LIFE: Life Investigation For Enceladus A Sample Return Mission Concept in Search for Evidence of Life

Abstract Life Investigation For Enceladus (LIFE) presents a low-cost sample return mission to Enceladus, a body with high astrobiological potential. There is ample evidence that liquid water exists under ice coverage in the form of active geysers in the "tiger stripes" area of the southern Enceladus hemisphere. This active plume consists of gas and ice particles and enables the sampling of fresh materials from the interior that may originate from a liquid water source. The particles consist mostly of water ice and are 1-10?μ in diameter. The plume composition shows H(2)O, CO(2), CH(4), NH(3), Ar, and evidence that more complex organic species might be present. Since life on Earth exists whenever liquid water, organics, and energy coexist, understanding the chemical components of the emanating ice particles could indicate whether life is potentially present on Enceladus. The icy worlds of the outer planets are testing grounds for some of the theories for the origin of life on Earth. The LIFE mission concept is envisioned in two parts: first, to orbit Saturn (in order to achieve lower sampling speeds, approaching 2 km/s, and thus enable a softer sample collection impact than Stardust, and to make possible multiple flybys of Enceladus); second, to sample Enceladus' plume, the E ring of Saturn, and the Titan upper atmosphere. With new findings from these samples, NASA could provide detailed chemical and isotopic and, potentially, biological compositional context of the plume. Since the duration of the Enceladus plume is unpredictable, it is imperative that these samples are captured at the earliest flight opportunity. If LIFE is launched before 2019, it could take advantage of a Jupiter gravity assist, which would thus reduce mission lifetimes and launch vehicle costs. The LIFE concept offers science returns comparable to those of a Flagship mission but at the measurably lower sample return costs of a Discovery-class mission. Key Words: Astrobiology-Habitability-Enceladus-Biosignatures. Astrobiology 12, 730-742.     

Collecting Samples in Gale Crater, Mars; an Overview of the Mars Science Laboratory Sample Acquisition, Sample Processing and Handling System

The Mars Science Laboratory Mission (MSL), scheduled to land on Mars in the summer of 2012, consists of a rover and a scientific payload designed to identify and assess the habitability, geological, and environmental histories of Gale crater. Unraveling the geologic history of the region and providing an assessment of present and past habitability requires an evaluation of the physical and chemical characteristics of the landing site; this includes providing an in-depth examination of the chemical and physical properties of Martian regolith and rocks. The MSL Sample Acquisition, Processing, and Handling (SA/SPaH) subsystem will be the first in-situ system designed to acquire interior rock and soil samples from Martian surface materials. These samples are processed and separated into fine particles and distributed to two onboard analytical science instruments SAM (Sample Analysis at Mars Instrument Suite) and CheMin (Chemistry and Mineralogy) or to a sample analysis tray for visual inspection. The SA/SPaH subsystem is also responsible for the placement of the two contact instruments, Alpha Particle X-Ray Spectrometer (APXS), and the Mars Hand Lens Imager (MAHLI), on rock and soil targets. Finally, there is a Dust Removal Tool (DRT) to remove dust particles from rock surfaces for subsequent analysis by the contact and or mast mounted instruments (e.g. Mast Cameras (MastCam) and the Chemistry and Micro-Imaging instruments (ChemCam)).     

A concept for NASA's Mars 2016 astrobiology field laboratory

The Mars Program Plan includes an integrated and coordinated set of future candidate missions and investigations that meet fundamental science objectives of NASA and the Mars Exploration Program (MEP). At the time this paper was written, these possible future missions are planned in a manner consistent with a projected budget profile for the Mars Program in the next decade (2007-2016). As with all future missions, the funding profile depends on a number of factors that include the exact cost of each mission as well as potential changes to the overall NASA budget. In the current version of the Mars Program Plan, the Astrobiology Field Laboratory (AFL) exists as a candidate project to determine whether there were (or are) habitable zones and life, and how the development of these zones may be related to the overall evolution of the planet. The AFL concept is a surface exploration mission equipped with a major in situ laboratory capable of making significant advancements toward the Mars Program's life-related scientific goals and the overarching Vision for Space Exploration. We have developed several concepts for the AFL that fit within known budget and engineering constraints projected for the 2016 and 2018 Mars mission launch opportunities. The AFL mission architecture proposed here assumes maximum heritage from the 2009 Mars Science Laboratory (MSL). Candidate payload elements for this concept were identified from a set of recommendations put forth by the Astrobiology Field Laboratory Science Steering Group (AFL SSG) in 2004, 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 MSL platform.     

Analysis of underivatized amino acids in geological samples using ion-pairing liquid chromatography and electrospray tandem mass spectrometry

The capability of detecting biomarkers, such as amino acids, in chemically complex field samples is essential to establishing the knowledge required to search for chemical signatures of life in future planetary explorations. However, due to the complexities of in situ investigations, it is important to establish a new analytical scheme that utilizes a minimal amount of sample preparation. This paper reports the feasibility of a novel and sensitive technique, which has been established to quantitate amino acids in terrestrial crust samples directly without derivatization using volatile ion-pairing liquid chromatography and tandem mass spectrometry equipped with an electrospray ionization source. Adequate separation of 20 underivatized amino acids was achieved on a C(18) capillary column within 26 min with nonafluoropentanoic acid (NFPA) as ion-pairing reagent. Each amino acid was identified from its retention time as well as from its characteristic parent-to-daughter ion transition. Using tandem mass spectrometry as a detection technique allows co-elution of some amino acids, as it is more specific than traditional spectrophotometric methods. In the present study, terrestrial samples collected from 3 different locations were analyzed for their water-extractable free amino acid contents, following the removal of metal and organic interferences via ion exchange procedures. This is the first time that amino acids in geological samples were directly determined quantitatively without complicated derivatization steps. Depending on the amino acid, the detection limits varied from 0.02 to 5.7 pmol with the use of a 1 microl sample injection loop.