect at least some of the drilled samples and launch them into orbit on a Mars ascent vehicle, where they can be captured by Esa’s Return Orbiter.

Capturing a football-sized return capsule in Martian orbit is one of MSR’s key technical challenges. Esa plays an important role in this and leads the development of the Return Orbiter.

The final phase, assuming a successful landing at the Utah Test and Training Range, will consist of a rigorous program of organic, geochemical and mineralogical analyzes that will take place under strict containment conditions. In this phase, the very best equipment that we as scientists have in laboratories around the world will be used.

But these challenging steps come at a cost, which NASA now proposes to reduce. For example, it can reduce the mass of a takeoff vehicle. And it has already dropped a planned British-built Fetch rover to collect drilled samples.

Even the option of using helicopters, as demonstrated by Ingenuity on Mars2020, is at risk – it could be Perseverance itself delivering the drill tubes to a liftoff rocket.

But these financial savings come at a scientific cost. In that scenario, fewer of the currently targeted 30 drill cores (each of the rock cores in the 6-inch tubes are about 2-3/4 inches long) would be returned to keep the ascent vehicle light.

The actual samples from an ancient delta, and a thick lava flow that has preserved traces of alteration by hot water, drilled into the Jezero crater have been stored on board or dropped in a depot.

These precious cores represent the results of previous Mars orbiter and lander missions, telling us where to land and making accurate predictions of what we would find.

Ultimately, the samples awaiting return to Earth offer our best chance in the near future to identify traces of ancient life beyond our own planet. It is difficult to imagine a more pressing task for space science.

If Perseverance continues to operate successfully – and the 12-year-old rover Curiosity, which I am working on, suggests it will – then we have the tantalizing prospect of sampling the rim of the Jezero crater.

This is a window into a new type of environment in Mars exploration: the excavated deep crust where ancient microbial life may have been protected from harsh surface radiation.

Chinese rivalry

There’s another, less scientifically sound reason why NASA and Esa are eager to maintain their successes in Mars exploration.

The Apollo program was boosted by the rivalry with the Soviet Union during the Cold War. Tragically, a new partnership with Russia’s Roscomos space agency, and the full potential for space exploration that could be realized in a more peaceful geopolitical environment, is not currently possible.

Roscosmos could no longer mount a credible MSR mission on its own. The Esa rover Rosalind Franklin was scheduled to launch on a Soyuz rocket in 2023, but after the invasion of Ukraine, that mission was quickly reconsidered.

China now has credible plans for a Mars Sample Return mission called Tianwen-3. The Chinese space agency aims to launch in 2028, with separate launches of land and ascent vehicles. If that challenging timeline can really be met, the samples could be returned to Earth by 2031.

In 2020, I argued that an era of new Chinese cooperation with the West could be possible. But four years later, I wonder if the history of the rivalry is repeating itself.

MSR is needed to answer some of our most important questions about Mars and habitable environments beyond Earth. But it also appears to be becoming a new symbol of space rivalry. That said, it could be a major reason why it will indeed be a success.

(John Bridges is Professor of Planetary Science, University of Leicester)