Questions tagged [adcs]

Attitude Determination & Control Systems measure the attitude of a spacecraft and often execute measures to adjust the attitude with respect to the celestial sphere, reference bodies, or other spacecraft. They can be active including computations, or passive.

Filter by
Sorted by
Tagged with
6
votes
1answer
114 views

How hard was it for the Shuttle to perform attitude control for the entire ISS? Did they have to calibrate?

This answer to the question How was the Space Shuttle Orbiter used for ISS Reboost? describes a procedure I never knew happened. When the shuttle was docked to the ISS it sometimes used its rear ...
5
votes
1answer
174 views

Why did Cassini have reaction wheels but Galileo, Juno and New Horizons don't?

Three gas giant planet orbiters are mentioned in this answer: Cassini - Uses Reaction Wheels and thrusters Galileo - Primarily managed via spinning the spacecraft and thrusters. Juno - Just ...
3
votes
1answer
50 views

Have magnetotorquers ever been used to spin-up a satellite?

Magnetotorquers are often used for momentum dumping of reaction wheels in smallsats, and they can use them as well for attitude control directly, per answers to Are there any modern cubesats or ...
1
vote
2answers
57 views

Are there any modern cubesats or smallsats that have relied only on magnetotorquers for attitude control?

This comment got me thinking... Question: Are there any modern cubesats or smallsats that have relied only on magnetotorquers for attitude control, sans reaction wheels or thrusters? Ideally an ...
4
votes
1answer
68 views

How does one impulsively null spacecraft nutation?

The Scott Manley video The Only Pilot to Shoot Down A Spacecraft - A Space Ace talks about the ASM-135 ASAT and its successful test launched from an F-15. He shows images from the page The F-15 ASAT ...
2
votes
0answers
87 views

Puzzler: which Apollo 8 astronaut would have been positioned furthest sunwards 20 minutes after lunar insertion?

This Classic @DavidHammen answer to the question Who has been the closest to/furthest from the Sun? says: This bodes well for an Apollo astronaut being the person closest to the Sun, but bodes ill ...
3
votes
1answer
73 views

How could Earth's magnetic field be used to determine a cubesat's attitude in LEO?

After reading this answer I thought that I'd read about a smallsat that used magnetometers to measure the Earth's magnetic field direction and magnitude along with a model for Earth's field and some ...
2
votes
1answer
79 views

Spacecrafts: NED frame to Orbit Frame or Body Frame Transformation

I calculate the geomagnetic field using IGRF model in Matlab. However, the output is in the NED coordinate frame and I want to tranform it into the Body frame. I've searched everywhere and I cannot ...
5
votes
1answer
447 views

How “hard” did Apollo 12 turn left just before it landed?

This answer to How much were the LMs maneuvered to their landing points? includes Figure 34 from Floyd Bennett's 1972 Apollo Experience Report - Mission Planning for Lunar Descent and Ascent; NASA TN ...
3
votes
1answer
86 views

What are “uncoupled attitude maneuvers” and why do them?

This answer to the question Apollo-11 delta-v “due to residual pressure in the docking tunnel pushing the spacecraft apart” detected as it happened? Was it corrected? quotes the following passage from ...
3
votes
1answer
282 views

What does it mean when the Voyagers “switch thrusters”?

The Gizmodo article NASA fights to keep the Voyager probes running after four decades says: As another example of the probes' need to adapt to circumstances to keep going, Voyager 2 has fired up ...
9
votes
2answers
208 views

How often do reaction wheels require desaturation, normally?

I'm sure the answer to this question is, "it depends" but I'm hoping for a ballpark number here. Let's assume you design a smallish satellite to point at the earth while orbiting. You have the ...
3
votes
1answer
165 views

What are Starlink's available momentum unloading strategies?

Today's Teslarati article SpaceX wants to offer Starlink internet to consumers after just six launches talks about the new website https://www.starlink.com/ shows several images from it, and tries to ...
2
votes
1answer
83 views

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

Gyroscopes are used in spaceflight as parts of inertial systems to monitor spacecraft attitude. They are not absolute, they will drift slowly over time and so need occasional calibration via other ...
2
votes
1answer
76 views

Satellite mission design/performance requirements to attitude/orbit control design specifications

Are there any good sources that discuss: the steps involved in deriving attitude/orbit control design specifications, from satellite mission design/performance requirements?
1
vote
2answers
130 views

How are New Shepard's tilting fins and gimbaling nozzle used together (or separately) to control the rocket?

