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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."
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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.
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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?
A NASA-funded test of an entirely new way to explode orbiting satellites has ended with promising success!
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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
You certainly get bonus points for irony using an Ariane 5 as an example of a rocket not blowing up...
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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.