This story was updated at 1:15 p.m. EST.
With NASA's Mars
Reconnaissance Orbiter just hours away from firing its engines to enter
orbit around the red planet, scientists on Earth are on pins and needles
waiting for the mission-critical event.
LIVE coverage of MRO's Mars arrival coverage begins at 3:30 p.m. EST. Click here. |
"It's a little bit nerve-wracking,
even though it's exciting," said Doug McCuistion,
director of NASA's Mars exploration program during a mission
briefing at the Jet Propulsion Laboratory in Pasadena, California Friday. "Today we're
here to insert the most capable orbiter ever sent to another planet."
With its six science
instruments and high-resolution cameras, MRO is expected to reveal more details
about Mars' surface, atmosphere and water cycle than any previous mission to
date. The spacecraft is right on target to ignite its engines just after 4:24 p.m. EST
(2124 GMT) today during a 27-minute maneuver that, mission managers hope, will
place the spacecraft orbit around Mars.
Orbital arrival is a
critical time for any planetary expedition, where the slightest glitch or
mistake can send the probe careening past the planet or plunging into its
atmosphere.
"NASA has about an
average grade of 'C' doing this," McCuistion said of
orbit insertion maneuvers. "But these guys will do it. We've got a great team."
Robert Lock, lead mission
manager for the orbiter at JPL, said MRO is right on track for today's orbit insretion maneuver. The spacecraft's flight path is so
precise that two last minute maneuvers - one slated for this morning and the
other for late yesterday - were unnecessary.
"We're very pleased that
we're exactly on trajectory," Lock said.
MRO is about 33,000 miles (53,108
kilometers) from Mars and closing at about 7,000 miles per hour (11,265
kilometers per hour), though that speed
should accelerate to 11,000 miles per hour (17,702 kilometers per hour) by the
time of today's engine burn. Mission managers will only be in contact with the
probe for the first 21 minutes of the 27-minute maneuver, leaving MRO to
complete the burn itself while on the other side of Mars.
Ground tracking stations in Spain
and California will be listening for MRO's signals as
it swings out from behind Mars at about 5:16 p.m. EST (2216 GMT), though flight
controllers will wait about 30 minutes to allow the orbiter to set itself to
rights in case it encountered any glitches while out of range, mission managers
said.
Final orbital arrival preparations
begin about two hours before the planned engine burn, when flight controllers
will direct MRO to pressurize its fuel tanks, they added.
Nothing to do but wait
While engineers and flight
controllers prepare for MRO's Mars
arrival, the mission's science teams awaits news that their probe
survives the ordeal.
"For the science teams right now,
this is a period of waiting," said MRO project scientist Richard Zurek during the briefing. "We've checked out the
instruments during the cruise [and] made sure the cameras are in focus."
Larger than any of the three other
orbiters currently studying Mars, NASA's $720 million MRO mission carries a
hefty suite of science tools to study the red planet in unprecedented detail. The
probe is expected to spend two years studying Mars and two more serving as a
communications relay between the red planet and Earth for future spacecraft.
The 4,806-pound (2,180-kilogram) MRO
probe is equipped with a six-instrument package that includes the ultra
high-resolution HiRISE camera, a ground-penetrating
radar and several other climate, atmosphere and surface scanning tools to
tracking Mars' water history and pinpointing potential landing sites for future
missions.
"It's the most technologically
advanced payload that we've ever sent to another planet," said James Graf,
NASA's MRO project manager at the Jet Propulsion Laboratory (JPL) in Pasadena,
California, said in a March 8
mission update. "I think we're ready."
But MRO's
arrival in Mars orbit is just the beginning of its pre-science phase.
The
spacecraft is expected to enter a 35-hour orbit today that ranges from 350
miles (563 kilometers) to 27,000 miles (43,452 kilometers) in altitude above
Mars. Over the next six months or so, the probe will dip into Mars' atmosphere
about 550 times in process called aerobraking, which uses friction and drag with the
planet's upper atmosphere to slow and shape its orbit.
Mission managers are targeting a
final circular orbit about 190 miles (305 kilometers) above the Martian
surface. MRO launched
from Earth on Aug. 12, 2005 atop an Atlas 5 rocket and spent seven months
flying to Mars.
"It's pretty exciting," NASA
researcher Candice Hansen-Koharcheck, a science team
member for MRO's HiRISE
camera, said Thursday of the planned orbital arrival. "I am just going to be a
basket of nerves."
NASA will broadcast MRO's Mars approach and orbital arrival live on NASA TV
beginning at 3:30 p.m. EST. SPACE.com's NASA TV feed is available here. You are welcome to
follow MRO's arrival using SPACE.com's Mars Reconnaissance
Orbiter mission special report by clicking here.
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