Scientists at the briefing also announced the first results from the craft's Thermal and Evolved-Gas Analyzer (TEGA).
This instrument bakes soil samples to temperatures as high as 1,800°F (1,000°C) and "sniffs" the gases they release. (Read more about the Phoenix lander's onboard instruments.)
The team reports that heat caused the sample to emit water vapor, indicating that the soil has water-containing minerals.
"This is what we were hoping to see," said TEGA leader William Boynton of the University of Arizona.
"The soil sample clearly has interacted with water in the past," Boynton said—but how long ago that happened is still an open question.
Getting data at all was a welcome relief for the TEGA team, which has been plagued by technical difficulties.
The researchers were taken by surprise when the soil they collected turned out to be very clumpy and unable to easily fall through a screen and into the instrument.
Vibrating the screen for extended periods of time eventually sent the soil through, but it also seems to have created a short circuit in some of the instrument's wiring.
Luckily the short was in a part of the instrument that has now completed its test, allowing it to be shut down.
To prevent additional shorts, the team has revised the protocol so that it reduces the amount of shaking.
The arm now sprinkles its samples rather than just dropping them into the instrument, Boynton said.
SOURCES AND RELATED WEB SITES