2001 to 2004 In the summer of 2001, the Jet Propulsion Laboratory requested mission concepts and proposals from industry-led teams (
Boeing,
Lockheed Martin, and
TRW). The science requirements included at least of samples, rover mobility to obtain samples at least from the landing spot, and drilling to obtain one sample from a depth of . That following winter, JPL made similar requests of certain university
aerospace engineering departments (
MIT and the
University of Michigan). Also in 2001, a separate set of industry studies was done for the Mars ascent vehicle (MAV) due to the uniqueness and key role of the MAV for MSR. Figure 11 in this reference summarizes the need for MAV flight testing at a high altitude over Earth, based on Lockheed Martin's analysis that the risk of mission failure is "extremely high" if launch vehicle components are only tested separately. In 2003, JPL reported that the mission concepts from 2001 were too costly. A subsequent study yielded a more affordable plan that was accepted by two groups of scientists: a new MSR Science Steering Group and the Mars Exploration Program Analysis Group (MEPAG). Instead of a rover and deep drilling, a scoop on the lander would dig deep and place multiple samples together into one container. After five years of technology development, the MAV would be flight-tested twice above Earth before the mission PDR (Preliminary Design Review) in 2009. Based on the simplified mission plan, assuming a launch from Earth in 2013, two weeks on Mars, and a 2016 return, technology development was initiated to ensure that potential Mars microbes would not contaminate Earth, and also that the Mars samples would not be contaminated with Earth-origin biological materials. The sample container would be clean on the outside before departing from Mars, with installation onto the MAV inside an "Earth-clean MAV garage". In 2004, JPL published an update on the 2003 plan. MSR would use the new large
sky crane landing system in development for the
Mars Science Laboratory rover (later named
Curiosity). An MSR Technology Board was formed, and it was noted that the use of a rover might return to the MSR plan, in light of the success with the
Spirit and Opportunity rovers that arrived early in 2004. A ascent rocket would carry of samples inside a payload, the Orbiting Sample (OS). The MAV would transmit enough telemetry to reconstruct events in case of failure on the way up to Mars orbit.
2005 to 2008 As of 2005, a rover had returned to the MSR plan, with a rock core drill, in light of results from the
Mars Exploration Rover discoveries. Focused technology development would start before the end of 2005 for mission PDR in 2009, followed by launch from Earth in 2013. Related technologies in development included potential advances for Mars arrival (navigation and descent propulsion), and implementing pump-fed liquid launch vehicle technology on a scale small enough for a MAV. In late 2005, a peer-reviewed analysis showed that ascent trajectories to Mars orbit would differ depending on liquid versus solid propulsion, largely because small solid rocket motors burn faster, requiring a steeper ascent path to avoid excess atmospheric drag, while slower-burning liquid propulsion might take advantage of more efficient paths to orbit. Early in 2006, the
Marshall Space Flight Center noted the possibility that a science rover would cache the samples on Mars, then subsequently a mini-rover would be sent along with the MAV on a sample return lander. Then, either the mini-rover or the science rover would deliver the samples to the lander for loading onto the MAV. A two-stage solid propellant MAV would be gas ejected from a launch tube. It would carry a payload—a diameter spherical package containing the samples. The second stage would send telemetry, and its steering thrusters would use hydrazine fuel with additives. The authors expected the MAV to need multiple flight tests at a high altitude over Earth. A
peer-reviewed publication in 2007 described testing of autonomous sample capture for Mars orbit rendezvous. Free-floating tests were done on board a NASA aircraft using a parabolic "zero-g" flight path. In 2007,
Alan Stern, then NASA's Associate Administrator for Science, was strongly in favor of completing MSR sooner, and he asked JPL to include sample caching on the
Mars Science Laboratory mission (later named Curiosity). A team at the Ames Research Center was designing a hockey puck-sized sample-caching device to be installed as an extra payload on MSL. A review analysis in 2008 compared Mars ascent to lunar ascent, noting that the MAV would pose not only a technical challenge, but also a cultural one for the planetary science community: given that lunar ascent has been done using known technology, and that science missions typically rely on proven propulsion for course corrections and orbit insertion maneuvers, similar to what Earth satellites do routinely.
