[meteorite-list] Russia Trying To Salvage Phobos-Grunt Mission

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Wed, 9 Nov 2011 16:28:17 -0800 (PST)
Message-ID: <201111100028.pAA0SHhZ015196_at_zagami.jpl.nasa.gov>

http://www.spaceflightnow.com/news/n1111/09phobosgrunt/

Russia trying to salvage Phobos-Grunt mission
BY STEPHEN CLARK
SPACEFLIGHT NOW
November 9, 2011

One day after a Russian Mars probe was left stranded in low Earth orbit,
engineers planned to begin trying to save the mission Wednesday in hopes
the problem was a relatively simple software glitch.

After launching from the Baikonur Cosmodrome on Tuesday, the
29,000-pound Phobos-Grunt spacecraft entered an orbit with a low point
of 128 miles and a high point of 216 miles. But the craft's propulsion
unit was supposed to fire twice later Tuesday night to raise its
altitude and inject the probe on a trajectory toward Mars.

Neither firing occurred, leaving Phobos-Grunt stuck in orbit.

Phobos-Grunt was orbiting out of range of Russian ground stations for
most of Wednesday, but its flight path was expected to pass over Russia
again beginning around 1900 GMT (2 p.m. EST).

Only then can Russian engineers begin to diagnose what caused Tuesday's
post-launch problems. Officials are hopeful they can trace the anomaly
to a software issue that could be solved with a reboot or patch.

Top Russian space managers said a hardware problem would pose more dire
consequences for the $163 million mission, according to news reports.

Vladimir Popovkin, head of the Russian space agency, said the engine
firing mishap could have been caused by a problem in the orientation of
the spacecraft or the probe's computer may not have sent an ignition
command on time.

Otherwise, the spacecraft was stable and in a known orbit, according to
Russian officials.

It was unclear if control teams would upload commands for the engine
burns Wednesday night, or if the next attempt to set course for Mars
would wait until another day.

The Russian space agency said they have two weeks to issue the commands
based on the spacecraft's orbital altitude and its energy supply. The
timeframe is different than the one initially stated by Popovkin, who
said engineers have three days to save the mission.

If Russia is unable to save the mission, the spacecraft would be subject
to atmospheric drag, lowering its altitude until it fell back to Earth.

Phobos-Grunt is more massive than NASA's Upper Atmospheric Research
Satellite, which re-entered Earth's atmosphere in late September. The
highly-publicized re-entry, which had a 1-in-3,200 chance of striking a
person, occurred over the Pacific Ocean.

A German scientific satellite fell to Earth in October with no reports
of damage to property.
 
Phobos-Grunt still carries a full load of toxic hydrazine and nitrogen
tetroxide propellant to reach Mars and enter orbit around the Red
Planet. The propellant potentially makes Phobos-Grunt a greater threat
to the public than either recent re-entry or the USA-193 spy satellite
that was shot down by U.S. missile in 2008 to avoid an uncontrolled fall
back to Earth.

U.S. government officials cited frozen hydrazine fuel in USA-193's fuel
tanks as the reason to worry about the satellite's uncontrolled
re-entry, leading the Bush administration to shoot down the spacecraft
before it could naturally decay from orbit.

Russian officials quoted in the RIA Novosti news agency said
Phobos-Grunt could remain in orbit for up to a month without a risk of
falling.

The Phobos-Grunt propulsion system is derived from the Fregat upper
stage, a hydrazine-fueled space tug that often places satellites in
high-altitude orbits above Earth.

The Fregat-based main propulsion unit was supposed to stay attached to
Phobos-Grunt for course correct maneuvers and a critical braking burn to
arrive in orbit around Mars in October 2012.

After getting to Mars, the probe was supposed to jettison the propulsion
unit and deploy China's Yinghuo 1 orbiter, which rides piggyback on
Phobos-Grunt for the journey there.

By early 2013, Phobos-Grunt was scheduled to approach Phobos and study
the moon with remote sensing instruments, giving Russian scientists data
needed to select a landing site.

Using a laser altimeter and radar navigation sensor, Phobos-Grunt was
expected to descend to the surface of the moon in February 2013. Because
of the weak gravity field at Phobos, the probe must make a gentle
landing with little margin for error.

After scooping up rock with a robot arm and placing the samples in a
canister, Phobos-Grunt's return capsule was designed to depart the moon
and target a landing back on Earth in August 2014 with nearly a
half-pound of soil.

After sending its samples back to Earth, Phobos-Grunt's core spacecraft
was supposed to remain on Phobos for a continued science mission for up
to a year.
Received on Wed 09 Nov 2011 07:28:17 PM PST