View source for Astronomy:Mars Astrobiology Explorer-Cacher

{{short description|Cancelled NASA Mars rover concept}}
{{Infobox spaceflight
| name                  = Mars Astrobiology Explorer-Cacher
| names_list            = <!--list of previous names if the spacecraft has been renamed. 
Include the dates applicable if possible, and separate each name with a linebreak. 
Omit if the spacecraft has only ever been known by one name. 
Do not include Harvard, COSPAR/NSSDC or SATCAT/NORAD/NASA designations as alternative names-->

<!--image of the spacecraft/mission-->
| image                 = [[File:MAX-C-Rover.jpg|250px]]
| image_caption         = <!--image caption-->
| image_alt             = <!--image alt text-->
| image_size            = <!--include px/em; defaults to 220px-->

<!--Basic details-->
| mission_type          = [[Astronomy:Rover (space exploration)|Rover]]
| operator              = [[Organization:NASA|NASA]]
| Harvard_designation   = <!--spacecraft launched 1962 and earlier only (eg. 1957 Alpha 2)-->
| COSPAR_ID             = <!--spacecraft launched since 1963 only (aka NSSDC ID; eg. 1998-067A)-->
| SATCAT                = <!--satellite catalogue number, omit leading zeroes (e.g. 25544)-->
| website               = <!--Homepage of the craft/mission, OFFICIAL PAGES ONLY-->
| mission_duration      = One Earth year (proposed)
| distance_travelled    = <!--How far the spacecraft travelled (if known)-->
| orbits_completed      = <!--number of times the spacecraft orbited the Earth - see below for spacecraft beyond Earth orbit-->
| suborbital_range      = <!--downrange distance reached if spacecraft did not enter orbit-->
| suborbital_apogee     = <!--altitude reached if spacecraft did not enter orbit-->

<!--Spacecraft properties-->
| spacecraft            = <!--Spacecraft name/serial number (eg. Space Shuttle ''Discovery'', Apollo CM-118), etc-->
| spacecraft_type       = <!--eg. GPS Block II, Kobalt-M, US-K, etc-->
| spacecraft_bus        = <!--eg. A2100M, Star-2, etc-->
| manufacturer          = <!--company or companies who built the satellite-->
| launch_mass           = {{convert|300|kg|abbr=on}}
| BOL_mass              = <!--spacecraft mass in orbit at beginning of operational life, after LEOP phase-->
| landing_mass          = <!--Mass after landing (recovered spacecraft only)-->
| dry_mass              = <!--spacecraft mass in orbit without fuel-->
| payload_mass          = <!--Mass of cargo carried by spacecraft (eg. for Space Shuttle), or total mass of instrumentation/equipment/experiments for mission-->
| dimensions            = <!--body dimensions and solar array span-->
| power                 = <!--end-of-life power, in watts-->

<!--Launch details-->
| launch_date           = <!--{{start date|YYYY|MM|DD|hh|mm|ss|TZ=Z}}-->
| launch_rocket         = [[Engineering:Atlas V|Atlas V]]
| launch_site           = <!--Where the rocket launched from, including complex and pad; do not include the full address or country-->
| launch_contractor     = <!--organisation(s) that conducted the launch (eg. United Launch Alliance, Arianespace, etc)-->
| deployment_from       = <!--place where deployed from-->
| deployment_date       = <!--date deployed-->
| entered_service       = <!--date on which the spacecraft entered service, if it did not do so immediately after launch-->
<!-- * - e.g. Proton-M/Briz-M not Proton-M, but Titan IV(401)A not Titan IV(401)A-Centaur-->

<!--transponder parameters-->
| trans_band            = <!--Transponder frequency bands-->
| trans_frequency       = <!--specific frequencies-->
| trans_bandwidth       = <!--bandwidth-->
| trans_capacity        = <!--capacity of the transponders-->
| trans_coverage        = <!--area covered-->
| trans_TWTA            = <!--TWTA output power-->
| trans_EIRP            = <!--equivalent isotropic power-->
| trans_HPBW            = <!--half-power beam width-->

<!--Only use where a spacecraft/mission is part of a clear programme of sequential missions. 
If in doubt, leave it out-->
| programme             = 
| previous_mission      =
| next_mission          =

<!--mission insignia or patch-->
| insignia              = <!--omit the "file" prefix-->
| insignia_caption      = <!--image caption-->
| insignia_alt          = <!--image alt text-->
| insignia_size         = <!--include px/em; defaults to 180px-->
}}