2009 to 2011 Early in 2009, the
In-Space Propulsion Technology project office at the NASA
Glenn Research Center (GRC) presented a ranking of six MAV options, concluding that a two-stage solid rocket with continuous telemetry would be best for delivering a sample package to Mars orbit. A single-stage pump-fed bipropellant MAV was noted to be less heavy and was ranked second. Later in 2009, the chief technologist of the Mars Exploration Directorate at JPL referred to a 2008 workshop on MSR technologies at the
Lunar and Planetary Institute, and wrote that particularly difficult technology challenges included: the MAV, sample acquisition and handling, and back
planetary protection. He then further commented that, "The MAV, in particular, stands out as the system with highest development risk, pointing to the need for an early start," leading to flight testing before preliminary design review (PDR) of the lander that would deliver the MAV. 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. ExoMars's first mission was planned to launch in 2018, with unspecified missions to return samples in the 2020–2022 time frame. As reported to the NASA Advisory Council Science Committee (NAC-SC) early in 2010, MEPAG estimated that MSR "will cost $8-10B, and it is obvious that NASA and ESA can't fund this amount by themselves." The cancellation of the caching rover
MAX-C in 2011, and later NASA withdrawal from ExoMars, due to budget limitations, ended the mission. The pull-out was described as "traumatic" for the science community. Inserting the spacecraft into Mars orbit, then returning to Earth, was noted to need a high total of velocity changes, leading to a conclusion that solar electric propulsion could reduce mission risk by improving mass margins, compared to the previously assumed use of chemical propulsion along with aerobraking at Mars. The ISPT team also studied scenarios for MAV flight testing over Earth, and recommended two flight tests prior to MSR mission PDR, considering the historical low probability of initial success for new launch vehicles. The NASA–ESA potential mission schedule anticipated launches from Earth in 2018, 2022, and 2024 to send respectively; a sample caching rover, a sample return orbiter, and a sample retrieval lander for a 2027 Earth arrival, with MAV development starting in 2014 after two years of technology development identified by the MAV design studies. The ISPT program summarized a year of propulsion technology progress for improving Mars arrival, Mars ascent, and Earth return, stating that the first flight test of a MAV engineering model would need to occur in 2018 to meet the 2024 launch date for the sample retrieval lander. The 2011 MAV industry studies were done by Lockheed Martin teamed with
ATK,
Northrop Grumman, and Firestar Technologies, to deliver a 5-kg (11-lb), 16-cm (6.3-inch) diameter sample sphere to Mars orbit. The Lockheed-Martin-ATK team focused on a solid propellant first stage with either solid or liquid propellant for the upper stage, estimated MAV mass in the range 250 to 300 kg (550 to 660 lb), and identified technologies for development to reduce mass. Northrop Grumman (the former TRW) similarly estimated a mass below 300 kg, using pressure-fed liquid bipropellants for both stages, and had plans for further progress. Firestar Technologies described a single-stage MAV design having liquid fuel and oxidizer blended together in one main propellant tank. 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. In particular, it endorsed the proposed
Mars Astrobiology Explorer-Cacher (MAX-C) mission in a "descoped" (less ambitious) form. This mission plan (cancelled in April 2011 for budget reasons) had been for NASA and ESA to each build a rover to send together in 2018.
