Questions tagged [rotation]

Questions regarding an object or spacecraft rotating around an axis.

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41
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6answers
18k views

Does a satellite naturally turn in phase with its orbit, always facing Earth?

Assume you want a satellite to constantly point its radio dish towards Earth while orbiting it, or its solar panels towards the Sun if it is instead orbiting it. Is any of the following true about ...
33
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2answers
41k views

Why is the rotation rate of Venus so slow?

Venus has an extremely slow rotation rate, to the point that it actually rotates slower than it revolves around the sun. In other words, its day is longer than its year. With the exception of Mercury, ...
27
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3answers
12k views

How do astronauts turn in space?

A recent question back in Physics asks whether there is a way for an astronaut to rotate when in microgravity and without touching anything else, while still conserving angular momentum. One way to ...
25
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5answers
5k views

How can you make a vacuum proof rotatable seal?

Many systems have been discussed where you have a rotating spacecraft for artificial gravity purposes, with a portion of the spacecraft that doesn't rotate, perhaps the engine for instance. I've been ...
22
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3answers
3k views

Qualitative differences between gravity and a spinning habitat

I'm aware that living in a spinning habitat has a couple of noticeable differences from being on terra firma. For instance, running in the direction of the spin ought to make you feel heavier, while ...
21
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1answer
5k views

Why does NASA intentionally spin space probes?

In several NASA animations of missions, I've noticed that the spacecraft is rotating while traveling in deep space. This was true of Curiosity when that video came out. Now the Juno mission ...
14
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2answers
2k views

Why does the Earth lose rotational velocity in the vacuum of space?

I think it is a well-known fact here that the Earth is slowly losing rotational velocity over time (some 1.4 milliseconds of the day are gained per hundred years). Eventually, this means that the ...
13
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1answer
6k views

Changing the rotational rate of a natural body

Let's say that for the purpose of terraforming, we need to speed up the rotation of a planet (like Venus), a moon or an asteroid to near Earthian day. How would we go about doing this? Can this be ...
11
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2answers
2k views

Using a fidget spinner to rotate in outer space

There is a question How do astronauts turn in space?, and related questions here and on physics.stackexchange, that detail how astronauts might maneuver by spinning their upper and lower body ...
10
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1answer
1k views

How do the roll-rings at the ISS work?

I get that on the ISS they need to keep the solar panels constantly rotating to keep them looking towards the sun. To transmit the electricity and data to and from the Solar panels truss structure ...
8
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1answer
294 views

What is "forward rotation" of a spacecraft?

According to ISRO's Mars Orbiter Mission (MOM): Forward rotation of the spacecraft has been completed successfully. What kind of maneuver is that and what is its purpose?
8
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1answer
563 views

Practicalities of docking with a large spinning space station

We've all seen countless examples of spinning habitats in fiction. However there are certain practicalities with these space stations that I can't get my head around, namely around how you'd dock with ...
7
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3answers
8k views

How to calculate the speed of rotation of a given point on the Earth's WGS84 ellipsoid, about its axis?

Launches often happen near the equator in order to take advantage of Earth's rotation speed. This is why more launches are towards the East than towards the West. How can one calculate the speed of ...
7
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3answers
1k views

Does a change in the rotational speed of something on its own axis (rpm) affect its orbit?

For example: if a satellite in orbit around earth had its prograde rotational speed increased from 60 rpm to 600 rpm, would its orbit be affected? Another example would be if earth’s rotational speed ...
7
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2answers
1k views

Would a Foucault pendulum work on the Moon and on the Galilean moons?

I wonder whether the Moon and the Jovian moons spin fast enough for a Foucault pendulum to swing on their poles. For instance, I think that it wouldn't swing on Mercury and Venus because these planets ...
7
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2answers
347 views

Do satellites in orbit undergo translational motion or rotational motion, when initially they are not given any additional spin?

Regarding the proposed duplicate: Thought the proposed duplicate has a similar titIe, I have read those answers and this question requires a different answer. We know satellites orbit around Earth, ...
7
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1answer
243 views

Would air circulate in a rotating station on its own?

