Space/Science — HabitableZone

Space/Science » in reply to re: The Rutan tourist vehicles are NOT space launchers

re: The Rutan tourist vehicles are NOT space launchers
gbaikie — (archived)

"There's a lot of uses for suborbital spaceflight, but I'm not sure point to point earth travel is among them: a decent sized hop still involves a lot more fuel and a more difficult re-entry than going up for ten minutes and then straight back down again. For a long hop (new york to tokyo) you're basically following the same flight path as an ICBM, and the re entry and fuel problems are the same if you want land instead of going splat."

With suborbital it is possible [not necessarily doable in near term] to go to Paris to New York using less jet fuel than today. Though you could be using around the same amount energy, but perhaps as much as 1/2 is electrical energy.
Suborbital's main advantage in terms of potentially saving fuel and obviously time is on longer hops.
For conventional aircraft of today, short trips require around 25% of fuel for take-off. For Suborbital it's almost all in the take off.
As for going spat, *perhaps* to solve this you will use some fuel in the landing part.

For space nerds, fuel is very important. For example, we wouldn't consider using rocket fuel to slow down the re-entry speed from orbit. But what happens if rocket fuel is much cheaper?
If you are charging $100,000 per ticket for say 200 lb human to have a joyride in Space. You charging about
500 per lb. If you get to the point of charging as low as 10,000 per ticket you charging $50 per lb.
Here, one is in the realm of cheap rocket fuel- in terms of fuel cost- not much different than what you pay on the ground.
So, instead of using 99% of fuel in a suborbital takeoff, you could use 85% to 90% in take off, and 10% to slow down.

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