2012 to 2013 In 2012, prospects for MSR were slowed further by a 38-percent cut in NASA's Mars program budget for fiscal year 2013, leading to controversy among scientists over whether Mars exploration could thrive on a series of small rover missions. A Mars Program Planning Group (MPPG) was convened as one response to budget cuts. In mid-2012, eight weeks before
Curiosity arrived on Mars, the Lunar and Planetary Institute hosted a NASA-sponsored three-day workshop to gather expertise and ideas from a wide range of professionals and students—as input to help NASA reformulate the Mars Exploration Program, in response to the latest Planetary Decadal Survey The
MAX-C rover (ultimately implemented as
Mars 2020,
Perseverance) was considered beyond financial reach at that time, so the summary report noted that progress toward MSR could include an orbiter mission to test autonomous rendezvous, or a
Phoenix-class lander to demonstrate pinpoint landing while delivering a MAV as a technology demonstration. The workshop consisted largely of three breakout group discussions for Technology and Enabling Capabilities, Science and Mission Concepts, and Human Exploration and Precursors. Wide-ranging discussions were documented by the Technology Panel, which suggested investments for improved drilling and "small is beautiful" rovers with an "emphasis on creative mass-lowering capabilities." The panel stated that MAV "functional technology is not new" but the Mars environment would pose challenges, and referred to MAV technologies as "a risk for most sample return scenarios of any cost range." MAV technology was addressed in numerous written submissions to the workshop, one of which described Mars ascent as "beyond proven technology", (velocity and acceleration in combination for small rockets) and a "huge challenge for the social system", referring to a "
Catch-22" dilemma "in which there is no tolerance for new technology if sample return is on the near-term horizon, and no MAV funding if sample return is on the far horizon." 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. As of late 2012, It was determined that the
MAX-C rover concept to collect samples could be implemented for a launch in 2020 (
Mars 2020), within available funding, using spare parts and mission plans developed for NASA's Curiosity Mars rover In 2013, the NASA
Ames Research Center proposed that a
SpaceX Falcon Heavy could deliver two tons of useful payload to the Mars surface, including an Earth return spacecraft that would be launched from Mars by a one-ton single-stage MAV using liquid bipropellants fed by turbopumps. The successful landing of the
Curiosity rover directly on its wheels (August 2012) motivated JPL to take a fresh look at carrying the MAV on the back of a rover. A fully guided 300-kg MAV (like Lockheed Martin's 2011 two-stage solid The absence of telemetry data during the 1999 loss of the
Mars Polar Lander had put an emphasis on "critical event communications", that was subsequently applied to MSR. Then, after the
MSL landing in 2012, requirements had been revisited with a goal to reduce MAV mass. Single fault tolerance and continuous telemetry data to Mars orbit were questioned. For the 500 grams (1.1 lb) of samples, a 3.6-kg (7.9 lb) payload was deemed possible instead of 5 kg (11 lb). The 2012 mini-MAV concept had single-string avionics, in addition to the spin-stabilized upper stage without telemetry.
2014 to 2017 In 2014–2015, JPL analyzed many options for Mars ascent, including solid, hybrid, and liquid propellants, for payloads ranging from 6.5 kg to 25 kg. Four MAV concepts using solid propellant had two stages, while one or two stages were considered for hybrid and liquid propellants. Seven options were scored for ten attributes ("figures of merit"). A single-stage hybrid received the highest overall score, including the most points for reducing cost and, separately, for reducing complexity, with the fewest points for technology readiness. Second overall was a single-stage liquid bi-propellant MAV using electric pumps. A pressure-fed bi-propellant design was third, with the most points for technology readiness. Solid propellant options had lower scores, partly due to receiving very few points for flexibility. JPL and NASA
Langley Research Center cautioned that the high thrust and short burn times of solid rocket motors would result in early burnout at a low altitude with substantial atmosphere remaining to coast through at high Mach numbers, raising stability and control concerns. With concurrence from the Mars Program Director, a decision was made in January 2016 to focus limited technology development funds on advancing a hybrid propellant MAV (liquid oxidizer with solid fuel). Starting in 2015, a new effort for
planetary protection moved the backward planetary protection function from the surface of Mars to the sample Return Orbiter, to "break-the-chain" in flight. Concepts for brazing, bagging, and plasma sterilization were studied and tested, with a primary focus on brazing, as of 2016.
