A new NASA probe
destined to dig into the arctic northern plains of Mars is on track for its
planned Saturday launch, mission managers said Thursday.
Perched
atop its 13-story Delta 2 rocket, NASA's
Phoenix Mars lander is set to launch towards the red planet at 5:26:34 a.m.
EDT (0926:34 GMT) during the first of two possible Saturday attempts from
Florida's Cape Canaveral Air Force Station.
"For summer
time in Florida, that is about the best time of day you can launch," said U.S.
Air Force Delta 2 launch weather officer Joel Tumbiolo in a Thursday briefing at
NASA's Kennedy Space Center in Cape Canaveral.
Current weather
forecasts offer an 80 percent chance of favorable conditions during Phoenix's
first launch opportunity, as well a second window that opens at 6:02:59 a.m.
EDT (1002:59 GMT), Tumbiolo added. About the only weather concern is the
possibility of thick clouds near the Mars probe's launch site, he added.
The $420
million Phoenix lander carries a mix of new science tools and recycled instruments
originally designed for NASA's ill-fated 1999
Mars Polar Lander and the canceled Mars Surveyor 2001 missions. The planned
90-day mission, researchers hope, will unlock secrets hidden within the red
planet's subsurface ice and soil near its north pole, and shed light on whether
the region could have once been habitable.
"Our
instruments are specially designed to find evidence for periodic melting of the
ice and to assess whether this large region represents a habitable environment
for Martian microbes," Phoenix principal investigator Peter Smith, of the University
of Arizona, said of the mission's planned landing zone.
Phoenix
carries seven primary experiment packages, including an eight-foot (2.4-meter) robotic
arm designed to scoop up martian soil and ice like a backhoe. It also carries
tiny, deck-mounted ovens and other instruments to sift for signs of organic
compounds within the martian soil, as well as a suite of Mars weather
monitoring tools.
If all goes
well, Phoenix is expected to land on May 25, 2008 in a flat region known as
Vastitas Borealis at a northern Mars latitude that is comparable to those of
northern Alaska, Greenland or Siberia on Earth, mission managers have said.
Phoenix's
descent to the martian surface, which relies on parachutes and a series of
pulse rocket thrusters, will mark NASA's first soft landing on Mars since the Viking
missions of the 1970s.
NASA launch
director Chuck Dovale said engineers are currently analyzing the impact of a
dropout in air conditioning around the protective, shroud-like launch fairing enveloping
Phoenix atop its Delta 2 rocket, but the glitch is not expected to be a problem
for Saturday's planned liftoff.
Originally
slated for an Aug. 3 launch, Phoenix's Earth departure was delayed
earlier this week after bad weather prevented the second stage
fueling of the probe's Delta 2 rocket. NASA has a 22-day launch window to send
Phoenix off towards Mars that closes Aug. 24. Beyond that, the space agency
would have to wait 26 months - just over two years - for Mars and Earth to once
again return to the proper orbital alignment for the mission.
With such a
restricted launch window NASA officials have said they would consider delaying
the planned
Aug. 7 launch of the space shuttle Endeavour from KSC to offer more flight
opportunities for Phoenix.
"We
have a three-week launch window, which is quite an extensive period,"
Deborah Bass, NASA's deputy project scientist for Phoenix at JPL, told
reporters Wednesday during a series of interviews on NASA TV. "I feel
confident that we'll get off Earth and on towards Mars within that time."
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