Astrogeology Science Center

Publications

Filter Total Items: 890
Publication Thumbnail
Year Published: 2000

Surface ages and resurfacing rates of the Polar Layered Deposits on Mars

Interpretation of the polar stratigraphy of Mars in terms of global climate changes is complicated by the significant difference in surface ages between the north and south polar layered terrains inferred from crater statistics. We have reassessed the cratering record in both polar regions using Viking Orbiter and Mariner 9 ...

Herkenhoff, Kenneth E.; Plaut, Jeffrey J.

Publication Thumbnail
Year Published: 2000

Surface properties of Mars' polar layered deposits and polar landing sites

On December 3, 1999, the Mars Polar Lander and Mars Microprobes will land on the planet's south polar layered deposits near (76°S, 195°W) and conduct the first in situ studies of the planet's polar regions. The scientific goals of these missions address several poorly understood and globally significant issues, such as polar meteorology, the...

Vasavada, Ashwin R.; Williams, Jean-Pierre; Paige, David A.; Herkenhoff, Kenneth E.; Bridges, Nathan T.; Greeley, Ronald; Murray, Bruce C.; Bass, Deborah S.; McBride, Karen S.

Publication Thumbnail
Year Published: 2000

The state and future of Mars polar science and exploration

As the planet's principal cold traps, the martian polar regions have accumulated extensive mantles of ice and dust that cover individual areas of ∼106 km2 and total as much as 3–4 km thick. From the scarcity of superposed craters on their surface, these layered deposits are thought to be comparatively young—preserving a record of the...

Clifford, S.M.; Crisp, D.; Fisher, D.A.; Herkenhoff, Kenneth E.; Smrekar, S.E.; Thomas, P.C.; Wynn-Williams, D. D.; Zurek, R.W.; Barnes, J.R.; Bills, B.G.; Blake, E.W.; Calvin, W. M.; Cameron, J.M.; Carr, M.H.; Christensen, P. R.; Clark, B. C.; Clow, G.D.; Cutts, J.A.; Dahl-Jensen, D.; Durham, W.B.; Fanale, F. P.; Farmer, J.D.; Forget, F.; Gotto-Azuma, K.; Grard, R.; Haberle, R.M.; Harrison, W.; Harvey, R.; Howard, A.D.; Ingersoll, A.P.; James, P.B.; Kargel, J.S.; Kieffer, H. H.; Larsen, J.; Lepper, K.; Malin, M. C.; McCleese, D.J.; Murray, B.; Nye, J.F.; Paige, D.A.; Platt, S.R.; Plaut, J.J.; Reeh, N.; Rice, J.W.; Smith, D.E.; Stoker, C.R.; Tanaka, K.L.; Mosley-Thompson, E.; Thorsteinsson, T.; Wood, S.E.; Zent, A.; Zuber, M.T.; Zwally, H.J.

Publication Thumbnail
Year Published: 2000

Topography and Stratigraphy of the Northern Martian Polar Layered Deposits Using Photoclinometry, Stereogrammetry, and MOLA Altimetry

We present two photoclinometric profiles across a trough in the martian northern polar layered terrain. Complications caused by albedo variations were avoided by using an early springtime Viking image with a thin cover of seasonal CO2 frost. The topographic profiles were constrained with stereogrammetric elevations derived from...

Fenton, Lori K.; Herkenhoff, Kenneth E.
.

Publication Thumbnail
Year Published: 2000

Variability of Mars' North Polar water ice cap: I. Analysis of Mariner 9 and Viking Orbiter imaging data

Previous studies interpreted differences in ice coverage between Mariner 9 and Viking Orbiter observations of Mars' north residual polar cap as evidence of interannual variability of ice deposition on the cap. However, these investigators did not consider the possibility that there could be significant changes in the ice coverage within the...

Bass, Deborah S.; Herkenhoff, Kenneth E.; Paige, David A.

Publication Thumbnail
Year Published: 1999

Geologic map of Ophir and central Candor Chasmata (MTM -05072) of Mars

The geologic map of Ophir and central Candor Chasmata is one of a series of 1:500,000 scale maps prepared for areas on Mars that are of particular scientific interest and may serve as potential future landing sites. This map is also part of a set that includes east Candor Chasma, west Candor Chasma, and Melas Chasma. The geologic interpretations...

Lucchitta, Baerbel K.
Geologic map of Ophir and central Candor Chasmata (MTM -05072) of Mars; 1999; I; 2568; Lucchitta, Baerbel K.

Publication Thumbnail
Year Published: 1999

Geologic map of the Galaxias quadrangle (MTM 35217) of Mars

The Galaxias region (MTM 35217) is one of a series of 1:500,000-scale science study areas on Mars sponsored by NASA's Planetary Geology and Geophysics Program. Situated near the northern limit of lava flows associated with Elysium Mons, this region includes a mixture of volcanic and nonvolcanic terrains. The region is also of interest for the...

