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SpaceX launches starship Mega-Rocket and catches its booster in midair on first try.
(www.smithsonianmag.com)
this post was submitted on 15 Oct 2024
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As far as I understood it, SpaceX uses the word "orbit" liberally. If it reaches the hight where an orbit would be possible, that's "being in orbit" for them. In an actual orbit, the rocket would not fall back down again in an hour or so without active breaking. If my understanding is incorrect, I'm happy to be corrected. And even of that was achieved soon, it's still all without demonstrating that the starship could actually carry a load and return it safely. Not even an inexpensive dummy load. All SpaceX is showing in their live feeds are empty cargo holds that fill up with hot gases and fumes during reentry.
No, that's not really right at all. With this last flight they brought the starship above 200km (100km is generally considered the point at which you're in space), so they definitely went much higher than they needed. In low earth orbit, the velocity needed to hold that orbit is about 28000 KM/H, they kept their velocity below 27000 KM/H for safety/responsibility reasons. That way, if something failed and they couldn't relight their engines, it would naturally come down anyway in a predictable manner. The closer you get to actual orbital speeds, the less predictable the re-entry and impact location will be, so 27000 KM/H is really as high as you want to go if you want to ensure predictable re-entry. It looks like they maxed out at 26750 kmh.
Also, after they reached 95% of orbital speeds, we know they still had lots of fuel in the tank because it had enough to slow down and land exactly where they wanted it to. And then... it still had enough to explode in a huge fireball, so clearly the rocket could have gone further. Or to look at it differently, all the propellant mass that got used up in that huge explosion at the end, that could have been payload mass. So clearly it has the capacity to put up a payload as well. I think the reason they haven't yet is that mastering the reusability aspects are just a higher priority than the payload bays, I think we all trust they can design a payload bay when it comes time for that.
So what you're saying is that SpaceX deliberatly doesn't let Starship orbit, to keep reentry predictable. Which is what Lichtblitz@discuss.tchncs.de said; they don't actually orbit.
Also note that 100km is the minimum height to be "in space", not the minimum height for achieving orbit.
Finally, I disagree with the note that having "enough fuel" to reach orbit means they have demonstrated such capability; I believe they easily could achieve this, but they haven't actually demonstrated it yet.
Lictblitz is saying they aren't capable of orbit. Which is very different from simply choosing not to.
No, I said they hadn't demonstrated it. But 95% is close enough, I stand corrected.