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First Exotic Space Thruster Test Ends in Explosion
KentuckyFC writes "A NASA-funded test of an entirely new way to control orbiting satellites has ended with the prototype arcing dangerously and parts of the machine exploding. The new propulsion system is based on the Lorentz force: that a charged particle moving through a magnetic field experiences a force perpendicular to both its velocity and the field. So the plan is to ensure that a satellite passing though the Earth's magnetic field is electrically charged so as to generate a force that can be used to steer the spacecraft. The advantage of the idea is that it requires no propellant, which is a big deal since most satellites' lifespans are limited by the amount of fuel they can carry. But the first ground-based tests haven't gone entirely to plan."
Disclaimer: I am not god.
We may not be created equal
But we can be treated equal.
From TFA: And as long as nobody gets hurt, a decent explosion livens up any experiment.
I'm pretty certain this is how Mythbusters got started.
Also from TFA: Obviously, a proplusion system that explodes while it is in operation needs some more work.
I dunno, kinda sounds like how rockets work.
I'm actually glad to see NASA doing stuff that might not work. It seems that a lot of the space work thats been happening in the last decade or two has been stuff that we know we can do. There are still failures, but those tend to be metric vs imperial units issues, not because they're pushing forward in to new areas.
All new technology generates it's share of failures along the way. In the early days NASA blew up a lot of rockets in the process of learning to get them in to space. As long as we're using it on unmanned craft (or on the bench), a decent rate of failures is alright by me if they're learning something from them.
I'd be concerned if I tested my exotic thruster and it didn't end in an explosion.
Give me Classic Slashdot or give me death!
Here is the story, based on my admittedly non-expert reading: To use the (very exciting) Lorentz steering technology, the sattelite has to have an electric charge. The method they used to obtain the charge is to apply a voltage to a radioactive substance and then allow solar wind to carry away the positive charge, leaving the sattelite negatively charged. The problem seemed to be that this process caused sparks to arc across the sattelite, which in turn damaged electronics and dislodged soldering.
I'm not sure why this is a big deal. Couldn't they just use a different kind of solder, or at least insulate vulnerable electronics from the charge?
My brain initially processed the title as, "First Erotic Space Thruster Test Ends in Explosion". Needless to say I was very disappointed when I read the summary.
Developers: We can use your help.
You should watch videos of our first satellite attempts. I'm surprised we didnt have more fried astronauts.
A NASA-funded test of an entirely new way to explode orbiting satellites has ended with promising success!
The enemies of Democracy are
let a little thing like an explosion deter me.
What?
Another variant of this is to have two weights connected by a wire tether and tide-locked to the primary, so the wire is oriented at roughly right angles to the orbit. Then you put a current in the wire by ejecting electrons on one end and collecting them at the other - making it into a motor that can accelerate or decelerate along the orbit. No reaction mass, run it off the solar collectors, etc. This also ran into issues with arcing.
They tried an experiment on this with the shuttle and a tether to a satellite they were launching, and found a problem: The motion along the orbit also causes it to act like a generator, powered by the orbital momentum. (This was known - and also has possible uses.) This produces a voltage gradient along the wire tether. So the tether has to be insulated to prevent arcing to the very low-pressure plasma that constitutes the high atmosphere and solar wind.
What they discovered was that minute flaws in the insulation caused localized arcs to the surrounding plasma. These were powered by the orbital motion relative to the earth's field and were very intense. They quickly melted through the thin tether.
So such a motor is not an impossibility. But it will require some heavy engineering work to get around this problem.
(It also says that large-scale tethered orbital structures have an additional problem to be solved: Keeping the tethers intact despite kilovolts of induced voltage along the tether and the resulting arcing.)
It's easy to think of space as filled with a hard vacuum. Unfortunately it's actually filled with very low pressure conductive plasma and near the Earth that's dense enough to be a major engineering issue.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
Will this screw up when the earths field begins fluctuating when poles being going into reversal again?
Mind you, when this begins, I suspect the last thing we would be worried about if/when this comes would be the odd satellite crashing back to earth.
"I bless every day that I continue to live, for every day is pure profit."
Wow, you had to stretch to come to your spurious conclusion about the myth that the government is full of incompetents and money wasters.
The Kruger Dunning explains most post on
Sure, you got the basic points all right. Now, let's see some advanced stuff:
It should go like this
NOT like this.
