[meteorite-list] Bright Chunks at Phoenix Lander's Mars Site Must Have Been Ice

[Ron Baalke]

Bright Chunks at Phoenix Lander's Mars Site Must Have Been Ice
Johnny Cruz
University of Arizona
June 19, 2008

Dice-size crumbs of bright material have vanished from inside a trench where
they were photographed by NASA's Phoenix Mars Lander four days ago,
convincing scientists that the material was frozen water that vaporized
after digging exposed it. 

"It must be ice," said Phoenix Principal Investigator Peter Smith of The
University of Arizona, Tucson. 

"These little clumps completely disappearing over the course of a few days,
that is perfect evidence that it's ice," Smith added. "There had been some
question whether the bright material was salt. Salt can't do that." 

The chunks were left at the bottom of a trench informally called
"Dodo-Goldilocks" when Phoenix's Robotic Arm enlarged that trench on June
15, during the 20th Martian day, or sol, since landing. Several were gone
when Phoenix looked at the trench early today, on Sol 24. 

Also early today, digging in a different trench, the Robotic Arm connected
with a hard surface that has scientists excited about the prospect of next
uncovering an icy layer. 

The Phoenix science team spent Thursday analyzing new images and data
successfully returned from the lander earlier in the day. 

Studying the initial findings from the new "Snow White 2" trench, located to
the right of "Snow White 1," Ray Arvidson of Washington University in St.
Louis, co-investigator for the robotic arm, said, "We have dug a trench and
uncovered a hard layer at the same depth as the ice layer in our other
trench." 

On Sol 24, Phoenix extended the first trench in the middle of a polygon at
the "Wonderland" site. While digging, the Robotic Arm came upon a firm
layer, and after three attempts to dig further, the arm went into a holding
position. Such an action is expected when the Robotic Arm comes upon a hard
surface. 

Meanwhile, the spacecraft team at Lockheed Martin Space Systems in Denver is
preparing a software patch to send to Phoenix in a few days so scientific
data can again be saved onboard overnight when needed. Because of a large
amount a duplicative file-maintenance data generated by the spacecraft
Tuesday, the team is taking the precaution of not storing science data in
Phoenix's flash memory, and instead downlinking it at the end of every day,
until the conditions that produced those duplicative data files are
corrected. 

"We now understand what happened, and we can fix it with a software patch,"
said Phoenix Project Manager Barry Goldstein of NASA's Jet Propulsion
Laboratory, Pasadena. "Our three-month schedule has 30 days of margin for
contingencies like this, and we have used only one contingency day out of 24
sols. The mission is well ahead of schedule. We are making excellent
progress toward full mission success." 

The Phoenix mission is led by Smith of the UA with project management at JPL
and development partnership at Lockheed Martin, located in Denver.
International contributions come from the Canadian Space Agency; the
University of Neuchatel, Switzerland; the universities of Copenhagen and
Aarhus, Denmark; Max Planck Institute, Germany; and the Finnish
Meteorological Institute.

LINKS:
http://phoenix.lpl.arizona.edu <http://phoenix.lpl.arizona.edu/> 
http://www.nasa.gov/phoenix

CONTACTS:
Sara Hammond, University of Arizona, Tucson (520-626-1974;
shammond at lpl.arizona.edu)
Guy Webster, Jet Propulsion Laboratory, Pasadena, Calif. (818-354-6278;
guy.webster at jpl.nasa.gov)
Dwayne Brown, NASA Headquarters, Washington (202-358-1726;
dwayne.c.brown at nasa.gov)