Quick Boost To Orbit

Proton Flight Pattern

Click on the pic to see the full size version where you can actually read the letters and numbers.

REVISED. Stu made a comment, which prompted me to re-evaluate my reasoning. I don't think Stu's objection is correct. Perhaps this revision will clarify the situation. Or not.

When launching a satellite into orbit the quicker you can get there, the less fuel it takes. Yes, I know, higher acceleration requires burning more fuel faster. But if you are accelerating faster, you don't need to spend as much time accelerating, which means you spend less time burning fuel. So the total amount of fuel required will be similar.

However, even if you are not accelerating, you still need to expend enough fuel to support the rocket, i.e. one gravity of acceleration. So the force needed just to support your launch vehicle is being expended until you get to orbit. If you accelerate faster, your time to orbit is quicker, and therefor you should not need to expend quite as much fuel just for support. You will burn the same amount of fuel for acceleration, but you will indeed need to burn it much faster in order to realize any savings on the support end.

A higher acceleration rate puts a greater strain on the payload. If the payload is just a piece of equipment, it can be designed and constructed to handle this increased strain. If we are launching a spacecraft containing people, that is another matter. People don't react well to rocket launches. It puts a big strain on them. Boosting the acceleration to a higher level could easily prove fatal.

One way to overcome this would be to immerse the person in a tank of water and equip them with SCUBA gear. The elevated force of acceleration during a rocket launch would be converted to higher water pressure, which would be equivalent to diving deeper under water.

On the Earth's surface, under one gravity of acceleration, water pressure is proportional to depth. One atmosphere of pressure (15 PSI, what we get at sea level under a pile of air 100 miles high) is about the same as what you get under 30 feet (10 meters) of water. Of course 30 feet under the surface of the sea the absolute pressure is two atmospheres (30 PSI), 15 PSI from the pile of air, and 15 PSI from the 30 feet of water.

A 30 foot tall tank of water sitting on the surface of the Earth is going to have a pressure gradient from 15 PSI (air pressure) at the top to 30 PSI at the bottom. A taller tank will have higher pressure at the bottom, a shorter tank will have a lower pressure.

Under the acceleration of a rocket launch, the pressure at the top surface will remain the same (the amount of air in the sealed spaceship is not going to change), but the pressure at the bottom will increase in direct proportion to the acceleration. A ten foot tall tank would have a pressure of 5 PSI while sitting on the ground, while under an acceleration of 10 G's (Gravities, 32 feet per second per second), the pressure would increase to 50 PSI, similar to what you would experience at a depth of 100 feet underwater. The diameter of the tank would make no difference. Likewise a tank 3 feet tall would only have a pressure differential of 15 PSI from top to bottom under 10 G's of acceleration.

So the question becomes how much difference in pressure can a human being tolerate? A person standing in a small diameter tank would experience a difference in 50 PSI from toes to nose. That might be a bit much, it might squeeze the blood out of your legs and into your head. A person lying down would experience a difference of only about 5 PSI, which might be tolerable.

For a person being launched in such a manner, a relatively small diameter tube could contain them, perhaps as small as three feet in diameter. Of course a tube big enough for a human filled with water is going to weigh considerable more than a human alone, but I think we can probably find a use for the water once we are in orbit. We would need a second tank to drain the water into after we had reached orbit. We would not want our astronaut to be operating underwater while in space. That would be silly. (Or would it? More study needed.)

I read a science fiction story some time ago that used a similar mechanism to protect pilots from extremely high accelerations. In this case they were military pilots flying star fighters (a la "Star Wars") at extremely high velocities and distances. The pilots were housed inside a sphere filled with water somewhere in the interior of their ship. The main thrust of the story seemed to be the psychological stresses these pilots suffered due to the power at their control versus the protection their spherical cocoon provided.

Update October 2016. Mucked around until text stopped overlapping photos.

Update January 2017 replaced missing photos.