My university physics prof was a retired satellite engineer for NASA. I don't really understand the specifics, but he took a class period one semester to go over the difficulties of building devices that work correctly in zero-G, because sometimes effects that are ignored on Earth have major impacts in space. Among those things is a requirement to balance the satellite to within very small tolerances using some pretty precise measuring devices. I don't remember the exact precision, but it was some fraction of a gram.
He gave an example of a program he worked on (an environmental imaging satellite) where the circuit created by the electrical bus was geometrically configured (accidentally) in such a way that a slight magnetic field was generated in part of the spacecraft. This part of the spacecraft would interfere with the Earth's magnetic field and produce some impossibly small force on that part of the spacecraft, sending it into a very slow, unintended, roll. The force produced was impossibly small, he used the analogy of a down feather from a baby parakeet resting on your hand. The result would have been that the spacecraft would have used all the mechanical energy in its flywheels trying to stay stable, and then used all of its maneuvering fuel and become useless in just a few days. It was caught during some sort of balance test and they had to reengineer the circuit to produce a magnetic field in the opposite direction to cancel out the effect.
He gave another example where an instrument package was delivered at the wrong weight due to a change in some insulator. I can't remember if it was too heavy or too light. They had to add small weights to a different part of the spacecraft to maintain balance. IIR he said it took them several weeks to get the weights in the right positions to pass the mass balance tests on various axes.
I have no idea how accurate this is, but I thought it was an interesting and not-intuitive insight into how things in space work differently than on Earth.
He had other interesting stories about thermal management issues and other similar.
He gave an example of a program he worked on (an environmental imaging satellite) where the circuit created by the electrical bus was geometrically configured (accidentally) in such a way that a slight magnetic field was generated in part of the spacecraft. This part of the spacecraft would interfere with the Earth's magnetic field and produce some impossibly small force on that part of the spacecraft, sending it into a very slow, unintended, roll. The force produced was impossibly small, he used the analogy of a down feather from a baby parakeet resting on your hand. The result would have been that the spacecraft would have used all the mechanical energy in its flywheels trying to stay stable, and then used all of its maneuvering fuel and become useless in just a few days. It was caught during some sort of balance test and they had to reengineer the circuit to produce a magnetic field in the opposite direction to cancel out the effect.
He gave another example where an instrument package was delivered at the wrong weight due to a change in some insulator. I can't remember if it was too heavy or too light. They had to add small weights to a different part of the spacecraft to maintain balance. IIR he said it took them several weeks to get the weights in the right positions to pass the mass balance tests on various axes.
I have no idea how accurate this is, but I thought it was an interesting and not-intuitive insight into how things in space work differently than on Earth.
He had other interesting stories about thermal management issues and other similar.