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Astrobiology Field Laboratory

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Template:Future spaceflight Template:Infobox Spacecraft The Astrobiology Field Laboratory (also known as AFL), is a proposed NASA unmanned spacecraft that would conduct a robotic search for life on Mars.[1][2] This mission, still in the conceptual phase, would land on Mars and explore a site thought to be a habitat. Examples of such sites are an active or extinct hydrothermal deposit, a dry lake or a specific polar site.[3]

If approved, the rover will be built by NASA's Jet Propulsion Laboratory, it would be based upon the Mars Science Laboratory rover design and it would carry astrobiology-oriented instruments, and ideally, a core drill. The original plans called for a launch as early as 2016,[4] however, recent budgetary constraints may cause significant delays.[5]

Mission

The rover would be the first mission since the Viking program landers of the 1970s to look for the chemistry associated with life (biosignatures), such as carbon-based compounds along with molecules involving both sulfur and nitrogen. The mission strategy will be to search for habitable zones by "following the water" and "finding the carbon."[1] In particular, it would conduct detailed analysis of geologic environments identified by the 2011 Mars Science Laboratory as being conducive to life on Mars and the signs of life, past and present. Such environments might include fine-grained sedimentary layers, hot spring mineral deposits, icy layers near the poles, or sites such as gullies where liquid water once flowed or may continue to seep into soils from melting ice packs.

Planning

The Astrobiology Field Laboratory (AFL) would be the next logical on site search platform that would follow the Mars Reconnaissance Orbiter (launched in 2005), Phoenix lander (launched in 2007), Mars Science Laboratory (to launch in 2011), the Mars Science Orbiter (to launch in 2016), and the ExoMars (to launch in 2016) projects in this strategic effort. This proposed mission has not yet begun its early planning stages or funding, and the mission will be modified in the coming time from multiple critical mission and engineering reviews. It should be noted that as the predecessor 'Mars Science Laboratory' results become better understood, the mission design of the AFL would also inevitably change as constraints are better matched with available resources. There are multiple possible variations of what could be called "AFL", and different scientists see these variations in different context, and with different systems of priority. However, the AFL mission and payload would be built upon the technology and scientific results of previous missions through a strategic planning process.[1] The AFL 'Science Steering Group' developed the following set of search strategies and assumptions for increasing the likelihood of detecting biosignatures:[1]

  1. Life processes produce a range of biosignatures such as lipids, proteins, amino acids and potential kerogen-like material which leave imprints on geology and chemistry, however, the biosignatures themselves may become progressively destroyed by ongoing environmental processes.
  2. Sample acquisition will need to be executed in multiple locations and at depths below that point on the Martian surface where oxidation results in chemical alteration. The surface is oxidizing as a consequence of the absence of magnetic field or magnetosphere shielding from harmful space radiation and solar electromagnetic radiation[6][7] —which may well render the surface sterile down to a depth greater than 7.5 metres (24.6 feet).[8][9] To get under that potential sterile layer, a core drill design is currently being studied. As with any trade, the inclusion of the drill would come at the mass expense available for other payload elements.
  3. Analytical laboratory biosignature measurements require the pre-selection and identification of high-priority samples, which could be subsequently subsampled to maximize detection probability and spatially resolve potential biosignatures for detailed analysis.

Payload

Currently, candidate payload elements are for the express purpose of identifying overall rover mass and power requirements for such a mission. The conceptual payload includes a Precision Sample Handling and Processing System that would replace and augment the functionality and capabilities provided by the Sample Acquisition Sample Processing and Handling system that is currently part of the 2009 Mars Science Laboratory rover.[1][10] The AFL payload will attempt to minimize any conflicting positive detection of life by including a suite of instruments that provide at least three mutually confirming analytical laboratory measurements.[3]

For the purpose of discerning a reasonable estimate on which to base the rover mass, the conceptual payload may include:[1]

  • Precision Sample Handling and Processing System.
  • Forward Planetary Protection for Life-Detection Mission to a Special Region.
  • Life Detection-Contamination Avoidance.
  • Astrobiology Instrument Development.
  • MSL Parachute Enhancement.
  • Autonomous safe long-distance travel.
  • Autonomous single-cycle instrument placement.
  • Pinpoint landing (100–1000 m) (if necessary to reach specific science targets in hazardous regions).
  • Mobility for highly sloped terrain 30° (if required to reach science targets).

