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SpaceX SN9 Explodes on Landing

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Re: SpaceX SN9 Explodes on Landing

#141

Post by GizmoSwan »

gridspy wrote: post #135
GizmoSwan wrote: post #125

Earlier quoted context omitted.

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.

Belly flop - https://youtu.be/vRPrLvVaQq8?t=145 (Yes, to reduce the falling speed. No, it lands vertically). Rapidly reusable - You can land it directly on (or next to) a launch platform, refuel it and launch it again the same day. Same as a regular aircraft. The Space shuttle had a disposable tank (which was lost on launch), recovered but basically destroyed solid rocket boosters (ditched into ocean) and finally on…

Does it use Nasa's pica heat shield. Nasa could have upgraded shuttle too to use their own tech so the shield tech is not material argument.

The boosters were recovered. https://www.nasa.gov/centers/marshall/about/star/shuttle_110...

Re: SpaceX SN9 Explodes on Landing

#142

Post by gridspy »

GizmoSwan wrote: post #141
gridspy wrote: post #135

Earlier quoted context omitted.

Belly flop - https://youtu.be/vRPrLvVaQq8?t=145 (Yes, to reduce the falling speed. No, it lands vertically). Rapidly reusable - You can land it directly on (or next to) a launch platform, refuel it and launch it again the same day. Same as a regular aircraft. The Space shuttle had a disposable tank (which was lost on launch), recovered but basically destroyed solid rocket boosters (ditched into ocean) and finally on…

Does it use Nasa's pica heat shield. Nasa could have upgraded shuttle too to use their own tech so the shield tech is not material argument. The boosters were recovered. https://www.nasa.gov/centers/marshall/about/star/shuttle_110...

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.

Re: SpaceX SN9 Explodes on Landing

#143

Post by sneak »

bondolo wrote: post #61
cmoscoe wrote: post #52

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…

The FAA seems to be concerned with exploded bits falling on innocent people. You are welcome to blow up your rockets all day long if you aren't putting other people at risk.

The SpaceX rockets don't fly anywhere near people. Nobody is underneath any part of their flight path or within any possible destruction radii.

Re: SpaceX SN9 Explodes on Landing

#144

Post by sneak »

ehsankia wrote: post #123
rglover wrote: post #28

Love seeing these tests for two reasons: 1.) Experiencing history in the making, especially knowing that the SpaceX team will eventually get it right. 2.) Realizing that even the best of the best have repeated failures and need to rely on iteration to get "there."

SpaceX themselves made a failure montage for Falcon 9 https://www.youtube.com/watch?v=bvim4rsNHkQ It's easy to forget how many failures that had, but look how far it has come, at this point I don't think they've had any major failures in 5+ years. Maybe a couple sea drone ship booster landing issues but zero mission failures in a very long time.

This is one of my favorite videos. On the SN9 explosion today my partner speculated that SpaceX should make one like this for Starship one day. :)

Re: SpaceX SN9 Explodes on Landing

#145

Post by GizmoSwan »

nwallin wrote: post #138
GizmoSwan wrote: post #105

Earlier quoted context omitted.

Nasa did the calculation with with ancient computers and these guys are speculating and not using proper technology to achieve success. It makes no sense in 2021. They should not be experimenting. Their simulations should be been solid before this stage. It is good way to burn cash.

I can't say I agree. They're developing this thing in stages; they've developed and tested the engines, they've developed and are testing launching the thing, they've developed and are testing the re-entry flop. They have partially developed the whole "landing" thing and if you're going to be testing the belly flop, you might as well put whatever you have with regards to landing through its paces as well. By having a…

You can't say a lot of things, so what!

Giant team is not prerequisite for doing proper simulation before launching a gigantic rocket. I am being sincere.

Nasa is in fact leading you on, to have some of their people wasting their time on this pseudo venture for optics.

You seem to be using faith as your guiding light too rather than reason. It is not a prototype bicycle for experimental launch.

It is all evident from down voting game that you are not open to criticism and gaming the boards.

Re: SpaceX SN9 Explodes on Landing

#146

Post by m4rtink »

avmich wrote: post #126
mempko wrote: post #11

Earlier quoted context omitted.

It's funny because the Soviets did it right, in that they funded smart people and gave them control. The Nasa's approach was to have people create proposals and get approval for funds. We have forgotten that the "fund smart people and let them do what they want" is the best approach. Look at Xerox Parc, Bell Labs, etc. Nasa's modern approach with SpaceX and other companies seems to reflect these hard learned lessons.

It's interesting to see that during Moon Race, in USSR there were 3 space design teams - Korolev's (later Mishin), Chelomey's and Yangel's - competing for resources, while NASA established centralized planning with everybody doing parts of the common project (with lots of money of course). It seems that "capitalistic" approach in USSR lost to more "communistic", central planning approach in USA.

Sure, but start of the "race" was pretty much the reverse - factions in the USA fighting for who will be allowed to launch the first satellite, resulting in the Vanguard fiasco. They had to bring in Von Braun in the end to do it, starting the centralization.

And in the USSR Glushko also played along initially, designing R-7 engines that are in use till today basically. Only later he stopped and started demanding all future engines to be hypergolic, which didn't go well with Korolev, especially for crewed vehicles.

Re: SpaceX SN9 Explodes on Landing

#148

Post by Laremere »

kevin_thibedeau wrote: post #107
walrus01 wrote: post #40

Earlier quoted context omitted.

They landed a lot of falcon 9 first stages without legs on the water, vertically, to test the control system. And a number of attempted barge landings with legs failed, before the first successful landing. Now it's almost a routine thing.

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.

The Falcon landed on land before it landed on a barge. Obviously landing on a moving/swaying barge is harder, however they had to start with water landings because they hadn't proved they could aim at their target. Once they crashed into the barge a few times, the FAA was convinced they'd only blow up the landing pad and not drop it on something else in the launch complex. So they got clearance for landing on land.

The early starhopper/starship flights proved what they needed to that they'd generally land on target.

Re: SpaceX SN9 Explodes on Landing

#149

Post by NortySpock »

GizmoSwan wrote: post #130
avmich wrote: post #127

Earlier quoted context omitted.

Simulations of certain things are still a problem today, even though less than it was in 1960-s. For example, trans-sonic aerodynamics is still hard. I'd imagine a good simulation of Raptor's inner flow when Starship does active maneuring can be a problem, especially if you also need to take into account material properties under dynamic loads.

Lets assume that is the case. That is where they should spend their cash to produce something of real value that can be reused. Simulation close to perfection is the end game. Not sending something chunky into space.

https://www.youtube.com/watch?t=2580&v=vYA0f6R5KAI&feature=y...

Yeah, they were doing high fidelity high performance computational fluid dynamics simulations and aerodynamic simulations by 2015.

So I think they've done the sims, and now they're doing it in real life.

Re: SpaceX SN9 Explodes on Landing

#150

Post by GizmoSwan »

gridspy wrote: post #142
GizmoSwan wrote: post #141

Earlier quoted context omitted.

Does it use Nasa's pica heat shield. Nasa could have upgraded shuttle too to use their own tech so the shield tech is not material argument. The boosters were recovered. https://www.nasa.gov/centers/marshall/about/star/shuttle_110...

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.

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