11
$\begingroup$

As mentioned in this discussion: How to keep humans pilots instead of AI in sci-fi future? the ability to handle G forces is a limiting factor on what pilots can do. Some of my solutions to address this will likely be to limit the delta V via various approaches, but I'm also looking into what I can do to make high G forces tolerable for humans.

The problem is that real inertial dampeners are rather high-tech. If you can install some inertia dampening field you have discovered a way to mess with a raw force of nature, and there have to be all kinds of other interesting technology that comes from such a discovery. I want a somewhat near-future work, advanced enough for space travel but not to the level of all tech being applied phlebotinum. Thus I don't want inertial dampeners that are some magic hand-wave field that 'just works'.

What are viable approaches that could be used to help pilots handle high G forces without full scale inertial dampeners? In a somewhat advanced future, but before we reach the point of energy fields and nano-robots what approaches may be viable that aren't, yet, viable for fighter pilots of the present?

I'm most interested in space-fighters, though I don't know if the fact that their in space really effects the issue of G force and inertia.

$\endgroup$

This question asks for hard science. All answers to this question should be backed up by equations, empirical evidence, scientific papers, other citations, etc. Answers that do not satisfy this requirement might be removed. See the tag description for more information.

  • 3
    $\begingroup$ Is removing the brain and wiring it directly into the controls an option or is that still regarded as too high tech? $\endgroup$ – Scott Downey May 12 '15 at 16:23
  • 6
    $\begingroup$ Two words: liquid breathing. $\endgroup$ – 2012rcampion May 12 '15 at 16:23
  • 5
    $\begingroup$ It's a common mistake, but you mean inertial "dampers." A dampener makes things wet. $\endgroup$ – user243 May 12 '15 at 22:27
  • 2
    $\begingroup$ Assuming that you have roughly current-tech fuel requirements for your engines, high Gs may be less of a problem, because it simply requires too much fuel to use frequent high G maneuvers in space. The high-G turning maneuvers that aircraft perform take advantage of air resistance and lift, which leads to those dramatic fast sweeping turns in movies to weave and dodge out of the enemy fire. Granted, you often see 'space fighters' in film moving as if they were aircraft, but I think that's only because people are more intuitively used to seeing birds/planes flying. $\endgroup$ – Dan Bryant May 12 '15 at 22:34
  • 1
    $\begingroup$ @JonofAllTrades A "damper" or a "dampener" "damp" something. Moisture is just one form of damping or dampening. The effects of the physics laws related to inertia are being "made soggy" so the effects are less successful. $\endgroup$ – killermist May 13 '15 at 1:08
19
$\begingroup$

This book has pretty much every idea devised to survive high g environments

An unprotected civilian in a sitting position can remain conscious up to 3-5 g's depending upon their fitness level.

Some ideas for increasing this:

  1. Put your pilots in a g-suit or its analog.
    These squeeze the extremities to keep blood flowing to the internal organs and brains of the pilot. Using these pilots can tolerate 5-6 g's for seconds to minutes (the g-suit typically adds around 1 g to a persons tolerance).

  2. Put your pilots in the recumbant/prone position.
    The human body tolerates g's better in some orientations than others. Combined with a g-suit, most trained pilots can remain conscious through 9 g maneuvers for short periods of time (typically less than 1 minute). In centrifuge tests, some subjects remained conscious at 15 g's for about a minute. This is the duration of the maneuver I don't know the physiological limitations of it.

  3. Train your pilots in how to tolerate high g's with the g-straining maneuver.

Pilots still need to practice the 'g-straining maneuver' that consists of tensing the abdominal muscles in order to tighten blood vessels so as to reduce blood pooling in the lower body. High g is not comfortable, even with a g-suit.

  1. Put your pilots in a g-bath / g-tank.
    A g-bath is a tank filled with fluid that possesses the same density as human protoplasm. The theory is that by supporting the body, the blood won't tend to pool and the pilot could remain conscious and alive at much higher g's. The US Navy has conducted experiments up to 16 g's with these and the pilots tolerated that quite well. The researchers felt they could go considerably higher than that but no one has conducted those tests.

The test below shows that someone survived g-forces up to 45 g's in experiments and 180 g's in crashes but both of these were instantaneous loads. So I'm not sure what the theoretical maximum g-load is.

