Mars Astrobiology Explorer-Cacher
Encyclopedia
The Mars Astrobiology Explorer-Cacher (MAX-C) was a NASA
concept for a Mars
rover
mission, proposed to be launched in 2018 together with the European ExoMars
rover. The rover concept was cancelled in April 2011 due to budget cuts.
The rover would have been solar powered
, with a maximum mass of 300 kg and based largely on Mars Science Laboratory
(MSL) components, but would have entailed a system tailored to the specific payload. The MAX-C rover would have performed an in situ astrobiological
exploration, evaluate the habitability potential of various Martian environments, and it would collect, document, and cache samples for potential return to Earth by a future mission.
are currently present, and the Martian geologic record offers tantalizing clue of many ancient habitable environments. If life emerged and evolved on early Mars then it is possible, and indeed likely, that physical or chemical biosignature
s are preserved in the exposed rock record. These discoveries and inferences make a compelling case for a rover mission designed to explore for evidence of past Martian life
.
Over most of the last decade, the Mars Exploration Program has pursued a strategy of "follow the water". While this strategy has been highly successful in the Mars missions of 1996-2007, it is increasingly appreciated that assessing the full astrobiological potential of Martian environments requires going beyond the identification of locations where liquid water was present. Thus, in order to seek signs of past or present life on Mars, it is necessary to characterize more comprehensively the macroscopic and microscopic fabric of sedimentary materials
. This type of information would be critical to select and cache of relevant samples for addressing the life question in samples intended for study in sophisticated laboratories on Earth.
The possible strategy of using rovers to collect and cache geological samples for possible subsequent return to Earth has been discussed as far back as at least the mid-1990s. In 2007 it was recommended sample caching on all surface missions that follow the Mars Science Laboratory
(MSL), in a way that would prepare for a relatively early return of samples to Earth. In mid-2007, NASA directed that a very simple cache be added to the MSL rover and, although they endorsed the potential value of sample caching, experts raised serious concerns regarding sample quality for this specific implementation. In November 2008, the cache was descoped to make room for tools to clean the rover's sample acquisition equipment, which were added due to sample handling problems encountered by the Phoenix
lander.
A mid-range rover concept was originally included in the planning work of the Mars Architecture Tiger Team (MATT). By the time of the MATT-3 report in 2009, the potential mission was referred to with several different working names, including both 'Mid-Range Rover' and 'Mars Prospector Rover', and the mission concept was generically envisioned as including a single MER
or MSL
-class rover with precision landing and sampling/caching capability. To provide a name that fit the mission concept better, it was changed in August 2009 from the generic Mid-Range Rover (MRR) to Mars Astrobiology Explorer-Cacher (MAX-C).
In April 2011, because of a budgeting crisis, a proposal was announced to fly only one rover in 2018 that would be larger than either of the vehicles in the paired concept, ExoMars
(ESA) and Max-C (NASA). One suggestion was that the new vehicle be built in Europe and take on a mixed identity of European and American instruments. NASA agreed to provide the interplanetary rocket and the "Sky Crane" landing system. Despite the proposed reorganization, the goals of the 2018 mission opportunity would stay broadly the same: namely, to look for signs of past or present life by drilling into the soil and packaging or caching rocks that able to be lifted and dispatched to Earthly laboratories by a subsequent mission.
s, evaluate paleo-environmental conditions, characterize the potential for preservation of biosignatures, and access multiple sequences of geological units in a search for evidence of past life and/or prebiotic chemistry. Samples necessary to achieve the scientific objectives of the proposed future sample return mission would be collected, documented, and packaged in a manner suitable for potential return to Earth
.
The primary science objective was to land at a site interpreted to represent high habitability potential, and with high preservation potential for physical and chemical biosignatures:
A secondary science objective would have been be to address the need for long-term atmospheric pressure data from the Martian surface. There were studies evaluating the possibilities for cooperative science between the MAX-C rover and the ExoMars
rover if landed together at the same location.
