Astronomy Now Online

Top Stories

Chandra weighs up supermassive

black hole

...thanks to an innovative new technique, the masses of black holes can now be derived from the temperatures of hot gasses compressed in the jaws of these celestial cannibals...

read more

Brightest star in the Galaxy has new competition

...Eta Carinae has a new rival for its long-held title of brightest star in the Milky Way, in the shape of the Peony nebula star...

read more

Water dampens Moon formation theory analysis of lunar rocks reveals enough water to challenge classic theories of lunar formation and evolution...

read more

Spaceflight Now +

Subscribe to Spaceflight Now Plus for access to our extensive video collections!
How do I sign up?
Video archive

STS-120 day 2 highlights

Flight Day 2 of Discovery's mission focused on heat shield inspections. This movie shows the day's highlights.


STS-120 day 1 highlights

The highlights from shuttle Discovery's launch day are packaged into this movie.


STS-118: Highlights

The STS-118 crew, including Barbara Morgan, narrates its mission highlights film and answers questions in this post-flight presentation.

 Full presentation
 Mission film

STS-120: Rollout to pad

Space shuttle Discovery rolls out of the Vehicle Assembly Building and travels to launch pad 39A for its STS-120 mission.


Dawn leaves Earth

NASA's Dawn space probe launches aboard a Delta 2-Heavy rocket from Cape Canaveral to explore two worlds in the asteroid belt.

 Full coverage

Dawn: Launch preview

These briefings preview the launch and science objectives of NASA's Dawn asteroid orbiter.

 Launch | Science

Become a subscriber
More video

Phoenix rasps frozen layer and scoops sample

Posted: July 17, 2008

Using the robotic arm’s powered rasp, Phoenix has successfully drilled into the cement-hard frozen soil at its landing site, loosening material that was later collected by the lander's scoop.

Over the last few days Phoenix has been clearing away loose soil from a subsurface layer of hard-frozen material within the Snow White trench that has been the focus of the mission so far. The motorised rasp tool then made two distinct holes in the trench, about one centimetre apart, which loosened the surrounding material.


The rasping tool on Phoenix drilled two holes (upper left and inset) into the cement-hard icy surface in the Snow White trench. Image: NASA/JPL-Caltech/University of Arizona/Texas A&M University.


The rasping apparatus, which is located on the back of the robotic arm scoop, is operated by a motor which rapidly rotates the tool. The angle of the rasp is gradually increased from its near horizontal starting position while it is rotating, so that shavings of the icy surface are kicked sideways onto a collection surface. After the rasp is stopped, a series of moves by the scoop then shifts the collected shavings from the back to the front of the scoop.

"While Phoenix was in development, we added the rasp to the robotic arm design specifically to grind into very hard surface ice," says Barry Goldstein, Phoenix project manager at NASA's Jet Propulsion Laboratory. "This is the exactly the situation we find we are facing on Mars, so we believe we have the right tool for the job. Honeybee Robotics in New York City did a heroic job of designing and delivering the rasp on a very short schedule."

The Robotic Arm Camera documented the chain of events but the images and data sent back to Earth yesterday suggest that the properties of the icy shavings changed slightly over the hours following its collection.

"This was a trial that went really well," says Richard Morris, a Phoenix science team member from NASA's Johnson Space Centre, Houston. "While the putative ice sublimed out of the shavings over several hours, this shows us there will be a good chance ice will remain in a sample for delivery [to Phoenix's laboratory ovens]”.


Members of NASA Phoenix Mars Mission's Robotic Arm engineering team test the arm's motorised rasp in the Payload Interoperability Testbed at the University of Arizona, Tucson. The testbed has a near-duplicate of the Phoenix lander for use in developing techniques to be used on Mars and for checking commands planned for the lander. Image: University of Arizona.

Phoenix will continue to test the rasping method and scooping action under the watchful eye of the lander’s cameras over the next few days, in preparation of collecting and delivering a sample for analysis in one of Phoenix's Thermal and Evolved-Gas Analyser ovens. The Phoenix team has also been testing the rasping and collection techniques on simulated Martian ice with a near-replica model of Phoenix in a test facility at the University of Arizona in Tucson.

Related Stories

Jul   11 First success with Phoenix soil probe... read more

Jul   10 Phoenix struggling with icy payload read more

Jul   03 Next Phoenix bake could be last read more

Jun  30 Phoenix soil could support life read more

Jun  23 Frozen water confirmed on Mars read more

Jun  19 Bright chunks must have been ice read more

Jun  17 First results from Phoenix bakery read more

Jun  12 An oven full of sand read more

Jun  10 Clumpy Martian soil challenges Phoenix read more

Jun  06 Closest view ever of Mars sand read more

Jun  03 Phoenix scoops up Martian soil read more

Jun  02 Phoenix sees possible ice read more

May 30 Phoenix flexes robotic arm read more

May 28 HiRISE captures Phoenix descent read more

May 26 Spectacular new colour view of Mars read more

May 23 Phoenix prepares for Mars landing read more