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132 votes
Accepted

Could Apollo astronauts 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 ...
Bob516's user avatar
  • 6,989
69 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, ...
user3528438's user avatar
  • 1,641
58 votes

Can't astronauts use ball point pens in space?

They can and they do use regular ballpoint pens as well as normal pencils, mechanical pencils, grease pencils, felt-tip markers ("Sharpies"), and pressurized "space pens". ESA ...
Schwern's user avatar
  • 8,016
57 votes

Could Apollo astronauts 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 ...
GNiklasch's user avatar
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44 votes
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Can/should you swim in zero G?

Two major problems present themselves right away. As the human body is almost neutrally bouyant with water, one might think that there are no issues with the actual movement in water. But this is only ...
Quietghost's user avatar
  • 2,476
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 ...
notovny's user avatar
  • 5,449
38 votes

When staying indoors, can missing gravity be replaced with blowing air?

in a building or closed vehicle on another planet, maybe air pressure could be used to imitate gravity There is no need to imitate gravity on another planet, because planets have gravity. Of course, ...
Jörg W Mittag's user avatar
32 votes

Could Apollo astronauts 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 ...
Russell Borogove's user avatar
30 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 ...
Kevin Fee's user avatar
  • 416
28 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 Buoyancy Neutral buoyancy simulates the weightless environment of space. First equipment is ...
Polygnome's user avatar
  • 6,956
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 ...
asdfex's user avatar
  • 15.1k
27 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 ...
Organic Marble's user avatar
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 ...
Organic Marble's user avatar
26 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 ...
Hobbes's user avatar
  • 128k
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 ...
GdD's user avatar
  • 20.3k
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 ...
Organic Marble's user avatar
24 votes

Why do people experience weightlessness on the way up in parabolic flight?

I feel like the most intuitive way of explaining this is by realizing that the aircraft throws you up into the air and then actively follows your path. You experience the throwing part as the ...
reciprocal lettuce's user avatar
23 votes
Accepted

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
UrasGungorPhys's user avatar
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 ...
uhoh's user avatar
  • 149k
22 votes
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Why do people experience weightlessness on the way up in parabolic flight?

When the spacecraft is "ascending" ... the capsule is being pushed upwards "against gravity" by the propulsion. This is a critical misconception -- there is no propulsion after 2:...
David McKee's user avatar
22 votes

“Parabolic”, suborbital and ballistic trajectories all follow elliptic paths. Is there a generic term for these trajectories?

All the analytical orbits I'm aware of are conic sections or conics, including parabolas, ellipses, and hyperbolas. This includes the truncated / terrain-intersecting trajectories you're using as ...
Erin Anne's user avatar
  • 11.5k
20 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 ...
Russell Borogove's user avatar
20 votes
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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 ...
Ghedipunk's user avatar
  • 1,167
20 votes

Why do people experience weightlessness on the way up in parabolic flight?

It’s all about acceleration. It does not matter what speed you are going or in what direction, throw that out of the window. All that matters is your acceleration relative to the “container” that you ...
Topcode's user avatar
  • 893
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 ...
Azendale's user avatar
  • 291
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 ...
Rory Alsop's user avatar
  • 13.6k
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 ...
Quitting Due To Antisemitism's user avatar
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 ...
Dragongeek's user avatar
  • 19.2k
16 votes

When staying indoors, can missing gravity be replaced with blowing air?

While not strong enough to produce "artificial gravity" in a microgravity environment such as an orbital space station (eg ISS), it should still be noted that air circulation, and ...
Dragongeek's user avatar
  • 19.2k

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