The Space Tether Experiment: detected enormous amount of Energy!

Do You remember the Tether Experiment, the STS-75 Tethered Satellite System deployment in 1996? Something went wrong, but the scientists were able to detect something amazing, measure and test before the satellite went adrift in space: An ENORMOUS amount of ENERGY...

Why we never heard something new about this epochal break thorough? Why no new developments in energy production from it?


www-istp.gsfc.nasa.gov...

The space tether experiment, a joint venture of the US and Italy, called for a scientific payload--a large, spherical satellite--to be deployed from the US space shuttle at the end of a conducting cable (tether) 20 km (12.5 miles) long. The idea was to let the shuttle drag the tether across the Earth's magnetic field, producing one part of a dynamo circuit. The return current, from the shuttle to the payload, would flow in the Earth's ionosphere, which also conducted electricity, even though not as well as the wire.

[...]The first attempt at the tether experiment ended prematurely when problems arose with the deploying mechanism, but the one on February 25, 1996, began as planned, unrolling mile after mile of tether while the observed dynamo current grew at the predicted rate. The deployment was almost complete when the unexpected happened: the tether suddenly broke and its end whipped away into space in great wavy wiggles. The satellite payload at the far end of the tether remained linked by radio and was tracked for a while, but the tether experiment itself was over.

[...] Later vacuum-chamber experiments suggested that the unwinding of the reel uncovered pinholes in the insulation. That in itself would not have caused a major problem, because the ionosphere around the tether, under normal circumstance, was too rarefied to divert much of the current. However, the air trapped in the insulation changed that. As it bubbled out of the pinholes, the high voltage ("electric pressure") of the nearby tether, about 3500 volts, converted it into a plasma (in a way similar to the ignition of a fluorescent tube), a relatively dense one and therefore a much better conductor of electricity.

The instruments aboard the tether satellite showed that this plasma diverted through the pinhole about 1 ampere, a current comparable to that of a 100-watt bulb (but at 3500 volts!), to the metal of the shuttle and from there to the ionospheric return circuit. That current was enough to melt the cable.

As the broken end whipped away from the shuttle, the plasma established electric contact with the ionosphere directly. The satellite on the distant end monitored the current: after about half a minute it stopped, then it reignited and flowed again for about another half minute, stopping for good when (presumably) all the trapped air was gone.

INVESTIGATION
ftp.hq.nasa.gov...

[...]But on Feb. 25 after the 12 mile tether began producing electricity an unexpected overload in electrical energy fluctuating between 2 and 10 times that which predicted due to inaccurate estimates in the electrical charge in the earths magnetic field, ionosphere, and possibly space radiation fried the tethers conductor cable and it broke severing it from the space shuttle..."

"This arcing produced significant burning of most of the tether material in the area of the arc," the board found. The tether was designed to carry up to 15,000 volts DC and handle tensile forces of up to 400 pounds (1780 newtons). It used super-strong strands of Kevlar as a strength-providing member, wound around the copper and insulation. However, postflight inspection of the tether end which remained aboard Columbia showed it to be charred. The board concluded that after arcing had burned through most of the Kevlar, the few remaining strands were not enough to withstand forces being exerted by satellite deployment.

Extensive, rigorous tests performed in support of the
investigation established that undamaged tether would not arc,
even when subjected to electrical potentials much higher than
the 3500 volts experienced during the mission.

This Tether Experiment, I believe, is one of the most tempting experiments since the start of the Space Age...

a reply to: Arken

Apparently the satellite that was lost was worth about half a billion dollars. I'm sure that left a bad taste in the mouths of the people holding the purse strings.

Here's a story from 1996 in the LA Times

There was another proposed experiment, ProSEDS (Propulsive Small Expendable Deployer System), that was originally supposed to launch in 2003 but was scrapped by NASA.

Scientists and engineers at NASA's Marshall Space Flight Center are developing a test model (left) of such a device that will use Earth's magnetic field to make a rocket stage re-enter the atmosphere in a few days instead of months. If it works, then America will have a powerful new tool to keep satellites up - even to explore the solar system - without using rockets.

It could even trim $2 billion a year off the cost of operating the International Space Station.

It won't quite work the same as a Space Coupe with steerable magnets. Instead, ProSEDS will use a 20 km (12-mile) extension cord that plugs into the magnetosphere and turns the cord into an electric motor that slowly raises or lowers a satellite's orbit.

The concepts behind ProSEDS - the Propulsive Small Expendable Deployer System - are derived from the Tethered Satellite System flown on the Space Shuttle in 1995 and 1996. Although the tether broke as it reached its 19.6 km (12-mile) length on its 1996 flight, scientists gathered a great deal of data about tether behavior during five hours of operation.

