[meteorite-list] Little Hope For Stuck Phobos Grunt Probe

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Tue, 22 Nov 2011 09:57:28 -0800 (PST)
Message-ID: <201111221757.pAMHvSAj004033_at_zagami.jpl.nasa.gov>

http://www.bbc.co.uk/news/science-environment-15841896

Little hope for stuck Phobos Grunt probe

By Jonathan Amos
BBC News
November 22, 2011


    Phobos-Grunt - Mishap sequence
    * 9 Nov: The probe launches successfully on its Zenit rocket from
      the Baikonur Cosmodrome
    * It is dropped off 11 minutes later in an elliptical orbit some
      345km above the Earth
    * Two firings from the probe's hydrazine-fuelled cruise stage were
      planed over South America
    * The first, lasting 11.5 minutes, should have raised the orbit of
      Phobos-Grunt to 4,000km
    * A second burn, four hours into the mission, was to have sent the
      probe on a path to Mars
    * Russian space agency officials say neither burn on the big cruise
      stage took place
    * The probe remains in a low-Earth orbit while the anomaly is
      investigated by engineers
    * After two weeks, contact is still impossible; but the probe
      maintains its orbit
    * Eventually, it would fall back to Earth. Roscosmos says perhaps
      between December and February

The Russian space agency has conceded there is now little chance of
reviving its Mars mission, Phobos-Grunt.

The probe has been stuck circling the Earth since its launch on 9
November, unable to fire the engine that would take it on to the Red Planet.

Engineers have tried in vain to contact the spacecraft, and Roscosmos
deputy head Vitaliy Davydov said the situation now looked very grim.

"One should be a realist," he was quoted as saying by RIA Novosti.

"If we've been unable to establish communication with [Phobos-Grunt] for
such a long time, there are few chances that we shall fulfil the
expedition now," were his comments reported by the Russian news agency
at a press conference in mission control centre at Korolev on the
outskirts of Moscow.

"If we establish contact [with the probe] and begin to understand what's
wrong with it, then we shall be able to draw some conclusions," Davydov
said.

Later, another Russian news agency, Interfax, quoted Davydov as saying
that Phobos-Grunt might fall from orbit anytime between late December
2011 and February 2012.

"It is an interesting question how [the probe] will behave. There is
fuel on board. If there is an explosion, it is one thing, but if it
simply starts falling apart with no explosion, then it is another
thing," Interfax reported the deputy head as saying.

The spacecraft weighed some 13 tonnes at launch - double the mass of
Nasa's recently re-entered UARS satellite.

What is more, most of the 13 tonnes is made up by the propellants
unsymmetrical dimethylhydrazine (UDMH) and dinitrogen tetroxide (DTO),
both of which are toxic.

If the Phobos-Grunt mission is truly lost, then professional and amateur
groups will be modelling its orbit in an attempt to determine precisely
where and when it might come down.

As with UARS, much of the spacecraft will burn up in the atmosphere; but
any parts made of high-temperature metals, such as titanium or stainless
steel, stand a chance of making it all the way to the surface.

Indeed, it is the fuel tanks that often survive the fall because their
spherical shapes enable them to spin up and dissipate heat more easily.

However, the probability is that any debris would hit the ocean, given
that more than 70% of the Earth's surface is covered by water. This was
the case with UARS and the German Rosat X-Ray telescope that returned to
Earth last month.

To date, Phobos-Grunt has been maintaining its orbit, but trackers will
be monitoring the spacecraft closely to catch any change in its behaviour.

The probe was built to land on the Martian moon Phobos and scoop up rock
for return to Earth. Such a venture would yield fascinating new insights
into the origin of the 27km-wide moon and the planet it circles.

The mission was also notable because China's first Mars satellite,
Yinghuo-1, was launched piggy-back on the main Russian spacecraft.

Jonathan.Amos-INTERNET at bbc.co.uk
Received on Tue 22 Nov 2011 12:57:28 PM PST