Time’s Up For Phobos-Grunt, Re-entry Expected Sunday

The waning gibbous moon joins Mars tonight in the southeastern sky. This map shows the sky around 11:30 p.m. local time. Created with Stellarium

Late tonight look to the east to see the moon line up below the Red Planet. Binoculars will reveal nice crater detail on the moon but don’t expect them to show much on Mars. Being a small planet only about twice the size of the moon, Mars requires a telescope to see any surface detail. With a magnification of about 70x, you might just see the planet’s tiny white polar cap. 200x will nail it as long as the air is reasonably steady.

While NASA’s Mars Science Laboratory continues on it path toward an August touchdown, the Russian Phobos-Grunt space probe, which has been stuck in Earth-orbit purgatory, will finally come flaming down through the atmosphere sometime this Sunday January 15. The exact time and location of re-entry aren’t known just yet due to uncertainties in its orbit and the upper atmosphere, but it’s expected to land in the Indian Ocean. For now. The satellite could still land anywhere between 51.4 degrees north and 51.4 degrees south latitude. I’ll keep you posted with updates through the weekend. You can also see its current ground tracks (areas it’s passing over) by clicking HERE.

**UPDATE 11:30 a.m. Sunday, Jan. 15: Latest reentry times HERE.

Phobos-Grunt, launched last November 8 by the Russian Space Agency ROSCOSMOS, failed to fire the rockets that would have set it on a course for Mars’ moon Phobos. Its main objective was to land there, drill up a rock sample and return it to Earth for study.

A mockup of the Phobos-Grunt lander. Credit: CNES

One of the concerns out there is the ship’s 8.3 tons of highly toxic hydrazine and nitrogen tetroxide fuel. ROSCOSMOS predicts it all to burn up high in the atmosphere before any pieces of the probe make it to the ground. Some 20-30 pieces with a total weight of about 440 lbs. are expected to survive the fiery descent. Fully-fueled, Phobos-Grunt weighs 29,100 lbs.

Keep an eye to the sky on Sunday and we’ll be in touch. In the meantime, if you have a few extra minutes and would like to learn more about all 41 past missions to Mars, the current Curiosity mission and two more in the works, check out the Planetary Society’s Missions to Mars site.

3 Responses

  1. Travis Kitch

    Hi Bob,

    This question is a little off topic to that of your blog, but it is planetary in nature and was inspired by my current reading of Asimov’s Foundation series. If you haven’t read the Foundation books they revolve around humanity’s far distant future in which we have advanced technologically as to have colonized 25,000,000 planets in the Milky Way Galaxy. This got me to thinking, as I have not heard a recent count, but what is the current number of confirmed known exo-planets? I believe there are many unconfirmed candidates as well. Is there an online resource that keeps an up-to-date tally (perhaps NASA)?

    Thanks, and clear skies,

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