In the beginning of the video Blue Origin New Shepard self-landing rocket launch with 38 research payloads (5/2/2019) the announcer mentions that both the tilting fins and the BE-3 engine nozzle ...
3
votes
2answers
224 views

How many times would two astronauts have to run around Skylab to turn it by 10 arc minutes?

This answer to the question starts with: This video may help to answer your question. Starting at about 00:24, you can see an astronaut running around the "exercise wheel" of Skylab (an early NASA ...
2
votes
1answer
65 views

Maintenance manouvers for a Dawn-Dusk SSO?

I'm in charge of the ADCS for a class project, which consists on a 25U-cubesat, in a 650-km dawn-dusk Sun-synchronous orbit or SSO. What are the orbit correction/maintenance manouvers a spacecraft ...
5
votes
2answers
130 views

Flat-spin transition manoeuvre: why is the angular momentum not constant?

In an article by Rahn and Barba, in which a flat-spin transition manoeuvre is investigated, the following figure is presented: I'm trying to reproduce this figure by integrating the following coupled ...
6
votes
1answer
124 views

What type of Kalman filters are preferred for satellite ADCS systems; what are the tradeoffs?

Are Unscented Extended Kalman filters (UEKF) preferred over Multiplicative Extended Kalman filters (MEKF) in satellite ADCS systems? What are the trade-offs for these two filters? I have read that ...
5
votes
0answers
133 views

Why does Orion's Jettison Motor, have four nozzles but eight Attitude Control Motors arranged in an octagon?

Spaceflight 101's Orion Spacecraft Overview shows the following tests for the escape system. Why are there eight ACS thrusters arranged octagonally? Is it just to reduce cosine losses or does this ...
11
votes
1answer
637 views

Did NASA tell the Skylab astronauts to “Stop running around!”?

This answer to the question starts with: This video may help to answer your question. Starting at about 00:24, you can see an astronaut running around the "exercise wheel" of Skylab (an early NASA ...
4
votes
2answers
199 views

How do we manage the residual magnetic moment of magnetorquer with a ferromagnetic core?

I'm currently working on a control algorithm, specifically in detumbling, for a 3U cubesat. I'm using magnetorquers for actuation and magnetometers to receive feedback. If I have no current passing ...
1
vote
1answer
131 views

Help with my tensor tension; how to derive and calculate this rigid body gravity gradient torque?

Tensors make me tense. Imagine a long thin rod in a circular orbit. The gravity gradient will produce a net torque on the rod whenever it is not oriented parallel, or perpendicular to the radius ...
3
votes
1answer
122 views

Help with Scott Manley's rigid body dynamics narration

I've just watched Scott Manley's video SpaceX's Water Landing Reveals Rocket "Secrets" (or, What We Learned from CRS-16) (again) and there's some rigid body dynamics in there where I'm not sure I am ...
8
votes
2answers
351 views

What are damper booms, and how do they facilitate triaxial stabilization?

I'd never heard of DODGE until I saw it mentioned this answer as the source of the first full color "full Earth" image. The spacecraft's primary function however was to experiment with gravity ...
4
votes
1answer
131 views

How do Mars spacecraft control attitude on final descent and landing?

When I watch videos of probes landing on Mars after cutting the parachutes off, they show the lander doing final orientation adjustments before touching down. The engines don't seem to have a ...
1
vote
1answer
296 views

During final descent how will InSight know cardinal directions in order to land with proper orientation?

As explained in @karthikeyan's answer the InSight lander will rely upon its landing system to orient the lander properly, so that once on the ground instruments such as the RISE antennas will be ...
0
votes
0answers
148 views

How are Voyager's 16 thrusters oriented?

@RussellBorogove's excellent answer to the question How do Voyager 1's Trajectory Control Thrusters differ from its Attitude Control Thrusters? describes the locations and usage patterns of the 16 ...
32
votes
2answers
6k views

How did the X-15 control attitude above the Kármán line?

This interesting, archived page https://www.webcitation.org/618QHms8h?url=http://www.fai.org/astronautics/100km.asp which I found in this answer, says: In the early 1960´s, the U.S. X-15 Aircraft ...
5
votes
1answer
172 views

Does the Soyuz spacecraft really try to achieve attitude accuracy of 0.5° from GLONASS and GPS signals?

This answer mentions that the Wikipedia article Soyuz MS (Союз МС, the latest revision of the Soyuz spacecraft, evolution of the Soyuz TMA-M) says: Instead of relying on ground stations for orbital ...
2
votes
1answer
107 views

Current status of the use of GPS mutli-antenna time differentials for satellite attitude determination?

