Mars sample-return mission

Thomas Zurbuchen, associate administrator for science at NASA Headquarters in Washington, expect such studies to allow several new discoveries at many fields.

[10] The density of the Mars atmosphere remained unknown at that time, so the Lockheed engineering author reported the analysis of trajectory options over a range of aerodynamic drag conditions for a 15-ton launch vehicle to reach a rendezvous orbit.

[14] In the mid-1980's, JPL mission planners noted that MSR had been "pushed by budgetary and other pressures into the '90s," and that the round trip would "impose large propulsion requirements.

In the late 1980s, multiple NASA centers contributed to a proposed Mars Rover Sample Return mission (MRSR).

[16][17] As described by JPL authors, one option for MRSR relied on a single launch of a 12-ton package including a Mars orbiter and Earth return vehicle, a 700-kg rover, and a 2.7-ton Mars ascent vehicle (MAV) which would use pump-fed liquid propulsion for a significant mass saving.

[21] In the mid-1990s, NASA funded JPL and Lockheed Martin to study affordable small-scale MSR mission architectures including a concept to return 500 grams of Mars samples using a 100-kg MAV that would meet a small Mars orbiter for rendezvous and return to Earth.

[24] In 1997, a detailed analysis of conventional small-scale rocket technology (both solid and liquid propellant) found that known propulsion components would be too heavy to build a MAV as lightweight as several hundred kilograms and "The application of launch vehicle design principles to the development of new hardware on a tiny scale" was suggested.

[25] In 1998, JPL presented a design for a two-stage pressure-fed liquid bipropellant MAV that would be 600 kilograms or less at Mars liftoff, intended for a MSR mission in 2005.

[26] The same JPL author collaborated on a notional single-stage 200-kg MAV intended to be made small by using pump-fed propulsion to permit lightweight low-pressure liquid propellant tanks and compact high-pressure thrust chambers.

Atop each MAV, a 3.6-kg, 16-cm diameter spherical payload would contain 500 grams of samples and have solar cells to power a long-life beacon to facilitate rendezvous with the Earth return orbiter.

The orbiter would capture the sample containers delivered by both MAVs and place them in separate Earth entry vehicles.

[36] The cancellation of the caching rover MAX-C in 2011, and later NASA withdrawal from ExoMars, due to budget limitations, ended the mission.

[39][40][41] The rover landed on 18 February 2021 in Jezero Crater to collect samples and store them in 43 cylindrical tubes for later retrieval.

[64] A previous plan would have used a large spacecraft that could carry out all mission phases, including sample collection, ascent, orbital rendezvous, and return flight.

They worked on the development of a Mars sample-return orbiter, which would capture and return the samples as part of a joint mission with other countries.

[82][86] In order to eliminate the risk of parachute failure, the current plan is to use the thermal protection system to cushion the capsule upon impact (at terminal velocity).

[88] Other scientists and engineers, notably Robert Zubrin of the Mars Society, argued in the Journal of Cosmology that contamination risk is functionally zero leaving little need to worry.

They cite, among other things, lack of any known incident although trillions of kilograms of material have been exchanged between Mars and Earth via meteorite impacts.

ICAMSR advocates more in situ studies on Mars, and preliminary biohazard testing at the International Space Station before the samples are brought to Earth.

[90][91] DiGregorio also supports a view that several pathogens – such as common viruses – originate in space and probably caused some mass extinctions and pandemics.