Due to the eccentricity of the Martian orbit, latitude access for a solar powered rover, northern latitudes are less severe on the power/thermal design than southern latitudes, allowing effective operation at sites as far north as 25°N and as far south as 15°S.
Given that scientifically interesting features often represent terrain that is too dangerous to land on, the landing ellipse is often driven to be placed right up against but not on top of features of interest. The result is that access is often a product of both ellipse size and rover traverse capability sufficient to get outside of that ellipse in a reasonable amount of time relative to the mission lifetime. The entry, descent and landing system would have been of high precision, and landing would occur with a targeting accuracy of 7 km (4.3 mi). The solar-powered rover would need to have a range of no less than 10 km (6.2 mi) and a lifetime of at least one Earth year.
have done.
The mass would have been about 300 kg, bigger than the MERs, comparable in mass to the ExoMars
rover, but lighter than the Mars Science Laboratory
.
entails high cost and risk, and it entails scientific sample selection, acquisition, and documentation for potential return to Earth, so it must also deliver unprecedented value. Even though any sample returned from Mars would be useful for some line of scientific inquiry, it is also true that not all samples would be equally useful for detailed scientific investigation. To address the highest priority scientific questions, selection of "outstanding samples" will be required. Samples necessary to achieve the scientific objectives of the proposed future sample return mission would be collected, documented, and packaged in a manner suitable for potential return to Earth. A future surface rendezvous would recover the cache and load it into the 'Mars Ascent Vehicle' for its delivery to Earth.
If, at the Mars Science Laboratory
rover landing site (2012), scientists do not recognize an outstanding sample, they will want to send a rover to an alternate site selected from orbital data and for which an argument could be made that there is better science or access potential; if MSL does discover outstanding samples, scientists would presumably want to send a rover back to collect them for return, therefore, having the MAX-C developed for a 2018 launch could save time and resources. The proposed sampling requirement would be to collect 20 samples at four sites outside the landing ellipse within one Earth year. The rover would then drive to a safe location to deposit the 20-sample cache for a fetch rover to potentially retrieve sometime after 2020. For such a scenario, the MAX-C rover would be expected to traverse 10 km in 150 driving sols, i.e., ~67 m/sol on average, so an improved rover autonomy would be needed for the candidate MAX-C mission.
The MAX-C rover would have been able to acquire samples through coring and abrasion. Coring was to be accomplished through the use of a core drill
that could produce cores of approximately 10 mm diameter up to 50 mm long, which would be encapsulated in individual sleeves with pressed-in caps. Abrading of surface material would be accomplished through the use of a specialized abrading bit placed in the coring tool. This tool would be intended to remove small amounts of surface material in order to allow instruments access past any dust and/or weathering layer. It would abrade a circular area of similar diameter to the core (8–10 mm). Translation of the arm would be used to scan the individual abrasion spots. The rover should be able to cache at least 38 core samples.
Based on a draft project schedule and a full JPL team experimental study, total project cost in dollars, not including launch vehicle, is estimated to be between $1.5-2.0 Billion.
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
concept for a Mars
Mars
Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...
rover
Rover (space exploration)
A rover is a space exploration vehicle designed to move across the surface of a planet or other astronomical body. Some rovers have been designed to transport members of a human spaceflight crew; others have been partially or fully autonomous robots...
mission, proposed to be launched in 2018 together with the European ExoMars
ExoMars
ExoMars is a European-led robotic mission to Mars currently under development by the European Space Agency with collaboration by NASA...
rover. The rover concept was cancelled in April 2011 due to budget cuts.
The rover would have been solar powered
Photovoltaic module
A solar panel is a packaged, connected assembly of solar cells, also known as photovoltaic cells...
, with a maximum mass of 300 kg and based largely on Mars Science Laboratory
Mars Science Laboratory
The Mars Science Laboratory is a National Aeronautics and Space Administration mission with the aim to land and operate a rover named Curiosity on the surface of Mars. The MSL was launched November 26, 2011, at 10:02 EST and is scheduled to land on Mars at Gale Crater between August 6 and 20, 2012...
