Wet Chemistry experiments on the 2007 Phoenix Mars Scout Lander mission: Data analysis and results

S. P. Kounaves, M. H. Hecht, J. Kapit, K. Gospodinova, L. Deflores, R. C. Quinn, William V. Boynton, B. C. Clark, D. C. Catling, P. Hredzak, D. W. Ming, Q. Moore, J. Shusterman, S. Stroble, S. J. West, S. M M Young

Research output: Contribution to journalArticle

86 Citations (Scopus)

Abstract

Chemical analyses of three Martian soil samples were performed using the Wet Chemistry Laboratories on the 2007 Phoenix Mars Scout Lander. One soil sample was obtained from the top ∼2 cm (Rosy Red) and two were obtained at ∼5 cm depth from the ice table interface (Sorceress 1 and Sorceress 2). When mixed with water in a ∼1:25 soil to solution ratio (by volume), a portion of the soil components solvated. Ion concentrations were measured using an array of ion selective electrodes and solution conductivity using a conductivity cell. The measured concentrations represent the minimum leachable ions in the soil and do not take into account species remaining in the soil. Described is the data processing and analysis for determining concentrations of seven ionic species directly measured in the soil/solution mixture. There were no significant differences in concentrations, pH, or conductivity, between the three samples. Using laboratory experiments, refinement of the surface calibrations, and modeling, we have determined a pH for the soil solution of 7.7(±0.3), under prevalent conditions, carbonate buffering, and PCo 2 in the cell headspace. Perchlorate was the dominant anion in solution with a concentration for Rosy Red of 2.7(±1) mM. Equilibrium modeling indicates that measured [Ca2+] at 0.56(±0.5) mM and [Mg2+at 2.9(±1.5) mM, are consistent with carbonate equilibrium for a saturated solution. The [Na+] and [K+] were 1.4(±0.6), and 0.36(±0.3) mM, respectively. Results indicate that the leached portion of soils at the Phoenix landing site are slightly alkaline and dominated by carbonate and Perchlorate. However, it should be noted that there is a 5-15 mM discrepancy between measured ions and conductivity and another species may be present.

Original languageEnglish (US)
Article numberE00E10
JournalJournal of Geophysical Research: Space Physics
Volume115
Issue number1
DOIs
StatePublished - Jan 2010
Externally publishedYes

Fingerprint

Phoenix (AZ)
mars
Mars
soils
chemistry
Soils
soil
experiment
Experiments
Carbonates
conductivity
carbonates
perchlorate
ion
Ions
perchlorates
carbonate
ion selective electrodes
Ion selective electrodes
data analysis

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

Cite this

Kounaves, S. P., Hecht, M. H., Kapit, J., Gospodinova, K., Deflores, L., Quinn, R. C., ... Young, S. M. M. (2010). Wet Chemistry experiments on the 2007 Phoenix Mars Scout Lander mission: Data analysis and results. Journal of Geophysical Research: Space Physics, 115(1), [E00E10]. https://doi.org/10.1029/2009JE003424

Wet Chemistry experiments on the 2007 Phoenix Mars Scout Lander mission : Data analysis and results. / Kounaves, S. P.; Hecht, M. H.; Kapit, J.; Gospodinova, K.; Deflores, L.; Quinn, R. C.; Boynton, William V.; Clark, B. C.; Catling, D. C.; Hredzak, P.; Ming, D. W.; Moore, Q.; Shusterman, J.; Stroble, S.; West, S. J.; Young, S. M M.

In: Journal of Geophysical Research: Space Physics, Vol. 115, No. 1, E00E10, 01.2010.

Research output: Contribution to journalArticle

Kounaves, SP, Hecht, MH, Kapit, J, Gospodinova, K, Deflores, L, Quinn, RC, Boynton, WV, Clark, BC, Catling, DC, Hredzak, P, Ming, DW, Moore, Q, Shusterman, J, Stroble, S, West, SJ & Young, SMM 2010, 'Wet Chemistry experiments on the 2007 Phoenix Mars Scout Lander mission: Data analysis and results', Journal of Geophysical Research: Space Physics, vol. 115, no. 1, E00E10. https://doi.org/10.1029/2009JE003424
Kounaves, S. P. ; Hecht, M. H. ; Kapit, J. ; Gospodinova, K. ; Deflores, L. ; Quinn, R. C. ; Boynton, William V. ; Clark, B. C. ; Catling, D. C. ; Hredzak, P. ; Ming, D. W. ; Moore, Q. ; Shusterman, J. ; Stroble, S. ; West, S. J. ; Young, S. M M. / Wet Chemistry experiments on the 2007 Phoenix Mars Scout Lander mission : Data analysis and results. In: Journal of Geophysical Research: Space Physics. 2010 ; Vol. 115, No. 1.
@article{8344f471d4fe49a3b4e1c097bfe3fd6e,
title = "Wet Chemistry experiments on the 2007 Phoenix Mars Scout Lander mission: Data analysis and results",
abstract = "Chemical analyses of three Martian soil samples were performed using the Wet Chemistry Laboratories on the 2007 Phoenix Mars Scout Lander. One soil sample was obtained from the top ∼2 cm (Rosy Red) and two were obtained at ∼5 cm depth from the ice table interface (Sorceress 1 and Sorceress 2). When mixed with water in a ∼1:25 soil to solution ratio (by volume), a portion of the soil components solvated. Ion concentrations were measured using an array of ion selective electrodes and solution conductivity using a conductivity cell. The measured concentrations represent the minimum leachable ions in the soil and do not take into account species remaining in the soil. Described is the data processing and analysis for determining concentrations of seven ionic species directly measured in the soil/solution mixture. There were no significant differences in concentrations, pH, or conductivity, between the three samples. Using laboratory experiments, refinement of the surface calibrations, and modeling, we have determined a pH for the soil solution of 7.7(±0.3), under prevalent conditions, carbonate buffering, and PCo 2 in the cell headspace. Perchlorate was the dominant anion in solution with a concentration for Rosy Red of 2.7(±1) mM. Equilibrium modeling indicates that measured [Ca2+] at 0.56(±0.5) mM and [Mg2+at 2.9(±1.5) mM, are consistent with carbonate equilibrium for a saturated solution. The [Na+] and [K+] were 1.4(±0.6), and 0.36(±0.3) mM, respectively. Results indicate that the leached portion of soils at the Phoenix landing site are slightly alkaline and dominated by carbonate and Perchlorate. However, it should be noted that there is a 5-15 mM discrepancy between measured ions and conductivity and another species may be present.",
author = "Kounaves, {S. P.} and Hecht, {M. H.} and J. Kapit and K. Gospodinova and L. Deflores and Quinn, {R. C.} and Boynton, {William V.} and Clark, {B. C.} and Catling, {D. C.} and P. Hredzak and Ming, {D. W.} and Q. Moore and J. Shusterman and S. Stroble and West, {S. J.} and Young, {S. M M}",
year = "2010",
month = "1",
doi = "10.1029/2009JE003424",
language = "English (US)",
volume = "115",
journal = "Journal of Geophysical Research: Space Physics",
issn = "2169-9380",
publisher = "Wiley-Blackwell",
number = "1",

