Hot answers tagged

75

Gravity is everywhere. There is never any actual true "zero gravity" in the universe. But if you're in freefall - meaning following gravity's pull rather than resisting it, or being blocked from following it (by the floor, your nearby planet, spaceship walls as it thrusts, or whatever) - you don't feel it, and that's the thing we call "...


45

Heh. So it turns out, figuring out the answer to this is precisely what I do for a living. The glib answer: it depends. It depends on how big an object you are worried about hitting. Are you worried about damaging wiring harnesses? Are you worried about causing a radiator leak? Punching a hole in the crew module? Annihilating the vehicle altogether? The ...


26

Sources: bar magnet (annotated with a red "X"), aluminum can (annotated with a green "OK" check mark) Beautiful video and demonstration, thank you! However... That magnet in microgravity doesn't actually orient itself at all I watched the video carefully and at 00:44 the first time the magnet is released it is pretty far away from the ...


26

Gravity has infinite range, so there is nowhere in the universe where you can be free from its influence. Sure, there are places such as supervoids where the influence of gravity will be very little, but there's nowhere where it is absent entirely. The day to day experience of 'gravity' - the feeling of standing on the surface of a planet - isn't really the ...


21

Safety Integrity Level (SIL) The way that we would conventionally test for and mathematically define the risks involved in space flight, including from debris, would be through SIL levels that describe the number of dangerous events that could acceptably occur in a single hour of space flight. This is very similar to avionics, railroad systems, and ...


13

Because the people that run it don't want that: The magnetic field of the ISS is quite weak. This would be a combination of deliberate and inadvertent , as it is built out of mostly nonmagnetic aluminum, plus any really significant magnetic field would be a bother to the many instruments, science packages and electronic equipment on board. The ISS has a much ...


10

This isn't an answer, just a minor addition to the previous answers. There have actually been cases where satellites have accidentally become magnetized and caused an undesirable magnetotorque; it is a legitimate consideration! From https://llis.nasa.gov/lesson/642 : An unanticipated roll torque was imparted to a commercial communications satellite launched ...


8

The right way to think about it is that, always and everywhere, weightlessness is the "artificial" kind. It is certainly true that the gravitational field is very weak far from any masses, but on the way to the moon the astronauts were coasting in free fall so it made no difference to their experience what the gravitational field strength was. Even ...


7

As other answers have noted, the bodies of most spacecraft are made of nonmagnetic aluminum. However, some smaller spacecraft do use the Earth's magnetic field for attitude control. These smaller spacecraft use current that the spacecraft runs through magnetic torque rods to adjust their attitude. There are two key issue with magnetic attitude control. The ...


5

It is exactly the same zero gravity as you experience in a plane paraboling to Earth. It 's a bit different from the gravity you experience in far-from-mass gravity in outer space though. In the ISS gravity is nearly zero at every point. But not precisley (though it is not easy toy measure if not impossible). There is always a gradient giving rise to tidal ...


5

This answer points out that there were 16 people in space (above 80 km) on July 11, 2021: Seven people on the International Space Station: Three Americans, two Russians, and one from both France and Japan. Three Chinese on the Tiangong Space Station. Six people on Virgin Galactic's Unity, including Richard Branson, two pilots, and three Virgin Galactic ...


4

That's a whole lot of questions for one post. So consider this a partial answer. Yes. Here's the official MAGIK video showing the maneuvers. My former coworker made the video. Some of the other answers can be derived from the video.


3

Richard Arnold returned with the rest of his Soyuz MS-08 crew after 196 days in space. Since then, no crew was or is planned to stay for at least a year. Christina Koch stayed the longest during this period, 328 days. (Scott Kelly stayed 340 days, but that was prior to this question.) Two of the future Soyuz MS-19 crew are planned to stay 354 days. ...


3

I can think of one reason to try to get a Starship Booster into orbit, even stripped of heat tiles, landing legs etc. Such a large hull in orbit could act as a high-capacity supertanker for Starship missions to the Moon and beyond. It could be topped off at a different cadence to Lunar Starship missions - say taking surplus fuel from Starship Starlink ...


2

The compass needle you saw is made from a magnetic material like steel. The ISS is made from a nonmagnetic material aluminum.


2

Two of the crewmembers of the future Soyuz MS-19 are scheduled to stay 354 days at the ISS. That will make it the longest stay at the ISS. No crewmember has stayed for one year, much less 2 years. Keep in mind that crew are sent up to perform work (experiments, maintenance) at the station, not merely to be occupants. It's not a hotel.


2

This image shows the principal direction words for the ISS (from In "spacecraft talk" is nadir just a fancy word for "down"?). The MLM is planned to be attached to the nadir side of the ISS Russian segment. Its long axis is planned to be parallel to the ISS Z axis. Here are three views generated from the official NASA visualization tool ...


1

There isn't a qualitative difference between the two situations you've presented, only quantitative. (And neither one can meaningfully be called "artificial" - both situations are real microgravity, as explained in other answers. You might apply "artificial" to astronaut training neutral-buoyancy tanks (although it seems that the usual ...


1

Supplemental answer: Being the sticlker that I am I can not remain silent any longer. tl;dr: There are billions of billions of points in the universe with zero gravitational acceleration! While each answer includes some form of the "gravity is everywhere because it never ends" (i.e. $1/r^2$ never goes to zero so everything pulls on everything) I ...


1

Or more precisely isn't it similar to the zero-gravity created by those big zero-g airplanes Yes, it's identical Note that you use the phrase: artificial zero-gravity There is no such thing as "artificial zero-gravity". It's a meaningless phrase. Note that you use the phrase: zero-gravity There is no such things as zero-gravity. Pilots etc. ...


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