Mars sample return mission
|Mission type||orbiter, lander, rover and sample return|
|Launch vehicle||Ares V, EELV or Ariane 5|
|Home page||Mars Sample Return Lander Mission Profile|
A Mars sample return mission (MSR) would be a spaceflight mission to collect rock and dust samples from Mars and to return them to Earth for analysis. One particular proposal, a joint project between NASA and ESA, would launch in 2018 with the sample return itself expected in the 2020-2022 time frame.
According to Louis Friedman, Executive Director of The Planetary Society, Mars sample return is often referred to by people in the planetary science community as the "holy grail" of robotic space missions, due to its high expected scientific return-on-investment.
In mid-2006, the international Mars Architecture for the Return of Samples (iMARS) Working Group was chartered by the International Mars Exploration Working Group (IMEWG) to outline the scientific and engineering requirements of an internationally sponsored and executed Mars sample return mission in the 2018–2023 time frame.
The scenario of the joint NASA/ESA mission will depend on the date of launch and performance of the launcher. Before 2018, only launchers such as Ariane 5 and the US EELV are available, while after 2018, the Ares V should be available, allowing simpler mission scenarios.
The mission would consist of an orbiter, a lander. The lander would include a Mars Ascent Vehicle (MAV), and possibly a rover. The orbiter would be designed to deliver the lander/MAV/rover probe to Mars and return sample rocks back to Earth for analysis. The MAV needs to be a miniature launch vehicle the size of a person, in order to deliver the samples to the orbiter (in case of launch with Ares V, the orbiter part can be skipped in favor of a direct ascent scenario).
The rover's main objective would be to collect a variety of rock samples using many instruments provided by scientists from NASA and ESA. If the rover is canceled, the lone lander would possibly have a robotic arm and/or hand to collect rock samples in replacement. But the lander could also have a proposed drilling machine to take samples from the Martian subsurface.
In this scenario, the sample return mission would span two launches at an interval of about four years. The first launch would be for the orbiter, the second for the lander. The rest of the mission would follow in the same way as the one-element mission design.
According to JPL's Mars Exploration Program manager Fuk Li, a consensus is now forming for a sample return mission split into a total of three launches. In this scenario, the sample-collection rover (e.g. MAX-C) would be launched separately first - preferably in 2018 - land on Mars, and carry out analyses and sample collection over a lifetime of at least 500 Sols (Martian days).
Four years later, the orbiter would be launched, followed by the lander (including the MAV) four years after that. Instead of a full-blown sample-collection rover, the lander would bring a smaller, simpler "fetch rover", whose sole function would be to hurry across the surface, retrieve the sample container from the sample-collection rover, and return it to the lander where it would be loaded onto the MAV. The rest of the mission would follow in the same way as the two-element mission design.
This design eases the schedule of the whole program greatly, giving controllers time to carry out all operations in a sound and scientifically well-designed manner. Furthermore, by spreading the landed mass across two payloads (the sample-collection rover and the lander), the program can rely on the landing system that already has been developed for Mars Science Laboratory, avoiding the costs and risks associated with developing a yet another landing system from scratch.
The return of Mars samples would be beneficial to science by allowing more extensive analysis to be undertaken of the samples than could be done by instruments painstakingly transferred to Mars. Also, the presence of the samples on Earth would allow scientific equipment to be used on stored samples, even years and decades after the sample return mission.
In 2006, MEPAG identified 55 important future science investigations related to the exploration of Mars. In 2008, they concluded that about half of the investigations "could be addressed to one degree or another by MSR", making MSR "the single mission that would make the most progress towards the entire list" of investigations. Moreover, it was found that a significant fraction of the investigations cannot be meaningfully advanced without returned samples.
The sample would also undergo laboratory examination for living or dead life forms. However, the difficulty of providing and maintaining life support over the months of transit from Mars to Earth remains to be solved. Providing for still unknown environmental and nutritional requirements is daunting. Should dead life forms be found in a sample, it would be difficult to conclude that those organisms were alive when obtained.