Tag: space junk

An unmanned spacecraft designed to get rid of space junk is set to launch in 2018, and use a new European built reusable launch system.

8:52 am

The competition heats up: An unmanned spacecraft designed to get rid of space junk is set to launch in 2018, and use a new European built reusable launch system.

Both components of this story are significant. First, a company has gotten the necessary financing to build the spacecraft, proving that there is profit to be made in the removal of space junk. Second, the launch system is simple and reusable, and will lower the cost of getting small payloads into orbit significantly. And it appears it is being built.

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NASA revealed Tuesday that last April the Fermi Gamma-Ray Telescope barely avoided a collision with an abandoned Russian satellite.

9:37 pm

NASA revealed Tuesday that last April the Fermi Gamma-Ray Telescope barely avoided a collision with an abandoned Russian satellite.

Fermi mission scientists first learned of the space collision threat on March 29, 2012 when they received a notice that the space telescope and Cosmos 1805 would miss each other by just 700 feet (213.4 meters). The mission team monitored the situation over the next day and it became clear that the two spacecraft, traveling in different orbits, would zip through the same point in space within 30 milliseconds of one another, NASA officials said.

They used Fermi’s thrusters to shift its orbit enough so the two spacecraft missed each other by 6 miles.

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Last night a piece of space junk missed ISS, but not by much.

8:14 am

Last night a piece of space junk missed ISS, but not by much.

The debris was only 8.7 miles from the station when it zipped by at about 16,000 miles per hour. That is very close, and had it hit, it would have done very significant damage.

The fragment was from an old Russian satellite, Cosmos 2251, that collided with an Iridium satellite in 2009, producing hundreds of fragments more than two inches across.

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Why things break in space

3:22 pm

Updated and bumped: I will be discussing this story on the the John Batchelor Show tonight, February 17, Friday, 12:50 am (Eastern), and then re-aired on Sunday, February 19, 12:50 am (Eastern).
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Someday, humans will be traveling far from Earth in large interplanetary spaceships not very different than the International Space Station (ISS). Isolated and dependent on these ships for survival, these travelers will have no choice but to know how to maintain and repair their vessels whenever something on them should break.

And things will break. Entropy rules, and with time all things deteriorate and fail.

Each failure, however, is also a precious opportunity to learn something about the environment of space. Why did an item break? What caused it to fail? Can we do something to prevent the failure in the future? Finding answers to these questions will make it possible to build better and more reliable interplanetary spaceships.

ISS is presently our only testbed for studying these kinds of engineering questions. And in 2007, a spectacular failure, combined with an epic spacewalk, gave engineers at the Johnson Space Center a marvelous opportunity to study these very issues.
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Phobos-Grunt due to crash to Earth anytime in the next ten hours

9:00 am

path of Phobos-Grunt's reentry

Updated and bumped. An updated prediction from Aerospace now calls for Phobos-Grunt to come down sometime between 9 and 3 pm (Eastern). This puts the U.S. now out of danger, though Europe, South America, Africa, Australia, and the southern half of Asia all remain in the spacecraft’s path.

Watch your heads! Phobos-Grunt is due to crash to Earth anytime in the next ten hours. And unfortunately, this new prediction has it flying over both North America and much of Europe and Africa during that time period.

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Toxic Russian Mars probe aims for Earth

5:50 pm

It now looks like the stranded and toxic Russian Mars probe, Phobos-Grunt, is likely aimed at Earth.

We are looking at an uncontrolled toxic reentry scenario. Phobos-Grunt . . . is fully-laden with unsymmetrical dimethylhydrazine and nitrogen tetroxide; that’s ten tons of fuel and oxidizer. The probe itself weighs-in at only three tons. . . . Phobos-Grunt’s batteries are draining and its orbit is degrading. It looks as if the probe will reenter later this month/early December. NORAD is putting a Nov. 26 reentry date on Phobos-Grunt.

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It looks bad for Phobos-Grunt

8:57 am

It looks bad for Phobos-Grunt.

“Overnight, several attempts were made to obtain telemetric information from the probe. They all ended with zero result,” Interfax quoted a source in the Russian space sector as saying. “The probability of saving the probe is very, very small,” added the source, who was not identified.

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A second large satellite will rain debris down in October

10:06 am

Even if UARS misses you today, don’t relax! A second large satellite, the 2.4 ton ROSAT X-Ray space telescope, is going to rain debris down late in October or early November.

On its ROSAT website, DLR estimates that “up to 30 individual debris items with a total mass of up to 1.6 tonnes might reach the surface of the Earth. The X-ray optical system, with its mirrors and a mechanical support structure made of carbon-fibre reinforced composite – or at least a part of it – could be the heaviest single component to reach the ground.”

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Don’t you dare touch my space junk!

11:01 am

cataloged objects in orbit

A just released National Research Council report on space junk, Limiting Future Collision Risk to Spacecraft: an assessment of NASA’s meteoroid and orbital debris programs, describes in great and worthwhile detail the increasing problem of orbital debris as well as the technical and budgetary problems that exist for removing it. It is especially worth reading for the stories, such as when a Colorado hiker heard a high-pitched sound and then found a still warm thirty-inch diameter sphere in a foot deep crater. The object turned out to be a titanium tank from a Russian upper stage rocket, launched two months earlier.

What I want to focus on here, however, is one issue the report discusses that, as far as I can tell, has generally been missed. Worse, this issue — somewhat ridiculous when you think about a little — will make removing most of the space junk in Earth orbit far more complicated than ever imagined by engineers.

Simply put, under already agreed-to international treaties, no nation can salvage or collect any debris placed in orbit by another nation. To do so will violate international law, and almost certainly cause an international incident. To quote the report:
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Why some space junk is impossible to track

7:32 pm

This ISS status update, dated June 28, explains why the piece of space junk that flew past the station that day was such a surprise. (Hat tip to NASA engineer James Fincannon for pointing this out to me.)

Last night at ~6:00pm EDT, NASA Houston FTC (Flight Control Team) received notification of an upcoming “red threshold” conjunction of the ISS with a piece of orbital debris (Object 82618, UNKNOWN), with a TCA (Time of Closest Approach) this morning at 8:08am EDT, – which was too late to begin planning for a DAM (Debris Avoidance Maneuver). Therefore, FTC and crew made preparations for crew sheltering in Soyuz 26S & 27S. PC (Probability of Collision) at last tracking fix (7:20am) remained in the Red box, at ~0.003, with a miss distance of 0.25 km radial, 0.375 km downtrack, 0.570 m crosstrack. The necessary reconfiguration procedures (USOS hatches closed, etc.) began 1.5 hrs before TCA (6:38am EDT), and the six crewmembers ingressed their Soyuz vehicles. At 8:08am the object cleared the ISS with no impact, and shortly thereafter the crew was given the Go for returning to the ISS. [The late notification occurred because of the high air resistance (drag) of the object (~175 times higher than ISS) which made its trajectory very sensitive to small errors in atmospheric density predictions at the current solar flux. Due to the high drag, there is no chance of a recurrence of Object 82618).] [emphasis mine]

In other words, the piece of junk was probably something like a piece of insulation, very light but with a large area, much like a sail. Thus, as it flies through the thin atmosphere at 200 to 400 miles altitude its velocity and direction can easily change, making it difficult, if not impossible, to predict its future trajectory.

The good news is that these same conditions mean that the orbit of the object will quickly decay (“due to high drag”) so that it poses no future threat to the station.

Unfortunately, there are many other objects like this in orbit, and they all pose a threat, mostly because of the difficulty of reliably predicting their orbits.

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