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Because you'd have to collect it in Earth's orbit, store it, and then supply some kind of power source to accelerate it again for thrust. At present ion-drive is simply lighter and cheaper than such a system. A better idea would be to shove a NEO into Earth orbit and mine it for fuel on site.

NB: Not an entirely practical nor a flawless idea, but still a better one I'm afraid.

ANTIcarrot.

Various fusion experiments around the world have shown that high tempreature plasma can be controlled (EG: kept away from walls) by magnetic fields.

ANTIcarrot.

http://www.futron.com/pdf/FutronLaunchCostWP.pdf
According to this Sealaunch charges $2431/lb. The SL homepage doesn't seem to give away prices. (Do any of them?) May I ask what your source is?

They launch with me because:
*I can significantly undercut the competition and still break even with only one or two launch contracts a year.
*I can test for and fix satellite failures in orbit, where as SeaLaunch just shugs their shoulders and says, "whoops."
*I don't require the customer to put all their eggs in one basket.
*I can put more into GSO than SeaLaunch for the estimated price per launch of $80M.
*I can assemble larger sattilites in orbit than can be folded into a Zenit launch shroud.
*Five or ten years down the line I can go back up there and refuel/upgrade/repair for much lower cost than replaceing it brand new.
*I'm more enviromentlly friendly and don't dump stages into the ocean.

This assumes that the DH-1 functions as advertised. Personally I'd favour a *metric* 'EI-2' which put up 5000kg, but still I think the DH-1 has it's uses.

ANTIcarrot.

It's supposed to be 0.999% reliable, equal to a modern business jet, and to require about as much maintinance. Anyone know how much that is? I was a litle conservative in my earlier estimates: Engines and tanks should last a hundred flights before serious maintinance/replacement is required. I'd assume that they'd be able to do 1000 flights apeace, eventually.

But even if it conks out after a hundred flights, a DH-1 can put 220,000kg into orbit during it's lifespan. And if an organisation is willing to spend extra money on down-range recovery of the first stage, that ammount can be 770MT to 1100MT. Hardly an ammount to be sneazed at, especially for a space-agency's first vehicle.

Don't forget the purpose of the DH-1 is not to just get people and cargo into space, but to get organisations up there as well.

ANTIcarrot.

As to DH-1 bombers...
If the warheads are kenetic, then they'll be blacked out by plasma all the way down (hence no radio/radar) and will have to rely on purely inertial guidence. If not they'll be falling slowly and it will take them a long time to drop the last ten miles. The first is unlikely to hit something as small as a CVN, the second will be sitting ducks for standard or seawolf missiles. Or you just hang a left and watch them fall harmlessly into the ocean. If a navy drops the ball so badly it can't see this coming then quite frankly they probably deserve it.

In practice the biggest concern for the US military would probably be DH-1 flying over Navada and taking high definition pictures of AREA-51.

As to operational costs...
Not sure. There does seem to be a little confusion over the $100/lb vs $1M/flight. In the last chapter published (as of May 5th) talked about operational practice of the prototype stage(s?). In particular there was some wrangling as to how long a pair of RL60s would last. Major operational costs seem to break down as follows though:
*New RL-60s every dozen flights
*New tanks every ~100 flights.
*Fuel per mission. Discussed in the early chapters. Works out at a few thousand per flight IIRC.
*Pilot fees.
*Ground rent for a few square miles for launch/landing zones.
*Hanger + small clean room.
*20 ton crane + misc servicing vehicles.

Technically, if the design is sound, it wouldn't require much more maintinance than a 747. The assumption being that as long as it was handled with care it would get though several flights without need for maintinance beyond checking the fault logs and topping up the oil.

Never know in practice though.

ANTIcarrot.

One of the lessons of 911 is that terrorists can be very clever about using commonally available technology and seem to avoid the high-tech stuff. When they used an 'FAE' bomb to attack an American embassy, it wasn't russian army surplus, but a normal fuel tanker with a conventional bomb as detonator. Want a remote detonator? Use a freshly stolen mobile and a $5 electronics kit.

