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69 votes

If human space travel is limited by the G force vulnerability, is there a way to counter G forces?

The problem isn't so much that humans cannot sustain high G forces for any extended length of time: The problem is that rockets cannot. If a rocket could sustain 1 g acceleration for a bit over a day, ...
David Hammen's user avatar
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60 votes

Could a spacecraft spin so fast that it spontaneously deconstructs?

Did it really happen? Yes. The investigation of Japanese Hitomi spacecraft's failure found that it was spinning too fast due to attitude control error. As a result, the spacecraft spun so fast that ...
Heopps's user avatar
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60 votes
Accepted

Could a spacecraft spin so fast that it spontaneously deconstructs?

To parallel @Heopps answer: Did it really happen? Yes. In spectacular fashion! In 1965 NASA launched a boilerplate Apollo command module on a Little Joe II rocket to test the Launch Escape System (...
Tom Spilker's user avatar
  • 18.3k
47 votes

If human space travel is limited by the G force vulnerability, is there a way to counter G forces?

Ignoring the major point that human tolerance of G forces is not the limiting factor on space travel, plenty of thought has been made on how to counteract G forces, not least by 60s sci-fi writers. ...
Ingolifs's user avatar
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21 votes
Accepted

How do vibrational isolators reduce the g-forces of a payload on a launch vehicle?

The g-forces from the rocket's acceleration remain unaffected, of course. What the vibrational isolators do is isolate the payload from vibrations. Without them, the payload would experience both the ...
CuteKItty_pleaseStopBArking's user avatar
19 votes
Accepted

How much acceleration g-force can prevent pilot from moving their arms?

According to the book Human Engineering guide for Equipment Designers, authored by Wesley E. Woodson and Donald W. Conover and published by the University of California Press, suggests the following ...
Edlothiad's user avatar
  • 2,137
18 votes
Accepted

Do astronauts wear G-Suits during the launch?

Shuttle crewmembers wore a g-suit, but only for entry. Anti-g Protection Crewmembers wear a g-suit for entry that provides pressure to the lower body separate from the ACES. The applied pressure ...
Organic Marble's user avatar
14 votes

Could a spacecraft spin so fast that it spontaneously deconstructs?

Reaction wheel? No, these are way overpowered in KSP, and don't exert nearly as high torque in real spacecrafts, never mind the issue of saturation (maximum speed of reaction wheel motor). But ...
SF.'s user avatar
  • 55.1k
14 votes
Accepted

How much G force is applied when correcting an orbit around Earth?

In practice, the g force applied for orbital corrections is very small. The satellite operator has plenty of time to make the correction, and if you are capable of accelerating the satellite at more ...
Russell Borogove's user avatar
12 votes
Accepted

Were shuttle seats reconfigured between launch and reentry to account for the different direction of acceleration?

The seats had a back angle adjustment that was changed from the ascent position for entry. Disappointingly, this is not mentioned in the press reference manual (https://science.ksc.nasa.gov/shuttle/...
Organic Marble's user avatar
11 votes

Could a spacecraft spin so fast that it spontaneously deconstructs?

Yes, absolutely. Every part of a spinning, rigid structure is undergoing acceleration towards the center, proportional to the radius from the axis of rotation and to the square of the angular ...
Russell Borogove's user avatar
9 votes

How do vibrational isolators reduce the g-forces of a payload on a launch vehicle?

The situation is a bit similar to driving up hill on a bumpy road. The car's suspension definitely transfers the "average force" from the road up to the passengers, but let's talk about what ...
uhoh's user avatar
  • 149k
8 votes

How do vibrational isolators reduce the g-forces of a payload on a launch vehicle?

Other than the "DC" (or low frequency part) of the g-forces, all the "AC" (or high frequency components) of the g-forces create both positive and negative contribution to velocity ...
AJN's user avatar
  • 1,030
6 votes
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Is there a G-force curve estimated for a SLS launch?

I haven't seen acceleration-vs-time curves published by NASA. The SLS Mission Planners Guide has a table of maximum expected acceleration. Looks like it is predicted to max out at 4.1 g.
Organic Marble's user avatar
6 votes

Do astronauts wear G-Suits during the launch?

As suggested above, during launch, conventional jet-fighter style G-protection is not used, because a crewmember will typically be positioned laid on their back, typically with the knees and feet up ...
MDBenson's user avatar
5 votes
Accepted

What is the constant g-phase in Apollo re-entry, and why does it not show up on the graph?