2018 to 2022 In April 2018, a
letter of intent was signed by NASA and ESA that may provide a basis for a Mars sample-return mission. The agreement came out of the 2nd International Mars Sample Return Conference in Berlin, Germany. The conference program was archived along with 125 technical submissions that covered sample science (anticipated findings, site selection, collection, curation, analysis) and mission implementation (Mars arrival, rovers, rock drills, sample transfer robotics, Mars ascent, autonomous orbit rendezvous, interplanetary propulsion, Earth arrival, planetary protection). In one of many presentations, an international science team noted that collecting sedimentary rock samples would be required to search for ancient life. A joint NASA-ESA presentation described the baseline mission architecture, including sample collection by the
Mars 2020 Rover derived from the
MAX-C concept, a Sample Retrieval Lander, and an Earth Return Orbiter. An alternative proposal was to use a SpaceX Falcon Heavy to decrease mission cost while delivering more mass to Mars and returning more samples. Another submission to the Berlin conference noted that mission cost could be reduced by advancing MAV technology to enable a significantly smaller MAV for a given sample payload. In July 2019, a mission architecture was proposed. In 2019, JPL authors summarized sample retrieval, including a sample fetch rover, options for fitting 20 or 30 sample tubes into a payload on a single-stage-to-orbit (SSTO) MAV that would use hybrid propellants, a liquid oxidizer with a solid wax fuel, which had been prioritized for propulsion technology development since 2016. Meanwhile, the Marshall Space Flight Center (MSFC) presented a comparison of solid and hybrid propulsion for the MAV. Later in 2019, MSFC and JPL had collaborated on designing a two-stage solid propellant MAV, and noted that an unguided spinning upper stage could reduce mass, but this approach was abandoned at the time due to the potential for orbital variations. Early in 2020 JPL updated the overall mission plan for an orbiting sample package (the size of a basketball) containing 30 tubes, showing solid and hybrid MAV options in the range . Adding details, MSFC presented designs for both the solid and hybrid MAV designs, for a target mass of at Mars liftoff to deliver 20 or 30 sample tubes in a payload package. In April 2020, an updated version of the mission was presented. The decision to adopt a two-stage solid rocket MAV was followed by Design Analysis Cycle 0.0 in the spring of 2020, which refined the MAV to a design having guidance for both stages, leading to reconsideration of an unguided spin-stabilized second stage to save mass. In October 2020, the MSR Independent Review Board (IRB) released its report recommending overall that the MSR program proceed, then in November NASA responded to detailed IRB recommendations. The IRB noted that MSR would have eight first-time challenges, including the first launch from another planet, autonomous orbital rendezvous, and robotic sample handling with sealing to "break-the-chain". The IRB cautioned that the MAV will be unlike any previous launch vehicle, and experience shows that the smaller a launch vehicle, the more likely it is to end up heavier than designed. Referring to the unguided upper stage of the MAV, the IRB stated the importance of telemetry for critical events, "to allow useful reconstruction of a fault during second stage flight." The IRB indicated that the most probable mission cost would be $3.8 to $4.4B. As reported to the NAC-SC was "very concerned about the high cost" of MSR, and wanted to be sure that astrobiology considerations would be included in plans for returned sample laboratories. Early in 2022 MSFC presented the guided-unguided MAV design for a mass reduction, and documented remaining challenges including aerodynamic complexities during the first stage burn and coast to altitude, a desire to locate hydrazine steering thrusters farther from the center of mass, and stage separation without tip-off rotation. While stage separation and subsequent spin-up would be flight tested, the authors noted that it would be ideal to flight test an entire flight-like MAV, but there would be a large cost. In April 2022, the
United States National Academies released the
Planetary Science Decadal Survey report for 2023-2032, a review of plans and priorities for the upcoming ten years - after many committee meetings starting in 2020, with consideration of over 500 independently submitted white papers, more than 100 regarding Mars, including comments on science and technology for sample return. The published document noted NASA's 2017 plan for a "focused and rapid" sample return campaign with essential participation from ESA, then recommended, "The highest scientific priority of NASA's robotic exploration efforts this decade should be completion of Mars Sample Return as soon as is practicably possible." Decadal white papers emphasized the importance of MSR for science, included a description of implementing MSR, and noted that the MAV has been underestimated despite needing flight performance beyond the state of the art for small rockets, needs a sustained development effort, and that technology development for a smaller MAV has the potential to reduce MSR mission cost. Decadal Survey committee meetings hosted numerous invited speakers, notably a presentation from the MSR IRB. As of March 2022, separate landers were planned for the fetch rover and the MAV, because together they would be too large and heavy for a single lander. A cost-saving plan as of July was to send only one lander with the MAV, and rely on the Perseverance rover to pass sample tubes to the MAV in the absence of a fetch rover. Two new lightweight helicopters on the MAV lander would serve as a backup for moving the samples on Mars.
