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Comment by SyzygyRhythm | Hacker News Reader

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!

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> 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.

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.

Nothing. Now that I’ve seen it once for me and once for you, both on comments that seemed lightweight-but-harmless, I’m convinced there’s some sort of bug. So don’t take it personally.

Also HN != YC. They’re separate organizations, iirc. When Sam Altman was running YC one of the first things he did was “refactor” HN so that it has editorial independence.

Either way, it would be hard to imagine someone from YC telling Dan “you should boost so-and-so” and him going along with it unless it directly benefitted the HN community.

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.

They didn't have to increase speeds, they already achieved orbital velocity. To circularize all they need to do is relight. Relighting an engine is very difficult for an engine like Raptor, but they've already demonstrated relight.

> They didn't have to increase speeds, they already achieved orbital velocity

My undertstanding is Starship didn't hit 17,000 mph [1]. LEO orbits tend to be 17,500 mph and up.

Like, I'm not arguing that SpaceX couldn't have circularised on previous tests. But it would have added material risk without any reward. And taking a ship, particularly a re-usable one, particularly a novel one, into its first orbital flight is always exhausting and novel.

[1] https://www.thespacereview.com/article/4761/1#:~:text=As%20S...

It is like a runway taxi test on a plane that is fully capable of flight. Sometimes the plane takes off unexpectedly but the plan is not to do it. Starship can do orbital insertion now despite no plan to do it yet.

Spacex explicitly on the streams said they shut off the engines early to avoid orbit. I don’t know why you would argue against them

You’re also incorrect that a separate burn is required for orbit. You only need to do that if you want a circular orbit.

"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.

I guess I was a little distracted by the tangent to starship over the orion/Artemis I was disappointed to see that after all these years NASA trying the old trick again and hoping people get excited.

As for spaceX and starship, I haven't kept up with it but I trust it's still putting NASA to shame wrt setting the state of the art.

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.

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.

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.

I was asking this myself just an hour ago, thank you

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