(MSL) components, but would have entailed a system tailored to the specific payload. The MAX-C rover would have performed an in situ astrobiological
Astrobiology
Astrobiology is the study of the origin, evolution, distribution, and future of life in the universe. This interdisciplinary field encompasses the search for habitable environments in our Solar System and habitable planets outside our Solar System, the search for evidence of prebiotic chemistry,...
exploration, evaluate the habitability potential of various Martian environments, and it would collect, document, and cache samples for potential return to Earth by a future mission.
History
The essential energy, water, and nutrient requirements to support and sustain life on MarsLife on Mars
Scientists have long speculated about the possibility of life on Mars owing to the planet's proximity and similarity to Earth. Fictional Martians have been a recurring feature of popular entertainment of the 20th and 21st centuries, but it remains an open question whether life currently exists on...
are currently present, and the Martian geologic record offers tantalizing clue of many ancient habitable environments. If life emerged and evolved on early Mars then it is possible, and indeed likely, that physical or chemical biosignature
Biosignature
A biosignature is any substance -such as an element, isotope, or molecule - or phenomenon that provides scientific evidence of past or present life. Measurable attributes of life include its complex physical and chemical structures and also its utilization of free energy and the production of...
s are preserved in the exposed rock record. These discoveries and inferences make a compelling case for a rover mission designed to explore for evidence of past Martian life
Life on Mars
Scientists have long speculated about the possibility of life on Mars owing to the planet's proximity and similarity to Earth. Fictional Martians have been a recurring feature of popular entertainment of the 20th and 21st centuries, but it remains an open question whether life currently exists on...
.
Over most of the last decade, the Mars Exploration Program has pursued a strategy of "follow the water". While this strategy has been highly successful in the Mars missions of 1996-2007, it is increasingly appreciated that assessing the full astrobiological potential of Martian environments requires going beyond the identification of locations where liquid water was present. Thus, in order to seek signs of past or present life on Mars, it is necessary to characterize more comprehensively the macroscopic and microscopic fabric of sedimentary materials
Sedimentary rock
Sedimentary rock are types of rock that are formed by the deposition of material at the Earth's surface and within bodies of water. Sedimentation is the collective name for processes that cause mineral and/or organic particles to settle and accumulate or minerals to precipitate from a solution....
. This type of information would be critical to select and cache of relevant samples for addressing the life question in samples intended for study in sophisticated laboratories on Earth.
The possible strategy of using rovers to collect and cache geological samples for possible subsequent return to Earth has been discussed as far back as at least the mid-1990s. In 2007 it was recommended sample caching on all surface missions that follow the Mars Science Laboratory
Mars Science Laboratory
The Mars Science Laboratory is a National Aeronautics and Space Administration mission with the aim to land and operate a rover named Curiosity on the surface of Mars. The MSL was launched November 26, 2011, at 10:02 EST and is scheduled to land on Mars at Gale Crater between August 6 and 20, 2012...
(MSL), in a way that would prepare for a relatively early return of samples to Earth. In mid-2007, NASA directed that a very simple cache be added to the MSL rover and, although they endorsed the potential value of sample caching, experts raised serious concerns regarding sample quality for this specific implementation. In November 2008, the cache was descoped to make room for tools to clean the rover's sample acquisition equipment, which were added due to sample handling problems encountered by the Phoenix
Phoenix (spacecraft)
Phoenix was a robotic spacecraft on a space exploration mission on Mars under the Mars Scout Program. The Phoenix lander descended on Mars on May 25, 2008...
lander.
A mid-range rover concept was originally included in the planning work of the Mars Architecture Tiger Team (MATT). By the time of the MATT-3 report in 2009, the potential mission was referred to with several different working names, including both 'Mid-Range Rover' and 'Mars Prospector Rover', and the mission concept was generically envisioned as including a single MER
Mars Exploration Rover
NASA's Mars Exploration Rover Mission is an ongoing robotic space mission involving two rovers, Spirit and Opportunity, exploring the planet Mars...
or MSL
MSL
- Organizations :* Major Series Lacrosse* Major Soccer League* Malaysia Super League* MBCgame Starleague * Metal Storm Limited, an Australian modern armament company...
