June 25, 2008

Dwayne Brown
Headquarters, Washington
202-358-1726
dwayne.c.brown@nasa.gov

Guy Webster 
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-6278
guy.webster@jpl.nasa.gov

Sara Hammond 
University of Arizona, Tucson 
520-626-1974 
shammond@lpl.arizona.edu

RELEASE: 08-160

NASA'S PHOENIX MARS LANDER PUTS SOIL IN CHEMISTRY LAB, TEAM DISCUSSES NEXT STEPS

TUCSON, Ariz. -- NASA's Phoenix Mars Lander placed a sample of Martian 
soil in the spacecraft's wet chemistry laboratory today for the first 
time. Results from that instrument, part of Phoenix's Microscopy, 
Electrochemistry and Conductivity Analyzer, are expected to provide 
the first measurement of the acidity or alkalinity of the planet's 
soil. 

The analysis of this and other soil samples will help researchers 
determine whether ice beneath the soil ever has melted, and whether 
the soil has other qualities favorable for life. 

The Phoenix team is discussing what sample to deliver next to the 
lander's other analytical instrument, which bakes and sniffs soil to 
identify volatile ingredients. Engineers have identified possible 
problems in the mechanical and electrical operation of that 
instrument, the Thermal and Evolved-Gas Analyzer, or TEGA. 

Scientists are studying information provided by TEGA's analysis of the 
first Martian soil sample put in that instrument. The instrument has 
eight single-use oven cells; each cell can analyze one sample. When 
doors for a second TEGA oven were commanded open last week, the doors 
opened only partway. Later, the team determined that mechanical 
interference may prevent doors on that oven and three others from 
opening fully. The remaining three ovens are expected to have one 
door that opens fully and one that opens partially, as was the case 
with the first oven used. 

"The tests we have done in our test facility during the past few days 
show the robotic arm can deliver the simulated Martian soil through 
the opening with the doors in this configuration," said William 
Boynton of the University of Arizona, Tucson, lead scientist for 
TEGA. "We plan to save the cells where doors can open wider for 
accepting ice samples." 

Scientists believe the first soil sample delivered to TEGA was so 
clumpy that soil particles clogged a screen over the opening. Four 
days of vibration eventually succeeded at getting the soil through 
the screen. However, engineers believe the use of a motor to create 
the vibration may also have caused a short circuit in wiring near 
that oven. Concern about triggering other short circuits has prompted 
the Phoenix team to be cautious about the use of other TEGA cells. 

Subsequent soil samples for TEGA will be delivered with a different 
method than the first. The newer method will sprinkle soil into the 
instrument to make it easier for particles to get through the 
screens. 

The Phoenix mission is led by Peter Smith at the University of Arizona 
with project management at NASA's Jet Propulsion Laboratory in 
Pasadena, Calif., and the development partnership at Lockheed Martin 
in Denver. International contributions are 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. 

EDITOR’S NOTE:  

NASA and the University of Arizona, Tucson, will hold a news media 
teleconference at 10:30 a.m. PDT, Thursday, June 26, to discuss 
science results and provide an update on future science gathering 
plans. To participate in the teleconference, news media should phone 
the JPL Media Relations Office at 818-354-5011 by 10 a.m. PDT, June 
26, to obtain the dial-in number and passcode. For more information 
about the mission, visit: 

http://www.nasa.gov/phoenix 

	
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