View source for Engineering:Signs Of LIfe Detector

{{short description|Spacecraft instrument to detect biosignatures}}
{{Infobox spacecraft instrument
| Name = Signs Of LIfe Detector<br/>(SOLID)
| Image =
| Caption =

| Operator = 
| Manufacturer = [[Organization:Spanish Astrobiology Center|Spanish Astrobiology Center]] ([[Organization:Spanish National Research Council|CSIC]]-[[Organization:Instituto Nacional de Técnica Aeroespacial|INTA]])
| Type = [[Biology:Immunoassay|Immunoassay]]
| Function = life detection
| Mission_Duration =
| Began = 
| Ceased = 
| Webpage = {{url|auditore.cab.inta-csic.es/solid/en/instrument/}}

| Mass = < {{cvt|7|kg|abbr=on}} <ref name='Parro Astrobio 2011'/>
| Dimensions =
| Number = <!--number launched-->
| Power_consumption =

| Spacecraft = <!--spacecraft it is hosted aboard-->
| SC_Operator = <!--operator of those spacecraft-->
| Launch = <!--Launch date (single instruments only)-->
| Rocket = 
| Launch_Site = 
| COSPAR = <!--COSPAR ID of host spacecraft-->
}}
'''Signs Of LIfe Detector''' ('''SOLID''') is an analytical instrument under development to detect extraterrestrial life in the form of [[Physics:Biomolecule|organic]] [[Astronomy:Biosignature|biosignature]]s obtained from a [[Engineering:Core drill|core drill]]  during planetary exploration.

The instrument is based on fluorescent [[Biology:Immunoassay|immunoassay]]s and it is being developed by the [[Organization:Spanish Astrobiology Center|Spanish Astrobiology Center]] (CAB) in collaboration with the [[Organization:NASA Astrobiology Institute|NASA Astrobiology Institute]]. SOLID is currently undergoing testing for use in [[Astronomy:Astrobiology|astrobiology]] space missions that search for common [[Physics:Biomolecule|biomolecule]]s that may indicate the presence of extraterrestrial life, past or present. The system was validated in field tests and engineers are looking into ways to refine the method and miniaturize the instrument further.
 
==Science background==

{{further|Astronomy:Astrobiology|Astronomy:Life on Mars}}
Modern [[Astronomy:Astrobiology|astrobiology]] inquiry has emphasized the search for [[Astronomy:Water on Mars|water on Mars]], chemical [[Astronomy:Biosignature|biosignature]]s in the [[Earth:Permafrost|permafrost]], soil and rocks at the planet's surface, and even [[Biology:Biomarker|biomarker]] gases in the atmosphere that may give away the presence of past or present life.<ref>{{cite conference| url=https://ntrs.nasa.gov/search.jsp?R=20120003707 |title=The Search for Life on Mars |last=Mumma |first=Michael J. |date=January 8, 2012 |conference=Origin of Life Gordon Research Conference |location=Galveston, TX |url-status=live |archiveurl=https://web.archive.org/web/20160604111239/https://ntrs.nasa.gov/search.jsp?R=20120003707 |archivedate=June 4, 2016}}</ref><ref name="NYT-20160912">{{cite news|last=Chang |first=Kenneth |title=Visions of Life on Mars in Earth's Depths |url=https://www.nytimes.com/2016/09/13/science/south-african-mine-life-on-mars.html |date=September 12, 2016 |work={{wipe|New York Times}} |accessdate=September 12, 2016 |url-status=live |archiveurl=https://web.archive.org/web/20160912225220/http://www.nytimes.com/2016/09/13/science/south-african-mine-life-on-mars.html |archivedate=September 12, 2016 }}</ref> The detection of preserved organic molecules of unambiguous biological origin is fundamental for the confirmation of present or past life,<ref name='Parro-Rivas 2008'/> but the 1976 [[Astronomy:Viking lander biological experiments|Viking lander biological experiments]] failed to detect organics on Mars, and it is suspected it was because of the combined effects of heat applied during analysis and the unexpected presence of oxidants such as [[Astronomy:Life on Mars#Perchlorates|perchlorates]] in the Martian soil.<ref>{{cite news |title=Did Viking Mars Landers Find Life's Building Blocks? Missing Piece Inspires New Look at Puzzle |date=2010-09-05 |url=https://www.sciencedaily.com/releases/2010/09/100904081050.htm |work=ScienceDaily |accessdate=2010-09-23 }}</ref><ref>{{cite news |title=Comment on "Reanalysis of the Viking results suggests perchlorate and organics at midlatitudes on Mars |first=Rafael |last=Navarro-González |display-authors=0 |doi=10.1029/2011JE003869 |journal=Journal of Geophysical Research |date=2011 |volume=116 |issue=E12|bibcode=2011JGRE..11612001B }}</ref> The recent discovery of near surface [[Astronomy:Water on Mars|ground ice on Mars]] supports arguments for the long-term preservation of biomolecules on Mars.<ref name='Stoker NASA 2005'>[https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20050176025.pdf Field simulation of a drilling mission to Mars to search for subsurface life.] C. R. Stoker, L.G. Lemke, H. Cannon, B. Glass, S. Dunagan, J. Zavaleta, D. Miller, J. Gomez-Elvira. Lunar and Planetary Science XXXVI (2005).</ref>

