Can't we just have reusable space ships with engines that burn some kind of fuel and we just replenish that fuel?
It seems a waste to use rockets and replace the whole rocket or most parts of it after each flight.
It seems a waste to use rockets and replace the whole rocket or most parts of it after each flight.
The reason it hasn’t been done in scale before SpaceX is that reusability is a hard problem to solve and it is/was more economical to use expendable launch vehicles than to develop recoverable and refurbishable stages.
You might also like to read about single-stage-to-orbit (SSTO) which is something of a pipe dream. The rocket equation is a bitch.
That said, refurbishing both the SRBs and the SSMEs after each use was labor-intensive and as such expensive.
The Soviet lookalike did use a single use rocket as its second stage, with the reusable part just being an orbiter.
Sounds suspiciously like one of those projects you propose when you want something finer short term but assume that they never survive to the point where they actually need to deliver?
Refurbishment of the shuttle orbiter took months and tens of thousands of work hours before it could fly again. It was pretty far from what ordinary people understand under "reuse", though not completely outside the meaning of the word.
This model works with a drop of fuel that evaporates and mix with the air. In a real rocket you most inject the fuel and oxygen from the tanks into the very hot and high pressure burning chamber, so you need pumps.
e.g., the Al-Li metal layer of Shuttle ET was 0.1" thick at thinnest points yet those ET were 150ft+ tall. iPhone back covers are thicker than that. Rocketry gears are infuriatingly flimsy relative to their size, but they have to be because that's what it currently takes to fly to space.
If we could build ships on the Moon from Lunar rocks out of a grinder, or if we could build an all-fusion spaceships, we can (relatively)easily have 2m thick radiation shielding, or 8km wide hulls, or anything we want.
But we're not doing it, but are stuck with lox-fuel chemical propulsion, so we can only make them so durable.
> The common soda can, a marvel of mass production, is 94% soda and 6% can by mass. Compare that to the external tank for the Space Shuttle at 96% propellant and thus, 4% structure. The external tank, big enough inside to hold a barn dance, contains cryogenic fluids at 20 degrees above absolute zero (0 Kelvin), pressurized to 60 pounds per square inch, (for a tank this size, such pressure represents a huge amount of stored energy) and can withstand 3gs while pumping out propellant at 1.5 metric tons per second. The level of engineering knowledge behind such a device in our time is every bit as amazing and cutting-edge as the construction of the pyramids was for their time.
https://ottawacitizen.com/news/local-news/museum-shrugs-as-a...
In service, of course, the necessary pressure would have been maintained by propellant boil-off.