NASA - Science News

When further analysis suggested that several ProSEDS key performance parameters could not be met, NASA decided not to fly the ProSEDS mission. It is thought that this decision was due, at least in part, to the feeling that the tether lifetime would not be sufficient to accomplish mission goals. It was expected that particle impacts on the tether would compromise the insulating properties of the insulated portion of the tether before mission science goals could be met. In addition, tightening of ISS safety requirements required an alteration of the ProSEDS orbit to such an extent that ProSEDS mission requirements and equipment performance could not be made to satisfy the emerging ISS safety requirements within the constraints of time and budget.

USU Space Dynamics Lab

links to more reading:

ProSEDS white paper - NASA
Wikipedia - Space tether missions

a reply to: theantediluvian

Thanks for the add-on

originally posted by: Arken
Do You remember the Tether Experiment, the STS-75 Tethered Satellite System deployment in 1996? Something went wrong, but the scientists were able to detect something amazing, measure and test before the satellite went adrift in space: An ENORMOUS amount of ENERGY...

Why we never heard something new about this epochal break thorough? Why no new developments in energy production from it?

That was kind of the idea, to generate a large voltage, even going back to the previous tether experiment STS 46 which was planned to generate 5000 volts, as Zorgon posted about in 2008:

www.abovetopsecret.com...

originally posted by: zorgon
below is the full report of the OTHER tether experiment STS 46 and you thought.....

Speeding through the magnetized ionospheric plasma at
almost 5 miles per second, a 12-mile-long conducting tethered
system should create a variety of very interesting plasma-
electrodynamic phenomena. These are expected to provide unique
experimental capabilities, including the ability to collect an
electrical charge and drive a large current system within the
ionosphere; generate high voltages (on the order of 5
kilovolts) across the tether at full deployment; control the
satellite's electrical potential and its plasma sheath (the
layer of charged particles created around the satellite)

...

Yet NASA reports... and Lockheed reports... and commission reports have all this info easily (well okay not THAT easily

) found in public sites?

So we DID hear about it and anybody who wanted to know what the tether experiments were about could find the information like Zorgon did.

The thing about energy is you not only have to produce it, you have to deliver it to a customer or user. That's not easy to do when the source is in orbit and the customers are all on Earth. The ISS already has solar panels. I'm not sure what you expect.

Aside from the power delivery problem, it may not be economical to produce the power at that altitude. We spend a lot of money boosting the ISS to keep it in orbit. A tether will have an even higher drag to mass ratio than the ISS, so you'd have to periodically boost the tether orbit too. You may spend more money launching fuel up in orbit to boost the tether's orbit than the value of the power you'd extract.

originally posted by: Arken
a reply to: theantediluvian

Thanks for the add-on

No problem. I wish more people were interested in space exploration and new energy sources! When I try to discuss space exploration with people IRL, a common sentiment is, "we have too many problems here on Earth to worry about space." What people fail to realize is that these aren't mutually exclusive concerns.

It's been clear to most forward thinking people for a very long time that our species destiny is to expand, first throughout our own solar system and eventually beyond. I for one am tired of waiting around for this happen. Global military spending is approaching $2 trillion — we're spending well over a 1000x the amount we do for space exploration on killing one another. What does this say about our species?

a reply to: theantediluvian

You are absolutely right: Space is our ultimate hope, for the future of the mankind...

a reply to: Arbitrageur

The thing about energy is you not only have to produce it, you have to deliver it to a customer or user. That's not easy to do when the source is in orbit and the customers are all on Earth. The ISS already has solar panels. I'm not sure what you expect.

You are right Arbitrageur, but you can use that energy for more big installations in space or on the Moon or use the Tethered "power station" like storage to send power cells (like batteries) in an outpost on the Moon.

originally posted by: Arken

Do You remember the Tether Experiment, the STS-75 Tethered Satellite System deployment in 1996? Something went wrong, but the scientists were able to detect something amazing, measure and test before the satellite went adrift in space: An ENORMOUS amount of ENERGY...

Why we never heard something new about this epochal break thorough? Why no new developments in energy production from it?

Interesting subject, I didn't even know this experiment took place back in 1996 so thanks for bringing this to my attention!

I can't tell whether or not there's a conspiracy element to this story or not, but I could indeed imagine a protective behaviour on behalf of industrial lobbyists in order to prevent world-changing innovations on a large scale.

With that said, I'm confident that natural forces (eg. geomagnetism, gravity etc.) can be used to harness electrical power on a much larger scale than we currently think. Such breakthroughs would certainly not make everyone happy, especially not those profiting from today's 'established' infrastructure & economy. Protectionism is IMO absolutely conceivable and probably a reality in many areas.

I will certainly keep an eye on this thread to see what others have to say ... S&F!

a reply to: jeep3r

I did not know about the high number of previous attempts of various agencies Civil and Military of this particular experiment, jeep3r.
Astonishing.