I know air circulation was a tricky problem on the ISS . I think that in a rotating station the air would be moving with the station, but the air against the “floor” would be moving faster or have ...
6
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3answers
4k views

How come we don’t put a huge windmill-like machine in space? [closed]

I am new to this sight, but since space being a vacuum there is little to no air resistance at all making a windmill spin forever. There is no wind in space however, if you spin it once, it should ...
6
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3answers
2k views

Can an orbit rotate around a non-orthogonal axis?

I'll attempt to draw a mental example, in case images are not kind (if they are kind, you can likely skip this first paragraph). Let us say that the Earth is at it's aphelion (arbitrary choice), and ...
6
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3answers
1k views

How much does the rotation of the Earth affect re-entry and could we go against it?

I was thinking about how many things are affected by the Earth's rotation, and was wondering how much more difficult a retrograde re-entry would be (where the Earth's rotation direction is assumed ...
6
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2answers
364 views

Could the Galilean moons tidally lock Jupiter?

From my understanding, given enough time, the gravity of the Moon is gradually increasing the time it takes for Earth to rotate around its axis, and that, as a result, in the distant future, Earth ...
6
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1answer
364 views

Did the manned NASA capsules rotate during descent?

Watching the NS-11 launch, I noticed that during descent when the main chutes were deployed, the capsule rotated quite a bit, and would rotate back. Was this an issue as well during the Mercury/...
5
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3answers
2k views

How does New Horizons control its attitude?

I used NASA's eyes tool to see what's going at the time of New Horizon's closest approach to Pluto. I realized that in the programmed sequence, New Horizons is rotated on its axis by more than 90° ...
5
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1answer
209 views

Moment of Inertia of a planet

Radio Doppler measurements were taken with Viking and twenty years later with Mars Pathfinder, and in each case the axis of rotation of Mars was calculated. By combining this data the core size was ...
5
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2answers
411 views

Would space ship/station rotation for artificial gravity cause the "axis" to also rotate?

Would space ship/station rotation for artificial gravity cause the "axis" to also rotate similar to that of a helicopter with out a tail rotor? Additionally would a second rotating section going in ...
5
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1answer
180 views

What stabilises the axial tilt of planets?

All known bodies of the space rotate around their axis. For example, Earth completes a full rotation cycle in about 24 hours. However, the axial tilt seems to be constant, even though it changes a ...
5
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2answers
179 views

EVA on rotating spacecraft - differences from microgravity

What would an extra-vehicular activity (EVA) be like on a spacecraft which consists of modules along a (100s of meters long) rotating tether that causes simulated gravity? See for example these slides ...
5
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1answer
164 views

In what circumstance would it be useful for a satellite’s angular velocity to differ from its reference frame’s angular velocity?

Casually reading “orbital mechanics for engineering students” on rigid body attitude dynamics, i see the following passage: $$M_{net}=\dot{H}_{rel} + \Omega\times H$$ Keep in mind that, whereas $\...
5
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1answer
83 views

How do orbits around Jacobi ellipsoids behave?

The Earth is a Maclaurin spheroid (aka. oblate). This affects orbits, most notably $J_2$ rotating the node line for inclined orbits, enabling thins like Sun-synchronous orbits. But the Maclourin ...
5
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1answer
414 views

How has the angular velocity of Earth changed over the past 100 years?

What is the total change in the Earth's Angular Velocity over the past 100 years? I have read other posts that discuss how much mass has been lifted out of Earth's Atmosphere. I'm trying to get an ...
4
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2answers
215 views

How to slow a spinning spacecraft externally?

I came accross the is question What are the consequences to breaking the ISS? and wander how would a spacecraft be made to stop spinning from the outside? Scenarios might include (but are not limited ...
4
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2answers
350 views

How to find ECI coordinates for a circular orbit

Suppose a satellite is orbiting Earth in a circular orbit, of which I know the inclination $i$, the right ascension of the ascending node $\Omega$, the semi-major axis $a$ (or orbit radius given that ...
4
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1answer
89 views

How can I generate Chebyshev cofficients from SPICE for J2000 Inertial to Moon ME Frame?

I want to extract the Chebyshev coefficients in order to be able to calculate the time-varying transformation from the ICRF / J2000 Inertial frame to the Moon ME (moon mean earth) frame. I know I can ...
4
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1answer
405 views

What is the point of rotation of an "umbrella ship"

Some nuclear powered spacecraft designs have been entertained where the radiator is arranged in a plate geometry which rotates. For example: http://www.projectrho.com/public_html/rocket/realdesigns....
4
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0answers
40 views

What is the highest RPM achieved through a spin-stabilized rocket/spacecraft?