-class rover with precision landing and sampling/caching capability. To provide a name that fit the mission concept better, it was changed in August 2009 from the generic Mid-Range Rover (MRR) to Mars Astrobiology Explorer-Cacher (MAX-C).
In April 2011, because of a budgeting crisis, a proposal was announced to fly only one rover in 2018 that would be larger than either of the vehicles in the paired concept, ExoMars
ExoMars
ExoMars is a European-led robotic mission to Mars currently under development by the European Space Agency with collaboration by NASA...
(ESA) and Max-C (NASA). One suggestion was that the new vehicle be built in Europe and take on a mixed identity of European and American instruments. NASA agreed to provide the interplanetary rocket and the "Sky Crane" landing system. Despite the proposed reorganization, the goals of the 2018 mission opportunity would stay broadly the same: namely, to look for signs of past or present life by drilling into the soil and packaging or caching rocks that able to be lifted and dispatched to Earthly laboratories by a subsequent mission.
Objectives
The main objective was at a site with high preservation potential for physical and chemical biosignatureBiosignature
A biosignature is any substance -such as an element, isotope, or molecule - or phenomenon that provides scientific evidence of past or present life. Measurable attributes of life include its complex physical and chemical structures and also its utilization of free energy and the production of...
s, evaluate paleo-environmental conditions, characterize the potential for preservation of biosignatures, and access multiple sequences of geological units in a search for evidence of past life and/or prebiotic chemistry. Samples necessary to achieve the scientific objectives of the proposed future sample return mission would be collected, documented, and packaged in a manner suitable for potential return to Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
.
The primary science objective was to land at a site interpreted to represent high habitability potential, and with high preservation potential for physical and chemical biosignatures:
- Early Noachian astrobiology — Prebiotic environmental context in which life potentially arose.
- Noachian-Hesperian stratigraphy — Whether surface conditions before and after the decline in erosion, aqueous weathering, fluvial activity, and magnetic field were habitable.
- AstrobiologyAstrobiologyAstrobiology is the study of the origin, evolution, distribution, and future of life in the universe. This interdisciplinary field encompasses the search for habitable environments in our Solar System and habitable planets outside our Solar System, the search for evidence of prebiotic chemistry,...
— Test life-related hypotheses in the context of another specific kind of geologic terrain. Sample collection that could have preserved evidence of prebiotic chemistry or life on MarsLife on MarsScientists have long speculated about the possibility of life on Mars owing to the planet's proximity and similarity to Earth. Fictional Martians have been a recurring feature of popular entertainment of the 20th and 21st centuries, but it remains an open question whether life currently exists on...
; characterize the potential for the preservation of biosignatures. - Methane emission from subsurface.
- Radiometric datingRadiometric datingRadiometric dating is a technique used to date materials such as rocks, usually based on a comparison between the observed abundance of a naturally occurring radioactive isotope and its decay products, using known decay rates...
- Deep core drillCore drillA core drill is a drill specifically designed to remove a cylinder of material, much like a hole saw. The material left inside the drill bit is referred to as the core....
— Core sampleCore sampleA core sample is a cylindrical section of a naturally occurring substance. Most core samples are obtained by drilling with special drills into the substance, for example sediment or rock, with a hollow steel tube called a core drill. The hole made for the core sample is called the "core hole". A...
s from a depth of ~ 2m - Polar layered deposits — investigate potential record of recent global climate changes.
- Mid-latitude shallow ice — investigate the habitability of mid-latitude ice, and how does perchloratePerchloratePerchlorates are the salts derived from perchloric acid . They occur both naturally and through manufacturing. They have been used as a medicine for more than 50 years to treat thyroid gland disorders. They are used extensively within the pyrotechnics industry, and ammonium perchlorate is also a...
affect the present day habitability of Mars. Could mid-latitude ice provide a resource for In Situ Resource Utilization (ISRU)?