Human g-tolerances
Human g-tolerances

G-Tolerances:

  • 1.5 g's, most people tolerate indefinitely
  • 2 g's, most people tolerate for hours to days
  • 3 g's, most people can tolerate for minutes
  • 5 g's, most people can't tolerate more than this when sitting
  • 6 g's, untrained humans in sitting position remain conscious for up to minutes
  • 9 g's, limits of trained pilot, in a g-suit, in semi-reclined position for around a minute
  • 10 g's, untrained humans remain conscious in prone position for up to 1 minute
  • 15 g's, highest any trained pilot, in a g-suit, and semi-reclined position has tolerated for seconds
  • 15 g's, average tolerated by trained pilot in a g-tank (results indicated considerably high g's could be tolerated but those tests haven't been done yet) four several seconds
  • 22 g's, untrained humans remain conscious in prone position for up to 10 second.
  • 46 g's, (instantaneous) maximum recorded experimental negative g-load survived by a human (caused permanent vision problems)
  • 180 g's, (instantaneous) maximum calculated g-load survived by a human in a crash.

High g's are terribly uncomfortable and dangerous for people not medically cleared

John Stapp rocket sled
John Stapp rocket sled

John Stapp was subjected to 15 g for 0.6 seconds and a peak of 22 g during a 19 March 1954 rocket sled test. He would eventually survive a peak of more than 46 g, with more than 25 g for 1.1 seconds.

$\endgroup$
  • $\begingroup$ Most of those seem risky as far as long-term damage to sensitive tissues, like the eyes (G forces squishing them out of shape, thus requiring classes or contact lenses to correct the condition) $\endgroup$ – user2813274 May 12 '15 at 17:25
  • $\begingroup$ Apparently the high negative 45 g (eyeballs out) test, did damage the test subject's cornea. Human eyes seem to tolerate the positive g's OK. $\endgroup$ – Jim2B May 12 '15 at 17:43
  • $\begingroup$ So you're saying the pilots should be lying prone in a liquid bath wearing a g suit? That's doable. And if it's oxygen bearing we're talking life support system and inertial dampers in one! $\endgroup$ – Isaac Kotlicky May 12 '15 at 23:36
  • $\begingroup$ The g-suit isn't necessary if you're in a g-bath. You'd use one or the other. As for the oxygenated fluids, theoretically replace air with fluid in the lungs would aid in g-toleration but I would think pushing the fluid in and out of the lungs would tire your diaphragm very quickly. I don't know what research has been done in that area. $\endgroup$ – Jim2B May 12 '15 at 23:48
  • 1
    $\begingroup$ In liquid breathing mechanical respiration is necessary because human lungs cannot handle the pumping burden. Even pressurized oxy-helium environments present a challenge due to pumping burden. $\endgroup$ – Gary Walker Sep 21 '15 at 9:18
8
$\begingroup$

Keep your pilots on the carrier doing their flying via remote control technology. The pilots still need to be in space near the fighters because of the limits to the speed of light. Their virtual cockpit could still be just like the real thing except for blacking out, and getting hurt and killed.

I.e., just the same thing the US is currently doing as it is coming to rely on remote control drones. This is certain to be only a first step toward unmanned fighters, regardless of how much the ex-pilots in the force resist the change. Pilots in vehicles only make it more expensive to operate and much more expensive in terms of replacing lost pilots.


It occurred to me that maybe the remote pilots don't even have to know that they are remote pilots -- perhaps due to built-in VR of their fully enclosed flight suit after all, they don't actually need a transparent face shield. Let's assume that pilots perform better when their life is on the line -- actually a reasonable assumption if it reduces unacceptably risky behaviors that destroy too many unmanned fighters due to lazy piloting. And now the pilots also believe they have inertial dampening fields too. Perhaps this is now a fully legitimate answer.

Recovery from "kills" could be explained as a last resort high tech force field, perhaps a Slaver stasis field. If you need to get rid of pilots ... no problem, the field did not work for them. Or it could also be that dying in the simulator naturally results in death in a certain percentage of cases. You have a reverse Ender's Game setup, one politically dirty, one politically clean. Of course those in charge would know the truth. News organizations could be fed misinformation, etc. so only the insiders would know the deception.

Of course, some might object that remote control is subject to hacking, jamming, and speed of light delays -- all true, but the remote advantages may still be larger overall. Still not real inertial dampening though; of course Barbie says, "Gravitics class is hard."

I should also point out at that having pilots in the carrier is not the same as having them in their fighters thanks to the speed of light. If you assume max acceleration of 100 g and a battle lasting 5 minutes the fighter could reach a distance of 0.147 light seconds from the carrier by accelerating in a straight line. How you can achieve such a high rate and duration of acceleration in a fighter is a very hard problem physics problem itself too. A lot of science fiction relays on hand-wavium, esp. where the hand waving is non-obvious. We all know that 100 g's will kill you and FTL is fanciful or beyond our physics, but most SF consumers are not bothered by a fighter having advanced acceleration and duration characteristics or forgetting about the time lag associated with relatively short distances.

$\endgroup$
5
$\begingroup$

Leave the cockpit not fixed to the space craft, so that it can move relative to it. It could be suspended on "elastic strings" inside a huge cavity inside the vessel or similar. By delaying acceleration, you could have the pilots survive short, strong bursts in the same direction, maybe to conduct an evasive maneuver. However, it would not help you with long sustained acceleration, because at some time the cockpit will hit the rear wall and then won't be able to delay the high g force any longer. You would need to make sure to damp the system as to prevent oscillations.

