NASA's Phoenix Mars Lander very likely exposed clumps of ice while digging a trench in the soil of the Martian arctic some days back, mission scientists said Thursday. According to Peter Smith, the mission's principal investigator, crumbs of bright material initially photographed in a trench dug up by the Lander's arm later vanished. The conjecture now is that they must have been frozen water that vaporised after being exposed to the elements.
"These little clumps completely disappearing over the course of a few days, that is perfect evidence that it's ice," Smith said. "There had been some question whether the bright material was salt. Salt can't do that."
The principal mission of the Phoenix Mars Lander is to study whether the arctic region of the Red Planet, where it has touched down, could be habitable. It carries a robotic arm to dig up soil samples, which, scientists hope, will allow it to confirm the presence of frozen water.
The robotic arm has already dug up soil and deposited it on ovens on board the Lander for analysis. The sample, heated in the ovens, however, has failed to yield evidence of water. Scientists say it is likely that the scooped up soil was too 'clumpy' to have filtered through the pores of the oven for analysis. They will now attempt to scoop up a more powdery sample for analysis.
The bright crumbs were seen in the bottom of a trench that the arm dug up on 15 June. Several of these crumbs were gone when the cameras looked into the trench again early Thursday, NASA said.
Phoenix's arm, meanwhile, encountered hard surface yet again while digging another trench on Thursday. Scientists are hopeful of uncovering an icy layer, NASA said. While the earlier trench was called ''Dodo Goldilocks,'' the new trench is called "Snow White 2."
The space agency clarified that the robotic arm went into a "holding position" after three attempts to dig further, a phenomenon that is expected when it strikes a hard surface.
The Phoenix Lander is a follow up programme to the 2002 Mars Odyssey mission that detected hints of a vast store of ice below the surface of Mars' polar regions. Phoenix's landing area has polygon shapes in the ground that are similar to those found in Earth's permafrost regions. Since the patterns on Earth are caused by seasonal expansion and shrinking of underground ice, it is assumed that the arctic terrain where the Lander has touched down would also have a covered layer of ice.
Meanwhile, a glitch in the Lander's flash memory had NASA engineers preparing and dispatching a software patch to fix the problem that surfaced Tuesday. Phoenix generated a large amount of duplicative file-maintenance data on Tuesday. This forced mission scientist to avoid storing science data in the flash memory and instead transmit it to Earth at the end of each day.
"We now understand what happened, and we can fix it with a software patch," said Barry Goldstein, the Phoenix project manager at NASA's Jet Propulsion Laboratory in Pasadena.
The Phoenix landed near Mars' north pole on 25 May and is expected to carry out its mission over a period of 90 days.