28

This is exactly how it works and how the orientation of many satellites is controlled. For example, the Hubble telescope has 4 fidget spinners installed, pointing in different directions - although they are commonly referred to as "reaction wheels". Unfortunately a typical fidget spinner is a bit too light to be really useful: We have to compare ...


27

In a ideal / non real world / perfect circular orbit situation, they wouldn't lose altitude. They're falling but missing the planet due to their "sideways" velocity. In the real world aerodynamic drag and other factors cause them to lose speed and therefore altitude. The animations at this wikipedia page explaining Newton's Mountain Cannon thought ...


26

When you have gravity heavy particulates like shavings, crumbs, large dust granules, etc. will fall to the ground where they can be cleaned or form part of the environment. In microgravity everything is suspended no matter the size, so there is a lot more stuff to deal with, including dust. Heavier particles take more energy to move, so they will take longer ...


17

Orbits don't have to be circular. If someone is orbiting in a non-circular (i.e. elliptical) orbit, their altitude will change, as in the yellow orbit in this picture: (credit: Søren Peo Pedersen via Wikimedia Commons) On the right side of the planet, the yellow satellite doesn't have enough speed to maintain its altitude, so its altitude decreases. By the ...


14

What is an atomic force microscope (AFM) in the first place? An AFM uses a very sharp tip to "probe" around the surface of an object. As it gets closer to or further away from the surface, tiny changes in force are observed from van der Waals or similar "atomic" forces. A computer can stitch together a grid of individual passes over the ...


11

Getting dust in one's eyes is a mild inconvenience at best. However, what happens if the dust particle lodges itself in a person's eye just when that person needs to do something critical? What happens if a dust particle cannot be easily or safely dislodged and the person has to endure having something in their eye for a prolonged period? The stress caused ...


10

The current US EVA hammer is just... a hammer. Source: EVA Tool Catalog


9

To use a hammer in microgravity, you need to be firmly anchored to the object you wish to pound on. Otherwise, you are at the mercy of action/reaction. As you swing the hammer, half of your effort will be spent moving the rest of your body back/around (it will be a complex motion counter to the swing of the hammer). Also, when the hammer hits, the force ...


7

Dust will damage machinery through more than just conducting electricity or hindering passive cooling. Fans in particular are vulnerable. Dust can slow down fans by adding weight to the blades or caking onto the shaft and increasing friction. Fine particles that get into the fan's casing have a hard time getting out. They grind against the fan's bearings ...


5

AFAIK, the main problem is static electricity, dust tends to stick to everything with a minimum charge, my personal guess is that if not properly handled the ventilation system could make it worse because dust will generate more static electricity by rubbing the vents. I know my answer is not as complete as others, however I noticed that nobody mentioned ...


4

Note: Engineering Judgement Applied when figuring what active proposal means No, there are no active proposals for a future crewed space station to use artificial gravity. The only planned space station which has a realistic chance of being built close to its announced schedule is the 'Chinese large modular space station' It is a free-fall design. You can ...


4

1 micro-g is defined as a millionth g, or 0.000001 g. The atmospheric drag alone produces 3 micro-g onto the ISS. I'm defining the upper border of microgravity at 0.0005 g, so everything just below that value can be referred to as "high microgravity", e.g. Deimos' surface gravity of 0.0003 g. Phobos on the other hand has almost twice Deimos' ...


4

You could use existing medical data to calculate the number of kidney stones patients to be expected for all the ISS astronauts and their stay time. Of course this number is valid for a stay on Earth surface only. If this number is small, no statistical inference about the frequency of kidney stones in extend microgravity is possible. From Wikipedia: In ...


3

One way of thinking about it, is considering that the Space Station is circling the Earth at 28000 kilometers per hour. circling the Earth. Like a bucket on a rope, being swung around your head. If the Earth did not have gravity, and you tied a rope to the ISS, it would be pulling very hard on that rope. This force results from Centrifugal Force Effect. The ...


3

One can talk about "levels of microgravity". In fact, there is (or was - I see nothing recent - their last annual report was in 2001 and I can find no web site for them) a scholarly group called the International Microgravity Measurements Group. Their charter was to discuss the levels and "quality" of microgravity in the various ...


3

Low enough gravity and you can have human wing-powered flight. I don't know how much of a sport it would make, but at low enough gravity you can run on water. If you can manage to arrange it, have a competition like high jumps--keep raising the bar (in this case, gravity) until only the top person makes it across. In a spin "gravity" environment ...


2

2019: https://www.roscosmos.ru/26185/ Исследования, проводимые космонавтами на борту Международной космической станции, меняют взгляд на процессы, которые моделируют на Земле. Олег Кононенко начал работать над российско-германским экспериментом «Плазменный кристалл», исследующим четвертое состояние вещества — плазму. Research carried out by astronauts ...


2

This link (https://www.cnbc.com/2021/05/25/axiom-space-ax-2-spaceflight-led-by-peggy-whitson-and-john-shoffner.html), and the others below, suggest that rather than doing medical-based research themselves, it appears to be more focused on "meta-research"; evaluating how research methods and techniques change in space: In addition to training for ...


2

It's possible to use reaction wheels to arbitrarily alter one's attitude, but a major limitation with reaction wheels is that if an object has rotational momentum and one wants it to maintain a constant attitude, the reaction wheel will have to spin forever unless or until one gives up on holding a constant attitude or one can transfer rotational momentum ...


2

Roskosmos has plans to build a Mir-type orbital station (without artificial gravity) using new ISS modules. Roskosmos after 50 years of work with orbital stations in Earth orbit plans to build a small lunar orbital station. All interests of Roscosmos on the Moon:


2

Maybe it will help to try and extrapolate from something intuitive. When cresting a hill on a rollercoaster, you will often feel "Zero-G", where you feel no force from anything touching you (i.e. you lift off the seat slightly, but aren't being pulled down by the restraints either). Obviously the roller coaster isn't somehow turning off gravity ...


1

The ISS looses height continuously due to the atmospheric drag. As you can see, reboosts (sudden peaks in altitude on graphs) are done on average about once per month, but there can be many consecutive months during which no adjustment in orbital altitude to the station is done. Image and blockquote from How often does ISS require re-boosting to higher ...


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