Constant-g was used in backup manual control modes. Note your quote says planned - the value of g the crew would fly was read up to them as part of the pad. See the discussion in your link. 191:58:13 ...
Organic Marble's user avatar
5 votes

What are the G-forces of Soyuz 3rd stage engine cutoff

3g (image below from this Quora answer), and it appears that the third stage cutoff is not the most intense. That one comes from the first stage cutoff, which is around 4g. Car crashes can be huge g ...
Michael Stachowsky's user avatar
5 votes

If human space travel is limited by the G force vulnerability, is there a way to counter G forces?

This is way beyond foreseeable economic possibilities, but the physics is sound: Gravity is a surefire, scalable, elegant way to counteract G forces from acceleration. A planet-sized spaceship with ...
Emilio M Bumachar's user avatar
5 votes

How much acceleration g-force can prevent pilot from moving their arms?

how much g-force would prevent the pilot from being able to move their limbs in order to control the space craft? How many times do they have to lift their arms? How much control of the limb do they ...
Russell Borogove's user avatar
4 votes

What G-forces do different launchers cause?

To supplement the other answers (and perhaps of historical interest) here's a Space Shuttle launch acceleration profile. Segment labels correspond to the following events/phases: A: liftoff to ...
Organic Marble's user avatar
4 votes

Is it possible, using known acceleration laws, to drastically lower force required to leave Earth's Gravitational pull?

A structure like that would reduce the amount of energy needed to get to orbit. But: getting a structure up to 17,500 mph would take vast amounts of energy. transporting the spacecraft from Earth ...
Hobbes's user avatar
  • 128k
4 votes

g-forces of suborbital versus orbital passenger travel

Back-of-the-envelope: The Shuttle kept ascent acceleration at or below about 3g - tolerable for most people; other human-rated launches have gone higher. Even under the 3g constraint, burn duration ...
Anthony X's user avatar
  • 17.6k
4 votes

Could a spacecraft spin so fast that it spontaneously deconstructs?

Could a spacecraft spin so fast that it deconstructs itself? What force would cause this (if it would) and which parts would be most susceptible to this force? It's not a matter of a force causing it,...
reirab's user avatar
  • 1,639
3 votes

G forces of Starship 1 when leaving Earth orbit?

In vacuum maneuvers will be taking place with the three vacuum Raptors, target hoped for thrust somewhere around 2500 kN each. For a loaded Starship at around 1000 tonnes F/m=a gives 7.5 m/s2 or just ...
GremlinWranger's user avatar
3 votes

Is it possible, using known acceleration laws, to drastically lower force required to leave Earth's Gravitational pull?

Your basic question seems to be whether we can build megastructures that use passive momentum and other orbital characteristics to make entering orbit simpler. We can, but the specific example isn't a ...
Nathan Tuggy's user avatar
  • 4,567
3 votes

g-forces of suborbital versus orbital passenger travel

The paper Great Expectations: Assessing the Potential for Suborbital Transportation says Suborbital tourism operators expect g-forces of +3g at the start of the ballistic phase and up to +6g ...
Organic Marble's user avatar
3 votes

Are Virgin Galactic tourists asked to take a 6 to 8G centrifuge test to qualify, and if so, what's the point?

https://bis-space.com/membership/voyage/VoyageIssue8-Virgin%20Galactic.pdf confirms that: The Virgin Galactic spaceship is designed to fly almost anyone to space without the need for long term ...
Franck Dernoncourt's user avatar
2 votes
Accepted

G - forces imparted by launchers

The best way to know is to check the payload planning guide for a particular launcher. Many modern launchers throttle down over the course of a flight to limit g-loading, so a simple rated-thrust ...
Russell Borogove's user avatar
2 votes

G - forces imparted by launchers

This is easy to calculate using our old friend $F = ma$ and knowing the thrust and mass at any given point in the launch: Take the combined thrust of all the engines $F$ in Newtons, remembering that ...
Jack's user avatar
  • 9,966
2 votes

How much G force is applied when correcting an orbit around Earth?

Using a very strong engine for high accelaration in a very short time requires additional mass for the rocket engine and the structure. Therefore additional fuel is necessary to accelerate the heavy ...
Uwe's user avatar
  • 49.2k

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