Up till now they've tended to avoid methods that are complex or materials that are difficult to access. I don't see them using a DH-1 type vehicle as a suicide space-truck when there are so many more lower-risk and more 'profitable' things they could do.

In an case the DH-1 would be easier to spot and track than an ICBM, and is designed to slow down during re-entry, making it easy to shoot down at fighter-altitude.

The concerns and possible solutions are discussed in chapter 23:
http://www.hobbyspace.com/AAdmin/archiv … ...e2.html

ANTIcarrot.

GCN, you do not seem to have read the Rocket Company. If you want to prove the DH-1 wouldn't work, then do just that: Prove it. But remember, 'I say so' does not count as proof. Cite paragraphs from that publication, or external sources please.

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Bill White,

Numbers sound right. However Russia isn't getting any poorer, and those rockets are made in the high-tech equivolent of sweat-shops. As russian living standards and wages go up, so will the price of those rockets. Not sure what the time-frame of this will be though.

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DH-1 comparisons:
At $100/lb 19760kg would cost $4.3M. Since a DH-1 flyer would want to only marginally undercut the competition, they'd launch it for ~$18M and pocket the $11.7M as profit.

Refueling the DH-1 in orbit requires 81,000lb of LH&LO, which would cost $8M assuming no losses. Call it $10M with. You then have an OTV capable of 7.5Kmps delta-V. That's more than enough to go to GSO and back again. Link two together and for the cost of $20M you can take ~15MT to GSO quite happily. In theory similar numbers could go to luna or mars.

I'm rather dubious when it comes to some of the numbers the example mars mission but they do kinda make sense if you assume more than one ship will be going.

ANTIcarrot.

The shuttle proves it can be done at huge cost in terms of man-hours and money. And why not have giant capsules? With that scale the square-cube rule would make parachutes impractical, but other things like jet engines and retro-rockets would become practical.

The DH-1 does return in a flyable state. It needs to be inspected, serviced, reloaded, remounted on top of the first stage and refueled. But that's basically what you do to a 747 on the tarmac. The process may take days instead of hours, but for a first of type vehicle, that's hardly a crippling feature.

Would you say that Stephen's Rocket wasn't a proper engine because it had to be cleaned daily? Or because it had limited capacity when compaired to the runner-up?

And I'm sorry, but you're just plain 'Earth is really flat' wrong about launch costs not affecting satellite prices. The reason satellites are so expensive is that launch costs mean they can't be fixed if they go wrong, so they have to work perfectly the first time. They are therefore complex and expensive. It's a feedback loop. Launching parts and assembling/testing in orbit before gently sending them to GEO would be easier and cheeper.

You also seem unreasonably certian the DH1 has no docking capacity. You've seen technical blueprints perhaps? May I point out the chapters up till now (2/5/04) have been about the prototypes vehicles and their fundimental problems. There could and probably is space in the nose for a docking system. Remember, a *docking* system doesn't have to be complex, as opposed to a docking/airlock combination. The DH-1 is supposed to be depressurised for deployment. The logical way to transfer cargo from ship to station is to use a mechanical arm to reach inside the DH-1's open hatch.

If you want soyuz style dockings, I'm sure the main hatch could be replaced with an airlock and the required docking aids. There'd be plenty of remaining volume and weight for several passengers and a small amount of cargo.

ANTIcarrot.

I think the intervening chapters (since April 18th) have laid many of JimM's points to rest.

*Even at twice the unit price there would be buyers.
*Even if several times the shuttle's launch cost/kilo a reasonable manned space programme could be sustained for a mere few hundred million dollars a year.
*Unlike big dumb rockets, the DH-1 can be launched by anyone who can buy one and lay claim to a few square miles of open space.
*Once flights/year and the number of DH-1s in operation reaches a critical value, prices could drop below values offered by any BDB option.

ANTIcarrot.