129 votes
Accepted

Could an Apollo astronaut stand up if they fell on the moon?

I believe it was John Young, during an Apollo 16 EVA fell to the lunar surface. Though awkward, he got up unassisted by attempting a series of what looks like push-ups until he was able to get ...
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  • 6,729
77 votes
Accepted

How can astronauts float in space without being affected by the gravitational force of nearby objects?

Objects in orbit are attracted to each other, it's just their mass is small enough that the force of gravity between them is infinitesimal. Gravitational acceleration is dependent on mass and distance....
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  • 18.7k
68 votes

What is the context of this seemingly "zero-gravity" photo on Earth?

The biggest give away is the size of this chamber: its too big for any of the known NASA's KC-135 or ZG's 727-200. That leaves us one other candidate: their Russian counterpart IL-76 MDK The interior, ...
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  • 1,249
57 votes

Could an Apollo astronaut stand up if they fell on the moon?

As always, the Apollo Lunar Surface Journal is a treasure trove of annotated examples. During the later (J) missions in particular, Ed Fendell, remotely operating the rover's TV camera, managed to ...
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  • 1,401
56 votes

Can't astronauts use ball point pens in space?

They can and they do use regular ballpoint pens. And normal pencils, mechanical pencils, grease pencils, felt-tip markers ("Sharpies"), and pressurized "space pens". ESA astronaut ...
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  • 7,365
54 votes
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What causes microgravity (i.e. non-zero gravity) in orbit?

The reason the Space Station is called a micro-g environment rather than a zero g environment is because the Space Station is rotating, because it's in low Earth orbit, and because it's big (for a ...
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  • 62.9k
39 votes

Is there a self-rounding celestial body from which an Olympian could jump into space?

No. Saturn's moon Mimas is the smallest body in the solar system known to be rounded through self-gravitation, and it still has a surface escape velocity of 159 m/s, far above the speed achievable by ...
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  • 4,351
36 votes
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What are the "unpleasant effects" of having a cold in microgravity?

This description of the Apollo 7 mission from NASA contains a more detailed description: Mucus accumulates, fills the nasal passages and does not drain from the head. The only relief is to blow ...
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  • 453
32 votes

Could an Apollo astronaut stand up if they fell on the moon?

Despite Charlie Duke's concern about it, given that the PLSS is massive, and would shift an astronaut's center of gravity far back from their natural distribution, it would be surprising if the ...
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29 votes

How do astronauts turn in space?

Although this has indeed "worked to bits" on the Physics and other SE sites it's worth looking at, for the sake of Space Exploration, the interesting history behind the analysis of the falling cat. ...
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28 votes
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Using a fidget spinner to rotate in outer space

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 ...
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  • 12.7k
27 votes
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How are hair and beard lengths maintained in space?

A haircut is done with an electric trimmer which has a vacuum hose attached. Wet shaving avoids this by trapping the cuttings in shaving foam, but some astronauts use electric razors, again with a ...
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  • 121k
27 votes
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Is there a change in altitude when "falling around earth"?

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 ...
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26 votes
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How do iPads on the ISS know which way is "up" for their users?

According to Robert Frost, Flight Controller at NASA: The onboard iPads are configured with the mute switch acting as the rotation lock. Should a crew member want to change the screen ...
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  • 376
26 votes

How is lower/no gravity simulated on a planet with gravity, without leaving the surface?

The two most commonly used techniques for humans are neutral buoyancy and parabolic flights. Neutral Buyoancy Neutral buoyancy simulates the weightless environment of space. First equipment is ...
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  • 6,760
26 votes

Why is dust such a problem in microgravity? Wouldn't proper air circulation and filtration take care of it?

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 ...
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  • 18.7k
25 votes

Tiny emergency propulsive device if stuck floating in a large volume in microgravity

I found a real world test of this. Dan Barry tried it when STS-96 was docked to the ISS. I've scanned his account from the book "Space Shuttle: the first 20 years." tl;dr - he escaped by ...
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25 votes
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Why did a shuttle astronaut have an open book during ascent?

Those are the Ascent Checklist and the Ascent/Entry Systems Procedures (AESP) book. These are used by the back-seater Mission Specialists (MSs) and contain copies of the cue cards and flip-books used ...
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22 votes

Would a higher air pressure on the ISS or elsewhere make it easier to "swim" in microgravity?

Would a higher air pressure on the ISS or elsewhere make it easier to “swim” in microgravity? Yes! But what's really important is the density, so instead of pressuring "normal air" you can ...
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  • 148k
21 votes
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Why might an astronaut wear their wristwatch very loosely aboard the ISS?

Nice observation, he is just doing it to show off! Check these out: https://twitter.com/cmdr_hadfield/status/326727757109268481?lang=en
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19 votes

Tiny emergency propulsive device if stuck floating in a large volume in microgravity

What if you just carried a couple of uninflated balloons with you? If you ever get stuck, just inflate the balloon, and then hold it near your center of mass, aim it away from you, and let the air ...
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  • 291
19 votes
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How was "Space Ram" (instant ramen noodles) prepared and eaten on the Space Shuttle?

Like many dehydrated space foods, it's prepared by injecting hot water through a port in an otherwise sealed bag, manually mixing it by massaging the bag, and waiting a few minutes; the noodles are ...
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19 votes
Accepted

Microgravity indicators

As Organic Marble points out, yes the US space program had G meters. They're likely to include these in future manned missions, as well. As for the true purpose of the toys: To humans, any sudden ...
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  • 1,157
18 votes

How can astronauts float in space without being affected by the gravitational force of nearby objects?

Consider this equation for gravitational attraction between two bodies: $$F = G \frac{m_1 m_2}{r^2}$$ where: $F$ is the force between the masses; $G$ is the gravitational constant (6....
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  • 75.3k
18 votes
Accepted

Was this printer shown the ISS in 2015 built specially to work in microgravity?

It's an Epson Stylus Color 800 - a pretty standard inkjet printer (a laser printer would be a nightmare - all that fine toner dust!) Here's an example of an Earthly one from a 1998 page of the ...
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  • 13.4k
17 votes

Is there a change in altitude when "falling around earth"?

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 ...
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16 votes

What does it take for a craft to perform a flight simulating weightlessness without having to fly a steep parabola/ellipse?

In order to achieve "weightlessness", you don't need to achieve a certain speed, you need to achieve a certain acceleration. Earth pulls down at approximately 9.8 m/s^2 which means that any object ...
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  • 14.6k
14 votes

What is the longest time that a mammal has spent in microgravity?

437 days in a single stretch. The mammal was a relatively standard specimen of Homo sapiens sapiens. Known affectionately as Valeri Polyakov by his handlers, the subject was launched to orbit on-...
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  • 7,078
14 votes
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How do we create a zero gravity environment on earth?

There are two methods which are used: Aircraft can fly on a trajectory that will simulate zero gravity for a few seconds, usually around 30. This is used for most short term zero gravity tests. It is ...
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  • 118k

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