27 May 2008
Perfect Landing Marks Start of New Mission on Mars
International effort supports first landing in Red Planet’s polar region
Washington -- On May 25, the fourth planet from the sun began hosting a new visitor -- NASA’s three-legged Phoenix spacecraft lowered itself onto the arctic plains of Mars, opened its eyes and sent back images of the pebble-strewn landscape.
After a 679-million-kilometer journey from Earth, the spacecraft touched down in a region called Vastitas Borealis at 68 degrees north latitude, 234 degrees east longitude. Fifteen minutes later, NASA’s Mars Odyssey orbiter relayed a message from Phoenix, letting engineers know that it had survived its difficult final descent.
The lander had beaten some discouraging odds -- in the international history of space travel, only five of 13 attempts to land on Mars have succeeded.
Phoenix entered the Martian atmosphere at a speed of nearly 5.8 kilometers per second, kicking off a seven-minute series of events designed to slow the lander to 0.002 kilometers per second before it reached the ground. During what NASA called the “seven minutes of terror,” one of the engineers announced each event as it was relayed by radio.
With each milestone Phoenix achieved -- cruise stage separation, parachute deployed, heat shield ejected -- mission team members at NASA’s Jet Propulsion Laboratory in California, Lockheed Martin Space Systems in Colorado and the University of Arizona cheered. When they heard Phoenix was safely on the ground, they went wild -- yelling, laughing, hugging and pounding each other on the back.
“In my dreams it hasn’t gone as perfectly as it went tonight,” Phoenix project manager Barry Goldstein, from NASA’s Jet Propulsion Laboratory (JPL), said during a post-landing briefing.
From JPL, NASA Administrator Michael Griffin called the landing “one of the technical pinnacles of the space business,” and said the experts who worked on the difficult mission “made it look easy.”
Leading the Phoenix mission is Peter Smith of the University of Arizona, with project management at JPL and development partnership at Lockheed Martin in Denver. (See “NASA Phoenix Spacecraft Descends to Red Planet May 25.”)
International contributions to the mission come from the Canadian Space Agency, the University of Neuchatel in Switzerland, the universities of Copenhagen and Aarhus in Denmark, the Max Planck Institute in Germany and the Finnish Meteorological Institute. The European Space Agency and the United Kingdom’s Science and Technology Facilities Council also are participating.
SAMPLING CYCLES
Phoenix’s planned operational life is 90 Martian days, each of which, called a “sol,” lasts about 40 minutes longer than an Earth day. Over its first few days on the planet, tasks for Phoenix include checking some instruments and systems and capturing more images of its surroundings.
After this characterization phase, the Phoenix team will have less than three months to conduct research in a series of cycles of digging and analysis. First, Phoenix will dig down to the icy layer and examine soil in place at the surface, at the icy layer and in between. It also will scoop up samples for analysis by its onboard instruments.
A key instrument will check for water and carbon-containing compounds by heating soil samples in tiny ovens and examining the vapors that are released. Another instrument will test soil samples by adding water and analyzing the dissolution products.
Cameras and microscopes will provide information on a range of size scales -- from microscopic features to a survey of the landscape by a mast-mounted camera. A weather station will provide information about atmospheric processes in an arctic region where a coating of carbon-dioxide ice comes and goes with the seasons.
WATER AND LIFE
Mars is a vast desert where water is not found in liquid form on the surface. One exception might be fleeting outbreaks that have been proposed to explain more recent flows of liquid down some Martian gullies. The arid surface is not the whole story, though. Other Mars missions have found that liquid water has persisted at times in Mars’ past and there is still plenty of water ice near the surface.
Water is key to answering four of the most important questions about Mars:
• Has Mars ever had life?
• How should people prepare to explore Mars?
• What can Mars teach scientists about climate change?
• How do geological processes differ on Mars and on Earth?
Because water is a prerequisite for life, a potential resource for human explorers and a major agent of climate and geology, NASA has chosen to focus on water while investigating Mars. The mission’s three main science objectives are studying the history of water in all its phases, determining if the Martian arctic soil could support life and studying Martian weather from a polar perspective.
But Phoenix will do more than explore the Red Planet, said Doug McCuistion, Mars exploration program director at NASA headquarters in Washington. It also will set the stage for the next mission, NASA’s Mars Science Laboratory, which launches in 2009 to deploy a long-distance rover carrying sophisticated science instruments for Mars.
“It won’t be going to the pole,” he said, “so it probably won’t see ice but it will sample a lot of materials and help us understand [in other regions] what Phoenix is going to help us understand in the northern polar regions.
More information about the Phoenix mission is available on the NASA Web site.
