Drive systems

DDHv wrote:

Caliban wrote:I realize that this subject has been hammered on ad nauseam- but there is still a need for our kind to develop these, as chemical drive systems, with the exception of ground to orbit, do not seem to be practical.So, I'd like to open the door to discussions on things like photon drives, light sails, mag drives, et.al. Ground to orbit systems, such as laser launchers and orbital elevators would seem to be the first step, but current infrastructure looks to be what we're limited to.

Having worked in the plastic film industry I am aware of how multilayer technology could be a first step to sustainable system wide access, along with how polymer technology could provide 'slingshot' type cargo movers. I am interested in what thoughts you folks might have on this subject.

anyone interested?

MAD-4A wrote:If you’re looking for just orbital access, you could convert a retired ICBM silo. Strip out all the equipment, line the walls with high powered (cut a car in half) lasers hooked to a dedicated power plant. Add reflecting mirrors to bounce each beam horizontally around the plane. Plug the hole with the payload/space craft. Fill with water & “Fire the lasers!” The water would superheat, turn to steam & POP – like a champagne cork, into orbit. Hmmm. Launching spacecraft on coal power - lol

Read Pournelle;s "High Justice." and following stories.

Or The Big Lifters by Dean Ing.

The idea of using a nuclear device to power a "Jules Vern" cannon is a topic that excites the writers of the "NextBigFuture" blog as well.

If I am reading the sources right, the "Plum Bob" tests utilized a dry shaft, and the shock wave alone was calculated to shoot the steel cap from the shaft at 6 X escape velocity. As the cap was never properly filmed (it only appears in one frame of the high speed film), this was never verified. Since the cap was never recovered, it may be somewhere in the outer solar system, but more likely the heat and aerodynamic pressure of flight in the atmosphere caused it to disintegrate.

The idea of filling the shaft with water is more sophisticated than a "steam cannon", the X-ray pulse from the devise going off turns the water into a plasma (in a tiny fraction of a second), and the coupling of the plasma with the projectile is calculated to be far more efficient than the shockwave alone.

Of course any variation of this system is most certainly not for launching people ito orbit.

Or try this:

<a>http://www.omaha.com/news/metro/working-toward-a-warp-drive-in-his-garage-lab-omahan/article_b6489acf-5622-5419-ac18-0c44474da9c9.html</a>

Hm... As i recall, there are much talk about quantum rocket drive. It's generally a electrorocket engine of some kind, working on virtual particles, created by vacuum fluctuations.

https://en.wikipedia.org/wiki/Quantum_v ... a_thruster

So, it theory, it's a rocket engine with unlimited propellant supply, and it's at leas theoretically possible. But the problem is, that the virtual particles appeared in pair with opposite charges, so if we accelerate one away, the other would be dragged to engine... So, it would work, but the thrust would be zero.

Maybe there is some way to bypass this, because there was at least a few encouraging experiments...

There are many ways to get stuff into orbit.

Gerald Bull used to use 16" Guns to shoot stuff into orbit and his 1000mm 39" gun would have done the trick as well.

Supplies such as Raw materials, rock, dirt water even air can be fired up with a cannon.

I've always wondered if a Dirigible could get high enough and be strong enough to use smaller rockets to accelerate into orbit. It would be ideal as it would give a large container to base a ship upon. Once you deflate the Weather like balloons the rigid outer skin would be an ideal starting point. From 20+ miles up and with a large supply of Hydrogen. Using the Hydrogen to get the Dirigible up would also give you a supply of Hydrogen for the rocket engines to get into orbit. Assuming one is making a Soup Can ship Similar to the Weber Cylinder ships only rotating to make gravity and with a Nuclear power plant on a boom at one end. Further away from the living section the less shielding needed for the nuclear power plant.

Aerogels sandwiched between Aluminum or Titanium skins should help with the particle shielding and deploying a concrete outer layer or until enough such material is available a Millimetre active armour defense with passive reactive armour could suffice. Plus internal rock and dirt layers. The concrete could be fired up and applied internally first externally after if need be.

Lord Skimper wrote:
I've always wondered if a Dirigible could get high enough and be strong enough to use smaller rockets to accelerate into orbit. It would be ideal as it would give a large container to base a ship upon.

No, it couldn't. Something like the stratospheric baloon (stratostat) may do the trick, but the lifting capability is extremely limited.

Just have to make the dirigible big enough. A mile long 1/4 mile in diameter and lots of hydrogen. Although if it is going to survive in space, it might be air tight and strong enough, one might want to use a vacuum for the lift.

Lord Skimper wrote:Just have to make the dirigible big enough. A mile long 1/4 mile in diameter and lots of hydrogen. Although if it is going to survive in space, it might be air tight and strong enough, one might want to use a vacuum for the lift.

You'd set the thing on fire the first time you launched a rocket off of it.

A dirigible really is not viable as a launch platform.

Getting into orbit is mainly a matter of velocity, not altitude. You need to be traveling horizontally at about 8 km/s. Altitude really only matters so that you don't run into anything, including air resistance. Also, rockets are more efficient at high altitude and especially in vacuum.

In aircraft terms, you need to be doing around mach 25. The Earth's rotation at the equator for a due east launch will give you a mach 2 start. Being carried up by a fast subsonic aircraft flying due east can give you the equivalent of another mach 2 or so (1 for speed plus 1 for altitude) (e.g. a Pegasus carried by an L1011). A dirigible isn't going to give you that extra speed.

Lord Skimper wrote:Gerald Bull used to use 16" Guns to shoot stuff into orbit and his 1000mm 39" gun would have done the trick as well.

He intended to, but AFAIK never actually did.

Lord Skimper wrote:I've always wondered if a Dirigible could get high enough and be strong enough to use smaller rockets to accelerate into orbit.It would be ideal as it would give a large container to base a ship upon.

Then you'd have to boost a large and rather flimsy structure to orbital velocities. Altitude alone does not help much.

Lord Skimper wrote:Once you deflate the Weather like balloons the rigid outer skin would be an ideal starting point.

Inflated/inflatable space stations are proposed - but to be launched in a compact form.

Lord Skimper wrote:Using the Hydrogen to get the Dirigible up would also give you a supply of Hydrogen for the rocket engines to get into orbit.

This supply of hydrogen would have an impractically low density (that's the point of lighter-than-air), resulting in relatively high structual mass fractions for a given strength and considerable drag.

Lord Skimper wrote:Aerogels sandwiched between Aluminum or Titanium skins should help with the particle shielding and deploying a concrete outer layer or until enough such material is available a Millimetre active armour defense with passive reactive armour could suffice. Plus internal rock and dirt layers. The concrete could be fired up and applied internally first externally after if need be.

Reasonable for a lunar structure or space station, not so much for a ground-to-orbit craft.

In summary, most proposals for non-rocket spacelaunch involve rather large structures for a reason, you need to achieve a speed of about 8 km/s.