2023 to 2024 At the start of 2023 it was revealed that a
"Mars Sample Fetch Helicopter" had been envisioned since at least 2021 by the team at
AeroVironment that created
Ingenuity to fly in the thin atmosphere of Mars. In a public budget meeting in March, NASA noted the high cost of MSR and had begun to assemble a second independent review board (MSR IRB-2) to assess the design, schedule, and required funding. The IRB-2 began working in May 2023 and released its report in September 2023. In January 2024, a related proposed NASA plan had been challenged due to budget and scheduling considerations, and a newer overhaul plan undertaken. The
American Institute of Aeronautics and Astronautics contrasted the mission cost challenge with the science value of returned samples, noting that multiple in-situ science missions could be done for the cost of MSR, but that an electron microscope for example would be too large to send to Mars. A response in March described the high mission cost as related to the size of the MAV and its huge lander, offering that innovation could lead to a smaller MAV. In April 2024, NASA formally responded to the IRB-2 report, with a report from the MIRT (MSR IRB Response Team) which noted the cost-saving value of a smaller MAV. On April 15, 2024, NASA Administrator
Bill Nelson and Science Mission Director
Nicola Fox announced the organization's response to the September 2023 independent review board's investigation, notably the finding that Mars Sample Return at its current design and cost, originally estimated at $7 billion with Earth re-entry by 2033, would now cost more than an unacceptable $11 billion and end in Earth re-entry no sooner than 2040. In response, Nelson and Fox stated that NASA would make requests to industry the next day to come up with alternatives that would likely utilize more proven mission architectures with longer heritages and comply with the board's recommendations, with responses preferred by fall 2024. They also said they would spend $310 million on the program for fiscal year 2024. In June 2024, following the agency's decision to open the mission to industry proposals, seven firms were selected to move forward in a 90-day mission study. In late July during the Tenth International Conference on Mars, JPL researchers announced that a newly acquired sample had the strongest potential yet for evidence of life. Presentations included plans for sample handling and curation upon return to Earth, including scientific equipment needed in the Sample Receiving Facility Another poster presentation described flight testing for launching off Mars, noting that a MAV could go a thousand miles if tested above Earth, farther than one-ton missiles, and that a smaller MAV for affordable delivery to Mars would likely need new technology resulting from iterative building and flight testing.
2025 In January 2025, NASA announced it would be pursuing two potential paths forward to land the MAV. The first option would use the
sky crane method used for
Curiosity and
Perseverance, and the second would "capitalize on using new commercial capabilities". Both options would use the
ESA's Earth Return Orbiter to receive and ferry the samples. In February 2025,
Space News published a summary of the MAV challenge, noting the absence of established expertise, given a lack of other missions or customers that would need something like a MAV to stimulate investment. Another opinion piece in March described a suggestion from
Rocket Lab for a firm fixed-price mission to return the samples, using a single-stage liquid propellant MAV. On March 31, a public meeting of the National Academies Committee on Astrobiology and Planetary Sciences included an update from Donya Douglas-Bradshaw, the new MSR Program Director at NASA headquarters. In summarizing the 2024 study results from industry and NASA teams, she noted that a smaller MAV is viable and extremely important, permitting the use of a heritage lander based on the JPL sky crane. New features would include "breaking the chain" on Mars instead of in Mars orbit (for backward planetary protection), and the use of RTG electricity instead of solar panels. She said that MSFC redesigned the two-stage solid propellant MAV from 450 kg to 350 kg without adding risk. On April 30, Douglas-Bradshaw presented a similar update to MEPAG, then in response to a question added that Rocket Lab had not submitted a proposal to NASA regarding the fixed-price MSR mission concept. In May 2025, the
Trump administration released its fiscal year 2026 budget proposal for NASA, in which they planned to cancel the MSR program on the American side. In January 2026,
U.S. Congress confirmed that MSR will not be funded, thus the mission can be considered cancelled. == Sample collection ==