Delta-V for LKO

[GoSlash27]

Well, getting spaceplanes and reueable rockets to space isn't necessarily a lot more time consuming, but getting them back is and that I hope is finally what I meant to say.

SanderB,

Yeah, I actually do understand what you're saying and I take that into account as well. The extra time required to put recoverable SSTOs into orbit and the time spent recovering them is pretty small compared to the time spent actively controlling an intercept, rendezvous, and docking.

But of course if you're not doing all that then it is a lot quicker and easier to just use a disposable lifter.

Best,

-Slashy

[Red Iron Crown]

Higher payload fraction, minimum stage mass, and minimum cost are worth optimizing for. DV isn't.

I would say that optimizing for dV is a stepping stone to the others. Or as UmbralRaptor put so elegantly (before cost was a thing in KSP):

The Stages of Rocket Design:

0. I don't know what any of these numbers mean.

1. More thrust!

2. More TWR! (engines per tank, boosters)

3. More Isp!

4. I want more ÃŽâ€V?

5. Oh, so that's how mass ratios work...

6. Fun with payload fractions!

[Sharpy]

There's little point struggling for "minimal dV" but it totally makes sense to develop one "that works for you" even if just to know how big a launch stage to build.

As for SSTO - yes, spaceplanes take longer time to land. (though recently I've been working on small ones that take obscenely short time to reach orbit... that 17-something TWR of Rapiers at optimal altitude makes for awfully fast speed gain. But still, landing takes some time if you want to do a horizontal one).

OTOH, SSTO rockets take less time to orbit than staged ones (subjectively - they take about the same or slightly more, but require less of *your* time, no need to observe fuel, drop stages, just start the gravity turn a little above the launchpad, switch engine off when AP=75km, circularize.) They do take time to land - but not very much, and they yield good savings in career mode. Of course that's quite pointless in science or sandbox, but then you could pick them for comfort and ease of use, then just deorbit them without paying attention to recovery - a 10s retrograde burn is hardly a big waste of time. (and nearly empty, after dropping the payload, they have quite excessive TWR; that 10s is a good 500-700m/s.)