I am certain that I read a year or three ago about an unmanned satellite that was going to be testing a method of attitude determination that relied upon two (or more) separate antennas on one ...
2
votes
1answer
360 views

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

Space.com's Hubble Space Telescope Apparently in 'Safe Mode' After Gyroscope Failure says: "It’s true. Very stressful weekend. Right now HST is in safe mode while we figure out what to do. Another ...
5
votes
2answers
1k views

Has a spacecraft ever used a four gimbal gyroscope? Did Michael Collins get his Christmas wish?

The question Did Michael Collins ask for a fourth gimbal for Christmas? Is there a recording or transcript? mentions that Apollo 11 Command Module Pilot Michael Collins is said to have asked for a ...
-1
votes
1answer
140 views

How can articulated spacecraft components increase the risk of gimbal lock?

This answer has got me baffled. In theory, yes. In practice, no. The problem is gimbal lock... There seems to be some risk of inducing gimbal lock if a spacecraft component of sufficient mass is ...
3
votes
1answer
241 views

Verify solar radiation torques on a satellite

I'm creating a design support system for Attitude control design of a spacecraft. For the attitude simulator, I have made a function to compute the solar radiation torque acting on the satellite which ...
12
votes
1answer
1k views

What is the principle behind Mariner 4's “Solar Pressure Vanes”? In what case(s) would they be effective?

The image below, found in this answer shows four "Solar Pressure Vanes" on Mariner 4. I've never heard of such a thing. I can imagine that it might have been thought to help favor the spacecraft's ...
4
votes
0answers
64 views

Spacecraft Inertial Data

I am a developer of motion analytics algorithms. I have been using a 9 Dof strap-down IMU on human and land vehicles for these algorithms. I Would be interested to test my algorithms with IMU data ...
1
vote
3answers
224 views

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

In comments and links therein below the question How does Curiosity know how to point and move it's high gain antenna in real time? there is mention of a gyrocompass. I am aware that gyros can be ...
2
votes
0answers
79 views

Finding reference quaternion of a satellite in orbit

How can i find the reference quaternion of a satellite after it has detumbled? I need the quaternion to be able to successfully actuate my payload, which in this case will be a hyperspectral imaging ...
0
votes
2answers
94 views

Tradeoffs using a battery/motor/gyro versus tangential thrusters to spin a spherical shell in space?

Using the Humanity Star (see this answer for example for background/context), consider two possibilities for spinning a small spherical shell at a low rate, say perhaps in the neighborhood of 2 to 10 ...
1
vote
1answer
818 views

What is Rocket Lab's new Curie “Kick Stage”?

This reddit points to Rocket Lab's news page Rocket Lab successfully circularizes orbit with new Electron kick stage. It is named Curie, presumably after Marie? According to the Rocket Lab's article: ...
3
votes
1answer
154 views

Initial condition for SGP4 in satellites without GPS, before the uplink of TLE data

I believe that the SGP4 model for orbit estimation for LEO satellites uses TLE data as initial condition. Some CubeSats chose to use up-link TLE data than installing GPS. My question is for the case ...
3
votes
1answer
252 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 ...
5
votes
1answer
176 views

How will GomX-4B manage angular momentum when using butane thrusters to move?

Phys.org's ESA's next satellite propelled by butane describes GomX-4B's butane powered cold gas thrusters, and how it will test them and use them to navigate to different distances from its partner ...
13
votes
1answer
2k views

How do Voyager 1's Trajectory Control Thrusters differ from its Attitude Control Thrusters?

There are several popular news items about the recent test of Voyager 1's Trajectory Control Thrusters to see if they can be used for attitude control to facilitate communication with Earth. The ...
2
votes
1answer
660 views

Placement of Reaction Wheels in a nano satellite

The reaction wheels rotate the satellite only about the centre of mass.If the reaction wheels are not placed about the principal axes,Will the amount of torque produced be the same as when they are ...
11
votes
1answer
1k views

How does JAXA's “Int-Ball” manage airflow to optimally navigate inside the ISS?

above: From the BBC's Japan's zero-gravity space drone sends first pictures from ISS. This is JAXA's GEM internal ball camera, or "Int-Ball". Kawaii! It looks like it uses a three axis attitude ...
1
vote
0answers
147 views

Would Mayak's large solar reflector have produced a stable attitude, or more likely start tumbling or rotating?

update: Answers to Two week mark; has Mayak (Маяк) been spotted yet? Reflector deployed? Astronomy “ruined”? indicate that the reflector did not deploy successfully (more at Mayak, a magnitude -10 (...
4
votes
1answer
306 views

Controller to reaction wheel interface

A typical controller generally gives control torques which should be applied about the axis of a satellite. How exactly is this torque applied using a reaction wheel? For example if control torques ...