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Does Hubble need to dump momentum of its reaction wheels?

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Does Hubble need to dump momentum of its reaction wheels?

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$begingroup$

Hubble has no thrusters, but it is large enough to have nontrivial gravity gradient and tidal forces acting on it. This would induce a torque that has to be cancelled by its reaction wheels. If I understand it correctly, this extra momentum, now stored in the wheels, would have to be dumped somehow. Does Hubble have any mechanism to do this on board? Alternatively, does it actually rely on the gravity gradient to dump momentum, rather than what I had assumed here? Does it actually need to dump momentum, and if not, why not?

reaction-wheel hubble

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edited 8 hours ago

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3

$begingroup$

Hubble has no thrusters, but it is large enough to have nontrivial gravity gradient and tidal forces acting on it. This would induce a torque that has to be cancelled by its reaction wheels. If I understand it correctly, this extra momentum, now stored in the wheels, would have to be dumped somehow. Does Hubble have any mechanism to do this on board? Alternatively, does it actually rely on the gravity gradient to dump momentum, rather than what I had assumed here? Does it actually need to dump momentum, and if not, why not?

reaction-wheel hubble

share|improve this question

edited 8 hours ago

Organic Marble

66.4k44 gold badges186186 silver badges284284 bronze badges

asked 9 hours ago

Michael StachowskyMichael Stachowsky

1,51033 silver badges1212 bronze badges

$endgroup$

add a comment | 

$begingroup$

Hubble has no thrusters, but it is large enough to have nontrivial gravity gradient and tidal forces acting on it. This would induce a torque that has to be cancelled by its reaction wheels. If I understand it correctly, this extra momentum, now stored in the wheels, would have to be dumped somehow. Does Hubble have any mechanism to do this on board? Alternatively, does it actually rely on the gravity gradient to dump momentum, rather than what I had assumed here? Does it actually need to dump momentum, and if not, why not?

reaction-wheel hubble

share|improve this question

edited 8 hours ago

Organic Marble

66.4k44 gold badges186186 silver badges284284 bronze badges

asked 9 hours ago

Michael StachowskyMichael Stachowsky

1,51033 silver badges1212 bronze badges

$endgroup$

share|improve this question

edited 8 hours ago

Organic Marble

66.4k44 gold badges186186 silver badges284284 bronze badges

asked 9 hours ago

Michael StachowskyMichael Stachowsky

1,51033 silver badges1212 bronze badges

share|improve this question

edited 8 hours ago

Organic Marble

66.4k44 gold badges186186 silver badges284284 bronze badges

asked 9 hours ago

Michael StachowskyMichael Stachowsky

1,51033 silver badges1212 bronze badges

edited 8 hours ago

Organic Marble

66.4k44 gold badges186186 silver badges284284 bronze badges

edited 8 hours ago

Organic Marble

66.4k44 gold badges186186 silver badges284284 bronze badges

asked 9 hours ago

Michael StachowskyMichael Stachowsky

1,51033 silver badges1212 bronze badges

asked 9 hours ago

Michael StachowskyMichael Stachowsky

1,51033 silver badges1212 bronze badges

1 Answer
1

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4

$begingroup$

Yes. It is done by magnetic torquers.

Magnetic torquer bars can provide control about the wheel-less
axis, but they must also continue to dump momentum from the wheels
to prevent wheel speed saturation.

(emphasis mine)

Source

Source

Another good reference on the attitude control system is here.

share|improve this answer

edited 8 hours ago

answered 9 hours ago

Organic MarbleOrganic Marble

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4

$begingroup$

Yes. It is done by magnetic torquers.

Magnetic torquer bars can provide control about the wheel-less
axis, but they must also continue to dump momentum from the wheels
to prevent wheel speed saturation.

(emphasis mine)

Source

Source

Another good reference on the attitude control system is here.

share|improve this answer

edited 8 hours ago

answered 9 hours ago

Organic MarbleOrganic Marble

66.4k44 gold badges186186 silver badges284284 bronze badges

$endgroup$

add a comment | 

4

$begingroup$

Yes. It is done by magnetic torquers.

Magnetic torquer bars can provide control about the wheel-less
axis, but they must also continue to dump momentum from the wheels
to prevent wheel speed saturation.

(emphasis mine)

Source

Source

Another good reference on the attitude control system is here.

share|improve this answer

edited 8 hours ago

answered 9 hours ago

Organic MarbleOrganic Marble

66.4k44 gold badges186186 silver badges284284 bronze badges

$endgroup$

add a comment | 

$begingroup$

Yes. It is done by magnetic torquers.

Magnetic torquer bars can provide control about the wheel-less
axis, but they must also continue to dump momentum from the wheels
to prevent wheel speed saturation.

(emphasis mine)

Source

Source

Another good reference on the attitude control system is here.

share|improve this answer

edited 8 hours ago

answered 9 hours ago

Organic MarbleOrganic Marble

66.4k44 gold badges186186 silver badges284284 bronze badges

$endgroup$

share|improve this answer

edited 8 hours ago

answered 9 hours ago

Organic MarbleOrganic Marble

66.4k44 gold badges186186 silver badges284284 bronze badges

answered 9 hours ago

Organic MarbleOrganic Marble

66.4k44 gold badges186186 silver badges284284 bronze badges

answered 9 hours ago

Organic MarbleOrganic Marble

66.4k44 gold badges186186 silver badges284284 bronze badges