$\endgroup$
  • $\begingroup$ Curses! I'd just thought of this one. An upvote for you sir! :) $\endgroup$ – Ayelis May 14 '15 at 22:46
  • $\begingroup$ Iow, packing peanuts. $\endgroup$ – JDługosz Apr 14 '16 at 6:24
4
$\begingroup$

One possibility is to enhance your humans.

Titanium (or carbon nanotubed?) re-enforced bones to handle the stress. Assisting pumps around the heart and major arteries, along with drugs, to increase blood flow and keep pilots from blacking out. Something similar to power exoskeleton to let them move their head and hands under extreme forces.

I wouldn't want to bet on what the above would do to your body - I'm sure the long-term medical prognosis would be bleak. It would be like profession football players, where the stress and impacts add up and make you old before your time. But if that's what you need to do to compete...

$\endgroup$
  • 2
    $\begingroup$ I don't think bones are going to be your first problem. The big one is all the hollow places inside you, like lungs and digestive system. To many G's and your lungs collapse, keeping you from breathing. Maybe something to go inside to feed oxygen directly to the blood? Other problem areas are soft tissues, like eyeballs, cartilage, internal organs, all being pushed out of place and out of shape... $\endgroup$ – AndyD273 May 12 '15 at 17:12
  • $\begingroup$ @AndyD273: now that you say that I think I remember a story along that lines, where pilots had to suppress their breathing entirely. Their lungs and internal structures were filled with a support fluid and their blood was run through a machine that injected oxygen. $\endgroup$ – Dan Smolinske May 12 '15 at 17:27
  • $\begingroup$ This was the direction I thought about going in. Make the body better. If you use a combination of medicine, surgery and evolution, it could easily raise the level of G-Forces the human body could withstand. $\endgroup$ – Jason May 12 '15 at 18:39
  • $\begingroup$ Another high g issue is that it puts strain on your circulatory system, meaning that if you have any weakened blood vessels they could blow. So instead of waiting 30 years for that weakened artery to blow, you just spend a while in high G and boom, hemorrhage. $\endgroup$ – AndyD273 May 12 '15 at 20:47
1
$\begingroup$

As you say, just give them low-tech inertial dampeners. If you're using inertial dampeners to mean the same as I am, then we already have the technology to do this and it's used in many places.

Take, for example, a military helicopter, which needs to be a rock-solid gun platform for snipers at times. No human pilot can possibly correct for wind and other outside influences fast enough that there is no noticeable movement in the helicopter, so they get a computer to do it.

This computer uses sensors such as the already-installed airspeed and altitude sensors (if they're accurate enough) to detect wind force against the aircraft, and up or down movement, to control output into the engines and the rotors to move the helicopter to counter the movement. Essentially:

Hovering → ASG (airspeed gauge) shows forward velocity → is there correlating control input from the pilot? → no - inference: wind on the front of the aircraft → pitch rotor forward to counter.

This sort of processing is incredibly simple for a computer to do, and I can write pseudo-code that describes it in few lines and not much time.

There are some differences in space, namely the lack of air resistance to measure speed by. Instead, your computer needs to know the force that the engines have put out and for how long in what direction. From that it can work out how fast the craft is going now, and apply some force to prevent the acceleration going over a preset maximum.

$\endgroup$
  • 3
    $\begingroup$ If I accelerate by 15 G forward and the computer detects this what would it do to compensate? It can't push 15 G in the other direction to even things out or I become a very condensed and messy stain to clean out of the cockpit. $\endgroup$ – dsollen May 12 '15 at 17:14
  • 1
    $\begingroup$ Later, in your electronics courses, you may take some very basic control theory and learn how difficult and complex it can be to write code for a hovering helicopter. And if you ever work with an IMU then you'll realize how the description in your last paragraph will be accurate for less than a minute. $\endgroup$ – Samuel May 12 '15 at 17:53
  • $\begingroup$ @dsollen Noting that Gs are not units of acceleration but of gravitational force (which, it is true, is sometimes used as acceleration), you accelerate in the other direction while the forward acceleration is happening. Once it reaches some threshold, the rearward acceleration is increased to match the forward, thus stopping the vehicle accelerating any more. $\endgroup$ – ArtOfCode May 12 '15 at 18:12
  • $\begingroup$ @Samuel I don't doubt it. I was describing the principles not the implementation - real control code would no doubt be very complex, but pseudo-code to describe the code is not. In theory, types of direct equation processing like this are fairly simple for a computer to do. $\endgroup$ – ArtOfCode May 12 '15 at 18:13
  • $\begingroup$ @ArtOfCode Actually, proper pseudocode would also be very complex. A high-level description of an overly simplified principle, what you've written here, would not be complex. If you're saying what you wrote is anything close to pseudocode then that's what I'm disagreeing with. But, in either case we can agree it's not as simple as it sounds. $\endgroup$ – Samuel May 12 '15 at 18:25
1
$\begingroup$

Cyborgzation, replace the body with artificial parts, brain augmented with microbots that, beyond the more obvious advantages, makes the brain more resilient to g forces. To me, this is probably what is going to happens in the future if we need to deal with such g-force, because it's (seems) easier.