(pun intended) I suspect possible solder join problems here. The voltages they're working with are not exactly known for freely arcing unless it's a short. I did notice no mention of the current involved tho. If it was a high current application, it points to someone not insulating correctly. Over-ionized maybe? The excerpt didn't fill too many details in.
I was surprised to learn that satellites are not refueled more often. After a bit of googling, this pdf came up. From page 15:
This was from 1996, but as I understand, basic shuttle capabilities haven't changed much (someone correct me if I'm wrong). I think nm is nautical mile (1.852km).
Billy Brown rides on. Yolanda Green bypasses Gary White.
Ya, but you might want to use protection or you'll get burned.
If you have a negatively charged target in a plasma the target will attract positive ions which will knock bits off of the target if they arrive with sufficient velocity, otherwise they'll stick and neutralize the charge. In a sputtering chamber we want those bits knocked off. If we're sputtering something non-metallic we need to use RF to keep it charged.
...is the one you don't learn anything from.
GO NASA!
One would think that NASA engineers had watched enough Star Trek to realize that if one does not reverse the polarity of the intermix injectors into the flow matrix before the plasma coolant leaks after a power surge then the warp core will breach...amateurs.
The best projects usually have a development report buried somewhere in their history that contains the phrase, "...and then it exploded."
Percy Spencer (microwave oven): "...and then the egg exploded."
James Watt (steam engine): "...and then the boiler exploded."
Alfred Nobel (dynamite): "...and then the nitroglycerin-soaked soil exploded."
Vladmir Titov (Russian cosmonaut): "...and then the Soyuz rocket exploded."
Werner von Braun (NASA engineer): "...and then the Jupiter rocket exploded."
Yang Liwei (Chinese Taikonaut): "...and then the Long March rocket exploded."
Sony test engineer: "...and then the battery exploded."
J. Robert Openheimer: "...and then the Trinity device exploded"...oh wait, that was supposed to happen.
A more personal anecdote:
Someone in the shop at work needed a simple room-temperature dryer for a special project, so he got some large diameter PVC pipe that was handy, filled it with a desiccant, put the material in that needed drying, and screwed the cap on. Then he left it alone for a few hours.
Apparently some sort of gas-producing chemical reaction took place, probably helped by the sun shining through the open door, (...wait for it...) and then the drying chamber exploded, blasting the plastic lid through the ceiling 25 feet overhead and covering the work bay with the tiny pellets of desiccant.
Engineering is fun.
Spacecraft charge has long been a problem with satellites. The OGO IV satellite (circa 1968) was frequently negative due to the fact that the electron temperature in the ionosphere is higher than the ion temperature. As such there is a net electron flow to the satellite until its charge repels the electrons for a balanced +/- flow. But this is not always the case since the solar panels on the craft have exposed electrical contacts. The charging panels can drive electrons away from the craft and give (every once in a while) a net positive charge to the craft. Plasmas are tricky beasts. Simulations of the space environment on earth are frequently wrong.
Yes there is humor here, but this should be +5 Insightful. Almost EVERY engineering endeavor has involved catastrophic failures at one point or another. If people stopped trying after one such failure we'd be using flint hand axes and making fire with a bow drill still, if even that.
If you want to deflect the plasma (and thereby use the resultant Lorenz force to thrust your spacecraft), you have to use microsecond pulses of surface charge, not continuous charge like you would get from a weak alpha-emitter. Continuous charge = intact plasma filament = charge lead right back to your surface. Break the filament and you still get the expansion of plasma, with the resultant force transferred to the spacecraft through the magnetic field.
The man who does not read good books has no advantage over the man who cannot read them. - Mark Twain
The circuit breaker feeding the distribution wires (that were damaged in some way by an unknown cause) apparently failed. These distribution wires are running somewhere between 7200 and 19800 volts relative to ground. What is happening is that as the wires burn down in various places, that voltage is crossing over to the 120 volt (relative to ground) wires going into the homes. The insulation on the home wiring would be rated for 600 volts, which means they could fail with as little as 2400 volts or less. Circuit breakers in the homes are irrelevant. The wires going to the homes, the meters on the sides of the houses, the circuit breakers inside, and other wiring in the houses, are getting at least 7200 volts and arcing is happening even right through the insulation.
Assuming that the house does not actually catch fire and burn down (if it did, the firemen can do nothing about it until the power is confirmed to be permanently off), all of the wiring inside, circuit breakers, and electrical fixtures, will have to be replaced due to the damaged insulation.
now we need to go OSS in diesel cars