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RGregoryClark OP t1_j8iddqh wrote

The key clue is it’s moved to the suborbital launch pad. This means it can launch without the SuperHeavy booster. With 6 engines it can launch fully fueled unlike the previous Starship test flights meant just to test landing.
The key question: what is the dry mass of this expendable version without flaps, legs, heat shield, or ballast tanks? If you know that you can calculate how much payload it can lift to orbit in a single stage.

Elon said the expendable version with only 3 engines might mass only 40 tons:

https://twitter.com/elonmusk/status/1111798912141017089?s=61&t=A46qVnS2GH4VVA-pQSUlkg

Add another 5 tons for 3 more engines and this version might mass 45 tons. However, the increased thrust may require strengthening of the tanks which would increase the dry mass. On the other hand, this version would have to support far less payload atop it then the max 250 tons of the full two-stage so would need reduced tank strengthening.

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RusticMachine t1_j8ixtpl wrote

> The key clue is it’s moved to the suborbital launch pad. This means it can launch without the SuperHeavy booster.

I think you’re confused. SpaceX has been testing all their Starship prototypes on the suborbital launch pad (e.g. cryo testing, static fires, etc.). This is not an indication it will launch from that platform.

Fyi, Starship by itself, even in an expandable configuration, cannot reach orbit. It needs SuperHeavy even if it were empty (also, the additional 3 engines are vacuum optimized and are only meant to be started at a higher altitude).

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RGregoryClark OP t1_j8n6931 wrote

The “Angry Astronaut” did a video from Boca Chica showing the Raptor work station being moved towards Ship 26:

https://www.youtube.com/live/MmUwHVji9b4

He says that’s only done if you are installing engines on the Starship. You don’t do that if you are only doing pressure testing. He notes though that it could be putting engines either on S26 or S25. Probably we’ll know by the end of today which ship is having engines installed.

Conceivably, it could only be doing static fire testing. Still, 6 engines are sufficient for it to take off fully fueled. Note, the expendable version is much lighter than the reusable version, having no top or bottom flaps, heat shield, legs, or ballast tanks. Any reasonable estimate of the dry mass of the expendable version allows for it to reach orbit with significant payload in a single stage.

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Bensemus t1_j8j8g8j wrote

What have you been smoking? This is likely either part of HLS, an expendable Starship for Starlink launches, or a tanker/depot test Starship.

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eberkain t1_j8jf8w2 wrote

Got to be a test for HLS, it would make zero sense to use expendable vehicles on starlink or tankers.

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Bensemus t1_j8jqrla wrote

Most likely HLS or a ground test vehicle of some kind but SpaceX may use some disposable Starships for Starlink. If their factory is up to 1 a day but they don’t have reuse figured out then disposable is a way to get some use out of them. Unlikely but possible.

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eberkain t1_j8jt77p wrote

Well the factory is more like 1 every 3 months, starlink needs to be as cheap as possible also, I can't imagine any scenario where they use expendable ships to launch starlink.

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LdLrq4TS t1_j8j73tn wrote

Yeah, no, it needs superheavy to reach orbit, what you see is a tanker to carry propelant for fuel depot.

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cjameshuff t1_j8jb1lv wrote

This would probably be closer to what the depot itself will be, as the tankers will need heat shields and flaps. This might also be some hybrid, maybe just a cheaper way to test propellant transfer when they're still working on recovery.

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colonizetheclouds t1_j8jrgml wrote

would make sense to test early HLS SN with orbital refuelling. Two tests at once.

If able to fuel successfully, send to moon.

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