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.
Green Valley
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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