VentureStar would have... had a much larger surface area exposed to damage in LEO, and a much larger surface exposed to the extremes of reentry. Seems those things would in reality necessitate a LOT more on ground process than originally thought (just as the Shuttle did), and wouldn't surprise me if significantly more than the Shuttle.
At the time of the early 70s shuttle downmass was considered extremely important. Again read Heppenheimer's book. ( it's free online http://history.nasa.gov/SP-4221/contents.htm ) It was thought that having the shuttle's ability to bring malfunctioning satellites back to earth would lead to cheaper satellites. Here's how it was thought to work. Satellites were and still are built to expensive high reliability standards. There exists a whole process for approval of materials and equipment for use in space. It HAS to work, no-one can go and fix it if it fails. Shuttle was going to change all that. The downmass capability meant that less expensive, less reliable, more commercial off-the-shelf material could be used in satellite construction. If it failed prematurely, there would be less concern. After we could send a shuttle crew up to repair in situ or bring home malfunctioning satellites. This was a major selling point of shuttle.I also remember a Newsweek article from about 1976 or so showing how the DoD could use the shuttle to kidnap Soviet satellites from orbit. What a way to trigger WWIII!
Quote from: Lobo on 04/06/2012 05:47 pmVentureStar would have... had a much larger surface area exposed to damage in LEO, and a much larger surface exposed to the extremes of reentry. Seems those things would in reality necessitate a LOT more on ground process than originally thought (just as the Shuttle did), and wouldn't surprise me if significantly more than the Shuttle.No, the larger surface area is one reason it wouldn't have required as much. The lower ballistic coefficient meant it could use an advanced metallic TPS, which was much more robust and much easier to refurbish.
At the time of the early 70s shuttle downmass was considered extremely important. Again read Heppenheimer's book. ( it's free online http://history.nasa.gov/SP-4221/contents.htm ) It was thought that having the shuttle's ability to bring malfunctioning satellites back to earth would lead to cheaper satellites. Here's how it was thought to work. Satellites were and still are built to expensive high reliability standards. There exists a whole process for approval of materials and equipment for use in space. It HAS to work, no-one can go and fix it if it fails. Shuttle was going to change all that. The downmass capability meant that less expensive, less reliable, more commercial off-the-shelf material could be used in satellite construction. If it failed prematurely, there would be less concern. After we could send a shuttle crew up to repair in situ or bring home malfunctioning satellites. This was a major selling point of shuttle.
I also remember a Newsweek article from about 1976 or so showing how the DoD could use the shuttle to kidnap Soviet satellites from orbit. What a way to trigger WWIII!
Would the "better" STS be "better" enough to need only days to reprocess for a subsequent mission? What do the economics look like with the originally envisioned high flight rate of 50 missions per year?
Quote from: Hog on 04/28/2012 03:54 pmWould the "better" STS be "better" enough to need only days to reprocess for a subsequent mission? What do the economics look like with the originally envisioned high flight rate of 50 missions per year?The better question is (even flying all possible payloads on the better STS) could you actually have 50 missions a year to fly? When I say "mission" I mean useful missions not inventing a reason to send some astronauts up to studdy how roaches behave in microgravity. I don't think the total US launches per year (even before Shuttle retirement) comes close to that.
The computers and sensors could rapidly determine the soundness of the structure, and tell how soon various parts need to be replaced, and the quality of the repair job. Trillions of transistors, and miles of microscopic fiber optic cables will be used. Only a few humans will be needed.
For me a better SLS would look like the SPACEX Falcon XX. 150 MT in orbit so much more capable, 10 metre fairing so could launch much more capable deep space Habitat, the present proposal will probably send the inhabitants nuts. Only €300 mill a launch versus a $1 bill+. With potential for reusability bringing that cost down by an order of magnitude. Freeing up cash for more deep space operationsThats is what a perfect SLS would look like
Oops sorry.
.Second to that, air breathing engines for lower energy landings.