Seems that The Tethered Experiment is "The Holy Grail" to put the feet in space...

And what amazes me is the overwhelming silence on this huge achievement.

1 amp at 3500 volts is not an enormous amount of energy. That's about what two and a half household vacuum cleaners would use.

originally posted by: nataylor
1 amp at 3500 volts is not an enormous amount of energy. That's about what two and a half household vacuum cleaners would use.

True, but imagine if the tether had multiple wires, and they were all feeding into a massive capacitor. As a pulse the energy could be enormous, maybe large enough to feed a mega powerful laser device that could destroy any target it was aimed at, be it in space or on earth!

I have been waiting a long time for this conversation. A looong time. When the subject was buried by UFO nuts, I figured it was gone forever.

And here it is. Pardon me for a moment while I sing a happy song. I'm so flush with emotions right now, that I can't reasonably stay on topic.



I gave the first star and flag to this thread when I saw it this morning before work.



It's just great to see people actually responded and talking about it.

/happy dance
Mike Grouchy

originally posted by: VoidHawk

True, but imagine if the tether had multiple wires, and they were all feeding into a massive capacitor. As a pulse the energy could be enormous, maybe large enough to feed a mega powerful laser device that could destroy any target it was aimed at, be it in space or on earth!

problem is, if the wires are close to each other, they'll essentially short circuit each other, as the principle depends on the free flow of electrons at the end of the tether. If a number of tethers are all connected to one central capacitor, they'll have a tendency to orient themselves all in the same direction, so they'll end up too close to each other even if they start out far apart.

It would be much easier and cheaper to use some solar panels if you're looking to generate a couple kilowatts of electricity. Then you're not towing around a massive structure that 1) inherently reduces your orbital velocity in order to work and 2) would be a huge navigational hazard even in the best of circumstances.

I wonder if a similar experiment is onboard the X-37, especially something like the ProSEDS, it is kinda a nice fit, if the experiment was a success it would explain the X-37 endurance record and maybe pave the way for semi-permanent LEO satellites, would be nice for earth imagery, spying, and low latency communication satellites.

But yeah, its a stretch but anyways....

I've always thought this experiment gave the Homopolar Generator credibility and maybe should be looked at some more.

originally posted by: Arken


Why we never heard something new about this epochal break thorough? Why no new developments in energy production from it?

A wire moving through a magnetic field producing electricity it's hardly new!

a reply to: nataylor

It would be much easier and cheaper to use some solar panels if you're looking to generate a couple kilowatts of electricity.

Keeping in mind that an induction generator is also an electric motor, apply current from PV panels to a tether.

The tether would be accelerated (positively or negatively, depending upon the polarity of the current) through the magnetic field, dragging the satellite with it. The result, fuel-less Delta V.

a reply to: Phage

Yup. NASA even addresses that in the Tethers in Space Handbook. There's a proposal for a tether-based reboost system for the ISS. But using the kind of tether used on the STS-75 mission, they calculate they would need 175 kilowatts of electricity to produce a tiny 0.7 Newtons of thrust with a 10km long tether. They discuss a different type of tether that might be able to produce the same thrust using 5-10 kilowatts. Keep in mind that the total maximum power output of the ISS' solar panels is 84 kilowatts, so 5-10 kW of constant usage would represent a significant drain. The proposal was also written in 1997, and I'm not sure it accounts for the current mass of the ISS and if 0.7 Newtons would be enough thrust to make it worthwhile.

For smaller satellites, there's going to be some tradeoff where the aerodynamic drag induced by a tether and the large solar panels you'd need is going to overcome the the thrust it would generate.

Excellent recent comments.

Arken, the tether did not PRODUCE energy, it converted it from momentum into electrical flow by using ion generators at both ends to makes a circuit through the ionosphere, to exploit the motion of a wire through a magnetic field and -- voici!! -- here's electricity.

That energy came out of the tether's momentum, so it would act as a brake and drop it into a lower orbit.

Conversely, as Phage explained, you could run it in reverse, put current into the wire to pull it forward and raise its own orbit.

But no energy was being created, only converted in form. It wasn't some magic power outlet in the sky that Arken seems to think.

These ideas have been around for decades, there are technical conferences about them, I'm sorry Arken got the idea it was all being hidden away because it hadn't come to his personal attention.

Heck, as part of the private plan to commercialize Mir in 1999, a US team fabricated an electrodynamic tether called 'Firefly' to be installed on the aging Russian station. I wrote about it for IEEE Spectrum magazine. Never actually got launched before Mir was steered into the Pacific.

Tethers in space have a great many terrific potentials, and deserve more attention, so attaboys all around on this thread.

The link to my story on my home page is broke, here's another:

www.friends-partners.org...

Also, here's the 'Flight Crew Procedures Handbook' chapter on tethers I wrote for NASA in 1986
www.jamesoberg.com...