[Spaceships] Designers' Championship I: ground to LEO

[Chansith]

Don't mind sanity too much. I am a Girl Genius fan. My motto is "What would Baron Wulfenbach do?"

[Crakkerjakk]

Reaction Engine, Laser Rocket (TL 9) [REAR]

Laser rockets uses a ground based laser battery that evaporates reaction mass producing thrust. Each Laser Rocket engine must be powered by a laser battery, 10 GW for sm+5, 30 GW for sm +6, 100 GW for sm+7, 300 GW for sm+8 etc (the standard 1-3-10 progression). Each engine produces 2G of thrust, and each fuel tank of ablative plastic propellant gives 0,45mps of delta-V.

Cost for the spaceship part of the engine is as a chemical rocket of same size, ablative plastic costs $200/ton.

This is the Laser Launch Engine system as converted by Boobis, and numbers double checked by me. Mind if we use that?

Main cost of launch is in the ground based power station, and a dedicated nuclear reactor should produce enough juice to send up a flight every five minutes.

[Chansith]

Originally Posted by Crakkerjakk

This is the Laser Launch Engine system as converted by Boobis, and numbers double checked by me. Mind if we use that?

Main cost of launch is in the ground based power station, and a dedicated nuclear reactor should produce enough juice to send up a flight every five minutes.

I'd certainly like to see how it comes out. If necessary we can hold a separate contest to design an orbital lighter for use on backwoods colonies, as a landing boat for exploration ships, etc.

Assume 10% per annum cost of capital (depreciation plus insurance plus interest), and that ground workers have average jobs. 1/6 down time for maintenance.

The big issue might turn out to be getting enough traffic to keep the load factor up. Assume a 75% load factor, but keep an eye on passenger numbers: if you start pushing a billion passenger movements a year that might be a problem.

[Crakkerjakk]

Well, you wire the plant into a local grid, any time traffic drops, you sell power output on the market for ground-based power

[Chansith]

Originally Posted by Crakkerjakk

Well, you wire the plant into a local grid, any time traffic drops, you sell power output on the market for ground-based power

That will help amortise the generator, but not the laser.

[Crakkerjakk]

Lasers. You build about 40,000 small ones, so you have exceptionally high reliability. Even if somehow, 5% of the lasers failed all at once, there would probably still be enough to get your payload in orbit, and you can do maintenance on the lasers without stopping launches. Plus, building one huge laser is much more expensive/technically difficult. And if you want to scale up your payload that you can launch, you just build more lasers.

[thtraveller]

Originally Posted by Chansith

By the way: is there any comment on the ground rules as set out?

What do you mean by "cost effective"?

I would normally calculate Return on Investment. So build cost may be only a small consideration.

What ticket price can we charge? (what will the market bear?)

[thtraveller]

Originally Posted by Chansith

How are things different on a backwoods colony planet where there is only a liner in orbit 10% of the time, and where there is only one spaceport?

Do you mean a backwoods planet with exactly the same stats as Earth? Or did you have a particular planet in mind, like the trace atmosphere and low gravity planet Mars? Or can we make up a planet to best fit our designs?

Hmm, this seems like two different competitions.

[Chansith]

Originally Posted by thtraveller

What do you mean by "cost effective"?

I mean "having a high ratio of effect achieved to cost borne", or, which is the same thing, a low ratio of cost to effect.

What is (at each TL) the shuttle that has the lowest ratio of total cost (ie. operating costs plus amortisation of investment) to the number of trips to orbit that it provides?

I would normally calculate Return on Investment. So build cost may be only a small consideration.

Include operating costs, such as maintenance, fuel, and wages.

What ticket price can we charge? (what will the market bear?)

Assume that you are in a competitive industry that is in long-run equilibrium. You cannot charge a higher price than your competitors, and they cannot charge a price lower than their costs including amortisation. Ticket price will be equal to cost at the stated price of capital.

[Chansith]

Originally Posted by thtraveller

Do you mean a backwoods planet with exactly the same stats as Earth? Or did you have a particular planet in mind, like the trace atmosphere and low gravity planet Mars? Or can we make up a planet to best fit our designs?

Take Earth as a representative habitable planet. In other words, take the planet as having the same characteristics as Earth except that its traffic will not support a full-time round-the-clock shuttle service.

Hmm, this seems like two different competitions.

It is. The 'how are things different' bit is an afterthought, not of the essence.

The essence is to establish what the price of a ticket to/from orbit is likely to be for a developed planet.