Cal Poly ACS: Why Are Reaction Wheels Angled at 29.3 Degrees?

In summary, the conversation discusses the design of reaction wheels in Cal Poly's ACS and the reasoning behind angling them at 29.3 degrees. The speaker suggests that this layout is a creative way to achieve redundancy without adding too much weight.
  • #1
Swankie
15
0
Here is a link to Cal Polys ACS they built. My question is: they claim each reaction wheel is angled at 29.3 degrees. Why would that be? My only guess is that they are each pointed at the CoM.
 
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  • #2
Your link is missing.

You certainly don't want three reaction wheels (one per axis). What if one fails? You certainly don't want six (two per axis), either. Too much weight. One way to get redundancy at a minimal cost is to get a bit creative in the layout, arranging the reaction wheels on the edges of the triangular faces of a right square pyramid.
 

1. What is the purpose of angling reaction wheels at 29.3 degrees?

The 29.3 degree angle is based on the Earth's tilt, also known as its axial tilt. This angle allows the reaction wheels to align with the Earth's spin axis, allowing for more efficient attitude control for spacecraft and satellites.

2. Why is the 29.3 degree angle specifically chosen?

The 29.3 degree angle is the specific tilt of the Earth's axis, so it is the most efficient angle for reaction wheels to be angled at in order to match the spin of the Earth. This prevents unnecessary energy usage and allows for smoother and more accurate attitude control.

3. Can other angles be used for reaction wheels?

While other angles may be possible, the 29.3 degree angle is the most optimal for efficient attitude control. Other angles may result in less stability and require more energy to maintain the desired orientation.

4. How do reaction wheels work at the 29.3 degree angle?

Reaction wheels are essentially spinning disks or flywheels that rotate at high speeds in order to change the spacecraft's orientation. At the 29.3 degree angle, the reaction wheels are aligned with the Earth's spin axis, allowing for the most efficient control of the spacecraft's attitude.

5. Are there any disadvantages to using the 29.3 degree angle for reaction wheels?

While the 29.3 degree angle is the most optimal for efficient attitude control, it may not be suitable for all spacecraft and missions. Some spacecraft may require different orientations for specific tasks, and in those cases, a different angle may be more suitable. Additionally, the 29.3 degree angle may not be as effective for spacecraft orbiting bodies other than Earth.

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