MARS EXPLORATION ROVER LANDING SITE MEMORANDUM 

      December 13, 2000 

      To: Project and Landing Site Personnel 

      From: M. Golombek and T. Parker 

      Re: High-priority sites for MER 

We have received the requests for MOC imaging of prospective MER landing sites.
Overall the sites suggested appear well thought out and have been carefully
considered.  The majority included discussion of the science objectives, the
site safety via remote sensing data, and a discussion of any existing MOC
images. These arrived as e-mail messages as requested. We also took all
specific sites discussed in the abstracts submitted to the Landing Site
Workshop. A total of 29 specific sites were found in these two sources. There
is remarkable consensus on one site, the Hematite site. This site is the
subject of about 10 talks in the workshop and received 14 "votes" (, which are
not subject to recount or Supreme Court jurisdiction). The next highest
requested were crater lakes, with 5 votes for Gale, 3 for Gusev, 4 for other
crater lakes, and 2 for a similar fluvial outflow region. Next highest were
sites in Valles Marineris, with 4 votes for canyon sites, 4 votes for Valles
Marineris outflow sites, and one for the Ganges sand sheet. Beyond these sites
that received multiple votes are sites were proposed in Elysium, Isidis and the
highlands. The specific sites proposed and the votes they received are
tabulated below.

Tim and I plotted these sites on the existing landing site map (including
landing site ellipse size and orientation adjustments) and asked if any
obvious, high-priority sites (from the election results discussed above) were
not identified that should have been. In the eastern hemisphere, we found no
obvious omissions. Most of the major high priority terrains discussed were
included in the sites identified. Terrains not included were not discussed such
as Medusae Fossae, knobby terrain, smooth plains, and ridged plains. In the
western hemisphere, most of the discussed terrains are also included in the
sites, although outside of the Hematite sites few are on Noachian cratered
terrain.

If the Hematite site is a clear consensus choice of the community (as appears
so far), then no other sites in western Arabia, Terra Meridiani, and Xanthe
Terra need be studied in much detail as they are all within the 37 degree solid
angle operations keep out zone for the second landing site. As you recall from
the MS '01 landing site selection activity, the Hematite was shown to be one of
the safest regions in the equatorial region (deemed safe for the legged '01
lander), suggesting that this site can be considered as an ultra safe site that
is also scientifically compelling.

The MGS spacecraft is entering a period of operations where the ground tracks
overlap or walk very slowly. During this period, MOC mosaics can be obtained if
the ground tracks overlap the landing sites. We are submitting the list of
sites below to Mike Malin (MOC PI) and the MGS project for mosaicing, which the
low walk rate during this unique period allows.

With regard to a preliminary list of sites for early extended mission imaging,
the community interest is clear. We propose that high-priority sites suitable
for targeting by MOC (requiring spacecraft roll) include: the Hematite sites,
Gale, Gusev and the Valles Marineris sites. The other sites would be maintained
as targets for nadir observations.

Please send all comments to us as soon as you can. 


      Sites Proposed "votes" 

      Hematite Total 14 
      TM10A/20B 5 
      TM11A/22B 3 
      TM21B 2 
      TM12A/23B 2 
      TM9A/19B 2 

      Gale Total 5 
      EP82A 5 
      Gusev Total 3 
      EP55A 3 
      Other Crater Lakes Total 4 
      Meridiani Crater 2 
      TM15A 
      TM16A 
      Crater:EP69A 1 
      Boeddicker.Cr:EP64A 1 
      DuriusVallis:EP56A 2 
      Outflow Area 

      Valles Mar., Canyon Total 4 
      VM53A 2 
      VM48A 1 
      VM44A 1 

      Valles Mar., Outflow Total 5 
      VM42A 2 
      VM41A 2 
      VM37A 1 

      Elysium 1 each 
      EP52B, EP74A, EP71A, EP62B 
      EP77A, EP61B, EP49B 

      Apollinaris Chaos:Newsite 2 
      11.1S, 188.5W 

      Isidis 1 each 
      IP85A/96B 
      IP98B 

      Cratered Terrain:TM24B 1 

     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 
      Matthew Golombek Mars Exploration Program 
      Jet Propulsion Laboratory Landing Site Scientist 
      Mail Stop 183-501 Mars Pathfinder Project Scientist 
      4800 Oak Grove Drive Phone: (818) 393-7948 
      Pasadena, CA 91109 Fax: (818) 393-5059 
      e-mail: mgolombek@jpl.nasa.gov 
      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^