After watching the Hazegrayart video If Rockets were Transparent I realized that I didn't really have a clear idea what the Space Launch System (SLS) is capable of doing.

Question: Is SLS capable of launching the core stage into LEO? If so, how much additional payload mass could it put there?

I'll note that this question was raised previously by @leftaroundabout in a comment below Could the SLS reach orbit without solid rocket boosters?

"bonus points:" If so, would that be considered as SSTO?

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    $\begingroup$ Well, then it's not much different from calling the Shuttle an SSTO. $\endgroup$ – leftaroundabout Jun 1 at 0:41
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    $\begingroup$ This is kind of equivalent of "is SLS capable of launching the core stage into LEO". A typical satellite is around 3000kg which is kind of negligible compared with the empty weight of the core stage itself. $\endgroup$ – user3528438 Jun 1 at 0:47
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    $\begingroup$ Also, if you allow SRB then it's more like a 1.5-STO like the recent 4th CZ-5 launch, while if you strictly require SSTO without SRB then is the thing capable of lift off by itself? $\endgroup$ – user3528438 Jun 1 at 0:51
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    $\begingroup$ @user3528438 I've changed the question accordingly, thanks! Also Could the SLS reach orbit without solid rocket boosters? has been answered with "Fully fueled, the first stage alone has only an 0.77:1 thrust-to-weight ratio" $\endgroup$ – uhoh Jun 1 at 0:52
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    $\begingroup$ nasa.gov/exploration/systems/sls/to-the-moon.html Here NASA says SLS is capable of delivering a 95 metric ton total upper stage and payload to LEO (a 100 mile sub-LEO?) silverbirdastronautics.com/LVperform.html This site actually allows you to calculate the payload capacity. $\endgroup$ – user3528438 Jun 1 at 1:18

According to Silverbird, SLS Block 1 with boosters but no upper stage, launching from Canaveral into a 185km circular orbit at 28º inclination, can orbit an estimated 66 tons of payload. (It actually gives a wide range of payload masses, 50-85 tons, because of uncertainties in its model of the SLS. I don't know how current Silverbird's data is.)

To the ISS 400km x 51º orbit its best estimate is 58 tons with an range of 42-76 tons.

NASA's 95 tons to 160km @ 28º claim, I assume, includes a final orbital insertion burn done with the ICPS upper stage.

This is not SSTO; the boosters function as a stage.

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  • $\begingroup$ Wow it can! So very roughly, double of the Space Shuttle? $\endgroup$ – uhoh Jun 1 at 4:13
  • $\begingroup$ Either 0.6x or 2.5x shuttle payload depending on whether you count the orbiter as payload. $\endgroup$ – Russell Borogove Jun 1 at 4:23

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