SOLID demonstrated that antibodies are unaffected by acidity, heat and oxidants such as perchlorates, and it has emerged as a viable choice for an astrobiology mission directly searching for biosignatures.<ref name='Parro Astrobio 2011'/>

For a time, the ExoMars' [[Engineering:Rosalind Franklin (rover)|''Rosalind Franklin'' rover]] was planned to carry a similar instrument called Life Marker Chip.<ref>{{cite journal |title=In situ biomarkers and the Life Marker Chip |journal=Astronomy & Geophysics |first=Zita |last=Martins |volume=52 |issue=1 |pages=1.34–1.35 |year=2011 |doi=10.1111/j.1468-4004.2011.52134.x |bibcode=2011A&G....52a..34M|doi-access=free }}</ref><ref>{{cite journal |title=Development status of the life marker chip instrument for ExoMars |journal=Planetary and Space Science |first1=Mark R. |last1=Sims |first2=David C. |last2=Cullen |first3=Catherine S. |last3=Rix |first4=Alan |last4=Buckley |first5=Mariliza |last5=Derveni |first6=Daniel |last6=Evans |first7=Luis Miguel |last7=García-Con |first8=Andrew |last8=Rhodes |first9=Carla C. |last9=Rato|last10=Stefinovic |first10=Marijan |last11=Sephton |first11=Mark A. |last12=Court |first12=Richard W. |last13=Bulloch |first13=Christopher |last14=Kitchingman |first14=Ian |last15=Ali |first15=Zeshan |last16=Pullan |first16=Derek |last17=Holt |first17=John |last18=Blake |first18=Oliver |last19=Sykes |first19=Jonathan |last20=Samara-Ratna |first20=Piyal |last21=Canali |first21=Massimiliano |last22=Borst |first22=Guus |last23=Leeuwis |first23=Henk |last24=Prak |first24=Albert |last25=Norfini |first25=Aleandro |last26=Geraci |first26=Ennio |last27=Tavanti |first27=Marco |last28=Brucato |first28=John |last29=Holm |first29=Nils |display-authors=5 |volume=72 |issue=1 |pages=129–137 |date=November 2012 |doi=10.1016/j.pss.2012.04.007 |bibcode=2012P&SS...72..129S}}</ref>

==Instrument==

[[File:Sandwich Immunoassay, ELISA.jpg|thumb|left|The two-site, non-competitive immunoassay consists of a biomolecule (in green) captured by an immobile antibody and "sandwiched" by a labeled antibody. When exposed to a laser beam, the fluorochrome label (in yellow) is excited and its fluorescent signal is measured.]]

SOLID was designed for automatic ''in situ'' detection and identification of substances from liquid and crushed samples under the conditions of outer space.<ref name='Parro Astrobio 2011'/><ref name='Parro GRA 2009'/> The system uses hundreds of carefully selected [[Biology:Antibody|antibodies]] to detect lipids, [[Biology:Protein|protein]]s, [[Chemistry:Polysaccharide|polysaccharide]]s, and [[Biology:Nucleic acid|nucleic acid]]s. These are complex biological polymers that could only be synthesized by life forms, and are therefore strong indicators —[[Astronomy:Biosignature|biosignature]]s— of past or present life.

