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.""

Re:Is a 30km rope

[Hoi Polloi]

If you RTFA you'd have read that the goal wasn't to reach the earth's surface but to lower something to a lower orbit.

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Re:Is a 30km rope

[eln]

Sure, but to do that, you'd need a 35,786 km [wikipedia.org] rope. I think we're gonna need a bigger spacecraft to haul that thing up there.

Re:Actually...

[lexarius]

But where did you put your magic bag while you were in there? It's dangerous to bring those inside, you know.

Tether Enabled SSTO

[StCredZero]

HASTOL stands for Hypersonic Airplane Space Tether Orbital Launch. This was studied by NASA. We currently have a hard time with a winged craft that can make it to orbit. Space elevators also require "Unobtanium" with unattainably high tensile strengths. But if we combine the two, we get something which is both technically feasible and capable of dirt-cheap earth to orbit. Basically, have an aircraft capable of very high altitude, and about half orbital velocity rendevous with a rotating tether (Rotovator) that can take a cargo the rest of the way to orbit.

PDF [google.com]
View as HTML [64.233.169.104]
More Cosmic Rope Tricks [strangehorizons.com]

Re:Spooling is hard

[dpbsmith]

"The whale line is only two thirds of an inch in thickness. At first sight, you would not think it so strong as it really is. By experiment its one and fifty yarns will each suspend a weight of one hundred and twenty pounds; so that the whole rope will bear a strain nearly equal to three tons. In length, the common sperm whale-line measures something over two hundred fathoms. Towards the stern of the boat it is spirally coiled away in the tub, not like the worm-pipe of a still though, but so as to form one round, cheese-shaped mass of densely bedded sheaves, or layers of concentric spiralizations, without any hollow but the heart, or minute vertical tube formed at the axis of the cheese. As the least tangle or kink in the coiling would, in running out, infallibly take somebody's arm, leg, or entire body off, the utmost precaution is used in stowing the line in its tub. Some harpooneers will consume almost an entire morning in this business, carrying the line high aloft and then reeving it downwards through a block towards the tub, so as in the act of coiling to free it from all possible wrinkles and twists."

--Herman Melville, "Moby-Dick, or the Whale"

Russian mission control, but ESA Student satellite

[Anonymous Coward]

The space rope trick was actually an ESA students project: YES2 [esa.int], the second Young Engineers Satellite.

According to the article [esa.int] at ESA:

The Second Young Engineers' Satellite (YES2) was activated and separated from the Foton-M3 spacecraft earlier today. The tether deployed for 8.5 km, after which the Fotino capsule was released on its way to Earth.

"We are very proud of the students' work, although we didn't reach the full 30 km deployment" said Roger Walker, YES2 project manager for ESA's Education Office. "The hard work of the YES2 team over the past five years has paid off with this largely successful demonstration."

YES2 was part of the Foton-M3 [esa.int] experiment, which concluded succesfully today.

The reentry capsule for the Foton-M3 spacecraft, which has been in low-Earth orbit for the last 12 days, successfully landed this morning in an uninhabited area 150 km south of the town of Kustanay in Kazakhstan, close to the Russian border, at 09:58 CEST, 13:58 local time.

The unmanned Foton spacecraft, which was launched on 14 September from Baikonur Cosmodrome, in Kazakhstan, carried a payload of 43 European experiments in a range of scientific disciplines - including fluid physics, biology, crystal growth, radiation exposure and exobiology.

Why the submitter didn't link to ESA is beyond me.

Re:Tether Enabled SSTO

[StCredZero]

Basically, the Rotovator stores kinetic energy which is transferred to the cargo being lifted. The Rotovator can be gradually accelerated back to its former speed by very high efficiency engines, like ion engines. This is much more economical than chemical rockets because: 1) the very high exhaust velocities reduce the fuel required by a couple of order of magnitude and 2) you can refuel periodically using the Rotorvator itself.

In addition, power can be beamed to the Rotorvator from the earth using lasers or microwaves, which further reduces the weight of the entire system.

Re:After a minute and a half on Google.

[Rei]

Ambient "temperature" is somewhat of an abstract concept when there's effectively no atmosphere. What matters most to how warm you are is how much radiation you're absorbing and how much you're radiating. I.e., insulation and color.

There's no way that they didn't consider the temperature of the tether. You consider the temperature of *everything* that goes into space.

What probably ruined this experiment is what ruined past experiments: oscillations. You can get axial oscillations from all sorts of sources, even things as little as variations in the speed of the motor can build up because of resonance. There's almost nothing to dampen them. We've had tethers outright snap because of this. We've also had tethers snap because of other things, of course. My "favorite" was the tether whose insulation had tiny pockets of trapped gas that expanded in the vaccum of space. The tether had become very high voltage because of moving through Earth's magnetic field, and the leak of gas allowed it to discharge in a plasma arc that cut the tether in half.

Not so simple a process as it at first seems.

Re:After a minute and a half on Google.

[RodgerDodger]

Not really, because temperature in space doesn't work the way you seem to think it does.

If it's -20C on Earth, a human will lose heat fast. Why? Because the heat will transfer from the person to the surrounding air via conduction.

In space, there's no air (duh). That means you don't lose heat from conduction - only via radiating. Furthermore, if this experiment was done in sunlight (probably), then rather than losing heat energy, the line would almost certainly have been gaining it.