A Mars sample-return (MSR) mission is a proposed mission to collect rock and dust samples on Mars and return them to Earth.[1] Such a mission would allow more extensive analysis than that allowed by onboard sensors.[2]
The three most recent concepts are a NASA–ESA proposal, a Chinese proposal, Tianwen-3, and a Russian proposal, Mars-Grunt. Although NASA and ESA's plans to return the samples to Earth are still in the design stage as of 2022, samples have been gathered on Mars by the Perseverance rover.
Once returned to Earth, stored samples can be studied with the most sophisticated science instruments available. Thomas Zurbuchen, associate administrator for science at NASA Headquarters in Washington, expect such studies to allow several new discoveries at many fields.[3] Samples may be reanalyzed in the future by instruments that do not yet exist.[4]
In 2006, the Mars Exploration Program Analysis Group identified 55 important investigations related to Mars exploration. 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 reported that a significant fraction of the investigations could not be meaningfully advanced without returned samples.[5]
One source of Mars samples is what are thought to be Martian meteorites, which are rocks ejected from Mars that made their way to Earth. As of April 2019, 266 meteorites had been identified as Martian, out of over 61,000 known meteorites.[6] These meteorites are believed to be from Mars because their elemental and isotopic compositions are similar to rocks and atmospheric gases analyzed on Mars.[7]
For at least three decades, scientists have advocated the return of geological samples from Mars.[8] One early concept was the Sample Collection for Investigation of Mars (SCIM) proposal, which involved sending a spacecraft in a grazing pass through Mars's upper atmosphere to collect dust and air samples without landing or orbiting.[9]
The Soviet Union considered a Mars sample-return mission, Mars 5NM, in 1975 but it was cancelled due to the repeated failures of the N1 rocket that would have launched it. Another sample-return mission, Mars 5M (Mars-79), planned for 1979, was cancelled due to complexity and technical problems.[10]
The United States' Mars Exploration Program, formed after Mars Observer's failure in September 1993, supported a Mars sample return.[11] One architecture was proposed by Glenn J. MacPherson in the early 2000s.[12]
In 1996, the possibility of life on Mars was raised when apparent microfossils were thought to have been found in Mars meteorite, ALH84001. This hypothesis was eventually rejected, but led to a renewed interest in a Mars sample return.[13]
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.[5]
A mission concept was considered by NASA's Mars Exploration Program to return samples by 2008,[14] but was cancelled following a program review.[15] In the summer of 2001, the Jet Propulsion Laboratory (JPL) requested mission concepts and proposals from industry-led teams (Boeing, Lockheed Martin, and TRW). That following winter, JPL made similar requests of certain university aerospace engineering departments (MIT and the University of Michigan).
In October 2009, NASA and ESA established the Mars Exploration Joint Initiative to proceed with the ExoMars program, whose ultimate aim is "the return of samples from Mars in the 2020s".[16][17] ExoMars's first mission was planned to launch in 2018 [4][18] with unspecified missions to return samples in the 2020–2022 time frame.[19] The cancellation of the caching rover MAX-C in 2011, and later NASA withdrawal from ExoMars, due to budget limitations, ended the mission.[20] The pull-out was described as "traumatic" for the science community.[20]
In early 2011, the US National Research Council's Planetary Science Decadal Survey, which laid out mission planning priorities for the period 2013–2022, declared an MSR campaign its highest priority Flagship Mission for that period.[21] In particular, it endorsed the proposed Mars Astrobiology Explorer-Cacher (MAX-C) mission in a "descoped" (less ambitious) form. This mission plan was officially cancelled in April 2011.
In September 2012, NASA announced its intention to further study several strategies of bringing a sample of Mars to Earth – including a multiple launch scenario, a single-launch scenario, and a multiple-rover scenario – for a mission beginning as early as 2018.[22][23] A "fetch rover" would retrieve the sample caches and deliver them to a Mars ascent vehicle (MAV). In July 2018, NASA contracted Airbus to produce a "fetch rover" concept.[24][25][26]
In April 2018, a letter of intent was signed by NASA and ESA that may provide a basis for a Mars sample-return mission.[27][28] In July 2019, a mission architecture was proposed.[29][30] In April 2020, an updated version of the mission was presented.[31]
A key mission requirement for the Mars 2020 Perseverance rover mission was that it help prepare for MSR.[32][33][23] The rover landed on 18 February 2021 in Jezero Crater to collect samples and store them in 43 cylindrical tubes for later retrieval.