The title explains it all. I know that the Star 48 kick motor rotated at 60 rpm through its burn. I'd like to know the fastest a rocket/stage has spun during a launch, as well as the highest ...
4
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0answers
10k views

Earth's rotation speed vs latitude [duplicate]

The above question may sound naive. Still I would be thankful to someone who helps me in understanding the concept. In the following link it is mentioned that earth's rotation speed with respect to ...
3
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3answers
500 views

At what altitude would I have to go in a lighter than air balloon to be above all wind and just have the earth rotate underneath me?

I know in the lower levels of the stratosphere we can still have 100 mph winds albeit low density winds. Could I possibly go high enough in a balloon or imaginary vertical craft that I would go above ...
2
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2answers
436 views

Could a satellite levitate above the magenetic fields of Earth?

Like the toy the base of the levitation could the Earth be the base and the space station the levitron? https://earthscience.stackexchange.com/questions/13854/where-on-earth-is-the-magnetic-field-...
2
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1answer
259 views

Does "Air Launch to Orbit" makes the best use of Earth's Rotation?

Usually, all artificial satellites are launched in the prograde direction, since this minimizes the amount of propellant required to reach orbit by taking advantage of the Earth's rotation. Further, ...
2
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1answer
568 views

Does Jupiter's high rotation speed affect its gravitational strength at the surface?

Jupiter's outer, equatorial atmosphere rotates at 12,517.12 meters/second, once every 9.5 hours, at a radius of 71,492 km. Geostationary orbital speeds for earth are around 3,000 meters/second, at a ...
2
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2answers
165 views

How much will Bennu rotate faster and faster with mirrors facing the Sun on its left side?

Several answers to the question "Why paint only one-half of Bennu" describe the Yarkovsky effect as an important force acting on the asteroid 101955 Bennu. But what about the radiation pressure of ...
2
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1answer
484 views

Converting J2000 to ECEF?

Say I get the orbital elements for the ISS from JPL Horizons. Say that data is expressed in J2000, an inertial frame. I want to express it in ECEF. This is a simple rotation transform. All I need is ...
2
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1answer
208 views

Is the retrograde (clockwise) rotation rate of Venus speeding up or slowing down?

In the update of the question "Would it be possible to "ride the wave" on Venus ?" there are links to articles in Science and in Science News that report that the atmosphere of Venus, hitting the ...
2
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1answer
282 views

How the interface between de-spun platform and rotating parts of a spacecraft with artificial gravity could work? [duplicate]

You might have seen large rotating wheel space stations with central de-spun hubs or platforms in sci-fi movies like The Martian. My question is, how could the sealing between the rotational and ...
2
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0answers
98 views

Asteroid Catalog

Where can one find asteroids or comets that contain water ice suitable for a human mission. Perhaps there is comprehensive catalog of small bodies that can be searched for characteristics such as: ...
1
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1answer
177 views

Query on movement of space shuttle during lift off: Three examples

I have a small query here on the three different movements that I perceived after looking at videos during take off of Challenger (1986), Columbia (2003) and Atlantis (2010). Challenger (1986): ...
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2answers
99 views

Earth rotation confusion on Stapledon book

Hi everyone i am reading the Scifi classic Star Maker by Olaf Stapledon. The Second chapter starts with the following paragraph: "WHILE I was thus contemplating my native planet, I continued to soar ...
1
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1answer
94 views

Optimal shape for a spinning ship/station - downsides of spheres? (Radiation shielding)

What is the optimum shape for a spacecraft? So I've already read this link, and a few other similar ones, and the main issues I am already aware of... but yet it still seems like a large majority of ...
1
vote
1answer
96 views

How are satellites, rocket launches and other space programs affecting the earth’s rotation? How will it be affecting living beings?

Want to know the effects of the active satellite, rocket launches and space programs that affect earth rotation? how? And their effects on living beings due to effect in earth rotation?
1
vote
2answers
735 views

Is centre of mass a factor in space without gravity?

Quick disclaimer; I'm not that well informed on many of the mechanics on space in general so sorry if this question is rather easy/basic. Is the center of mass in a object a factor in space when ...