And give us a SPECTACULAR air show!
Niven & Pournelle got the idea from Project Thor; Thor was one of the ideas being kicked around in the Star Wars SDI program back in the 1980’s. They also used a lot of the other Star Wars SDI proposals in Footfall - nuclear-weapon powered gamma-ray lasers, for instance.
I got the impression that Pournelle actually proposed project Thor, although I could be wrong… Wasn’t Pournelle an advisor during the Star Wars projects?
The HARP project looked into high-altitude gun launches using modified 16" naval guns with sub-calibre, saboted ammunition. Early trials reached maximum altitudes of 112 km which is getting close, and projected altitudes of 160km, which is “space”, just about! Although as others have pointed out - getting a projectile into space is less than half the story, you also need it to have enough lateral velocity to stay there.
The HARP data is interesting - takeoff acceleration was 20000g, and the electronics in the “Martlet 2” projectiles were encapsulated in a mixture of epoxy and sand.
Further to Peter Morris’s post, here is an article that investigates the man-hole cover in space.
Karl Kruszelnicki writes in his book, ‘Great Moments in Science’,
Turns out that there could have been a man-hole cover launched during a series of nuclear tests known as ‘Operation Plumbob’ designed by Bob Brownlee.
Here is a link to Operation Plumbob (compliments of way-back). Look at test Pascal A.
Wish I was there to see the worlds largest roman candle.
I think you mean stable orbit, I don’t think an orbit even means one full revolution, but I could be wrong. Also you might be able to do so w/ the help of the moon, or launch it from earth into lunar, or for that matter martian or solar orbit unpowered.
I realize that any machinery or electronics will be pretty much toast in this method of launch but a solid object might be OK. Reasons for such a launch that I can think of:
To see if we can do it.
Anti-Satilite weapon.
Good non-explosive ground weapon when it does come down.
Launch raw material so it can be used in space (ISS, shuttled to lunar colony, or whatever else we might build in space someday)
I once worked on a Laser Propulsion project (as I’ve mentioned on the Board before). The ultimate goal was to shoot a conical payload into orbit from the ground, using shots from a ground-based laser to first ablate a thin surface layer of the frustrum of material attacvhed to the payload, then to pump energy into it via inverse brehmstrahllung, causing a Laser-Sustained Detonation Wave (LSD). This way the “engine” effectively stays on the ground, and all you have to send up is the payload and reaction mass. Probably the closest thing to the OP’s idea – you’re still feeding energy into the thing as it goes up, but it’s not as if your projectile is a rocket or anything.
Most of the work on this has died off, but the last I heard Leik Myrabo of RPI was still blasting his Apollo Lightcraft off for short runs at White Sands. In his case, though, he doesn’t even carry reaction mass – he uses the surrounding air as his expansion medium, and his hope is to get the payload going fast enough so that when the air thins out it’ll keep on going.
SF stories treating this are Jerry Pournelle’s High Justice, Michael Kube-McDowell’s The Quiet Pools, and Dean Ing’s The Big Lifters.
Brehmstrahllung-lager would make an excellent name for a brand of beer.
Ok, using the values in the link: a muzzle velocity of 3600 m/s, and a 20 m long barrel, I get an acceleration of 324,324.32 ms[sup]-1[/sup], which is about 33,095 G. I just can’t see an electronics package surviving that kind of stress.
Inverse-Brehmstrahllung-lager would presumably make you make you more sober as you drunk it
I’m almost positive I heard Pournelle in an interview on Art Bell’s show say that he did, indeed, work on SDI in some capacity.
I’ve seen (small, simple) electronics packages with higher shock ratings than that. It’s probably pretty hard to design a large, useful satellite system to withstand those shocks though. Certainly it would add a lot of weight over a payload designed for a more gradual launch.
Here’s a company making accelerometers with 50000g limits. There was a JPL proposal to launch probes to Mars with bullet-shaped penetrators to tunnel a few inches into the soil. The penetrators were supposed to have some sort of drill inside them (so this is not just electronics but moving parts too) and I think they had accelerations ~50000g.
That’s true, Jinx, but it’s not the point. Escape velocity still has meaning. Escape velocity is how fast you have to be going so that the cumulative effect of gravity, all the way to infinity, never quite catches up with you.
Something launched with less than escape velocity will eventually fall back down. Maybe after 5 feet, maybe after 10 billion light-years.
Something launched with exactly escape velocity will slow down asymptotically to zero…but never quite stop. The limit of velocity is zero as altitude approaches infinity.
Something launched with any speed greater than excape velocity will always slow down (with decreasing deceleration) due to the Earth’s gravity, but will not stop, even at infinity.
So, yes, Earth’s gravity is felt all the way to infinity…but it may not be enough to ever stop you, if you’re going fast enough.
He’s usually credited as having written the portion of Reagan’s speech where he launched SDI. He’d previously founded the Citizens Advisory Council on National Space Policy, which was effectively a pro-SDI pressure group. However, I’m not aware of him ever being employed by any of the projects involved in any specific technical capacity - his role was at a policy level.
Incidentally, if you actually read antechinus’ links, it’s clear that the “manhole in space” story is almost certainly a myth.
Yeah, if you read about Pascal B in the link above, the article in the February/March 1992 issue of Air & Space magazine, published by the Smithsonian has an error in the use of the term “Project Thunderwell” in connection to Pascal B. “Project Thunderwell” was never constructed.
It was the Air & Space article that stated the ‘manhole cover’ story.
Also from the link …
The drill doesn’t have to have moving parts if it’s an ultrasonic drill.
…or a sonic screwdriver.
True, but I think you need a moving arm to mount it on.