How To Ground a Space Vehicle?

You're an idiot. A Google idiot with an idiot gmail address. Go get lost.

Graham

This is the classic difference between grounding and bonding. If you have an equipotential bonding grid you don't care if you are grounded. Think of the bird on the power line.

Ok this is reasonable i thought the same but how can you keep the same potential at the grid because there is a input for ex. sollar array. and also how about electronic discharge.

When the space vehicle is a Faraday cage, you don't need ground to keep discharges out. Inside, everything is ground.

Meindert

In a previous occupation I did a lot of work in lightning mitigation on computer networks in Florida. The first thing we figured out is there is no such thing as "ground". You can have a very extensive grounding electrode system and 100 meters away another installation with the same type electrode system might be fluxuating by dozens of volts in a storm. That brings you back to bonding. As long as everything is referenced to a single bonding plane with a fat copper wire, those transients bring you up and then back down. You don't care whether you are zero volts or 1000 volts referenced to some hypothetical "ground". In the case of your space craft you really only care about transients generated on board and Mr Kirchoff says they will all reconcile themselves on board. You just need to assure it happens over your desired path. Whether you are a million volts above "ground" on some distant planet is inconsequential.. An example, closer to earth, would be a helicopter. They could be hundreds or thousands of volts "above ground" cruising through the air but you don't know it until you drop a steel cable to someone on the surface. They will get the snot knocked out of them if they don't bond it first.

And it's most important that your grounding scheme be in he form of a tree. If you have any loops in your grounds, watch out!

Al

Could you drop that cable on Phil? Please?

Biggest problem I have heard about grounding problems have been to possibility of attacting a 'cloud' of ionized particles of one polarity or another. This is usually solved by outgassing a neutral stream of both polarities to compensate...

Charlie

The Earth itself is suspended in vacuum and isn't grounded to anything. Just pretend the satellite is its own planet. However, now that you brought up the question, I wonder if they get sparks when the shuttle touches the space station.

-- john

well, it's all relative, where would the current go when they bonk each other?

martin

How do they moor a blimp? Use an insulating rope?

Thanks, Rich

They always have a box of dirt down in the cargo hold.

Cheers! Rich

The same "scienific" way I have seen when in my teens. You borrow from your grandma a flower pot and stick in it a 1/2 mm.sq copper wire connected to the grounding screw. Important, remember to water it twice weekly!

Have fun

Stanislaw Slack user from Ulladulla.

Don't forget to ground the fuel truck either !

Graham

They drop a ground cable first. They do the same for an airplane (well, not 'drop' but connect one to the airport grounding system).

I don't know about satellites, but aircraft have static bleeders. Little metal points, that allow accumulated charge to discharge without building up high voltages relative to the surrounding. The pointy ends create very high E fields (for a given charge), causing the surrounding air to break down at much lower charge levels. This keeps the RF from the resulting discharge down to a minimum. Lots of little, low current discharges instead of the occasional big buildup and then Bang!

Same place charges go when you touch the leads of a charged cap together.

-- Paul Hovnanian mailto: snipped-for-privacy@Hovnanian.com

------------------------------------------------------------------ "The day Microsoft makes something that doesn't suck is probably the day they start making vacuum cleaners" - Ernst Jan Plugge

There lots of people with a disgusting sense of humor but i see they don't know a thing about esd and the importance of grounding.I have started my first post with the sentence "I have been thinking", I have been thinking because because i am writing a report about spacecraft harness design,limitations etc. you idiots( not the one who tried to help me).

So as you see from the paul's answer:Some of you have said that satellite is a faraday cage but aircrafts are also faraday cage and i have known that they were using the chasis of the aircraft paul has extended the subject. I have found a document of space craft and they are using two level composite material with keeping them at the different potentials( it is like you have said bonding.) and assign to a ground point at the craft surface and at the launching station they connect a blockhouse and ground the craft.

If you charge the very small areas(the most given example is the nail head) with a great amount of charge , very small volume of air around that surface will become conductor and you can't keep your charges at that small area so it doesn't matter you want it or not that area will be discharged .this is one of the ideas at the medium that contains air that is why i said vacuum you can't do the same at the space.i have nothing to do with the charge balance of a system.