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Can Starship reach orbit without superheavy, now that it's been upgraded as of Jan 2022 to 9 engines (added 3 vacuum raptors) and stretched tanks? Back in 2018 Elon said on twitter that the earlier version technically could do it but without useful payload. If so it becomes the first SSTO, and could be very effective since most commercial satellites are small. Maybe a big deal?

It might be necessary to fill up part of the cargo space with extra fuel tanks...

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    $\begingroup$ Where can I find more information on the starship updates (perhaps include in question)? $\endgroup$ Jan 7 at 23:30
  • $\begingroup$ @BrendanLuke15: As always, it is just a single throwaway sentence in a single tweet by Elon Musk. The first sentence of this question literally has everything in it that is publicly known. $\endgroup$ Jan 8 at 17:08
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Back in 2018 Elon said on twitter that the earlier version technically could do it but without useful payload.

And he also said:

It technically could, but wouldn’t have enough mass margin for a heat shield, landing propellant or legs, so not reusable

These design changes will not have significantly changed that. He's also repeatedly directly stated that Earth is just the wrong planet for SSTO, and the numbers back him up.

People need to stop jumping on every little design tweak with "can it do SSTO now?". The answer is "no". Tomorrow, the answer will still be "no". SSTO is not needed. The compromises that would be required to make it possible mean it is not even desirable. It is not the ultimate ideal that launch systems are striving toward.

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  • $\begingroup$ Or the answer is "Yes", like it was yesterday, just without a useful payload. I can think of a couple of reasons to put an empty Starship into orbit. $\endgroup$ Jan 13 at 16:51
  • $\begingroup$ @ChrisB.Behrens Except you're not just "putting an empty Starship in orbit". You're developing a SSTO Starship variant, modifying ground infrastructure to support it, developing a whole set of launch procedures around the SSTO variant, and launching it to a very limited selection of possible destination orbits. Or...you could just launch a normal Starship, and then it doesn't even need to be empty, so you could save an additional Starship launch that would otherwise be required to supply it. $\endgroup$ Jan 13 at 17:29
  • $\begingroup$ You wrote: 'People need to stop jumping on every little design tweak with "can it do SSTO now?". The answer is "no". Tomorrow, the answer will still be "no". ' Kind of harsh... If this is correct, it will be good news for a lot of small-sat startups. Because an SSTO starship would likely put them out of business. $\endgroup$ Jan 13 at 21:47
  • $\begingroup$ I think we're kind of missing the point here. There's no REAL reason to launch SSTO aside from the symbolic. But that symbolic value is pretty enormous - first SSTO flight looks pretty nice on a resume. As such, it would be a relatively low effort affair done once all the hard stuff had been worked out. It would be stunt... But you could make a case that Apollo 11 was, too. $\endgroup$ Jan 13 at 23:12
  • $\begingroup$ If we could get SSTO with a decent payload fraction, now... A man can dream of nuclear rockets. $\endgroup$
    – ikrase
    Jan 14 at 5:43
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Yes it seems likely that the upgraded Starship would be able to reach orbit without Superheavy. However it does depend upon the exact configuration and there are many variables such as the thrust of the engines, payload mass, dry mass of Starship, the new fully tanked thrust of Starship and so on.

That said I'm not sure that it would be very efficient (small payload mass) and even if possible it might not be used in that capacity.

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  • $\begingroup$ Even if the payload to orbit is small, seems like this would be competitive with the many upcoming small-sat launch offerings that are not fully reusable, thus should have a big impact on their prospects. Wouldn't a fully reusable SSTO starship have lower $/kg? $\endgroup$ Jan 8 at 22:19
  • $\begingroup$ Well it depends on a lot of variables. How many times can Starship be reused? How much cargo can a SSTO Starship actually lift? What engine changes are needed for SSTO? How often can ride shares be arranged with other satellites, to propellant dumps or with Starlink sats? $\endgroup$
    – Slarty
    Jan 8 at 23:38
  • $\begingroup$ @CharlieWallace "Wouldn't a fully reusable SSTO starship have lower \$/kg?": a SSTO will have far lower payload fraction than a TSTO. You're putting far more mass into orbit to put the same payload into orbit, and every gram has to be carefully shaved to the bare minimum, because every gram of spacecraft mass is one gram less of payload. And every bit of your spacecraft that leaves the pad has to come back through a full-orbital reentry. Why do you expect this to result in a lower \$/kg? $\endgroup$ Jan 16 at 2:09
  • $\begingroup$ Responding to " Why do you expect this to result in a lower $/kg?" Because unlike current smallsat launchers, an SSTO starship is fully reusable. So despite the extra mass reaching orbit, the launch cost is far lower, since you are not throwing away the rocket. Assumes a mature starship design will be able to refly a lot of times, thus the fuel is the main cost along with modest operational expenses. Seems competitive for small payloads, because of course an SSTO starship won't be able to loft much. $\endgroup$ Jan 17 at 5:48
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    $\begingroup$ Yes Starship won't be flying SSTO for anything except perhaps a demo/test $\endgroup$
    – Slarty
    Jan 17 at 23:05

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