133
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 ...
- 6,907
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....
- 19.9k
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, ...
- 1,641
58
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 ...
- 1,430
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 ...
- 7,996
44
votes
Accepted
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 ...
- 2,466
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 ...
- 5,410
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, ...
- 18k
36
votes
Accepted
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 ...
- 463
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 ...
- 167k
29
votes
Accepted
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
...
- 406
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 ...
- 6,906
28
votes
Accepted
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 ...
- 14.9k
27
votes
Accepted
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 ...
- 126k
27
votes
Accepted
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 ...
- 178k
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 ...
- 19.9k
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 ...
- 178k
25
votes
Accepted
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 ...
- 178k
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 ...
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
- 406
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 ...
- 149k
22
votes
Accepted
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:...
- 346
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 ...
- 9,995
20
votes
Accepted
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 ...
- 167k
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 ...
- 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 ...
- 291
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 ...
- 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....
- 76.5k
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 ...
- 13.7k
Only top scored, non community-wiki answers of a minimum length are eligible