}

TY - JOUR

T1 - Wet Chemistry experiments on the 2007 Phoenix Mars Scout Lander mission

T2 - Data analysis and results

AU - Kounaves, S. P.

AU - Hecht, M. H.

AU - Kapit, J.

AU - Gospodinova, K.

AU - Deflores, L.

AU - Quinn, R. C.

AU - Boynton, William V.

AU - Clark, B. C.

AU - Catling, D. C.

AU - Hredzak, P.

AU - Ming, D. W.

AU - Moore, Q.

AU - Shusterman, J.

AU - Stroble, S.

AU - West, S. J.

AU - Young, S. M M

PY - 2010/1

Y1 - 2010/1

N2 - Chemical analyses of three Martian soil samples were performed using the Wet Chemistry Laboratories on the 2007 Phoenix Mars Scout Lander. One soil sample was obtained from the top ∼2 cm (Rosy Red) and two were obtained at ∼5 cm depth from the ice table interface (Sorceress 1 and Sorceress 2). When mixed with water in a ∼1:25 soil to solution ratio (by volume), a portion of the soil components solvated. Ion concentrations were measured using an array of ion selective electrodes and solution conductivity using a conductivity cell. The measured concentrations represent the minimum leachable ions in the soil and do not take into account species remaining in the soil. Described is the data processing and analysis for determining concentrations of seven ionic species directly measured in the soil/solution mixture. There were no significant differences in concentrations, pH, or conductivity, between the three samples. Using laboratory experiments, refinement of the surface calibrations, and modeling, we have determined a pH for the soil solution of 7.7(±0.3), under prevalent conditions, carbonate buffering, and PCo 2 in the cell headspace. Perchlorate was the dominant anion in solution with a concentration for Rosy Red of 2.7(±1) mM. Equilibrium modeling indicates that measured [Ca2+] at 0.56(±0.5) mM and [Mg2+at 2.9(±1.5) mM, are consistent with carbonate equilibrium for a saturated solution. The [Na+] and [K+] were 1.4(±0.6), and 0.36(±0.3) mM, respectively. Results indicate that the leached portion of soils at the Phoenix landing site are slightly alkaline and dominated by carbonate and Perchlorate. However, it should be noted that there is a 5-15 mM discrepancy between measured ions and conductivity and another species may be present.

AB - Chemical analyses of three Martian soil samples were performed using the Wet Chemistry Laboratories on the 2007 Phoenix Mars Scout Lander. One soil sample was obtained from the top ∼2 cm (Rosy Red) and two were obtained at ∼5 cm depth from the ice table interface (Sorceress 1 and Sorceress 2). When mixed with water in a ∼1:25 soil to solution ratio (by volume), a portion of the soil components solvated. Ion concentrations were measured using an array of ion selective electrodes and solution conductivity using a conductivity cell. The measured concentrations represent the minimum leachable ions in the soil and do not take into account species remaining in the soil. Described is the data processing and analysis for determining concentrations of seven ionic species directly measured in the soil/solution mixture. There were no significant differences in concentrations, pH, or conductivity, between the three samples. Using laboratory experiments, refinement of the surface calibrations, and modeling, we have determined a pH for the soil solution of 7.7(±0.3), under prevalent conditions, carbonate buffering, and PCo 2 in the cell headspace. Perchlorate was the dominant anion in solution with a concentration for Rosy Red of 2.7(±1) mM. Equilibrium modeling indicates that measured [Ca2+] at 0.56(±0.5) mM and [Mg2+at 2.9(±1.5) mM, are consistent with carbonate equilibrium for a saturated solution. The [Na+] and [K+] were 1.4(±0.6), and 0.36(±0.3) mM, respectively. Results indicate that the leached portion of soils at the Phoenix landing site are slightly alkaline and dominated by carbonate and Perchlorate. However, it should be noted that there is a 5-15 mM discrepancy between measured ions and conductivity and another species may be present.

UR - http://www.scopus.com/inward/record.url?scp=77649120568&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=77649120568&partnerID=8YFLogxK

U2 - 10.1029/2009JE003424

DO - 10.1029/2009JE003424

M3 - Article

AN - SCOPUS:77649120568

VL - 115

JO - Journal of Geophysical Research: Space Physics

JF - Journal of Geophysical Research: Space Physics

SN - 2169-9380

IS - 1

M1 - E00E10

ER -