A secondary science objective would have been be to address the need for long-term atmospheric pressure data from the Martian surface. There were studies evaluating the possibilities for cooperative science between the MAX-C rover and the ExoMars
ExoMars
ExoMars is a European-led robotic mission to Mars currently under development by the European Space Agency with collaboration by NASA...
rover if landed together at the same location.
Landing
The proposed MAX-C mission would have arrived at Mars in January 2019 in the northern hemisphere during winter given the favorable atmospheric pressure at this season and performance of the 'sky crane' delivery system.Due to the eccentricity of the Martian orbit, latitude access for a solar powered rover, northern latitudes are less severe on the power/thermal design than southern latitudes, allowing effective operation at sites as far north as 25°N and as far south as 15°S.
Given that scientifically interesting features often represent terrain that is too dangerous to land on, the landing ellipse is often driven to be placed right up against but not on top of features of interest. The result is that access is often a product of both ellipse size and rover traverse capability sufficient to get outside of that ellipse in a reasonable amount of time relative to the mission lifetime. The entry, descent and landing system would have been of high precision, and landing would occur with a targeting accuracy of 7 km (4.3 mi). The solar-powered rover would need to have a range of no less than 10 km (6.2 mi) and a lifetime of at least one Earth year.
Rover
The MAX-C rover would have relied on significant inheritance of MSL spacecraft design, flight design, test design, test and handling hardware to minimize cost and risk. This solar-powered rover required a range of no less than 20 km (12.4 mi) and a lifetime of at least 500 Martian days (sols). Since many of the geologically interesting terrains on Mars expose stratified layers on slopes in craters, channels, and hillsides, it would be extremely useful for the proposed MAX-C mission to be capable to navigate on slopes of up to 30 degrees, as both of the Spirit and Opportunity MERsMars Exploration Rover
NASA's Mars Exploration Rover Mission is an ongoing robotic space mission involving two rovers, Spirit and Opportunity, exploring the planet Mars...
have done.
The mass would have been about 300 kg, bigger than the MERs, comparable in mass to the ExoMars
ExoMars
ExoMars is a European-led robotic mission to Mars currently under development by the European Space Agency with collaboration by NASA...
rover, but lighter than the Mars Science Laboratory
Mars Science Laboratory
The Mars Science Laboratory is a National Aeronautics and Space Administration mission with the aim to land and operate a rover named Curiosity on the surface of Mars. The MSL was launched November 26, 2011, at 10:02 EST and is scheduled to land on Mars at Gale Crater between August 6 and 20, 2012...
.
Proposed science instrumentation
The rover would have carried instrumentation sufficient to scientifically select samples for caching. It is assumed that this translates to the following measurements and possible payload suite:- Must be able to remotely (i.e. with mast-mounted instruments) characterize outcrops and identify features of interest (panoramic camera, Near-IR SpectrometerInfrared spectroscopyInfrared spectroscopy is the spectroscopy that deals with the infrared region of the electromagnetic spectrum, that is light with a longer wavelength and lower frequency than visible light. It covers a range of techniques, mostly based on absorption spectroscopy. As with all spectroscopic...
) - Must be able to collect microscaleimagery of outcrops; contact instrument (microscopic imagerMicroscopeA microscope is an instrument used to see objects that are too small for the naked eye. The science of investigating small objects using such an instrument is called microscopy...
) - Must be able to expose unweathered rock surfaces using a surface abrasion tool (abrading bits)
- Must be able to measure mineralogy at micro-scales on the abraded rock surfaces; contact instrument (Raman spectroscopyRaman spectroscopyRaman spectroscopy is a spectroscopic technique used to study vibrational, rotational, and other low-frequency modes in a system.It relies on inelastic scattering, or Raman scattering, of monochromatic light, usually from a laser in the visible, near infrared, or near ultraviolet range...
