Water found on Mars

Laboratory tests aboard NASA’s Phoenix Mars Lander have identified water in a soil sample. The lander’s robotic arm delivered the sample Wednesday to an instrument that identifies water vapors produced by the heating of samples.

“We have water,” says William Boynton of the University of Arizona, lead scientist for the Thermal and Evolved-Gas Analyzer (TEGA). “We’ve seen evidence for this water ice before in observations by the Mars Odyssey orbiter and in disappearing chunks observed by Phoenix last month, but this is the first time martian water has been touched and tasted.”

With enticing results so far and the spacecraft in good shape, NASA also announced operational funding for the mission will extend through September 30. The original prime mission of 3 months ends in late August. The mission extension adds 5 weeks to the 90 days of the prime mission.

“Phoenix is healthy and the projections for solar power look good, so we want to take full advantage of having this resource in one of the most interesting locations on Mars,” says Michael Meyer, chief scientist for the Mars Exploration Program at NASA Headquarters in Washington.

The soil sample came from a trench approximately 2 inches deep. When the robotic arm first reached that depth, it hit a hard layer of frozen soil. Two attempts to deliver samples of icy soil on days when fresh material was exposed were foiled when the samples became stuck inside the scoop. Most of the material in Wednesday’s sample had been exposed to the air for 2 days, letting some of the water in the sample vaporize away and making the soil easier to handle.

“Mars is giving us some surprises,” says Phoenix principal investigator Peter Smith of the University of Arizona. “We’re excited because surprises are where discoveries come from. One surprise is how the soil is behaving. The ice-rich layers stick to the scoop when poised in the Sun above the deck, different from what we expected from all the Mars simulation testing we’ve done. That has presented challenges for delivering samples, but we’re finding ways to work with it and we’re gathering lots of information to help us understand this soil.”

Since landing on May 25, Phoenix has been studying soil with a chemistry lab, TEGA, a microscope, a conductivity probe and cameras. Besides confirming the 2002 finding from orbit of water ice near the surface and deciphering the newly observed stickiness, the science team is trying to determine whether the water ice ever thaws enough to be available for biology and if carbon-containing chemicals and other raw materials for life are present.

The mission is examining the sky as well as the ground. A Canadian instrument is using a laser beam to study dust and clouds overhead.

“It’s a 30-watt light bulb giving us a laser show on Mars,” says Victoria Hipkin of the Canadian Space Agency.

A full-circle panorama of Phoenix’s surroundings has also been completed by the spacecraft.

“The details and patterns we see in the ground show an ice-dominated terrain as far as the eye can see,” says Mark Lemmon of Texas A&M University, lead scientist for Phoenix’s Surface Stereo Imager camera. “They help us plan measurements we’re making within reach of the robotic arm and interpret those measurements on a wider scale.”

Astronomy Magazine

Phoenix continues sample-collection tests

NASA’s Phoenix Mars Lander’s science and engineering teams are testing methods to get an icy sample into the Robotic Arm scoop for delivery to the Thermal and Evolved Gas Analyzer.

Provided by the Jet Propulsion Laboratory

July 10, 2008
NASA’s Phoenix Mars Lander’s science and engineering teams are testing methods to get an icy sample into the Robotic Arm scoop for delivery to the Thermal and Evolved Gas Analyzer (TEGA).

Ray Arvidson of Washington University in St. Louis, Phoenix’s “dig czar,” said the hard Martian surface that Phoenix has reached proved to be a difficult target, comparing the process to scraping a sidewalk.

“We have three tools on the scoop to help access ice and icy soil,” Arvidson said. “We can scoop material with the backhoe using the front titanium blade; we can scrape the surface with the tungsten carbide secondary blade on the bottom of the scoop; and we can use a high-speed rasp that comes out of a slot at the back of the scoop.”

“We expected ice and icy soil to be very strong because of the cold temperatures. It certainly looks like this is the case and we are getting ready to use the rasp to generate the fine icy soil and ice particles needed for delivery to TEGA,” he said.

Scraping action produced piles of scrapings at the bottom of a trench on Monday, but did not get the material into its scoop, information returned from Mars on Monday night confirmed. The piles of scrapings produced were smaller than previous piles dug by Phoenix, which made it difficult to collect the material into the Robotic Arm scoop.

“It’s like trying to pick up dust with a dustpan, but without a broom,” said Richard Volpe, an engineer from NASA’s Jet Propulsion Laboratory, Pasadena, California, on Phoenix’s robotic arm team.

Images from the lander’s robotic arm camera showed that the scoop remained empty after two sets of 50 scrapes performed earlier Monday were collected into two piles in the trench informally named “Snow White.” These activities were a test of possible techniques for collecting a sample of ice or ice-rich soil for analysis.

The mission teams are now focusing on use of the motorized rasp within the robotic arm scoop to access the hard icy soil and ice deposits. They are conducting tests on Phoenix’s engineering model in the payload interoperability testbed at The University of Arizona in Tucson to determine the optimum ways to rasp the hard surfaces and acquire the particulate material produced during the rasping. The testbed work and tests on Mars will help the team determine the best way to collect a sample of Martian ice for delivery to TEGA.

Astronomy

Mercury, Up-Close Again

Planetary science is much about comparisons. Studying other bodies in our solar system with different sizes and compositions provides essential context for understanding Earth’s formation and evolution. Three planets–Mercury, Venus, and Mars–and the Moon, are most like Earth in their initial composition and relative size, but their differences are enlightening. The Moon, Venus, and especially Mars have all been visited and probed recently by spacecraft. Now it is Mercury’s turn. The MESSENGER^* spacecraft flew by the planet and observed it in January. The papers in this Special Issue feature these observations. After two more passes, it will settle into orbit around Mercury in 2011.

Mercury was visited by one earlier spacecraft, Mariner 10, in the mid-1970s. Its observations, and some difficult ground-based studies, provided most of our information on the planet, but raised many enigmatic questions. Despite being the smallest planet, Mercury has an actively generated magnetic field like that on Earth, but unlike that on the Moon, Mars, and Venus, and a huge iron-rich inner and molten outer core. Images of half of the surface revealed abundant scarps thought to indicate contractional faults, implying that Mercury was originally a bit larger early in its history. The extent to which its surface was shaped by impacts or volcanism was uncertain and debated. Its proximity to the Sun means that it has intense interactions with the solar wind, which, despite the magnetic field, impacts the surface of the planet, altering it and excavating some ions. Ground-based radar data hinted that ice may be present in shadowed regions of the poles.

The first MESSENGER observations provide some important early answers and a wealth of data for further study. Observations of the surface by several instruments reveal that Mercury does have a volcanic history. More contractional faults are seen in areas observed by Mariner and in an additional ~20% of the planet seen up close for the first time. A variety of impact craters help reveal relative ages of surface units and enrich the role of impact processes in shaping the planet. Impacts and solar bombardment have greatly weathered the surface; most of the iron is not in silicate minerals but apparently in nanoscale metal or oxide grains. In addition to sodium, MESSENGER detected ablation of calcium from the planet and in its magnetotail and measured in greater detail the magnetic field and its effect on its space environment.

This first pass did not cover the polar regions, so confirmation of the presence of ice will have to await future observations, which will also image other parts of the planet and come as the Sun’s activity increases. But already MESSENGER has helped fill in Mercury’s history and environment, allowing a better understanding of all the terrestrial planets, including Earth.

SCIENCE MAGAZINE