RCgothic

I guarantee you're not saying anything SpaceX haven't already thought of. This isn't their first re-entry. Just sit tight and some day (very likely this year) you'll get your wish.

Starship is not a spaceplane. It doesn't need high L/D. Re-entry vehicles don't *need* any lift. Vostok and Voskhod don't have any. All re-entry vehicles need is stability (Starship is actively stable) and a TPS (which Starship has). Also it's not a pure cylinder. It has fins. SpaceX are not idiots. I guarantee if it had to be another shape it would be another shape.

Cylinders are also lifting bodies.

Except for the craft that are round, no craft are round.

Still stainless steel. TPS evolved from transpiration to tiles but otherwise still present.

Well we'll just have to see, but I wouldn't bet money against.

That wouldn't prevent a collision, it'd just be hit by shrapnel instead of a single larger piece. And Starlink does have an automated avoidance system, and it's a very capable and responsive system. Part of the row between OneWeb and SpaceX is that Starlink is capable of conducting such manoeuvres on short notice, typically 12h before the estimated time of collision. In this instance because the probability of collision was low 1 in10⁴-10⁵ and falling, SpaceX were planning to wait until around then to make a decision, because 10⁵ is their threshold for manoeuvres. OneWeb's sat needs longer to set up a manoeuvre, so they opted not to wait. OneWeb therefore asked SpaceX to turn off their automated system so that it didn't accidentally counteract the manouevre OneWeb were performing. At the time of the collision, the sats missed by over a km with a probability of collision of less than 1 in 10⁸. It wasn't a close call. So OneWeb complain to the regulator that they had to manoeuvre around an unmanoeuvrable Starlink and WTH are SpaceX playing at. That was an outright fabrication. SpaceX were being communicative, cooperative, and responsive, and the Starlink would have manouevred on its own if it had needed to.

The recent incident between Starlink and OneWeb wasn't a near miss, and the automated collision avoidance manoeuvre system on Starlink was non-operative at OneWeb's request. Naughty OneWeb telling porkies.

And it's the fluid dynamics of the fuel system that's tricky. Not the aerodynamics.

Look, if Russia want to try and build their own space station, nobody's stopping them. But it'll be expensive less capable than a combined effort. Meanwhile the US and its continuing international partners will just put up a couple of outfitted Starships, NBD.

Well in any case, the reason re-entry bodies are blunt - to move the shockwave away from the hull - is also accomplished by being larger. 1) Starship is larger. 2) There's no evidence cylinders don't work - in fact spheres do (Vostok and Voskhod) which are worse. 3) SpaceX aren't amateurs. They know what they're doing.

Good spot here. Potentially Lunaship's tanks have gotten bigger.

This is a great thread on the Crew-2 post-Launch Readiness Review/Pre-Launch briefing. Lots of interesting information and sensible questions (unusually) with good answers.

The Indian military didn't tell ISRO that it was being asked to deploy an ASAT target. Wow.

Wow, the LOX issue was towards the top end of my estimate. That's an extra 1.3 tonnes! With the vent system not sure it still remains at liftoff, but boiling off a tonne of LOX surely isn't easy. That'd be worth over 100kg of additional payload.

Again, not a pressure vessel so doesn't have to be cylindrical. It's not that cylinders don't work, it's that these other shapes have additional benefits *if free to choose them.* Pressure vessels that aren't cylinders incur enormous mass penalties. So yes, it has a flat belly because it can. That doesn't mean non-flat bellies don't work. See Vostok and Voskhod.

If NASA had enough money to pick any of the three it wanted, SpaceX would still have got it is my interpretation of that document. The only reason not to would be keeping angry congresspeople appeased, which wasn't one of the scoreable criteria.

The shuttle wasn't primarily a pressure vessel, it was free to deviate from a cylinder without excessive stress concentration or mass penalty for a bit of extra aerodynamic efficiency which it desperately needed (heck of a cross range requirement). I also note that the top of the shuttle was a half cylinder, which isn't noticeably better than a cylinder for vortex shedding. I also note that a blunt bottom pushes the shockwave away from the hull and blends into the wings, thereby limiting re-entry heating, so that shape may have other functions than aerodynamics. Finally, almost any shape is a lifting shape if presented at an angle of attack, even a sphere if you spin it. It's just a question of how efficient, and efficiency doesn't matter very much if not very concerned about L/D. Bricks do fly if they're going fast enough.

Well of course the rivals would say that, whilst planning to add to the problem they're complaining about.

Turbulence is irrelevant at hypersonic speeds. Basically punches a hole through the atmosphere with vacuum behind. If all you intend to do is aerobrake at high altitude and thrusters have enough control authority, it's no big deal. It would be a problem for landing, but that's why all the variants that land have fins.

SN15 slips to NET Wednesday: And general production roundup:

This decision looks bonkers. 1) Not New Glenn. Ouch, that's embarrassing. 2) Not Vulcan, which uses BO's engines. Again, ouch. 3) Atlas V *starts* from about 10x Falcon 9's internal cost to SpaceX, so that's a huge cost handicap before they even start. 4) Thought ULA were supposed to be phasing Atlas out? Better put that larger fairing to use and launch a lot of sats at once. The heaviest Atlas can put up about 25% more mass than F9 in reusable mode but at a still higher price that perhaps counters the benefit of using a heavier variant.

A 2-stage starship fully fuelled could weigh more than a Saturn V on the pad. Imagine a Saturn *starting* from LEO. Starship can do that. Tanker flights are inexpensive. And then they could be daisy chained. Stick a third on the back. 3 stages can send a fully fuelled starship over a km/s past earth's escape velocity and still recover both tugs to LEO propulsively. Four stages? That's a thousand tons to Trans Jupiter Injection. If they can sort out trans-shipping of cargo, there's really no limit to the payload a starship can take along (as long as it doesn't all have to land).

Ooh! I really like this idea! And it gets even better with a 22m variant fairing Starship-tug filled to the cylindrical extent. ~2400m3 or ~2150t of propellant. I'd probably keep some manner of fins and aerobrake back into LEO without landing. It could even go up with all RVacs as the intent is for it to never land.