PMID- 25085177
OWN - NLM
STAT- PubMed-not-MEDLINE
DCOM- 20150520
LR  - 20140802
IS  - 1089-7623 (Electronic)
IS  - 0034-6748 (Linking)
VI  - 85
IP  - 7
DP  - 2014 Jul
TI  - Organic cleanliness of the Mars Science Laboratory sample transfer chain.
PG  - 075111
LID - 10.1063/1.4890279 [doi]
AB  - One of the primary science goals of the Mars Science Laboratory (MSL) Rover, 
      Curiosity, is the detection of organics in Mars rock and regolith. To achieve 
      this, the Curiosity rover includes a robotic sampling system that acquires rock 
      and regolith samples and delivers it to the Sample Analysis at Mars (SAM) 
      instrument on board the rover. In order to provide confidence that any 
      significant organics detection result was Martian and not terrestrial in origin, 
      a requirement was levied on the flight system (i.e., all sources minus the SAM 
      instrument) to impart no more than 36 parts per billion (ppb by weight) of total 
      reduced carbon terrestrial contamination to any sample transferred to the SAM 
      instrument. This very clean level was achieved by a combination of a rigorous 
      contamination control program on the project, and then using the first collected 
      samples for a "dilution cleaning" campaign of the sample chain prior to 
      delivering a sample to the SAM instrument. Direct cleanliness assays of the 
      sample-contacting and other Flight System surfaces during pre-launch processing 
      were used as inputs to determine the number of dilution cleaning samples needed 
      once on Mars, to enable delivery of suitably clean samples to the SAM experiment. 
      Taking into account contaminant redistribution during launch thorough landing of 
      the MSL on Mars, the amount of residue present on the sampling hardware prior to 
      the time of first dilution cleaning sample acquisition was estimated to be 60 
      ng/cm(2) on exposed outer surfaces of the sampling hardware and 20 ng/cm(2) on 
      internal sample contacting surfaces; residues consisting mainly of aliphatic 
      hydrocarbons and esters. After three dilution cleaning samples, estimated 
      in-sample contamination level for the first regolith sample delivered to the SAM 
      instrument at the Gale Crater "Rocknest" site was bounded at </=10 ppb total 
      organic carbon. A Project decision to forego ejecting the dilution cleaning 
      sample and instead transfer the first drill-acquired sample at the "John Klein" 
      site to SAM resulted in an estimated level of terrestrial contamination of </=430 
      ppb. The estimated terrestrial contamination for portions from the second 
      drill-acquired sample, at Cumberland, was </=69 ppb; the estimate for a future, 
      third, drilled sample is </=38 ppb. These levels are comparable in magnitude to the 
      SAM instrument blanks at the nanomole level (as chlorohydrocarbon).
FAU - Blakkolb, B
AU  - Blakkolb B
AD  - Jet Propulsion Laboratory, California Institute of Technology. 4800 Oak Grove 
      Drive, Pasadena, California 91109, USA.
FAU - Logan, C
AU  - Logan C
AD  - Jet Propulsion Laboratory, California Institute of Technology. 4800 Oak Grove 
      Drive, Pasadena, California 91109, USA.
FAU - Jandura, L
AU  - Jandura L
AD  - Jet Propulsion Laboratory, California Institute of Technology. 4800 Oak Grove 
      Drive, Pasadena, California 91109, USA.
FAU - Okon, A
AU  - Okon A
AD  - Jet Propulsion Laboratory, California Institute of Technology. 4800 Oak Grove 
      Drive, Pasadena, California 91109, USA.
FAU - Anderson, M
AU  - Anderson M
AD  - Jet Propulsion Laboratory, California Institute of Technology. 4800 Oak Grove 
      Drive, Pasadena, California 91109, USA.
FAU - Katz, I
AU  - Katz I
AD  - Jet Propulsion Laboratory, California Institute of Technology. 4800 Oak Grove 
      Drive, Pasadena, California 91109, USA.
FAU - Aveni, G
AU  - Aveni G
AD  - Jet Propulsion Laboratory, California Institute of Technology. 4800 Oak Grove 
      Drive, Pasadena, California 91109, USA.
FAU - Brown, K
AU  - Brown K
AD  - Jet Propulsion Laboratory, California Institute of Technology. 4800 Oak Grove 
      Drive, Pasadena, California 91109, USA.
FAU - Chung, S
AU  - Chung S
AD  - Jet Propulsion Laboratory, California Institute of Technology. 4800 Oak Grove 
      Drive, Pasadena, California 91109, USA.
FAU - Ferraro, N
AU  - Ferraro N
AD  - Jet Propulsion Laboratory, California Institute of Technology. 4800 Oak Grove 
      Drive, Pasadena, California 91109, USA.
FAU - Limonadi, D
AU  - Limonadi D
AD  - Jet Propulsion Laboratory, California Institute of Technology. 4800 Oak Grove 
      Drive, Pasadena, California 91109, USA.
FAU - Melko, J
AU  - Melko J
AD  - Jet Propulsion Laboratory, California Institute of Technology. 4800 Oak Grove 
      Drive, Pasadena, California 91109, USA.
FAU - Mennella, J
AU  - Mennella J
AD  - Jet Propulsion Laboratory, California Institute of Technology. 4800 Oak Grove 
      Drive, Pasadena, California 91109, USA.
FAU - Yavrouian, A
AU  - Yavrouian A
AD  - Jet Propulsion Laboratory, California Institute of Technology. 4800 Oak Grove 
      Drive, Pasadena, California 91109, USA.
LA  - eng
PT  - Journal Article
PL  - United States
TA  - Rev Sci Instrum
JT  - The Review of scientific instruments
JID - 0405571
EDAT- 2014/08/03 06:00
MHDA- 2014/08/03 06:01
CRDT- 2014/08/03 06:00
PHST- 2014/08/03 06:00 [entrez]
PHST- 2014/08/03 06:00 [pubmed]
PHST- 2014/08/03 06:01 [medline]
AID - 10.1063/1.4890279 [doi]
PST - ppublish
SO  - Rev Sci Instrum. 2014 Jul;85(7):075111. doi: 10.1063/1.4890279.