Reducing costs of sending ships into orbit

[Faeelin]

I'm currently seting up a presentation on why Bush's plan isn't going to work and makes no sense.The sticking poitn of space travel seems to be getting things in orbit cheaply.

So, what methods could ATL governments use?

[NapoleonXIV]

There was a plan I read about several years ago that based itself on capturing back the energy needed to launch things into orbit. The principal was that at present we use tons of fuel to launch things out of the gravity well and then throw the energy away into dangerous heat on reentry. Wouldn't it be nice if we had some sort of counterweight, like on elevators, which would mean we wouldn't have to lift the entire mass each time but get back some of the falling objects energy to lift the ascending ones.

The device suggested was a sort of backwards mass driver, which would capture and hold ascending objects and take their energy off into electricity. It would use this to launch other objects.

One problem would be that its 150 km long.

Another idea, which doesn't really solve the cost/launch problem but could make it profitable is the power satellite. Satellites with really huge solar panels could beam power back to earth. The beam would only be concentrated so much that an antenna array of about a square mile or so would be required; and thus be safe if it would happen to go astray since it would only be a few watts over normal levels (which would nevertheless add up over a square mile.) NASA did feasibility studies on this about 10 years ago which gave it among the highest marks for practicality, but nothing more was ever heard of it.

[Max Sinister]

A skyhook / spacelift / however you want to call it? (For those who never heard of before: It's essentially a big cable (more than 10000 km long) that's hooked with one end to the Earth (somewhere at the equator), while the other end is floating in space (inertia makes that it won't fall on Earth), and you can use it to send whatever you want into space - you let it go up on the cable just like a lift. And you can use it too if you want to bring matter from space back onto Earth (fly to the end in space and let it go down).

It would be very expensive to build (we don't have fibers strong enough to build a 10000 km cable), but much cheaper if it's in work (i.e. cheaper than rockets).

[Faeelin]

Hmm. Now, the question is, can I stand in front of a class and say the government should build a tower to orbit using nanotech to produce carbon tubes?

[NapoleonXIV]

Originally Posted by Faeelin

Hmm. Now, the question is, can I stand in front of a class and say the government should build a tower to orbit using nanotech to produce carbon tubes?

Certainly, all teachers should have a reputation of being nuts, it increases their authority. OTOH if you're a student, well all the girls love the class clown.

[Norman]

I am (unfortunately) old enough to remember when there was a lot of hope for space 'planes'. The X-15 for example, actually was able to touch the edge of space, but this approach was abandoned when the different governments decided to develop missile based space programs because every lauch was an implicit threat that they could send a missile anywhere they wanted.

What if the old X-15 program had not been terminated, and it was decided to keep both programs alive? We might now have planes that take off, with attached rockets that later detach and shoot themselves into space.

Payloads would have been smaller, but each would have cost much less to get into space.

[Faeelin]

Were those the air-augmented rockets used by companies like Marquardt

[Norman]

NO, actually I misled you a bit, the entire X-15 rocket plane was attached to a jet which took it as high as it could, then released the Rocket plane. As I recall (imperfectly I'm sure) the Rocket would pick up speed from its drop, then fire the rocket.

These guys literally flew to the edge of space in little one-man jets. The X-15 was constructed out of very state of the art materials, but this was back in the early to mid-60's. As I remember the program was plagued by issues of weight and heat which presented a series of problems they couldn't get around. But still every launch was much less expensive than a rocket launch.

Times have changed, we have much stronger, lighter and more heat materials and better fuels. If we had continued to explore this area of aeronautical science, who knows where we would be.

[Tyr]

I don't see why a aircraft can't be made that uses regular engines to get as high as it safely can then switches to rocket engines.

[Faeelin]

Hmm. 8 comments on this, 0 on the establishment of a hereditary german empire and a mediterranean power based on sicily in the Prince of Peace.

Isn't that a scramjet?

[Norman]

The biggest problem is that you wold then have to carry an engine system that you use only part of the time. For example, if you have a dual jet-rocket system, you use the jet to the upper limit of its usefulness, thenswitch to the rocket, unless you jettison the jet engines, you are still carrying them with you, and this adds to the cost of getting nto space.

Conversely, if you use a two step approach, say a very carefully designed supersonic jet that lifts the rocket to the jet's outer limit of operation, then the rocket 'plane' only has to carry the weight of the rocket into space.

[Straha]

Originally Posted by Faeelin

Hmm. 8 comments on this, 0 on the establishment of a hereditary german empire and a mediterranean power based on sicily in the Prince of Peace.

Isn't that a scramjet?

dude medieval WIsz are so twentieth century but good thread!

[aktarian]

Originally Posted by Faeelin

Hmm. 8 comments on this, 0 on the establishment of a hereditary german empire and a mediterranean power based on sicily in the Prince of Peace.

Isn't that a scramjet?

you will always have geeks around but you woun't always have people with interest in europan political history.

[Norman]

ouch! That hurt!

[Tucker Dwynn]

One the top competiters in the <a href="http://www.xprize.org">X-Prize</a> is from scaled composites. They have a very similar method to the x-15. A modified jet (White Knight) has the sub-orbiter (Space Ship One) slung under its belly. They take it up to 50,000 feet, drop space ship one, and it fires it's rocket motor. A partial rocket flight test got SSO pass Mach 1, then it gladed back down.
If the size of the crafts were doubled, then maybe it would have enough umph to get into low eart orbit. The working model is planned to achive an altitude of 62 miles.

[wkwillis]

Carbon nanotubes are so strong in relation to their weight that they make building single stage to orbit and return vehicles trivial. Cessna could build them. They are far to expensive to use now, and the world production ability is trivial. The mass ratio of a spaceship is how much fuel you need to go to orbit vs how much spaceship, for a given weight of payload. Carbon nanotubes make the fuel tank weight trivial so the cheap fuel is all you need, and you don't need hugely expensive turbopumps and a very expensive fuel tank to get a decent specific impulse.
A linear accelerator in orbit is a Kingsbury-Arnold Spaceport. It makes it as expensive to go to the moon as it is to go to Australia by reducing the acceleration required to reach orbit. It's 2.5KpS to get up 300 Km above the atmosphere and then 7.5 KpS to stay in orbit. With a K-A Spaceport you only need to get to 300 Km and the Spaceport provides the 7.5KpS. The latest design uses independent magnetic sails (that kite on the solar wind) made of superconductor loops to swoop around your space ship and accelerate it once you get up.
I know a lot about this subject.

[DuQuense]

I Like the X-15 Idea--- Wasn't there a Sci-fi story where the ex russian spy reveals the whole Rocket to space thing, Was a deriperate attemp to Bankrupt the US. Russia being scared the US X-plane would work.

[Norman]

It is interesting to consider what the effect on our cultural psyche would have been if our manned program had gone along the lines of the X series.

Consider, flights woudl be less expensive.

We would probably have a larger number of 1 and 2 man ships.

Rather that use huge rockets to lauch big payloads, we would use the smaller craft to ferry smaller payloads.

This would result in more of a permanent presence in space, probably several space stations, some with manufacturing capacity to put together satelites.

Private fortunes could fund space exploration.

[NHBL]

Perhaps a mass driver could be used for getting bulky, not very fragile materials into orbit. If it's only used for durrable materials, the acceleration could be quite high, so at least construction materials and water get up there cheap.

[DuQuense]

Thens theres that Guy out in California with his "Super High Voltage" Anti Grav that the US Govt Surpressed in the 50's.