Space Rope Trick Experiment Goes Awry

Tjeerd writes "An experiment that envisaged sending a parcel from space to Earth on a 30-kilometre tether fell short of its goal yesterday when the long fibre rope did not fully unwind, Russian Mission Control said. It was intended to deliver a spherical capsule, called Fotino, attached to the end of the tether back to Earth — a relatively simple and cheap technology that could be used in the future to retrieve bulkier cargoes from space.""

Is a 30km rope

[Tastecicles]

...really long enough? One would have thought that to drop something 150km one would need a 150km rope? ...and something to reduce friction as the probe gets towed along the ground at 17,000 kilometres per hour....

Space Elevators endanger EVERYONE.

[Anonymous Coward]

The idea is so ill-thought out and ridiculous that I can't understand why people blithely accept it. Do we really need super-strong, miles-long cables hovering over us like swords of Damocles?

Even sci-fi authors like Kim Stanley Robinson have included disaster scenarios when contemplating this technology, but irl nobody ever discusses the massive dangers.

The tech is premature and unnecessary at this point, and the risk/reward is insane. This isn't a chicken/egg scenario. Let's get something going in space before we kill thousands and destroy millions in property for nothing.

what?

[Anonymous Coward]

wouldn't there be an equal and opposite reaction pulling the space part down to the earth part?

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Previous try

[Harmonious Botch]

From new scientist

Experimental space tether fails to deploy * 15:17 11 May 2007 * NewScientist.com news service * Kelly Young A trio of mini-satellites has failed in their attempt to deploy a kilometre-long tether in space. The setback means the low-cost Multi-Application Survivable Tether (MAST) experiment, launched on 17 April, may not achieve its goal of testing the survivability of a thin, braided tether in space. Over the past week, mission managers determined that the tether-deploying element, known as Ted, had properly separated from the tether inspector, a tiny satellite called Gadget. But a glitch in the restraint system kept Ted from pushing away hard enough to keep unreeling the tether from its spool. So the tether deployed just a few metres, rather than a full kilometre. Robert Hoyt, chief executive officer of Tethers Unlimited, which designed the picosatellites, says mission managers suspect they know what caused the glitch, but the company is not ready to disclose this to the public yet. "I don't think we'll ever know for sure," he says. Space tethers could one day be used to fling satellites into different orbits, thus saving satellite companies money on fuel. Or tethers could enable clusters of satellites to fly in formation and prevent them from drifting away from one another over time. Such an application might be useful in interferometry, where images from several telescopes, spaced some distance apart, are combined to give greater resolution. Some data Despite the setback, the MAST team at Tethers Unlimited, a company in Bothell, Washington, US, still may be able to get other data from Gadget to learn how a short tether behaves in microgravity. MAST team members discussed having Gadget crawl down the tether to Ted to try to restart the deployment, but they decided that option was too risky. "If we were to have Gadget start to crawl, there is the possibility of the satellites banging together, which would be very likely to damage solar cells and other systems," Hoyt says. This was not the first setback for the mission, which costs less than $1 million. After launch, the satellite team could not get a signal from Ted (see No signal yet heard from tether-deploying satellite). But they said that this should not have affected Ted's ability to deploy the tether. Longest tether Then, sky watchers who had been on the lookout for the deployed tether and satellites from the ground had not seen anything when MAST was scheduled to appear overhead. "That's one confirmation that the tether is not deployed to a very long length," Hoyt told New Scientist. In other space tether news, the longest planned space tether just got a little closer to launch. The satellite, a project of 500 students in Europe known as Young Engineers Satellite 2 (YES2), was shipped to its launch site in Russia from the Netherlands on 10 May. YES2, a project of the European Space Agency, is scheduled to launch in September. If everything goes as planned, the satellite will unroll a 30-kilometre-long tether that is a mere 0.5 millimetres thick. The end of the tether will be attached to a small round capsule called Fotino that will eventually re-enter Earth's atmosphere and attempt to land

Re:Is a 30km rope

[Tim82]

Very true.... However, if it was in geostationary orbit, the object would need to be 35,786 km [wikipedia.org] from the Earth's surface, not 30 km.

Spooling is hard

[Animats]

Managing big spools of line is surprisingly difficult. Oceanographers run into this all the time, as they try to lower a few miles of line into the ocean. The textile industry runs into it when they try to use very large spools so they can run machinery longer without splicing. Designing something to unspool 30Km of line under near-zero tension in zero G is non-trivial.

Here's a discussion of spool winding [amacoil.com], if you're really interested. There are even companies that specialize in spool winding [independentusa.com].

Re:Is a 30km rope

[dmatos]

Technically, to lower it down enough that it was no longer travelling at orbital velocity, at which point the tether would be released, and the capsule would fall through the atmosphere before a parachute opened up.

Given that LEO is at least 200km, the object would still be at 170km when released, and would have to survive the entire brunt of the re-entry problems. I'm not sure how lowering something on a tether is more economical/effective than using thrust to de-orbit, though.

FedEx Satellites

[Maximum Prophet]

Interestingly enough, FedEx does/did have satellites. Why you ask? In the 1980's what was then Federal Express worked with the fax companies to develop the Group III fax standard. Every FedEx station got one of these large fax machine complete with hard drives and a plain paper printer. The theory was, people would go to a FedEx location, have their documents faxed to somewhere else, where, for a fee, a courier would deliver it to the recipient. Alternately, high value customers, like law firms, would get a smaller thermal machines for mostly sending to the FedEx station which would forward it to the target station for delivery. The satellites were used to route the data between stations w/o using a phone line. Remember, this was before the Internet, and most companies who used fax would buy them in pairs to send between sites. Almost no one else would have a fax machine that could talk to your fax machine.

Federal Express spend *billions* on the system, and it failed utterly. What happened was the same companies that helped them develop the Group III standard made their thermal machines cheap and interoperatable. Soon, everyone had them, and the thermal paper wasn't too bad. You could always photocopy it once if you wanted a more permanent record. That, and falling long distance phone prices made it overall cheaper to fax a document than to have FedEx do it for you.

To sum up, FedEx has already been to space. They are looking at it, and it's always way too expensive for any kind of regular service. (except some data)

After a minute and a half on Google.

[ahfoo]

I get the following:

The tether was made of Dyneema.

Wikipedia says this is a synonym for ultra high molecular weight polyethylene

    Regarding the weaknesses of UHMWPE, thermal properties are highlighted and consist of the following:

The weak bonding between olefin molecules allows local thermal excitations to disrupt the crystalline order of a given chain piece-by-piece, giving it much poorer heat resistance than other high-strength fibers. Its melting point is around 144 to 152 degrees Celsius, and according to DSM, it is not advisable to use UHMWPE fibers at temperatures exceeding 80 to 100C for long periods of time. It becomes brittle at temperatures below -150C.

      Googling for the temperature outside of the space station turns up a Yahoo answers page.

http://answers.yahoo.com/question/index?qid=20061215121108AASpIMx&show=7 [yahoo.com]

        Which says the answer is -250 F. Convert to Celsius and we get -156.7C

          Maybe this helps to explain what might have happened.