How does NASA intend to keep Mars samples secure from contamination (and from infecting Earth)?

NASA's Mars Sample Return Mission is getting closer. When Perseverance gathered the first sample that would be returned, the whole mission architecture reached a new milestone. But what happens once that sample arrives? NASA and its partner, ESA, are still working on it, but they recently produced an information sheet outlining what will happen during the first step of that procedure, which involves returning to Earth. That return will take place in the midst of the desert in the western United States, at a location known as the Utah Test and Training Range (UTTR). While this may appear to be an unlikely location for such a crucial mission, it has significant advantages.

First, because it is in the continental United States, it has relatively simple access to modern laboratory equipment that is available throughout the country. NASA is the most probable choice to be able to mobilize all of the resources required to quarantine the sample and keep it away from the rest of the Earth's environment, therefore reducing the possibility of a Martian superbug escaping. One of the reasons the CIA is avoiding a water landing is to ensure secure containment. This would reduce the impact on the samples, but it would also increase the likelihood that the capsule would sink into the water and the little particles of Mars within it would be lost to the sea. Avoiding that would be preferable, thus landing on land is preferable.

However, that land must be separated, which is another advantage of the UTTR. Not only is it not near any highways, but it also has restricted air space due to extensive rocket and plane testing. Being separated also means that if something goes wrong with the trajectory, the capsule is less likely to have an influence on anything essential. This is especially crucial considering the landing mechanism chosen for the MSR capsule. It will descend to the earth using only aerobraking and no parachute. As a result, it will go far quicker than traditional parachute-assisted capsule returns. However, NASA estimates that the samples and their containers will survive the hit. The absence of a parachute simplifies the capsule's construction and reduces its weight, both of which are critical criteria given that the capsule must return from Mars.

Even so, the impact will leave a noticeable mark on the landscape. NASA has already started testing with a mock-up of the MSR's sample return capsule. This has resulted in the formation of a succession of 1.3-meter-wide craters in the terrain as well as the ejection of debris 15 meters out from the crater. Assuming the samples and capsule survive, the next step would be to securely transport them to a laboratory for adequate analysis. After all, it is the entire aim of the Mars Sample Return mission. That element of the initiative has yet to be specified, but knowing that the samples will wind up in the midst of the Utah desert is a start.