NASA and ESA Agree on Mars Sample Return Mission

April 27, 2018 – A future mission to Mars that has been in the concept stage for a considerable amount of time is finally getting legs. NASA and the European Space Agency yesterday signed a letter of intent to fly to Mars and back, the first round trip between Earth and another planet.

Called the Mars Sample Return (MSR) mission, it would give Earth-based scientists an opportunity to obtain surface samples from the Red Planet for study here on Earth. To date, Martian meteorites, and robotic sampling done by landers and rovers have been the only sources of detailed data about the composition of the planet’s surface.

What is envisioned for MSR?

A lander and rover combination could be the primary tool for sample collection. The lander would also include an ascent vehicle with sufficient payload capacity to break free of Martian gravity and head back to Earth where a descent module would be released to parachute down to Earth.

The announcement was made at the ILA Berlin Air and Space Show by Thomas Zurbuchen, NASA’s associate administrator for science. Both partners are open to other participants in this venture including national and commercial space program operators.

Of course, the hope is that evidence of past life on Mars will be unveiled in returned samples. This could be in the form of fossil microbes. Current Martian surface conditions are not likely to be amenable to any biological life form that we here on Earth know of. The levels of radiation bombarding the surface combined with a very thin atmosphere make it highly unlikely. But if the MSR has a tool able to do core sampling several meters into the subsurface, it may find an environment where Martian life may still thrive. That means any return samples from the MSR will be subject to the strictest quarantine regime.

In other Martian news, ESA has released the first images taken by its ExoMars Trace Gas Orbiter currently studying the Martian atmosphere. This orbiting spacecraft is equipped to detect small amounts of different gasses within the atmosphere. One of those is methane gas. On Earth methane has largely a biological origin. And because methane present today can only have produced in the recent past, finding it in the air of Mars is intriguing. This isn’t methane coming from extinct life but rather coming from a present or near-present source.

Speculation suggests that the methane may be coming from beneath the permanently frozen subsurface of Mars. This suggests that something is alive inside the Red Planet, microorganisms that produce methane as part of a metabolic process.

Another potential source of methane could be purely chemical in origin. The gas could be produced from the oxidation of iron in structures known as clathrate hydrates which can be found in association with terrestrial hot springs and volcanic vents here on Earth.

A third potential source could be metamorphosis of Martian rocks occurring in low-temperature states. In this case, olivine, which is found on Mars, could be reacting to subsurface water could form a mineral known as serpentine which when exposed to Mars’ carbon dioxide atmosphere and the presence of hydrogen, could produce methane. Those who put forward this explanation argue that subsurface hydrothermals on Mars may be the active agents in creating this chemical response.

As the ExoMars Trace Gas Orbiter circles the planet it will be looking for isotope ratios in the carbon and hydrogen, the two components of methane (CH4). Methane as an outgassing from life here on Earth tends to use Carbon-12 and 13 isotopes. If the orbiter spots the presence of these then the explanation may very well be that Mars has life.

That makes it even more important to ensure that any samples taken from Mars by the MSR be kept under the highest levels of quarantine ever put in place for space missions.

When will MSR happen? ESA and NASA both have rover missions planned for the early 2020s. MSR will probably not launch until the mid-2020s at the earliest.