SOLID consists of two separate functional units: a Sample Preparation Unit (SPU) for extractions by ultrasonication, and a Sample Analysis Unit (SAU), for fluorescent [[Biology:Immunoassay|immunoassay]]s.<ref name='Parro GRA 2009'/> The antibody microarrays are separated in hundreds of small compartments inside a [[Biology:Biochip|biochip]] only a few square centimeters in size.<ref name='Parro Astrobio 2011'>{{cite journal | doi = 10.1089/ast.2010.0501 | pmid=21294639 | bibcode=2011AsBio..11...15P | volume=11 | issue=1 | title=SOLID3: A Multiplex Antibody Microarray-Based Optical Sensor Instrument forIn SituLife Detection in Planetary Exploration | year=2011 | journal=Astrobiology | pages=15–28 | last1 = Parro | first1 = Víctor | last2 = de Diego-Castilla | first2 = Graciela | last3 = Rodríguez-Manfredi | first3 = José A. | last4 = Rivas | first4 = Luis A. | last5 = Blanco-López | first5 = Yolanda | last6 = Sebastián | first6 = Eduardo | last7 = Romeral | first7 = Julio | last8 = Compostizo | first8 = Carlos | last9 = Herrero | first9 = Pedro L. | last10 = García-Marín | first10 = Adolfo | last11 = Moreno-Paz | first11 = Mercedes | last12 = García-Villadangos | first12 = Miriam | last13 = Cruz-Gil | first13 = Patricia | last14 = Peinado | first14 = Verónica | last15 = Martín-Soler | first15 = Javier | last16 = Pérez-Mercader | first16 = Juan | last17 = Gómez-Elvira | first17 = Javier}}</ref>

SOLID instrument is able to perform both "sandwich" and competitive immunoassays using hundreds of well characterized and highly specific  antibodies.<ref name='Parro-Rivas 2008'>[https://link.springer.com/article/10.1007/s11214-007-9276-1 Protein Microarrays-Based Strategies for Life Detection in Astrobiology]. Víctor Parro, Luis A. Rivas, and Javier Gómez-Elvira. ''Space Science Reviews'', March 2008, Volume 135, Issue 1–4, pp 293–311.</ref> The technique called "sandwich immunoassay" is a non-competitive immunoassay in which the [[Chemistry:Analyte|analyte]] (compound of interest in the unknown sample) is captured by an immobilized antibody, then a labeled antibody is bound to the analyte to reveal its presence.<ref name='Parro Astrobio 2011'/> In other words, the "sandwich" quantify antigens (i.e. [[Physics:Biomolecule|biomolecule]]s) between two layers of antibodies (i.e. capture and detection antibody). For the [[Biology:Immunoassay#Competitive, homogeneous immunoassays|competitive assay]] technique, unlabeled analyte displaces bound labelled analyte, which is then detected or measured.

An optical system is set up so that a [[Physics:Laser|laser]] beam excites the fluorochrome label and a [[Engineering:Charge-coupled device|CCD]] detector captures an image of the microarray that can be measured.<ref name='Parro 2007.0126'>{{cite journal | doi = 10.1089/ast.2007.0126 | pmid=19105755 | bibcode=2008AsBio...8..987P | volume=8 | issue=5 | title=SOLID2: An Antibody Array-Based Life-Detector Instrument in a Mars Drilling Simulation Experiment (MARTE) | year=2008 | journal=Astrobiology | pages=987–999 | last1 = Parro | first1 = Víctor | last2 = Fernández-Calvo | first2 = Patricia | last3 = Rodríguez Manfredi | first3 = José A. | last4 = Moreno-Paz | first4 = Mercedes | last5 = Rivas | first5 = Luis A. | last6 = García-Villadangos | first6 = Miriam | last7 = Bonaccorsi | first7 = Rosalba | last8 = Eduardo González-Pastor | first8 = José | last9 = Prieto-Ballesteros | first9 = Olga | last10 = Schuerger | first10 = Andrew C. | last11 = Davidson | first11 = Mark | last12 = Gómez-Elvira | first12 = Javier | last13 = Stoker | first13 = Carol R.}}</ref>

