Washington
As NASA's Phoenix Lander prepared to dig on Mars after an incredible 422-million mile voyage, an Indian American engineer who was among those who helped steer it there hoped it would tell if the red planet could support life.

"It's going to answer the age-old question of are we alone in the universe" said Prasun Desai, a senior engineer at NASA's Langley Research Centre in Hampton, Virginia, who led the team that made the mission to mars successful.

"What we're looking for is the presence of minerals in the rocks and soils. We're hoping to look for organic molecules. We're not looking for life directly. But we're hoping to see the signature," he said Monday.

Desai, aerospace engineer Jill Prince and research engineer Eric Queen from Langley were responsible for the entry, descent and landing of the spacecraft - sometimes called the "seven minutes of terror" - as NASA scientists in the control room in Pasadena, California stood on edge waiting for the touch down Sunday.

"It was an amazing feeling. The radar is on, we got good data and the soft landing happened almost flawlessly," said Desai. In those final moments, it really felt like "a fast roller coaster, but everything worked out great".

Launched Aug 4, 2007, Phoenix seemed to be in perfect health after its nine month long 422-million mile journey to the red planet as a new set of instructions was sent to the spacecraft Monday. The results, including more photographs, were expected soon. After about a week of checking out the spacecraft and its systems, the science mission will begin by digging up a soil sample.

From the narrow swath of images seen so far, "we see a flat, barren landscape that is kind of lumpy," Peter H. Smith of the University of Arizona, the mission's principal investigator told reporters Monday in Pasadena.

The lumpiness is a result of polygon-shaped furrows in the landscape that are caused by repeated expansion and contraction of an underground layer of water ice. When temperatures drop, the ice contracts and cracks.

Dust probably falls in the cracks, creating a shallow depression on the surface above. When temperatures rise, the ice expands again and, because the cracks have been filled, the centres of the polygons buckle upward.

When such cracks form in wetter parts of Earth's Arctic region, "melted ice runs into the cracks and re-freezes, so you end up getting what are called ice wedges," Dr. Smith said.

If this mission were to find ice wedges in the cracks on Mars, he added, "that would mean there was a very wet environment sometime in the past in this region, and that would be a major discovery for our science team."

In 2002, an orbiting spacecraft detected vast amounts of ice not far below Mars's surface. "But does the ice melt?" Dr. Smith asked. "That's the real question."

The solar-powered three-legged robotic Lander will manipulate a 7.7-foot arm to scoop up samples of underground ice and soil lying above the ice. Onboard laboratory instruments will analyse the samples. Cameras and a Canadian-supplied weather station will supply other information about the site's environment.

One research goal is to assess whether conditions at the site ever have been favourable for microbial life. The composition and texture of soil above the ice could give clues to whether the ice ever melts in response to long-term climate cycles. Another important question is whether the scooped-up samples contain carbon-based chemicals that are potential building blocks and food for life.

Langley's expertise in Mars landers started decades ago when it led the Viking project in the 1970s. Viking successfully landed two spacecraft on Mars in 1976. Researchers are still using data from those missions today.

"Many aspects of the design are still relying on the technology, the heritage of the Viking vehicle itself. The capsule shape is very similar," said Desai. "Viking also did a soft landing on Mars back in the mid-70s and we're doing the same here. So we're relying on a lot of the heritage that Viking pioneered."

Phoenix uses hardware from a spacecraft built for a 2001 launch that was cancelled in response to the loss of a similar Mars spacecraft during a 1999 landing attempt. Researchers who proposed the Phoenix mission saw the unused spacecraft as a resource for pursuing a new science opportunity.