by Note to the Editor: Jonathan Lunine is the David C. Duncan professor of physical sciences at Cornell University. He served on the Independent Review Board of the NASA Mars Sample Return in 2023. Read more opinion on CNN.
How weak is our planet’s ability to support life? The answer may come from one of our closest planetary neighbors.
Orbiting spacecraft and rovers deployed on Mars over the past twenty years have found strong evidence of conditions billions of years ago that were very different from today’s dry, cold environment. When and why did Mars change? Understanding Mars’ past can provide important clues to the future of our own planet.
Today, we are on the threshold of answering these questions. Since 2021, NASA’s persistence rover, designed and built by the Jet Propulsion Laboratory (JPL), has been collecting samples to return to Earth in a technology mission called Mars Sample Return (MSR) that is currently under development.
And yet, the political storms that hit Washington, DC, threaten to leave those precious samples stranded on Mars, by giving NASA far less than is needed to design and build the spacecraft that will return the samples . If Congress doesn’t restore that funding, scientists may not see them.
To understand the inestimable value of the samples, we only need to look at the place where Endurance landed: a crater called Jezero. At the western end of the crater is a river channel and a large pile of sediment similar to what geologists call “deltas,” the places on Earth where rivers meet the sea. Today the river channel has no water, and the delta sits on a dry and bare crater floor. But both are evidence of an ancient time when water flowed on Mars, breaching the ruler’s wall and dumping sediment in a giant crater lake.
Has water flowed on Mars long enough for life to have started? Why did this and other corners dry up, and when?
To answer these questions, Endurance is collecting samples of the crater floor, the delta and the hills above it. It is carefully guided by a large team of scientists who are world experts in the geology and climate of ancient Mars. The rover itself is a mechanical marvel, drilling into the rock and packing the pulverized material into more than 30 sample containers the size and shape of laboratory test tubes. Inside these tubes are valuable samples of Mars that hold the clues to when and how Mars went from Earth-like habitability to uninhabitable deserts.
To tease out the history of Mars and its climate from these rocks requires analyzing them in massive, power-hungry, user-intensive instruments here on Earth. These instruments can determine the presence of materials at concentrations that cannot be achieved by the much smaller instruments carried directly to Mars inside a spacecraft.
Ground laboratories are uniquely able to precisely measure the ages of rocks using a technique called radioisotope dating. Finding the precise ages of lunar rocks was one of the most important results of the Apollo missions, putting the earliest history of Earth and the moon on a complete timeline. Creating such a chronology for Martian history would also have profound scientific results.
Mars Sample Return is one of the most challenging and complex robotic missions ever attempted, requiring the largest lander ever sent to Mars, carrying a rocket to launch the samples from the surface into Martian orbit. Another spacecraft – to be built by the European Space Agency – would pick up the sample capsule in orbit and launch it towards Earth. The US National Academy of Sciences has designated this mission as the highest priority in US planetary exploration for the next decade in two major strategic plans.
And yet, the return of the samples may never happen. The legislative chaos this year in Washington has left NASA without a definitive budget for this fiscal year, forcing the agency to plan for the lower of two proposed levels of funding for the Mars Sample Return. As a result, hundreds of people were laid off from the program at JPL earlier this year and the project has stalled.
Persistence continues to fill its sample tubes, waiting for the day a ship arrives to bring these precious Martian samples home to Mother Earth. Will the US complete their mission or allow an emerging space power like China to retrieve them? Or will the samples simply be abandoned on Mars? What would be the impact on the nation’s long-term leadership in deep space exploration if Mars Sample Return were the first major space mission we failed to complete due to a failure of will?
Mars has secrets about what planet can support life, locked away in the samples waiting to be returned to Earth. Just this month Congress reaffirmed MSR as the highest priority of the 2022 Decennial Planetary Science Survey and tasked NASA with developing a realistic plan and funding profile that will achieve the return of the samples. NASA needs to provide that plan to Congress as soon as possible so Congress can move forward with adequate funding. Leaving the samples stranded on Mars was a national embarrassment.
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