The instrument is able to detect a broad range of molecular size compounds, from the [[Chemistry:Amino acid|amino acid]] size, [[Chemistry:Peptide|peptide]]s, [[Biology:Protein|protein]]s, to whole cells and [[Biology:Spore|spore]]s, with sensitivities at 1–2 [[Physics:Parts-per notation|ppb]] (ng/mL) for biomolecules and 104 to 103 spores per milliliter.<ref name='Parro Astrobio 2011'/><ref name='Parro GRA 2009'/> Some compartments in the microarray are reserved for samples of known nature and concentrations, that are used as controls for reference and comparison. SOLID instrument concept avoids the high-temperature treatments of other techniques that may destroy organic matter in the presence of Martian oxidants such as [[Astronomy:Life on Mars#Perchlorates|perchlorates]].<ref name='Parro Astrobio 2011'/>

==Testing==

A field prototype of SOLID was first tested in 2005 in a simulated Mars drilling expedition called MARTE (Mars Analog Rio Tinto Experiment)<ref name='Parro GRA 2009'/><ref name='Parro 2007.0126'/><ref>[https://ti.arc.nasa.gov/m/pub-archive/1328h/1328%20%28Cannon%29.pdf MARTE: Technology Development and Lessons Learned from a Mars Drilling Mission Simulation.] (PDF) Howard N. Cannon, Carol R. Stoker, Stephen E. Dunagan, Kiel Davis, Javier Gómez-Elvira, Brian J. Glass, Lawrence G. Lemke, David Miller, Rosalba Bonaccorsi, Mark Branson, Scott Christa, José Antonio Rodríguez-Manfredi, Erik Mumm, Gale Paulsen, Matt Roman, Alois
Winterholler, Jhony R. Zavaleta. (2005)</ref> where the researchers tested a drill {{cvt|10|m|abbr=on}} in depth, sample-handling systems, and immunoassays relevant to the search for life in the Martian subsurface. MARTE was funded by the NASA [[Engineering:Astrobiology Science and Technology for Exploring Planets|Astrobiology Science and Technology for Exploring Planets]] (ASTEP) program.<ref name='Stoker NASA 2005'/> Using the sample cores, SOLID successfully detected several  biological polymers in extreme environments in different parts of the world, including a deep South African mine, Antarctica's McMurdo Dry Valleys, Yellowstone, Iceland, [[Earth:Atacama Desert|Atacama Desert]] in Chile, and in the acid water of Rio Tinto.<ref name='Parro GRA 2009'>[https://www.researchgate.net/profile/Luis_Rivas5/publication/228416443_The_SOLID_Signs_Of_LIfe_Detector_instrument_concept_an_antibody_microarray-based_biosensor_for_life_detection_in_astrobiology/links/0fcfd507bf80586762000000.pdf SOLID (Signs Of LIfe Detector) instrument concept: an antibody microarray-based biosensor for life detection in astrobiology.] (PDF) V. Parro, L.A. Rivas, J.A. Rodríguez-Manfredi, Y. Blanco, G. de Diego-Castilla, P. Cruz-Gil, M. Moreno-Paz, M. García-Villadangos, C. Compostizo, P.L. Herrero, and the SOLID Team. ''Geophysical Research Abstracts'', Vol. 11, EGU2009-8614-1, 2009. EGU General Assembly 2009.</ref><ref name='Parro 2011.0654'/>

Extracts obtained from [[Astronomy:Terrestrial analogue sites|Mars analogue sites]] on Earth were added to various [[Chemistry:Perchlorate|perchlorate]] concentrations at −20&nbsp;°C for 45 days and then the samples were analyzed with SOLID.<ref name='Parro Astrobio 2011'/> The results showed no interference from acidity or from the presence of 50 mM [[Chemistry:Perchlorate|perchlorate]] which is 20 times higher than that found at the ''Phoenix'' landing site.<ref name='Parro Astrobio 2011'/> SOLID demonstrated that the chosen antibodies are unaffected by acidity, heat and oxidants such as perchlorates, and it has emerged as a viable choice for an astrobiology mission directly searching for biosignatures.<ref name='Parro Astrobio 2011'/>

