9 votes
Accepted

What was back-up plan in case of Apollo CSM Primary Guidance System IMU went to gimbal lock?

The Apollo attitude control system starts from a known orientation established by taking star sightings, then uses gyroscopes to track the change in orientation over time. The problem with gimbal lock ...
6 votes
Accepted

What are Starlink's available momentum unloading strategies?

Per Elon via twitter, magnetic torquers. Magnetic torque rods for desaturation of momentum wheels.
  • 5,872
5 votes
Accepted

How do rate gyros measure yaw, roll and pitch rates?

In this figure, ζ is the input axis, η is the output axis, and the spin axis is obvious. If the vehicle is rotated around the axis ζ (the input axis) with an angular velocity ωζ, the frame will ...
5 votes
Accepted

Are new precision gyroscopes used in spaceflight pretty much all optical?

A hemispherical resonator is an example of a mechanical gyroscope that has no bearing parts and for practical purposes no moving parts either. See the Wiki page here. I actually find the description ...
  • 8,968
4 votes
Accepted

Hubble's one-gyro mode; how does it work for attitude control, stabilization, and slewing?

Some of the confusion may arise in that the gyros under discussion are not used to actually change the attitude of the HST...that is done by Reaction Wheel Assemblies, (separate spinning devices) and ...
3 votes
Accepted

Can gyroscopic stabilization be done without any rotating parts?

Gyroscopes used as sensors can be mechanical, ie with spinning parts, or electrical in which case lasers are often used. Movement is measured and the output is some sort of data which goes to a ...
  • 19k
2 votes

What were the relative orientations of the Hubble Space Telescope's three star cameras, six rate gyros and four reaction wheels optimized for exactly?

Not a real answer, but some thoughts that are too long for a comment I doubt there was a concern about optimizing the directions for easier calculations. Positions are fixed and known, so all ...
  • 13.5k
2 votes

What is the precision attitude estimation strategy for satellites, under impulsive thrust manoeuvres?

This needs to be assessed on a case-by-case basis, with simulations, and with all hardware and algorithms properly modeled. But to give an ideia of what is concerned and what is usual: Image blur on ...
  • 1,879
2 votes

What is a gyrocompass and how might one be used by a planetary rover?

A gyrocompass mounts a gyroscope in a particular way so that its axis (eventually) self-aligns with the axis of the planet, e.g. Earth’s, rotation. In this way you get a self-contained indication of ...
  • 12.4k
2 votes
Accepted

What is a gyrocompass and how might one be used by a planetary rover?

Planets rotate. Place an accurate gyroscope on a table and you can readily observe earth's rotation. A 3-axis gyroscope measures the axis of rotation and angular velocity around it. Angular velocity ...
  • 1,132
2 votes

What is a gyrocompass and how might one be used by a planetary rover?

Gyrocompass is type of non magnetic compass. It is similar in principle of gyroscope but not same. The principle namely is gyroscopic precession. One can definitely use the gyroscope/gyroscopic ...
  • 2,818

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