Power source

It has been proposed that the Astrobiology Field Laboratory use radioisotope thermoelectric generators (RTGs) as its power source, like the ones to be used on the Mars Science Laboratory.[1] The radioactive RTG power source is to last for about one Martian year, or approximately two Earth years, with an extended mission lasting another Martian year. Solar power is not an efficient power source for Mars surface operations because solar power systems cannot operate effectively at high Martian latitudes, in shaded areas, in dusty conditions or during the winter time. Furthermore, solar power cannot provide power at night, thus limiting the ability of the rover to keep its systems warm, reducing the life expectancy of electronics. RTGs can provide reliable, continuous power day and night, and waste heat can be used via pipes to warm systems, freeing electrical power for the operation of the vehicle and instruments.

Science

Though the current AFL science justification does not include a pre-definition of potential life forms that might be found on Mars, the following assumptions are made:[1]

  1. Life utilizes some form of carbon.
  2. Life requires an external energy source (sunlight or chemical energy) to survive.
  3. Life is packaged in cellular-type compartments (cells).
  4. Life requires liquid water.

Within the region of surface operations, identify and classify Martian environments (past or present) with different habitability potential, and characterize their geologic context. Quantitatively assess habitability potential by:[1]

  • Measuring isotopic, chemical, mineralogical, and structural characteristics of samples, including the distribution and molecular complexity of carbon compounds.
  • Assessing biologically available sources of energy, including chemical, thermal and electromagnetic.
  • Determining the role of water (past or present) in the geological processes at the landing site.
  • Investigate the factors that will affect the preservation of potential signs of life (past or present) This refers to the potential for a particular biosignature to survive and therefore be detected in a particular habitat. Also, post-collection preservation may be required for later sample retrieval, although that would necessitate a further assessment of precision landing of Mars sample return mission mission.[3]
  • Investigate the possibility of prebiotic chemistry on Mars, including non-carbon biochemistry.
  • Document any anomalous features that can be hypothesized as possible Martian biosignatures.

It is fundamental to the AFL concept to understand that organisms and their environment constitute a system, within which any one part can affect the other. If life exists or has existed on Mars, scientific measurements to be considered would focus on understanding those systems that support or supported it. If life never existed while conditions were suitable for life formation, understanding why a Martian genesis never occurred would be a future priority.[1] The AFL team stated that it is reasonable to expect that missions like AFL will play a significant role in this process, but unreasonable to expect that they will bring it to a conclusion.[3]

See also

References

  1. ^ a b c d e f g h i j Beegle, Luther W. (August 2007). "A Concept for NASA's Mars 2016 Astrobiology Field Laboratory". Astrobiology. 7(4):: 545–577. Retrieved 2009-07-20. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)CS1 maint: extra punctuation (link)
  2. ^ "Missions to Mars". Jet Propulsion Laboratory. NASA. February 18, 2009. Retrieved 2009-07-20.
  3. ^ a b c d Steele, A., Beaty (September 26, 2006), "Final report of the MEPAG Astrobiology Field Laboratory Science Steering Group (AFL-SSG)", in Steele, Andrew (ed.), The Astrobiology Field Laboratory, U.S.A.: the Mars Exploration Program Analysis Group (MEPAG) - NASA, p. 72, retrieved 2009-07-22 {{citation}}: |format= requires |url= (help); Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |coeditors= ignored (help)
  4. ^ "Mars Astrobiology Field Laboratory and the Search for Signs of Life". Mars Today. September 1, 2007. Retrieved 2009-07-20. {{cite news}}: Cite has empty unknown parameter: |coauthors= (help)
  5. ^
  6. ^ NASA Mars Global Surveyor
  7. ^ Arkani-Hamed, Jafar; Boutin, Daniel (July 20-25 2003). "Polar Wander of Mars: Evidence from Magnetic Anomalies" (PDF). Sixth International Conference on Mars. Pasadena, California: Dordrecht, D. Reidel Publishing Co. Retrieved 2007-03-02. {{cite conference}}: Check date values in: |date= (help); Unknown parameter |booktitle= ignored (|book-title= suggested) (help)CS1 maint: multiple names: authors list (link)
  8. ^ Dartnell, L.R. et al., “Modelling the surface and subsurface Martian radiation environment: Implications for astrobiology,” Geophysical Research Letters 34, L02207, doi:10,1029/2006GL027494, 2007.
  9. ^ "Mars Rovers Sharpen Questions About Livable Conditions". Jet Propulsion Laboratory. NASA. February 15, 2008. Retrieved 2009-07-24. {{cite news}}: Cite has empty unknown parameter: |coauthors= (help)
  10. ^ "A Concept for NASA's Mars 2016 Astrobiology Field Laboratory". SpaceRef. September 1, 2007. Retrieved 2009-07-21. {{cite news}}: Cite has empty unknown parameter: |coauthors= (help)
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