SpaceX's third towering Starship rocket, standing some 397 feet (121 meters) tall and wider than the fuselage of a 747 jumbo jet, lifted off at 8:25 am CDT (13:25 UTC) Thursday from SpaceX's Starbase launch facility on the Texas Gulf Coast east of Brownsville. SpaceX delayed the liftoff time by nearly an hour and a half to wait for boats to clear out of restricted waters near the launch base. /)

Part rocket and part spacecraft, Starship is designed to launch up to 150 metric tons (330,000 pounds) of cargo into low-Earth orbit when SpaceX sets aside enough propellant to recover the booster and the ship. Flown in expendable mode, Starship could launch almost double that amount of payload mass to orbit, according to Musk. //

wagnerrp Ars Legatus Legionis
14y
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Hispalensis said:
Yes, I was thinking of a modified Starship with a detachable nose, so that you can use the two stage boost. I my mind today even with the partial success they have already validated something that looks awfully like an SLS, but in an order of magnitude faster development time.
SLS is a 1.5-stage rocket that carries Orion and ICPS to orbit (or nearly so). ICPS then has (nearly) its whole propellant capacity to get Orion to TLI. Starship is a 2-stage rocket, and by the time it makes orbit, it has already spent most of its propellant.

The first half of the rocket equation is specific impulse (exhaust velocity), which for which SLS wins. The second half of the rocket equation is mass ratio, and while SLS starts in orbit with a fresh second stage, Starship has already spent 6km/s getting there. Again, SLS wins. Starship couldn't even make it to TLI, possibly not even fully expended. But it's not supposed to. It's supposed to be an optionally 3-stage rocket, where Starship starts fresh and fully fueled in orbit after it has been refueled. It's a "distributed" third stage.

Apples to apples, one disposable SLS gets 80-100t to LEO, and one disposable Starship gets 250-300t to LEO. If you strapped a Dragon capsule on top, you would have 15t less that. Again apples to apples, one disposable SLS gets itself plus 25t of Orion to TLI (3km/s away), and five disposable Starships get itself plus 150t to the Lunar surface (6km/s away). If one were so inclined, they could develop a Lunar ascent stage to carry Orion and ESM all the way to Earth return, load it all up in a Starship, land it on the Moon, and still have over half the payload remaining for other hardware. //

wagnerrp Ars Legatus Legionis
14y
24,910
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Super3DPC said:
When payload bay doors moved to open, you can see a lot of outgassing of remaining air inside. Maybe this is why attitude control was lost and Starship can’t stop spinning. Maybe they just didn’t have enough control authority from their RCS to counter such massive amount of outgassing. There is more than 500 cubic meters of volume inside that payload bay.
Their only "RCS" is from venting ullage in the propellant tanks. It's not impossible that they starved the system, especially if they had to deal with a lot of unexpected thrust from the payload bay. RCS depletion would explain why they were unable to stabilize for the burn, or right themselves for re-entry. If pressure is sufficiently low, it may also be a structural concern, though it's doubtful they were in thick enough atmosphere to worry about buckling.