In 2018, another field test took place at the Atacama Desert with a rover called ARADS (Atacama Rover Astrobiology Drilling Studies) that carried a core drill, SOLID instrument, and another life detection system called Microfluidic Life Analyzer (MILA).<ref name='ARADS 2018'>[https://www.nasa.gov/ames/arads Atacama Rover Astrobiology Drilling Studies (ARADS)]. NASA, 26 February 2018.</ref> MILA processes minuscule volumes of fluid samples to isolate [[Chemistry:Amino acid|amino acid]]s, which are building blocks of [[Biology:Proteins|proteins]]. The rover tested different strategies for searching for potential evidence of life in the soil, and established that roving, drilling and life detection can take place in concert.<ref name='ARADS 2018'/>

===Status===

These tests validated the system for planetary exploration.<ref name='Parro 2011.0654'>{{cite journal| pmc=3242637 | pmid=22149750 | doi=10.1089/ast.2011.0654 | volume=11 | issue=10 | title=A microbial oasis in the hypersaline Atacama subsurface discovered by a life detector chip: implications for the search for life on Mars | year=2011 | journal=Astrobiology | pages=969–96 | last1 = Parro | first1 = V | last2 = de Diego-Castilla | first2 = G | last3 = Moreno-Paz | first3 = M | last4 = Blanco | first4 = Y | last5 = Cruz-Gil | first5 = P | last6 = Rodríguez-Manfredi | first6 = JA | last7 = Fernández-Remolar | first7 = D | last8 = Gómez | first8 = F | last9 = Gómez | first9 = MJ | last10 = Rivas | first10 = LA | last11 = Demergasso | first11 = C | last12 = Echeverría | first12 = A | last13 = Urtuvia | first13 = VN | last14 = Ruiz-Bermejo | first14 = M | last15 = García-Villadangos | first15 = M | last16 = Postigo | first16 = M | last17 = Sánchez-Román | first17 = M | last18 = Chong-Díaz | first18 = G | last19 = Gómez-Elvira | first19 = J| bibcode=2011AsBio..11..969P }}</ref> Some improvements to be addressed in the future are instrument miniaturization, extraction protocols, and antibody stability under outer space conditions.<ref name='Parro-Rivas 2008'/><ref name='Parro 2007.0126'/> SOLID would be one of the payloads of the proposed [[Astronomy:Icebreaker Life|Icebreaker Life]] to Mars,<ref name='Dirt 2013'>{{cite journal | title = The Sample Handling System for the Mars Icebreaker Life Mission: From Dirt to Data | journal = Astrobiology | date = April 2013 | author1 = Davé, Arwen; Sarah J. Thompson, Christopher P. McKay, Carol R. Stoker, Kris Zacny, Gale Paulsen, Bolek Mellerowicz, Brian J. Glass, David Willson, Rosalba Bonaccorsi, and Jon Rask. | s2cid = 41629118 | volume = 13 | issue = 4 | pages = 354–369 | doi = 10.1089/ast.2012.0911 | pmid = 23577818 | bibcode=2013AsBio..13..354D}}</ref><ref>[https://www.hou.usra.edu/meetings/abscicon2015/pdf/7224.pdf The Icebreaker Mission to Search for Life on Mars.] C. Stoker, C. McKay, W. Brinckerhoff, A. Davila V. Parro, R. Quinn. Astrobiology Science Conference 2015.</ref><ref>[https://www.hou.usra.edu/meetings/lpsc2018/pdf/2927.pdf Life-detection Mars analog testing at Rio Tinto.] B. Glass, V. Parro, D. Bergman, C. Stoker1, A. Wang, T. Stucky, M. García-Villadangos, J.M. Manchado, and S. Seitz. 49th Lunar and Planetary Science Conference 2018 (LPI Contrib. No. 2083).</ref> or a lander to [[Astronomy:Europa (moon)|Europa]].<ref>[http://meetingorganizer.copernicus.org/EPSC2009/EPSC2009-443.pdf SOLID (Signs Of Life Detector) Instrument: A Bioaffinity microarray-based instrument for life detection on Europa.] V. Parro. EPSC Abstracts. Vol. 4, European Planetary Science Congress. September 2009.</ref>

==References==
{{reflist}}

{{Satellite and spacecraft instruments}}
{{Astrobiology}}
{{Extraterrestrial life}}

[[Category:Astrobiology]]
[[Category:Fluorescence]]
[[Category:Molecular biology]]
[[Category:Spacecraft instruments]]
[[Category:Space science experiments]]
[[Category:Spectrometers]]

{{Sourceattribution|Signs Of LIfe Detector}}