When and where will Russia's doomed probe to a Martian moon fall back to Earth? The RIA-Novosti news service caused a stir when it reported that the 13-ton Phobos-Grunt spacecraft would crash in southwestern Afghanistan at 2:22 a.m. Moscow time on Jan. 14. The report attributed the prediction to the U.S. Strategic Command, but experts say it's way too early to be that precise about the Phobos-Grunt debris zone.

"Yes, it is much too early to predict" the circumstances of Phobos-Grunt's re-entry, Gene Stansbery of NASA's Orbital Debris Program Office at Johnson Space Center told me today.

The U.S. Strategic Command is being circumspect as well, deferring comment to NASA and to Roscosmos, Russia's space agency.

The most that can be said about the impact zone right now is that it will be somewhere between 51.4 degrees north and 51.4 degrees south latitude. That's a swath of the planet that stretches from Calgary, Alberta (or Ghent, Belgium) in the north to the Falkland Islands in the south and takes in the vast majority of the world's population. Satellite-watcher Marco Langbroek reports on the See-Sat-L discussion forum that the predicted time of re-entry is Jan. 13, plus or minus 11 days. A couple of weeks ago, Roscosmos estimated that re-entry would come sometime between Jan. 6 and 19.

Typically, the projected area of the debris zone can't be narrowed down until hours before re-entry, if then. It's possible that RIA-Novosti picked up on a prediction that was centered around a precise time and place of re-entry, but left out the part about the plus-or-minus uncertainty. (You can see where Phobos-Grunt is right now by checking the Heavens-Above website.)

The spacecraft was launched from Russia's Baikonur Cosmodrome in Kazakhstan on Nov. 9 local time, and was supposed to leave Earth orbit hours later for the trip to Phobos, the larger of Mars' two moons. Along the way, it would have deployed a Chinese mini-probe in Martian orbit. If everything went well, the $165 million Phobos-Grunt mission would have brought a sample of Phobos soil back to Earth in 2014. ("Phobos-Grunt," or the more correctly transliterated "Fobos-Grunt," is Russian for "Phobos-Soil.")

Everything didn't go well, as we now know: The spacecraft's upper-stage thrusters didn't fire, and it's been stuck in Earth orbit ever since. This month, Russian officials finally gave up on attempts to revive the craft and admitted that it would fall to its destruction next month.

Most of the spacecraft's mass consists of the toxic propellants it would have used to get to Phobos. There's also a small amount of radioactive cobalt-57 that was meant to power a spectrometer. The Russians say that the fuel will burn up in Earth's atmosphere, and that the cobalt won't pose a contamination threat.

Twenty to 30 parts from the probe with a total weight of up to 440 pounds (200 kilograms) are expected to survive the plunge. One of those parts could be the sample return capsule, which is designed to withstand the intense heat of atmospheric re-entry. David Warmflash, the principal investigator for one of the mission's experiments, said "it is quite possible" that his team's LIFE capsule will make it back to Earth intact.  

If it lands in Afghanistan, the chances of recovery might be poor, given the proximity to a war zone. But if it lands in the ocean, which is currently the likeliest scenario, the chances aren't any better. Over the past few months, two other high-profile satellites — NASA's Upper Atmosphere Research Satellite and Germany's ROSAT space telescope — fell through the atmosphere over the South Pacific and the Bay of Bengal, respectively, and no trace of them was ever found.

More about Phobos-Grunt and other falls to Earth:

• Mars probe to crash to Earth in January
• Russian leader suggests punishing space failures
• Skywatcher snaps photos of stranded probe
• Christmas Eve fireball sparked by Russian rocket debris
• Russian communications satellite falls after launch

Alan Boyle is msnbc.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

IKI

An artist's conception shows the Phobos-Grunt probe orbiting Mars. The spacecraft, which was designed to land on the Martian moon Phobos, has been stuck in Earth orbit since its launch on Nov. 9.

Russia's stranded Phobos-Grunt spacecraft reportedly has lost its main opportunity to go to Mars, land on one of its moons and return to Earth with a sample. Nevertheless, efforts to revive it continue.

Little information has come from the Russian Space Agency since the 13-ton probe was launched on Nov. 9, but reports from Russian news outlets say that controllers couldn't make contact before the planned window of opportunity closed today for the round trip to Mars and its moon Phobos.

Phobos-Grunt ("Phobos-Soil") was designed to scoop up a soil sample from Phobos and bring it back to Earth. It was also supposed to deliver a 250-pound (115-kilogram) Chinese mini-orbiter to study Mars' atmosphere. Before launch, Phobos-Grunt was hailed as Russia's comeback try for interplanetary exploration. But since the orbital glitch, it's been viewed as one more in a long string of failures for Russian Mars probes.

The Interfax news agency quoted an unnamed source in the space industry as saying that there was still an outside chance of going ahead with the trip to Phobos. "This would be possible if Phobos-Grunt received a new flight program, which would involve acceleration with the use of complex ballistic maneuvers, for instance, through the moon and with high fuel expenditure," the source was quoted as saying. "But by mid-December, even this opportunity to fire the spacecraft toward Mars will be gone."

For days, observers have been talking about a potential "consolation prize" for the $163 million mission: perhaps a trip to the moon and back, or to an asteroid. But this assumes that Russian Mission Control will be able to establish contact, upload new instructions and have the probe fire its engines properly to get out of Earth orbit. None of those tasks has yet been achieved.

So what's the problem? Here's one of the leading hypotheses: For some reason, a fault led to the probe's failure to fire its engines for leaving Earth orbit, but Mission Control can't send the commands to reset the software because the fuel tanks are blocking an antenna that needs to be clear.

NASA and the European Space Agency have been trying to help the Russians make contact, and all those efforts are continuing. At one point, orbital debris experts said Phobos-Grunt's orbit was on a decaying track that would lead to a fiery re-entry in December. But satellite observers now say the orbit has been more stable than initially predicted, and re-entry may be held off until January or later. It's almost as if Phobos-Grunt is trying to save itself.

The probe carries about 10 tons of toxic hydrazine and nitrogen tetroxide propellants, plus a smidgen of radioactive cobalt-57. Experts are debating whether the fuel would burn up in the atmosphere, or whether some of it would survive the fall and cause an environmental problem. Chances are that the debris from Phobos-Grunt would fall into the ocean, as was the case for NASA's UARS satellite and Germany's ROSAT satellite. But you can expect to hear more about the toxic-spill angle as the time of re-entry approaches — unless, that is, the spacecraft undergoes a miraculous resurrection.

In the meantime, NASA's next Mars probe — a one-ton rover known as Curiosity or Mars Science Laboratory — is due for launch on Saturday. The plan for that $2.5 billion mission is nearly as ambitious as Phobos-Grunt's. The six-wheeled, car-sized rover will have to be lowered to the Martian surface next August from a hovering "sky crane." Let's hope the Great Galactic Ghoul sees fit to spare Curiosity, if not Phobos-Grunt.

Update for 8:30 p.m. ET: David Warmflash, the lead investigator for the Phobos-LIFE experiment aboard Phobos-Grunt, says in a Twitter update that the "window for going to Mars [is] still open, not window for going and returning with Phobosian sample." I've tweaked this posting to reflect that scenario.

Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter or following the Cosmic Log Google+ page. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.