The Mars 2020 mission landed the Perseverance rover in Jezero crater in February 2021. It collected multiple samples and packed them into cylinders for later return. Jezero appears to be an ancient lakebed, suitable for ground sampling.[38][39][40]
In the beginning of August 2021, Perseverance made its first attempt to collect a ground sample by drilling out a finger-size core of Martian rock.[41] This attempt did not succeed. A drill hole was produced, as indicated by instrument readings, and documented by a photograph of the drill hole. However, the sample container turned out to be empty, indicating that the rock sampled was not robust enough to produce a solid core.[42]
A second target rock judged to have a better chance to yield a sufficiently robust sample was sampled at the end of August and the beginning of September 2021. After abrading the rock, cleaning away dust by puffs of pressurized nitrogen, and inspecting the resulting rock surface, a hole was drilled on September 1. A rock sample appeared to be in the tube, but it was not immediately placed in a container. A new procedure of inspecting the tube optically was performed.[43] On September 6, the process was completed and the first sample placed in a container.[44]
Samples Taken | Date | Contents | Sample Name and Image | Rock Name | Location | Notes |
---|---|---|---|---|---|---|
Tube 1[45] | 7 July 2021 | Witness Tube | N/A | N/A | North Séítah Unit[46] | This was taken as a dry-run in preparation for later sampling attempts, and did not aim to sample a rock. |
Tube 2 | 5 August 2021 | Atmospheric Gas | N/A (failed attempt of caching rock sample) |
Roubion | Cratered Floor Fractured Rough Unit[47] | Attempted to sample the rock but did not succeed, as they didn't reach the bit carousel and the caching system stored and sealed an empty tube. However in this process, it collected atmospheric samples. |
Tube 3[48] | 1 September 2021 | Soil Sample | Montdenier |
Rochette | Citadelle, South Séítah Unit | Successful sample.[49][50][51] |
Tube 4 |
8 September 2021 | Soil Sample | Montagnac |
Sampled from same rock as previous sample. | ||
Tube 5[53] | 15 November 2021 | Soil Sample | Salette |
Brac | Brac Outcrop, South Séítah Unit | |
Tube 6[53] | 24 November 2021 | Soil Sample | Coulettes |
|||
Tube 7 | 18 December 2021 | Soil Sample | Robine |
Issole | Issole, South Séítah Unit | |
Tube 8 | 29 December 2021 | Soil Sample | N/A (Abandoned sample from this site due to Core Bit Dropoff.) |
Pebble-sized debris from the first sample fell into the bit carousel during transfer of the coring bit, which blocked the successful caching of the sample.[54] It was decided to abandon this sample and do a second sampling attempt again. Subsequent tests and measures cleared remaining samples in tube and debris in caching system[55][56] The tube was reused for second sample attempt, which was successful. | ||
31 January 2022 | Soil Sample | Malay | ||||
Tube 9 | 7 March 2022 | Soil Sample | Hahonih |
Sid | Sid, Séítah Unit | |
Tube 10 | 13 March 2022 | Soil Sample | Atsah |
The NASA-ESA plan is to return samples using four missions: a sample collection mission (Perseverance), a sample retrieval mission (Sample Retrieval Lander 2 (SRL2) + fetch rover), a sample launcher mission (Sample Retrieval Lander 1 (SRL1) + Mars ascent vehicle + robotic arm), and a return mission (Earth Return Orbiter).[57] The design is intended to ease the project schedule, giving controllers time and flexibility to carry out the required operations.[58][59] The mission hopes to resolve the question of whether Mars once harbored life.
The Mars 2020 mission landed the Perseverance rover, which is storing samples to be picked up later. As a backup option, Perseverance could deliver samples to the return vehicles if needed.
The sample retrieval mission involves landing a fetch rover with flexible wheels on Mars, which will collect the samples with a robotic arm and transport them to the SRL1 lander. SRL1's robotic arm will be used to extract the samples and load them into the Sample Return Capsule in the Ascent Vehicle. This mission is scheduled to launch in 2028 onboard the SRL2 lander.[57] It is planned to land near the Octavia E. Butler Landing site in 2029. If Perseverance is still operational, it could deliver sample tubes to the landing site of SRL1.
MAV is a NASA-built, 3-meter long, two-stage, solid-fueled rocket that will deliver the collected samples from the surface of Mars to the Earth Return Orbiter. It is planned to be catapulted into the air just before it ignites, at a rate of 16 feet (5 meters) per second, to remove the odds of wrong liftoff like slipping or tilting of SRL1 under rocket's shear weight and exhaust at liftoff. This Vertically Ejected Controlled Tip-off Release (VECTOR) system adds a slight rotation during launch, pitching the rocket up and away from the surface, like a missile is thrown up from its silo. MAV would enter a 380 km orbit.[60] It will remain stowed inside a cylinder on the SRL1 and will have a thermal protective coating. The rocket's first stage would be run by a single updated STAR-20 engine burning for 70 seconds, while the second stage would have a single updated STAR-15 engine burning for another 27 seconds. They would be separated by a coast phase, after which the sample container would be released in orbit. As of early 2022, the second stage is planned to be spin-stabilized to save weight in lieu of active guidance, while the Mars samples will result in an unknown payload mass distribution.[60]
MAV is scheduled to be launched in 2028 onboard the SRL1 lander.[57]
ERO is an ESA-developed spacecraft.[61][23] It includes the NASA-built Capture and Containment and Return System to rendezvous with the samples delivered by MAV in low Mars orbit (LMO).
