How To Ground a Space Vehicle?

Hey, true story!

When I worked in the Crestline central office, at the end of a dry summer, we would notice our noise readings on the phone lines would be up, so we had to take a hose out back, and open the 'wells' over the ground rods, and water them. First time we did this, we found out that most of them were 'sealed' by paint, and we had to break the lids loose to get the water in.

Was only a few dB of noise, but it was definitely measurable!

Charlie

Voltage is a relative thing. If you're out in space, it doesnt really matter much what your voltage is relative to Earth. You could be a zillion volts positive, due to a solar flare shooting protons at you, and it really makes no difference.

Now if you go approach some other spacecraft, it might be a zillion volts negative. You might want to extend a long 100 megohm probe to equalize your relative voltages. Or tolerate the possible SNAP! of a small lightning bolt.

Actually, if there are solar particles out there they may help equalize your relative voltages without needing a special probe.

Since youi are in almost-vacuum (+/- solar particles) I don't think you will get a lightning bolt, at least not as we are used to seeing them in Earth atmosphere.

I spent a few years on a U.S. Navy ship as a radio operator. Seagoing ships are practically the only vehicles that can still use lead paint, and the entire hull was the ground, conducting in relation to the ocean. It was very effective.

Comparing this idea to a ship in space, I'd like to remind everyone that space is not a true vacuum, but is a litter of dust and gas. I don't know the physics of it, but it would seem to me not to be a "ground" at all, but an area of dissipation. We do know that radio works in space.

Now that you have me interested, I'll have to go and do some research.

Michael

Ok the discussion is over here it is.I answered my own question :P

thanks for who helped and tried to help.

It's an interesting question. If there are a lot of both negative and positive ions from the solar wind, say, it would seem as if a charged spacecraft could neutralize itself by attracting the needed particles and repelling the others. On the other hand, since a lot of those particles are moving pretty fast, and the electrons can be accelerated laterally easier than the protons, it might end up with a net charge. I'll be interested to see what you find out.

-- john

I saw this static bleeder today at some helicopter (it is a secret :) ) and it is keeping away the charge from the helicopter and not related with the electrical system or grounding

Actually there is a much simpler answer: just equalize charge. Back in the

1970's when MOS was new and ESD damage was just getting to be known, charge equalization prevented damage most of the time. They do this with space vehicles SOP. BTW above 150 miles up it is a better vacuum than almost all vacuum tubes ever made, not very conductive at all, including solar wind effects.

joseph2k

I googled up a couple of interesting sites-

Satellites Get a Charge Out of Space

Space Charge

Among the interesing points, the low orbit environment is a plasma, which interacts with power systems, and the photoelectric effect from solar UV charges spacecraft.

-- john