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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)? $\endgroup$
    – BrendanLuke15
    Jan 7, 2022 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. $\endgroup$
    – Jörg W Mittag
    Jan 8, 2022 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. $\endgroup$
    – Chris B. Behrens
    Jan 13, 2022 at 16:51
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    $\begingroup$ @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. $\endgroup$
    – Christopher James Huff
    Jan 13, 2022 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. $\endgroup$
    – Charlie Wallace
    Jan 13, 2022 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. $\endgroup$
    – Chris B. Behrens
    Jan 13, 2022 at 23:12
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    $\begingroup$ I'm really not seeing the symbolic value of throwing away a reusable spacecraft on an empty flight when it could have been used to deliver ~100 t of payload...and then come back to do it again. "Never fell into the SSTO tarpit" looks better on a resume. $\endgroup$
    – Christopher James Huff
    Jan 16, 2022 at 1:51
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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? $\endgroup$
    – Charlie Wallace
    Jan 8, 2022 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, 2022 at 23:38
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    $\begingroup$ @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? $\endgroup$
    – Christopher James Huff
    Jan 16, 2022 at 2:09
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    $\begingroup$ @CharlieWallace Really? SpaceX has been reusing boosters for years, several other companies and nations are working on reusable boosters, the Starship launch system is explicitly intended to be fully reusable...and you're still assuming the booster in a staged system is expended in order to give an advantage to SSTO? Try again. $\endgroup$
    – Christopher James Huff
    Jan 17, 2022 at 21:38
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    $\begingroup$ Yes Starship won't be flying SSTO for anything except perhaps a demo/test $\endgroup$
    – Slarty
    Jan 17, 2022 at 23:05
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The upper stage of StarShip can't reach orbit by itself. This would be a single stage to orbit launch and nobody has ever been able to make it work. You have to have SuperHeavy as the first stage.

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    – Lady Be Good
    Oct 1 at 18:32

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