ERO is scheduled to launch on an Ariane 64 rocket[62] in 2027 and arrive at Mars in 2028,[57] using ion propulsion and a separate propulsion element to gradually reach the proper orbit. The orbiter will retrieve and seal the canisters in orbit and use a NASA-built robotic arm to place the sealed container into an Earth-entry capsule. It will raise its orbit, release the propulsion element, and return to Earth during the 2033 Mars-to-Earth transfer window.
The Capture/Containment and Return System (CCRS) would stow the sample in the EEV. EEV would return to Earth and land passively, without a parachute. The desert sand at the Utah Test and Training Range and shock absorbing materials in the vehicle were planned to protect the samples from impact forces.[63][33][23] EEV is scheduled to land on Earth in 2033.[64]
China is considering a Mars sample-return mission by 2030,[65][66] to be called Tianwen-3.[67] A plan was adopted in 2021 that proposes to retrieve samples by a sample collection lander with a Mars ascent vehicle within an aeroshell attached to a propulsion module (not another orbiter like Tianwen-1 mission). The mission would launch in November 2028 on a Long March 3B. Samples would be sent to Earth on an Earth Return Orbiter and transferred into a re-entry capsule, both of which, would be launched on a Long March 5 in November 2028, with return to Earth in September 2031.[68][69]
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. This would have required the super-heavy-lift Long March 9 launch vehicle.[66][70][71] The needed technologies were tested during the Tianwen-1 mission launched in 2020.[70][71] Another plan involved the 2020 HX-1 mission to cache the samples for retrieval in 2030.[72]
France has worked towards a sample return for many years.[73] This included concepts of an extraterrestrial sample curation facility for returned samples, and numerous proposals.[73] 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.[73]
On 9 June 2015, the Japanese Aerospace Exploration Agency (JAXA) unveiled a plan named Martian Moons Exploration (MMX) to retrieve samples from Phobos or Deimos.[74][75] Phobos's orbit is closer to Mars and its surface may have captured particles blasted from Mars.[76] The launch from Earth is planned for September 2024, with a return to Earth in 2029.[77] Japan has also shown interest in participating in an international Mars sample-return mission.
A Russian Mars sample-return mission concept is Mars-Grunt.[78][79][80][81][82] It adopted Fobos-Grunt design heritage.[79] 2011 plans envisioned a two-stage architecture with an orbiter and a lander (but no roving capability),[83] with samples gathered from around the lander by a robotic arm.[78][84]
Whether life forms exist on Mars is unresolved. Thus, MSR could potentially transfer viable organisms to Earth, resulting in back contamination — the introduction of extraterrestrial organisms into Earth's biosphere. The scientific consensus is that the potential for large-scale effects, either through pathogenesis or ecological disruption, is small.[85][86][87][88][89] Returned samples would be treated as potentially biohazardous until scientists decide the samples are safe. The goal is that the probability of release of a Mars particle is less than one in a million.[86]
The proposed NASA Mars sample-return mission will not be approved by NASA until the National Environmental Policy Act (NEPA) process has been completed.[90] Furthermore, under the terms of Article VII of the Outer Space Treaty and other legal frameworks, were a release of organisms to occur, the releasing nation(s) would be liable for any resultant damages.[91]
The sample-return mission would be tasked with preventing contact between the Martian environment and the exterior of the sample containers.[86][90]
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). The sample container would be designed to withstand the force of impact.[90] To receive the returned samples, NASA proposed a custom Biosafety Level 4 containment facility, the Mars Sample-Return Receiving facility (MSRRF).[92][93]
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.[94]
The International Committee Against Mars Sample Return (ICAMSR) is an advocacy group led by Barry DiGregorio, that campaigns against a Mars sample-return mission. While ICAMSR acknowledges a low probability for biohazards, it considers the proposed containment measures to be unsafe. ICAMSR advocates more in situ studies on Mars, and preliminary biohazard testing at the International Space Station before the samples are brought to Earth.[95][96] DiGregorio accepts the conspiracy theory of a NASA coverup regarding the discovery of microbial life by the 1976 Viking landers.[97][98] DiGregorio also supports a view that several pathogens – such as common viruses – originate in space and probably caused some mass extinctions and pandemics.[99][100] These claims connecting terrestrial disease and extraterrestrial pathogens have been rejected by the scientific community.[99]
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: CS1 maint: archived copy as title (link) Mars Sample Return Discussions As presented on February 23, 2010 This article incorporates text from this source, which is in the public domain.