151–160 of 317 posts
Earlier quoted context omitted.
*While building the first space rockets in the world, literally making it up as they went. That's not quite the same situation SpaceX is in right now.
Actually it is the same situation. The launch was fine. What blew it up is something nobody has attempted before.
Earlier quoted context omitted.
No orbital upper stage has been rapidly reusable. No existing rocket has tried to perform either the "belly flop" or the "Landing flip manouver" that SpaceX is trying to do. The failures are due to complex issues (fuel tanks, valves, engine reliability under complex forces) not simple control system issues (choosing wrong thrust, not able to orient using thrusters, etc)
I don't understand the term belly flop or rapidly reusable. Do You mean that it is becoming horizontal to reduce the falling speed rate to land on its belly? shuttle was reused and landed on wheels parallel to its belly.
Also important to note that Starship is going to be an interplanetary vehicle. And that means it needs to be able to land in places with little to no atmosphere on a surface with no runway.
The Space Shuttle was an impressive engineering marvel, especially for the time, but even if it could leave low earth orbit, there was no way it could land anywhere other than Earth.
Earlier quoted context omitted.
SpaceX Starship boosters are refueled after they land themselves using a pump. Shuttle solid rocket boosters have their shells fished out of the ocean by a boat. Then they return to the factory to be broken into sections and filled with a solid propellent. Different tech.
Yes but in real life they are not necessarily landing in the same spot the same day to be reused again. They could have multiple replacement boosters. Regardless, I have no problem with the booster return design unless it induces reckless danger to human life. The explosion is not a positive data.
1. People doing analysis and hoping to check everything through engineering rigor and (hopefully) good assumptions
2. Test early and often, learning along the way until many positive tests have proven the system
I'd prefer 2. Look at systems like SLS to see the schedule results of (1).
No people were put on Falcon launches until almost 100 successful launches. I imagine a similar situation for StarShip. For example NASA is funding in orbit refuelling experiments (unmanned) and also a StarShip moon landing (unmanned) which will help prove the system prior to human flight.
Don't worry, plenty of people will carefully do analysis (1) later on. But the data they will review will include telemetry from real flights rather than just hopeful simulation / analysis results.
Earlier quoted context omitted.
Actually it is the same situation. The launch was fine. What blew it up is something nobody has attempted before.
It's totally different because only the government is allowed second chances! Everyone else has to get it right the first time. Especially if they're competing with !
Soon after SN8 Elon tweeted that they knew the problem. So they quickly added Helium to pressurize SN9, which is a bandaid given their deliberate elimination of Helium and the fact there isnt any on Mars. Now we see what looks like even worse relight capability. I wonder if recent departures are related in some way. They failed plenty before, but this seems different.
That's a lot of speculation. We don't yet know why one of the Raptor engines failed to relight. The Raptor is a very new engine with only a handful of minutes of flight time. Keep in mind they also replaced a couple of the engines before the flight. I imagine SpaceX still be considers them development engines. You can also see some debris fly off of the bottom of the rocket just as it's performing its flip maneuver.…
Yes it is, but I didn't speculate as to how that might be related. It is a bit of a stretch.
Earlier quoted context omitted.
Actually it is the same situation. The launch was fine. What blew it up is something nobody has attempted before.
Never attempted what? Relight an engine? Engines are routinely re-lit, especially on upper stages, yet Space-X gets it wrong with regularity. The Russians and Arianespace do it just fine.
Anyway, landing Starship involves a bunch of things never before attempted: landing a fully-reusable second stage, landing a vehicle of this size, relighting and running engines during the belly-flop-and-flip maneuver, and flying and relighting full-flow staged-combustion engines. Probably some other firsts too.
Earlier quoted context omitted.
That's probably what FAA was peeved about SN8. They might have been expecting a water landing and didn't like that an unproven rocket was sent back to dry land.
No, it was the last minute engine swap.
Earlier quoted context omitted.
Never attempted what? Relight an engine? Engines are routinely re-lit, especially on upper stages, yet Space-X gets it wrong with regularity. The Russians and Arianespace do it just fine.
I'm sorry, what? SpaceX are the undisputed champions of re-lighting engines. They've landed orbital rockets 73+ times, each of which involves multiple engine re-lights while falling through the atmosphere. Let alone gets it wrong "with regularity" — the Falcon 9 Block 5 is a remarkably reliable rocket. Anyway, landing Starship involves a bunch of things never before attempted: landing a fully-reusable second stage, l…
Earlier quoted context omitted.
On the 'repeated failures' piece, that's somewhat new for aerospace. Traditionally, things would be over-engineered, and losing a test vessel would be considered a bad thing. SpaceX seems very content to blow up a bunch of rockets on their way towards not blowing up rockets. This seems to have caused at least part of their recent issues with the FAA, who seem to be less ok with explosions. It will be very interesting…
Plenty of American rockets failed, especially early on! https://www.youtube.com/watch?v=13qeX98tAS8
Earlier quoted context omitted.
This was my thought even before launch. SN9 could explode on the pad.
I though they pump it with fuel shortly before start?
Or alternatively during fuelling, SpaceX had that issue during Amos-6.