13 votes
Accepted

How is charge dissipated in ion-propulsed spacecraft?

Equalizing the charge of an ion thruster is a real problem. It is not possible to eject only positive xenon ions over a long time. The space craft would charge negatively and ions would be "...
Uwe's user avatar
  • 49k
10 votes

Thrust of ion thruster when spacecraft is charged

This is a great question! To first order charging doesn't matter. What matters is the exit velocity of the ions, determined by the acceleration potential difference $V_b$. In a simple situation the ...
uhoh's user avatar
  • 149k
7 votes

How are differences in electrical potential between docking (or berthing) vehicles mitigated?

See @msalters comment on a related question which links to a paper on the subject. From a quick read of the paper, what seems to happen is that in LEO (ie at the ISS) the plasma (ionized gas) of the ...
Steve Linton's user avatar
  • 19.6k
7 votes
Accepted

How do spacecraft measure their own charge?

The ISS measures its charge using the Floating Potential Measurement Unit. This device works as follows (from Data Analysis of the Floating Potential Measurement Unit aboard the International Space ...
Organic Marble's user avatar
6 votes
Accepted

How does one use the SEAESRT charging hazard graphic that NOAA provides?

I'm not sure exactly how they use the data (though this handbook might have some interesting reading, but I can answer the latter half. From the link you posted: The Spacecraft Environmental ...
fyrepenguin's user avatar
  • 1,663
5 votes

Is a spacecraft able to measure it's current electric charge in some way?

The ISS has a device called the Floating Potential Measurement Unit that handles this task. The linked page has a link to a pdf that describes it in more detail.
Tristan's user avatar
  • 17.3k
4 votes
Accepted

What generates static charge on the ISS?

You are right; objects in space collect I+ and e- simultaneously. This results in a negative charge due to the rate at which these different particles are collected. Since electrons are far lighter ...
Olgidos's user avatar
  • 450
4 votes
Accepted

Why were the three 122-cm diameter conductive spheres for charge collection in the Shuttle's Space Experiments with Particle Accelerators black?

From page 10 of "Space Experiments with Particle Accelerators (SEPAC): Description of instrumentation": A set of three truncated spherical conductors was selected. The spheres will be ...
Christopher James Huff's user avatar
4 votes
Accepted

How did three 1.2 meter spheres and a Xe+ plasma contactor keep the Shuttle "grounded"? What did they look like?

An excellent summary of the mission can be found here: https://earth.esa.int/web/eoportal/satellite-missions/a/atlas SEPAC involves the firing of a 1.6 Å 7.5 kV electron beam accelerator from the ...
Freddie R's user avatar
  • 2,544
3 votes
Accepted

How is Parker Solar Probe so robust against coronal mass ejections?

In the absense of any better suggestions, I'm going to go out on a limb here and suggest that the carbon-carbon parasol does, in fact, provide enough shielding from all flavours of solar radiation ...
Starfish Prime's user avatar
2 votes

Is there any possible reason to direct the electron gun specifically towards the ion trail behind an ion thruster?

There are a lot of ions in space already, adding a few from the thruster is not really that big of a deal. They are moving so fast that it won't really make a huge difference being neutral or not, ...
PearsonArtPhoto's user avatar
  • 121k
2 votes

How do spacecraft measure their own charge?

You can use a direct approach to the measurements. For sign, you can measure whether electrons are attracted to or repelled by the craft - or ions repelled or attracted. For field strength you can ...
C. Towne Springer's user avatar
2 votes

How is charge dissipated in ion-propulsed spacecraft?

Ion drive spacecraft need to eject a net neutral amount of charge. Otherwise, the spacecraft would become so charged that the ion exhaust would just be sucked right back to the spacecraft. It takes an ...
ikrase's user avatar
  • 8,874
2 votes

Why do satellites have capacitance?

Why do satellites have capacitance? Capacitance is some ratio of charge to potential difference, with a constant in front. Whenever some charge is added to something, be it a person, a cow, or a bit ...
uhoh's user avatar
  • 149k
1 vote

How did three 1.2 meter spheres and a Xe+ plasma contactor keep the Shuttle "grounded"? What did they look like?

What did they look like? Unsurprisingly, like black spheres! Supplementarily, I've just run across the following image in Popular Science's The silliest names scientists have given very serious ...
uhoh's user avatar
  • 149k

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