GOLDEN, Colorado - NASA's next mission to Mars--the Phoenix lander--is undergoing readiness testing in preparation for an early August launch window.
For the first time since NASA's Viking missions in the 1970's, the plan calls for Phoenix to safely settle down on Mars using a set of onboard rocket thrusters--no airbags this time as successfully used by NASA's last three red planet landings.
When Phoenix touches down within the northern polar plains of Mars, it will be ready for research duties. This stationary probe is armed with a robotic scoop to dig and scratch into the martian surface for answers regarding the history of water on Mars and the planet's potential as an extraterrestrial address for life.
The spacecraft is the first in the space agency's low-cost, Scout-class of a space mission. Phoenix did experience technical challenges, particularly in the craft's radar system, causing a cost overrun from an earlier cost-cap figure of $386 million.
Phoenix project officials discussed the spacecraft's status and future voyage today at a press briefing held at Lockheed Martin Space Systems near Denver, the site where the Mars lander was built and being readied for flight.
Still being discussed is exactly where to touch down in order to avoid dangerous geography, said Peter Smith, Phoenix principal investigator at the University of Arizona in Tucson.
Smith said that scientists thought they had selected a safe Phoenix landing spot. However, new imagery of that selected area taken by a super-powerful camera system onboard NASA's Mars Reconnaissance Orbiter found it littered with enormous boulders. "It was not a very safe place to land," he said.
Using both the MRO and NASA's Mars Odyssey orbiter, three sites are now being intensely mapped, to assure that Phoenix has a high probability of touching down safely.
In plotting out landing areas, "we paint the parts green that we think are the safest places...and we have a place we call 'Green Valley' now that's so green that it looks very secure for us," Smith told reporters today.
Picking the actual piece of martian real estate that Phoenix will plop down on is expected in early March, Smith said. "We want to select both a safe site and a scientifically interesting site...with safety being number one of course...or else we don't get anything."
Seven minutes of terror
Getting Phoenix down through the red planet's atmosphere onto the landscape of Mars is the most harrowing part of the mission, said Barry Goldstein, Phoenix project manager at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California.
"We get seven minutes of terror," Goldstein explained. Trying to deliver a vehicle like this from a high speed and heated plunge of 12,600 miles per hour to zero and a100 million miles away "is no easy shot," he added.
Goldstein said that in March of last year, the Phoenix project started having "some significant challenges" in bringing the mission in at a $386 million cost cap. The team notified NASA Headquarters of the overrun last August, requesting a new slug of money, he added, roughly $31 million.
At a meeting last week, Goldstein said that NASA officials gave the project a go-ahead, although the final price tag of the mission has yet to be fully vetted. "The vehicle is behaving very nicely. Things are looking good technically as well as with the schedule and where we are headed. We have no threats to launch at this point," he said.
Exercise in optimization
Phoenix is to be shipped to Florida in early May and undergo final pre-launch checkout, said Edward Sedivy, Phoenix program manager at Lockheed Martin Space Systems. The lander is "very strong and very robust from the test perspective," he noted.
A Boeing Delta 2 booster is to hurl Phoenix toward Mars.
The three-legged, solar-powered Phoenix carries a flat deck outfitted with science instruments, a camera-tipped mast, as well as a highly flexible robot arm. "It's really quite a packaging challenge," Sedivy said. "This is really an exercise in optimization."
Once Phoenix is operating on Mars, after softly setting itself down on the red planet in late May 2008, the objective of the mission is to use its sterilized arm, scoop and grinder to gather ice samples for on-the-spot study.
"We will try and analyze the properties of the ice and its relationship to the soil and the atmosphere," Smith pointed out. "It's the water that we expect to find there...and be the first mission to actually reach down and get a handful of icy soil and analyze it."
The search for evidence of a habitable zone and assess the biologic potential of the ice-soil boundary is high on the scientific agenda for Phoenix.
Scientists will interpret this data and try to understand "what the truth of Mars really is in this area," Smith observed. At the end of the Phoenix lander mission, researchers hope to witness the planet's onslaught of polar ice that will permeate the spacecraft's exploration area.
"At our landing site there will be as much as three feet of solid carbon dioxide ice...we don't expect to survive through the winter," Smith concluded.
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