Comment by SyzygyRhythm
4 days ago
Starship "making LEO" is not a significant challenge--the existing flights have explicitly targeted a (very slightly) suborbital trajectory. They could have done otherwise at any point, but for now it's more important to guarantee that the stage comes down immediately. None of their current objectives require more than ~1/2 of an orbit.
Starship v3 flying will be a significant leap, though. It's the first with the Raptor v3 engines and has many other improvements as well, such as updated grid fins and hot staging ring. It will be the first that achieves close to the intended capacity of ~100 tons.
Propellant transfer is indeed a significant challenge. They have already demonstrated internal transfers between tanks, but not between spacecraft.
Very exciting times ahead!
> Starship "making LEO" is not a significant challenge
Of course it is. I say this as someone who sturdied astronautics.
You’re broadly correct, though. My point is the action shifts to Hawthorne and West Texas for the next year or so. Then pivots back to NASA for Artemis IV.
It’s not a significant challenge compared to what they’ve already done.
Each of those previous tests could have easily gone to LEO running the engines just a tiny bit longer.
OPs point is that they intentionally didn’t.
achieving LEO means you need a relight to have a controlled reentry. You don’t want that if you want to avoid countries being mad at you while you iron out those controls
> It’s not a significant challenge compared to what they’ve already done
I don't know an aersospace engineer, within SpaceX or without, who would agree. When you increase speeds you increase energies faster. That has an effect on everything from pump performance to re-entry physics.
> Each of those previous tests could have easily gone to LEO running the engines just a tiny bit longer
Which risks recovery. Given they were replacing their Raptors in the next refresh, pushing an already-obsolete engine for shits and giggles doesn't make sense when you can get good data on e.g. skin performance.
> achieving LEO means you need a relight to have a controlled reentry. You don’t want that if you want to avoid countries being mad at you while you iron out those control
There is zero indication diplomatic pressure has been a constraint on the U.S. space programmes in the last couple years.
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Odd. As a side note, your comment was posted [dead]. I vouched it to restore it back to life.
This is the second time I’ve seen such insta-dead comments. (One was my own, and I thought I did something wrong. Now it looks like there’s some kind of bug in HN that’s killing on-topic comments when they’re posted.)
Your comment wasn’t deep or insightful, but not every comment should be. A simple rejection of a premise is certainly on-topic. So it’s hard to argue that your comment was “bad”. That narrows the possibilities down to a bug in the algorithm. Maybe the mods are experimenting with ML auto classifying whether new comments should be killed or not.
Aww. Thanks. Wonder what I did to piss of YC.
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"Project Gemini has entered the chat." Did I do that right? Anyway, what are we talking about?
> Did I do that right?
Unless you’re trying to make a reference to the Gemini programme. No.
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I was curious since I hadn't heard from Starship in a while, but by the looks of it they plan to launch the first V3 later this month!
Their objectives keep shifting and starship is far behind schedule. Sure, it's a success if you keep objectives small. They could have tried for LEO ages ago but didn't. Each launch should maximize learning and having small objectives is anathema to that. And very wasteful.
If you think Starship is behind, look at the 'competition'.
Learnings per flight may not be maximal, but they are measured with enough risk so that bureaucrats will approve it (not restrict future launches) and other countries won't be impacted by a failure.
What would going into LEO have taught them? They have been there hundreds of times.
They don’t have small connectives, or was catching the Super Heavy booster and then reusing it too small for you? Not everything they are doing is public.
How do they hope to make prop transfer work without a working heat shield to enable reuse of the tankers? Unless SpaceX pulls a hat trick, Starship is borderline useless.
There's no reason the tankers need to be reusable. They can probably lift more fuel without all the cruft needed for controlled re-entry.
They have a working heat shield (see last flight). It may not be quickly reusable, but that doesn’t matter at this stage. For the transfer test, just left over fuel in two Starships is enough. They aren’t full blown finished tankers yet. For HLS, if they are unable to get Starship reuse working in time, they can use expendable tankers.
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I was asking this myself just an hour ago, thank you