FIRST ANNOUNCEMENT – NOVEMBER 2000

Dear Colleagues:

You are invited to participate in the First Landing Site Workshop for the two 2003 Mars Exploration Rovers. The workshop will be held January 24–25, 2001, at the NASA Ames Research Center in Mountain View, California.

An overview of the 2003 Mars Exploration Rovers (MERs) can viewed at http://athena.cornell.edu. A summary of NASA's Mars exploration strategy is at http://mars.jpl.nasa.gov/mep/mslides/index.html. Web tools for visualizing and analyzing relevant Mars data as well as an archive of previously proposed landing sites are available at http://marsoweb.nas.nasa.gov/landingsites/. In addition, a Web-based GIS interface for relevant Mars data is available at http://webgis.wr.usgs.gov/.

An Overview of Workshop Objectives:
The purpose of the Landing Site Workshop is to evaluate potential landing sites best suited to achieving stated mission science objectives within the constraints imposed by engineering requirements and the necessity of ensuring a safe landing. A NASA-appointed Landing Site Steering Committee and the Mars Exploration Rover Project will use the results of the workshop as the basis for narrowing the list of potential landing sites under consideration. Community consensus with respect to high priority sites will also be solicited. In addition, the workshop will provide a means for identifying potential landing sites as targets for the MGS MOC during the upcoming extended mission.

Mission Science Objectives:
Science objectives for the MERs relate to definition of the history of water and climate on Mars in locations where conditions may have been favorable for life. More specifically, the goal of each MER is to determine the aqueous, climatic, and geologic history of a site on Mars where conditions may have been favorable to the preservation of evidence of possible pre-biotic or biotic processes. Scientific criteria used in identification and selection of landing sites include locations possessing clear evidence for surface processes involving ancient water. Hence, potential sites encompass a wide range of possible settings, and may include former lacustrine or hydrothermal environments.

A more detailed description of the mission science objectives and requirements is available at http://athena.cornell.edu. The Rover's scientific instruments will be used to read the geologic record at the site, to investigate what role water played there, and to determine how suitable the conditions would have been for life.

Mission Engineering Constraints:
Because the ability to ensure a successful landing for both MERs is paramount, consideration of landing sites must include comprehensive assessment of limitations imposed by mission engineering constraints. Although these constraints continue to be established and refined, a description of preliminary values related to allowable locations, elevation, and surface properties follows. A complete description of mission engineering constraints is available at http://marsoweb.nas.nasa.gov/landingsites/mer2003 and at http://webgis.wr.usgs.gov/mer.

Both MERs are expected to operate on the surface of Mars for a minimum of 90 sols, with the second rover arriving 52 sols after the first. The operation of two rovers likely requires that the first rover (MER-A) be separated by roughly 37° (solid angle) from the second (MER-B) on the surface. Both MERs are required to land below the -1.3 km MOLA defined elevation, with respect to the MOLA defined geoid. Expected power usage and thermal cycling of the rovers further restricts the landing sites for MER-A and MER-B to between 15°S to 5°N and 5°S to 15°N, respectively.

Analysis of the expected flight path angle at atmospheric entry and dispersions produced by the atmosphere yield landing ellipses of approximately 80 km by 30 km for MER-A at 15°S up to roughly 360 km by 30 km for MER-B at 15°N. In addition, the approximate orientation of the ellipse rotates from 80° at 15°S to 89° at 5°N for MER-A and from 109° at 15°N to 103° at 5°S for MER-B, respectively, for the opening of the launch window. Ellipse sizes and orientations can be derived by linearly extrapolating between these end member values. All ellipse widths are 30 km. The MER project will not firm up these engineering constraints until the Critical Design Review for the mission in May 2001, but any required changes will be quickly reported on the landing site Web sites.

Images of the potential landing sites must appear hazard free and possess slopes generally less than 15°. Total rock coverage of the sites should be less than 20% (as derived from thermal inertia measurements), which should equate to surfaces possessing less than 1% rocks larger than 0.5 m high. In addition, radar reflectivity of the sites must be greater than 0.05 and extremely high albedo and low thermal inertia regions are to be avoided. Areas with fine component thermal inertia values of less than 3–4 × 10-3 cal cm-2 s-0.5 K-1 or cgs units (equivalent to 125–165 J m-2 s-0.5 K-1 or SI units) will not be considered. Finally, because the landing system has no means of reducing horizontal velocity, expected low-altitude winds must be less than 20 m/s.