The '''Mars Astrobiology Explorer-Cacher''' ('''MAX-C'''), also known as '''Mars 2018 mission''', was a [[Organization:NASA|NASA]] concept for a [[Astronomy:Mars|Mars]] [[Astronomy:Rover (space exploration)|rover]] mission, proposed to be launched in 2018 together with the European [[Astronomy:ExoMars|ExoMars]] rover.<ref name='MAX-C'>{{Citation| first=Scott | last=McLennan | contribution=Proposed 2018 Mars Astrobiology Explorer-Cacher (MAX-C) Mission| title=Proposal of the MEPAG Mid-Range Rover Science Analysis Group (MRR-SAG)| publisher=NASA's [[Organization:Jet Propulsion Laboratory|Jet Propulsion Laboratory]]| date=September 10, 2009| contribution-url=http://mepag.jpl.nasa.gov/decadal/MAX-C_DS_presentation_v15.pdf}}</ref><ref>[http://www.lpi.usra.edu/pss/july2009/presentations/05MEPAG.pdf Mars Exploration Program Analysis](July 9, 2009)</ref><ref name=MAX-CProposal>[http://mepag.jpl.nasa.gov/decadal/LisaMPratt.pdf Mars Astrobiology Explorer-Cacher (MAX-C): A Potential Rover Mission for 2018] {{webarchive|url=https://web.archive.org/web/20100528034922/http://mepag.jpl.nasa.gov/decadal/LisaMPratt.pdf |date=2010-05-28 }} (September 15, 2009)</ref> The MAX-C rover concept was cancelled in April 2011 due to budget cuts.<ref>{{cite news | first = Peter B. | last = de Selding | title = ESA Halts Work on ExoMars Orbiter and Rover | date = 20 April 2011 | url = http://www.spacenews.com/civil/110420-esa-halts-work-exomars.html | archive-url = https://archive.today/20120524180452/http://www.spacenews.com/civil/110420-esa-halts-work-exomars.html | url-status = dead | archive-date = May 24, 2012 | work = Space News | access-date = 2011-04-21}}</ref><ref>{{cite news | first = Amy | last = Svitak | title = U.S., Europe Plan Single-rover Mars Mission for 2018 | date = 18 April 2011 | url = http://www.spacenews.com/civil/110418-single-rover-mars-mission-2018.html | archive-url = https://archive.today/20120524180453/http://www.spacenews.com/civil/110418-single-rover-mars-mission-2018.html | url-status = dead | archive-date = May 24, 2012 | work = Space News | access-date = 2011-04-21}}</ref>

The rover would have been solar powered, with a maximum mass of 300&nbsp;kg and based largely on the [[Engineering:Curiosity (rover)|''Curiosity'' rover]] components, but would have entailed a system tailored to the specific payload. The MAX-C rover would have performed an ''in-situ'' [[Astronomy:Astrobiology|astrobiological]] exploration, evaluate the habitability potential of various Martian environments, and it would have collected, documented, and cached samples for potential return to Earth by a future mission.<ref name=development>[http://mepag.jpl.nasa.gov/decadal/SamadAHayati.pdf Strategic Technology Development for Future Mars Missions (2013-2022)] {{webarchive|url=https://web.archive.org/web/20100528044137/http://mepag.jpl.nasa.gov/decadal/SamadAHayati.pdf |date=2010-05-28 }} (PDF) 15 September 2009</ref>

The [[Astronomy:Mars 2020|Mars 2020]] mission with its ''[[Engineering:Perseverance (rover)|Perseverance]]'' rover had similar scientific objectives as Mars 2018 and MAX-C.

== History ==
The essential energy, water, and nutrient requirements to support and sustain life on Mars are currently present, and the Martian geologic record offers tantalizing clue of many ancient habitable environments.<ref name='final report'>{{Citation| contribution=Mars Astrobiology Explorer-Cacher: A potential rover mission for 2018| title=JPL Document Review| editor-first=Lisa | editor-last=Pratt | pages=94 pp| date=October 14, 2009| contribution-url=http://mepag.jpl.nasa.gov/reports/MRR-SAG_Full_Report_v64b.pdf}}</ref> If life emerged and evolved on early Mars then it is possible, and indeed likely, that physical or chemical [[Astronomy:Biosignature|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.<ref name='final report'/>

For over a 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 [[Earth:Sedimentary rock|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.<ref name='final report'/>

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 [[Organization:Mars Science Laboratory|Mars Science Laboratory]] ''Curiosity'' rover, 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 ''Curiosity'' 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 [[Engineering:Phoenix (spacecraft)|Phoenix]] lander.<ref name='final report'/>