Make their bodies magnetic so they travel fairly together with the ship. By drinking/injecting some iron-like fluid, preferably organic and non-toxic, you could make their cells easier to magnetize. The magnetic field counters partially or fully the force going to one direction, a suit might be a good idea. The problem with this idea is that at a cellular level what is not magnetic could be ripped off the cell.

An alternative would be genetic manipulation, stronger heart and arteries, harder brain and organs, etc. With things like CRISPR today I don't see this alternative that "magical".

$\endgroup$
0
$\begingroup$

Depending on the propulsion method, you may not need to.

A gravametric engine (maybe not as high-tech as it sounds), wouldn't produce any 'felt' G-forces on the pilot, since every atom accelerates equally, there is no strain.

It may be possible at higher tech levels, to do something similar with a non-gravimetric field instead, creating a 'inertial dampener' of sorts. Remember that they don't need to be as effective as the Star Trek ones. If you can make a body magnetic or affected simultaneously by a force, then you can apply that force to counter any acceleration.

Limitations include how quickly they can react to g forces and deal with them, they may react better to more predictable accelerations for example.

Other solutions to your problem however include: 1> Making a sufficiently intelligent computer to compete with an experienced pilot(with computer assist), makes the computer very delicate/large/expensive, giving them another reason not to be used even if they can take the G-forces a human can't. 2> Thrust to weight ratios in space aren't high enough for G-forces to matter given fuel limitations. If you are been totally realistic, then almost all battles will be fought at distances of 0.5-1 light second with large laser cannons, not close quick manoeuvring dog-fights. 3> Remote control? 4> How hard is it to disable a remote computer? Perhaps its too hard to shield them from enemy emp blasts?

$\endgroup$
  • $\begingroup$ Star trek inertial dampeners are a joke. They were always falling out of their chairs during maneuvers and when they were off-line, nothing was obviously different. I suspect the writers did not understand (or mostly care) about the official version described in the tech manuals. $\endgroup$ – Gary Walker May 13 '15 at 16:24
  • $\begingroup$ Why do you say a gravimetric engine is "maybe not as high-tech as it sounds", can you think of any real proposals that would be compatible with existing physics? As for magnetics, all materials have the property of diamagnetism which causes some degree of repulsive force in the presence of an external magnetic field, so with sufficiently strong external fields you can do tricks like levitating frogs, with far more powerful magnets you could counter g-forces for humans. $\endgroup$ – Hypnosifl Jul 4 at 16:36
  • $\begingroup$ I mean that simply, we may find it easier than we thought. Lots of discoveries happen by accident and scientists trying a completely unrelated experiment suddenly find they accidentally managed to create a gravametric field instead of a magnetic one or whatever. Just call it Quantum! $\endgroup$ – Drenzul Jul 5 at 21:18
0
$\begingroup$

Firing mass weapons would also be an issue. The recoil has drawbacks. I have thought of a way to avoid this, I think, by using a centrifuge method to accelerate the mass. Letting it fly at the target does not cause a recoil as such but does impart a twist or spin into the parent craft. Firing a second mass of equal size in the same direction (same target) but spinning in the opposite direction should remove that effect. Downside, I suspect there will be a good deal torque between the two sides of the weapon, shortening its overall life. Won't help a life form much in turns etc. but it should help out with overall fighter performance.

$\endgroup$
  • $\begingroup$ Yeah but the gyro-scoptic affect would make it really hard to turn when the weapon was charged to fire making it a bugger to aim for a large enough gun for recoil to actually matter. Generally the impulse from projectile shells in space would be low enough to be insignificant anyway, less than the force the retros on the other side of the ship should be able to counter anyway. Perhaps good for a smaller ship designed to sit at the end of a battle with a massive spinal mounted weapon.... but you will still get recoil when you are it! Momentum conservation still applies! $\endgroup$ – Drenzul Jul 5 at 21:23

protected by L.Dutch Jul 4 at 16:41

Thank you for your interest in this question. Because it has attracted low-quality or spam answers that had to be removed, posting an answer now requires 10 reputation on this site (the association bonus does not count).

Would you like to answer one of these unanswered questions instead?

Not the answer you're looking for? Browse other questions tagged or ask your own question.