All persons planning to participate in the workshop should review both the science and engineering constraints carefully, as only those landing sites that meet these constraints will be accepted for presentation at the workshop.

Examples of Potential Landing Sites:
A preliminary evaluation of potential landing sites was made by placing ellipses of the proper size (for each 2.5° in latitude) in all locations that are below -1.3 km in elevation, had acceptable fine component thermal inertia values, and were free of obvious hazards in the Mars Digital Image Mosaics (smooth and flat in the MDIM without scarps, large hills, depressions or large fresh craters). This analysis reveals that nearly 200 potential landing sites meet these criteria: 100 sites for MER-A and 85 for MER-B. Sites encompass a wide range of settings on the Martian surface including western Arabia Terra, Terra Meridiani, Chryse Planitia, Xanthe Terra, Valles Marineris, Elysium Planitia, Isidis Planitia, and Syrtis Major. Geologic units within these regions that may be accessed are similarly diverse and range from Noachian Plateau dissected, hilly, cratered, and subdued cratered units to Hesperian ridged plains, channel materials, and the Vastitas Borealis Formation to Amazonian smooth plains, channel materials, volcanics knobby materials and the Medusae Fossae Formation.

A complete listing of all of these sites can be viewed at http://marsoweb.nas.nasa.gov/landingsites/mer2003 and at http://webgis.wr.usgs.gov/mer. The preliminary list of potential landing sites included on the Web sites is not intended to be comprehensive, and persons are encouraged to identify and discuss additional potential landing sites that may also meet the mission science and engineering criteria.

How to Participate:
All members of the scientific community are encouraged to participate in this important activity. Persons wishing to make a presentation at the workshop are urged to carefully review the science objectives and engineering constraints at the Web sites noted above.

Most of the workshop will be devoted to submitted papers describing:  (1) the overall types of sites for the MERs based on their scientific and programmatic rationale and their suitability for safe landing and roving; and (2) individual landing sites on Mars and their scientific merit and safety. Individuals must prepare an abstract (standard LPSC format) summarizing their topic. Talks advocating an individual site must summarize the science merits and demonstrate that the proposed location satisfies the mission science and engineering requirements. A clear statement of the rationale for continued consideration as a possible landing site should also be included. A program will be prepared from the submitted abstracts and will be posted along with logistical information in early January 2001.

Abstracts are due by December 8, 2000 (no exceptions) and should be submitted using the electronic submission form provided. Detailed instructions on abstract format and submission and templates are also provided.

Badging and Logistics for the Workshop:
All workshop participants who do not have a U.S. government or military ID must obtain a visitor's badge to gain access through the Ames gate. All pre-registered participants will have a badge waiting for them at the Ames Visitor Badging Office (open from 6:00 a.m. to 6:00 p.m.). You must show a photo ID to be issued your badge. Allow ample time (~30 minutes) to pick up your badge before the workshop begins. Badges for foreign national visitors require substantial additional lead time for processing. Please contact the local organizer immediately (Ginny Gulick at vgulick@mail.arc.nasa.gov) for additional instructions if you are a foreign national and expect to attend the meeting.

Hotel vacancies in the Silicon Valley area are very scarce. It is therefore imperative that you arrange hotel accommodations as far in advance of the meeting as possible:  it may be difficult to obtain a reservation in the vicinity of Ames less than two weeks before the workshop. Details on hotels will be posted shortly at this Web site. In addition, there are rooms located on base at NASA Ames. These rooms are located in old Navy housing but are actually very nice. All rooms have a refrigerator, and some have microwave ovens and TVs. The nicer rooms are near the center of the base, have phones, and are $50 (no tax). The rooms on the edge of the center (1 mile from the meeting site) do not have phones and are $35 (no tax). Check in is until 10 p.m. (NOT 24 hour). If you wish to stay in the base housing call 650-603-7101 to make reservations and let Ginny Gulick know the dates you will need to have access to Ames.

The workshop will be held in the Space Science Auditorium located in Building 245 at Ames. Seating is limited to 100 people. Oral presentations are strongly preferred as there is limited space for poster presentations.

Input from the science community is critical to identification of optimal landing sites for the MERs. We look forward to your involvement in this process!

Regards,
John Grant and Matt Golombek
Co-Chairs, Mars Landing Site Steering Committee

Back to Top Back to 2003 Mars Exploration Rovers main page