Originally Posted by
mike-wsm
The simple arithmetic of rocket science says everything you throw away is advantageous.
To maximise payload. SSTO isn't about maximising payload it's about minimising cost, and the way to do that is to have a reusable spacecraft with fast turnaround.
And we've already built SSTOs: both Atlas and S-II were capable of reaching orbit without dropping anything even if they were never used that way. What we've never built is a reusable SSTO, and if you're throwing the whole thing away anyway there's not much benefit to an expendable SSTO.
BTW, I went to a talk on Skylon (the follow-on to Hotol) about ten years ago, and it seemed to be a pretty clever design. The problem as I see it is that there's no confirmed market big enough to justify anyone investing the amount of money required to actually build something like it and make it work.