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Questions tagged [sensors]

Questions about instruments to collect data from the environment.

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0answers
129 views

How do you calibrate the accelerometers of an IMU in space, outside the GPS range?

IMU measurements are corrupted by drifts and errors, which accumulate over time. In space, gyroscopes can be calibrated using e.g., a star tracker as an absolute reference. GPS can serve as an ...
2
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1answer
61 views

Nadir sensor for a spacecraft attempting to land

Is it possible theoretically for a sensor to detect Nadir? This could actually be of extreme value as generally spacecraft attempting to land need to maintain certain heading w.r.t Nadir as a function ...
8
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2answers
201 views

What sensors or combination of sensors do rockets use during takeoff for their orientation?

I know that after using up rockets and before reaching final orbit, satellites use Earth, Sun, Star trackers to find the absolute position depending on the application and orbit. After that, they use ...
3
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2answers
246 views

Avoiding rocks when landing on Mars

I'm landing an unmanned spacecraft on Mars (or substitute your astronomical body of choice here.) I would like to avoid rock outcrops and land on relatively soft soil. What kind of sensor could ...
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6answers
5k views

How much more expensive are scientific instruments for space use?

The discussion on How cold is the Martian sky at night? Or the day for that matter? made me wonder. How much more expensive are scientific instruments on spacecraft or landers, compared to their ...
3
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2answers
109 views

Spacecraft Horizon Sensors for Lunar orbit

Recall that "traditional" horizon sensors for Earth missions utilize the IR wavelength regime since this can reveal a good contrast between the cold space and the warm Earth-limb edge. If we were to ...
1
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2answers
97 views

Gravity Model measurement technique

Geopotential model are used whenever propgation has to be done of the orbit. Geopotential model models the potential of earth via spherical harmonics. These models are generally published by NASA as ...
2
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1answer
39 views

Concentration of gases in an atmosphere

this question made me think what type of technique is used to get concentration of gases on planets? One can get the composition using spectrometry but is there anyway to tell concentration of each ...
9
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1answer
522 views

How does a gamma ray altimeter work? What kind of sensor is used?

The answers to the Space SE question Soyuz landing ground detection really surprised me. A gamma ray altimeter is used by the returning Soyuz capsule to detect the presence of solid ground immediately ...
37
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4answers
4k views

Soyuz landing ground detection

How does Soyuz detect the ground to fire its retro rocket at the end stage? Is there any paper/reference describing the full entry descent and guidance algorithm and sensor suite used in Soyuz? If ...
3
votes
2answers
96 views

Remaining fuel estimation/measuring Strategy in a spacecraft

During descent of a spacecraft to any planetary body the spacecraft uses retro engine with variable throttle to reduce the vehicle velocity to zero at touchdown. Inorder to compute for the amount of ...
1
vote
0answers
37 views

Atomic Inertial Sensor

In relation to the question I was looking for the perfect sensor that would help me achieve perfect non rotating spacecraft. My search made me look for exotic phenomenon that can be utilized for such ...
3
votes
1answer
154 views

Effect of permanent magnet and solid core magnetorquer on magnetometer reading

Permanent magnet as passive stabilization and magnetorquer with solid core as active stabilization has been used over the year in satellites.But the would have magnetic field lines, wouldn't they ...
7
votes
2answers
334 views

Can we detect the projected ISS shadow on the earth surface

Looking at an ISS transit picture: I started wondering wether we could see the ISS shadow passing on the earth. My intuition tells me that it would be impossible with the naked eye, but do we have ...
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0answers
80 views

Detection of micrometeoroid impacts on the lunar surface using thermal imaging?

For a student project we are looking into the possibility of detecting micrometeoroid (micrometer-size) impacts on the lunar surface with cubesats equipped with a thermal imaging device. We have found ...
4
votes
2answers
572 views

Generally, what types of sensors are used in rocket guidance systems?

I was wondering how a rocket adjusts its position to ensure it takes the desired path. What sensors, or generally technology, are used to gain data on the rocket's position, where it is heading and ...
7
votes
2answers
272 views

Which of the outer planets could you see with the naked eye if you were in close proximity?

My question is which of the outer planets you could see with the naked eye if you were in close proximity to them. It's pretty obvious the human eye can see the inner planets through to Mars, but I ...