De Hon, Rene A.; Mouginis-Mark, Peter J.; Brick, Eugene E.
Geologic map of the Galaxias quadrangle (MTM 35217) of Mars; 1999; I; 2579; De Hon, Rene A.; Mouginis-Mark, Peter J.; Brick, Eugene E.

Publication Thumbnail
Year Published: 1999

Does Europa have a subsurface ocean? Evaluation of the geological evidence

It has been proposed that Jupiter's satellite Europa currently possesses a global subsurface ocean of liquid water. Galileo gravity data verify that the satellite is differentiated into an outer H2O layer about 100 km thick but cannot determine the current physical state of this layer (liquid or solid). Here we summarize the geological evidence...

Pappalardo, Robert T.; Belton, Michael J.S.; Breneman, H.H.; Carr, M.H.; Chapman, Clark R.; Collins, G.C.; Denk, T.; Fagents, S.; Geissler, Paul E.; Giese, B.; Greeley, R.; Greenberg, R.; Head, J.W.; Helfenstein, P.; Hoppa, G.; Kadel, S.D.; Klaasen, K.P.; Klemaszewski, James E.; Magee, K.P.; McEwen, Alfred S.; Moore, J.M.; Moore, W.B.; Neukum, G.; Phillips, C.B.; Prockter, L.M.; Schubert, G.; Senske, D.A.; Sullivan, R.J.; Tufts, B.R.; Turtle, E. P.; Wagner, Robert; Williams, K.K.

Publication Thumbnail
Year Published: 1999

Observations of Phobos, Deimos, and bright stars with the Imager for Mars Pathfinder

The Imager for Mars Pathfinder (IMP) was used to observe several objects during the Martian night. The satellites, Phobos and Deimos, were observed on two occasions each, through the IMP geological filters covering the wavelength range 440 nm to 1 μm. The observations were converted to geometric albedo using triaxial ellipsoid models of the...

Thomas, Nick; Britt, D.T.; Herkenhoff, Kenneth E.; Murchie, Scott L.; Semenov, B.; Keller, H.U.; Smith, P.H.

Publication Thumbnail
Year Published: 1999

Mars Pathfinder spectral measurements of Phobos and Deimos: Comparison with previous data

The Imager for Mars Pathfinder (IMP) acquired four spectra of parts of the sub‐Mars hemispheres of Phobos and Deimos. The measured region of Phobos is expected to be a mixture of the two spectral units identified on that satellite from Phobos 2 data, and the IMP spectra of Phobos are intermediate to the two units as expected. The derived geometric...

Murchie, Scott L.; Thomas, Nick; Britt, Daniel; Herkenhoff, Kenneth E.; Bell, James F.

Publication Thumbnail
Year Published: 1999

Overview of the Mars Pathfinder Mission: Launch through landing, surface operations, data sets, and science results

Mars Pathfinder successfully landed at Ares Vallis on July 4, 1997, deployed and navigated a small rover about 100 m clockwise around the lander, and collected data from three science instruments and ten technology experiments. The mission operated for three months and returned 2.3 Gbits of data, including over 16,500 lander and 550 rover images,...

Golombek, M. P.; Anderson, R.C.; Barnes, J.R.; Bell, J. F. III; Bridges, N. T.; Britt, D.T.; Brückner, J.; Cook, R.A.; Crisp, D.; Crisp, J.A.; Economou, T.; Folkner, W.M.; Greeley, R.; Haberle, R.M.; Hargraves, R.B.; Harris, J.A.; Haldemann, A.F.C.; Herkenhoff, Kenneth E.; Hviid, S.F.; Jaumann, R.; Johnson, J. R.; Kallemeyn, P.H.; Keller, H.U.; Kirk, Randolph L.; Knudsen, J.M.; Larsen, S.; Lemmon, M. T.; Madsen, M.B.; Magalhães, J.A.; Maki, J.N.; Malin, M.C.; Manning, R.M.; Matijevic, J.; McSween, H.Y.; Moore, H.J.; Murchie, S.L.; Murphy, J.R.; Parker, T.J.; Rieder, R.; Rivellini, T.P.; Schofield, J.T.; Seiff, A.; Singer, R.B.; Smith, P.H.; Soderblom, Laurence A.; Spencer, D.A.; Stoker, C.R.; Sullivan, R.; Thomas, N.; Thurman, S.W.; Tomasko, M.G.; Vaughan, R.M.; Wänke, H.; Ward, A. W.; Wilson, G.R.

Publication Thumbnail
Year Published: 1999

Aeolian features and processes at the Mars Pathfinder landing site

The Mars Pathfinder landing site contains abundant features attributed to aeolian, or wind, processes. These include wind tails, drift deposits, duneforms of various types, ripplelike features, and ventifacts (the first clearly seen on Mars). Many of these features are consistant with formation involving sand-size particles. Although some features...

Greeley, Ronald; Kraft, Michael; Sullivan, Robert; Wilson, Gregory; Bridges, Nathan; Herkenhoff, Kenneth E.; Kuzmin, Ruslan O.; Malin, Michael; Ward, Wes