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 [[Astronomy:Mars Exploration Rover|Mars Exploration Rover]] or [[Organization:Mars Science Laboratory|Mars Science Laboratory]]-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).<ref name='final report'/>

[[File:Curiosity - The Next Mars Rover.jpg|thumb|Both MAX-C and the Mars 2020 ''Perseverance'' rover were envisioned to use features developed for the ''Curiosity'' rover ]]
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, [[Astronomy:ExoMars|ExoMars]] (ESA) and MAX-C (NASA).<ref name='single rover'>{{cite news | first = Jonathan| last=Amos | title = US and Europe mull single 2018 Mars rover | date = 7 April 2011 | url = https://www.bbc.co.uk/news/science-environment-13002214 | work = BBC News | access-date = 2011-04-08}}</ref> One suggestion was that the new vehicle be built in Europe and take on a combination of European and USA instruments. NASA proposed to provide a launch rocket and the "Sky Crane" landing system.<ref name='single rover'/> In February 2012, NASA terminated its participation in ExoMars due to budgetary cuts,<ref name="Feb 14">{{cite news |first=Frank |last=Morring Jr. |title=NASA Units Hope For Robotic Mars Mission In 2018 |date=14 February 2012 |url=http://www.aviationweek.com/Article.aspx?id=%2Farticle-xml%2Fasd_02_14_2012_p01-02-424988.xml |work=Aviation Week |access-date=4 January 2016 |archive-date=7 April 2014 |archive-url=https://web.archive.org/web/20140407074505/http://www.aviationweek.com/Article.aspx?id=%2Farticle-xml%2Fasd_02_14_2012_p01-02-424988.xml |url-status=dead }}</ref><ref>{{cite news |first=Ken |last=Kremer |title=Experts React to Obama Slash to NASA's Mars and Planetary Science Exploration |date=1 February 2012 |url=http://www.universetoday.com/93512/experts-react-to-obama-slash-to-nasas-mars-and-planetary-science-exploration/ |work=Universe Today }}</ref> and when Congress reinstated funding for Mars exploration after a loud outcry from planetary scientists and enthusiasts, NASA announced in December 2012 the [[Astronomy:Mars 2020|Mars 2020]] rover and, later, that it would indeed prepare a sample cache.<ref>[http://astrobites.org/2014/09/09/mars-2020/ Instruments selected for Mars 2020, NASA's latest rover]. ''Astrobites'', Joseph O'Rourke. September 9, 2014.</ref>

== Objectives ==
The main objective was at a site with high preservation potential for physical and chemical [[Astronomy:Biosignature|biosignature]]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 [[Astronomy:Earth|Earth]].<ref name=MAX-CProposal />

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.
* [[Astronomy:Astrobiology|Astrobiology]] — 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 Mars; characterize the potential for the preservation of biosignatures.
* [[Astronomy:Atmosphere of Mars#Methane|Methane emission]] from subsurface.
* [[Physics:Radiometric dating|Radiometric dating]]
* Deep [[Engineering:Core drill|core drill]] — [[Earth:Core sample|core sample]]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 [[Chemistry:Perchlorate|perchlorate]] affect the present habitability of Mars. Could mid-latitude ice provide a resource for In-Situ Resource Utilization (ISRU)?

A secondary science objective would have been 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 [[Astronomy:ExoMars|ExoMars]] rover if landed together at the same location.<ref>{{Citation | title = Two Rovers to the Same Site on Mars, 2018: Possibilities for Cooperative Science | journal = Astrobiology | date = September 2010 | volume = 10 | issue = 7 | pages = 663–685| doi=10.1089/ast.2010.0526 | bibcode=2010AsBio..10..663M | pmid = 20932131 | author1 = MEPAG 2-Rover International Science Analysis Group (2R-iSAG) | postscript = .}}</ref><ref name='Salvo'>{{citation | contribution = Proposed Mars Astrobiology Explorer –Cacher (MAX-C) & ExoMars 2018 (MXM-2018) Mission Formulation Status | title = 22nd MEPAG Meeting | editor-first1 = Christopher G. | editor-last1 = Salvo | editor-first2 = Anders | editor-last2 = Elfving | publisher = Jet Propulsion Laboratory | place = Monrovia, California, USA | date = March 17, 2010 | contribution-url = http://mepag.jpl.nasa.gov/meeting/mar-10/MEPAG_status_March_2010_v5.pdf }}</ref>

== 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.<ref name='final report'/>  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 the ellipse in a reasonable amount of time relative to the mission lifetime. The entry, descent and landing system would have been of high precision with a targeting accuracy of {{convert|7|km|mi|abbr=on}}.<ref name='final report'/> The solar-powered rover would have needed to have a range of no less than {{convert|10|km|mi|abbr=on}} and a lifetime of at least one Earth year.

