Bright Chunks At Phoenix Lander's Mars Site Must Have Been Ice
Bright Chunks At Phoenix Lander's Mars Site Must Have Been Ice
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. 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."
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