) - Must be able to measure bulk elemental chemistry on the abraded rock surfaces; contact instrument (Alpha particle X-ray spectrometer)
- Must be able to measure organic compoundOrganic compoundAn organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...
s on the abraded rock surfaces; contact instrument (Raman spectroscopy) - Must be able to correlate composition to micro-scale structures and textures in the rocks (microscopic imager)
Sample cache
Returning samples from Mars is essential to meeting the Mars Exploration Program’s highest priority scientific objectives. However, a Mars sample return missionMars Sample Return Mission
A Mars sample return mission would be a spaceflight mission to collect rock and dust samples from Mars and to return them to Earth for analysis...
entails high cost and risk, and it entails scientific sample selection, acquisition, and documentation for potential return to Earth, so it must also deliver unprecedented value. Even though any sample returned from Mars would be useful for some line of scientific inquiry, it is also true that not all samples would be equally useful for detailed scientific investigation. To address the highest priority scientific questions, selection of "outstanding samples" will be required. Samples necessary to achieve the scientific objectives of the proposed future sample return mission would be collected, documented, and packaged in a manner suitable for potential return to Earth. A future surface rendezvous would recover the cache and load it into the 'Mars Ascent Vehicle' for its delivery to Earth.
If, at the Mars Science Laboratory
Mars Science Laboratory
The Mars Science Laboratory is a National Aeronautics and Space Administration mission with the aim to land and operate a rover named Curiosity on the surface of Mars. The MSL was launched November 26, 2011, at 10:02 EST and is scheduled to land on Mars at Gale Crater between August 6 and 20, 2012...
rover landing site (2012), scientists do not recognize an outstanding sample, they will want to send a rover to an alternate site selected from orbital data and for which an argument could be made that there is better science or access potential; if MSL does discover outstanding samples, scientists would presumably want to send a rover back to collect them for return, therefore, having the MAX-C developed for a 2018 launch could save time and resources. The proposed sampling requirement would be to collect 20 samples at four sites outside the landing ellipse within one Earth year. The rover would then drive to a safe location to deposit the 20-sample cache for a fetch rover to potentially retrieve sometime after 2020. For such a scenario, the MAX-C rover would be expected to traverse 10 km in 150 driving sols, i.e., ~67 m/sol on average, so an improved rover autonomy would be needed for the candidate MAX-C mission.
The MAX-C rover would have been able to acquire samples through coring and abrasion. Coring was to be accomplished through the use of a core drill
Core drill
A core drill is a drill specifically designed to remove a cylinder of material, much like a hole saw. The material left inside the drill bit is referred to as the core....
that could produce cores of approximately 10 mm diameter up to 50 mm long, which would be encapsulated in individual sleeves with pressed-in caps. Abrading of surface material would be accomplished through the use of a specialized abrading bit placed in the coring tool. This tool would be intended to remove small amounts of surface material in order to allow instruments access past any dust and/or weathering layer. It would abrade a circular area of similar diameter to the core (8–10 mm). Translation of the arm would be used to scan the individual abrasion spots. The rover should be able to cache at least 38 core samples.
Technology development
A cost of $70M is estimated to fund the technology development activities; the mission concept would require technology development in four key areas:- Coring, encapsulation, and caching: Lightweight tools/mechanisms for obtaining and handling cored samples.
- Instruments: Additional technology focus to mature instruments that could address the measurement needs posed herein, particularly the micro-scale mineralogy, organics, and elemental composition mapping.
- Planetary protection/contamination control: Bio-cleaning, cataloguing of bio-contaminants, and transport modeling to ensure cached samples would be returnable.
- Rover navigation: On-board image processing and navigation to increase traverse rate.
- Precision landing: A major scientific priority is to improve access to complex terrain, which requires significantly narrowing the landing ellipse.
Based on a draft project schedule and a full JPL team experimental study, total project cost in dollars, not including launch vehicle, is estimated to be between $1.5-2.0 Billion.