== Rover ==
The MAX-C rover would have relied on significant inheritance of [[Organization:Mars Science Laboratory|MSL's]] [[Engineering:Curiosity (rover)|''Curiosity'' rover]] 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 {{convert|20|km|mi|abbr=on}} and a lifetime of at least 500 Martian days (sols).<ref name='Salvo'/> 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 [[Astronomy:Mars Exploration Rover|Spirit and Opportunity MERs]] have done.

The mass would have been about 300&nbsp;kg, bigger than the [[Astronomy:Mars Exploration Rover|MERs]], comparable in mass to the [[Astronomy:ExoMars|ExoMars]] rover, but lighter than the ''Curiosity'' rover.

==Proposed science instrumentation==
The rover would have carried instrumentation sufficient to scientifically select samples for caching. It was assumed that this translates to the following instruments and capabilities:<ref name='Salvo'/>
*Must be able to remotely (i.e. with mast-mounted instruments) characterize outcrops and identify features of interest (panoramic camera, [[Physics:Infrared spectroscopy|Near-IR Spectrometer]])
*Must be able to collect microscaleimagery of outcrops; contact instrument ([[Engineering:Microscope|microscopic imager]])
*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 ([[Physics:Raman spectroscopy|Raman spectroscopy]])
*Must be able to measure bulk elemental chemistry on the abraded rock surfaces; contact instrument ([[Astronomy:Alpha particle X-ray spectrometer|Alpha particle X-ray spectrometer]])
*Must be able to measure [[Chemistry:Organic compound|organic compound]]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.<ref name=MAX-CProposal /> However, a Mars sample return mission 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.<ref name=MAX-CProposal /> To address the highest priority scientific questions, selection of "outstanding samples" would be required.<ref name='MAX-C'/> 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.<ref name='MAX-C'/><ref>{{cite news |url=http://cosmiclog.msnbc.msn.com/archive/2010/02/24/2211442.aspx |archive-url=https://web.archive.org/web/20100227064804/http://cosmiclog.msnbc.msn.com/archive/2010/02/24/2211442.aspx |archive-date=2010-02-27 |title=Bringing back Mars life |work=MSNBC News |date=February 24, 2010 |first=Alan |last=Boyle}}</ref>

If, at the MSL ''Curiosity'' 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,<ref name=MAX-CProposal /> therefore, having the MAX-C developed for a 2018 launch could have saved 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&nbsp;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.<ref name=development />

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 [[Engineering:Core drill|core drill]] that could produce cores of approximately 10&nbsp;mm diameter up to 50&nbsp;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&nbsp;mm). Translation of the arm would be used to scan the individual abrasion spots.<ref name='final report'/> The rover should be able to cache at least 38 core samples.<ref name='Salvo'/>

== Technology development ==
A cost of $70M was estimated to fund the technology development activities;<ref name='final report'/> the mission concept would require technology development in four key areas:<ref name=MAX-CProposal /><ref name='final report'/>
* 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 [[Organization:JPL|JPL]] team experimental study, total project cost in dollars, not including launch vehicle, was estimated to be between $1.5-2.0 Billion.<ref name=MAX-CProposal />

== See also ==
*{{annotated link|Astronomy:Astrobiology}}
*{{annotated link|Organization:Astrobiology Field Laboratory}}
*{{annotated link|Astronomy:Biological Oxidant and Life Detection}}
*{{annotated link|Astronomy:ExoMars}}
*{{annotated link|Astronomy:Exploration of Mars}}
*{{annotated link|Astronomy:Life on Mars}}
*{{annotated link|Astronomy:Mars 2020}}
*{{annotated link|Astronomy:Mars Exploration Rover}}
*{{annotated link|Organization:Mars Science Laboratory}}
*{{annotated link|Engineering:Signs Of LIfe Detector}}
*{{annotated link|Engineering:Viking program}}

== References ==
{{reflist}}

==External links==
*[https://web.archive.org/web/20120602001007/http://www.astrobio.net/index.php?option=com_videocast&task=showall&id=10 Videos on the MAX-C rover field tests] (2010)

{{Mars spacecraft}}
{{Astrobiology}}

[[Category:Missions to Mars]]
[[Category:Cancelled spacecraft]]
[[Category:Proposed NASA space probes]]

{{Sourceattribution|Mars Astrobiology Explorer-Cacher}}