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Starship Flight 5: Launch and booster catch [video]

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Re: Starship Flight 5: Launch and booster catch [video]

#981

Post by LorenPechtel »

mhandley wrote: post #877
ChuckMcM wrote: post #516

Pretty impressive. The engineering team at SpaceX is really something. Some thoughts; The 'chopsticks catch' was amazing to watch. Seems like it adds a lot of risk and clearly the booster needs additional fire suppression systems :-) perhaps the tower could mount something that sprays the booster like the barges have for the F9 boosters. The heatshield held out for a much longer time, the asymmetric heating on the fl…

As to whether catching the booster adds risk - I'm not sure it does. First, to the extent the booster is out of position in the x (sideways) direction, the chopsticks can move to accomodate error. But actually I think this dimension is the easiest of the three, as the booster has plenty to time to null any error in this dimension. In the y direction (direction of travel towards the tower), the rails on the chopsticks…

And with a barge recovery the legs must have enough spring to deal with waves. The tower doesn't move, they can get a lower landing velocity.

Re: Starship Flight 5: Launch and booster catch [video]

#982

Post by LorenPechtel »

chippiewill wrote: post #964
stetrain wrote: post #901

Earlier quoted context omitted.

> It's possible that SpaceX programed the AFTS to trigger some time after the rocket touched down in the water. Just to make sure that it completely submerges quickly. The SpaceX host on the stream said that they were going to try and touch it down on the water at more of an angle than the previous flight to attempt to get it to survive the initial splash-down so they could get some more data and video footage. Obvio…

Yeah, I don't think SpaceX planned for a RUD on tip-over (even if they did anticipate it). I think they've towed stuff in the sea before so I would have thought that'd be their preference if it were possible.

They don't want the booster actually landing in the water. They managed to do one test so well it survived--and then it became a hazard to navigation.

Re: Starship Flight 5: Launch and booster catch [video]

#983

Post by e_y_ »

jondiggsit wrote: post #765
kovvy wrote: post #734

Earlier quoted context omitted.

Reusability increases costs if you don't reuse often enough. The shuttle would have been much, much, cheaper per launch if it had flown more often. The expected costs for the shuttle included a range based on how often it flew which turned out to be reasonably accurate. They were much worse at predicting which end of the range they would be flying in. At the rate they ended up flying they had the extra costs of reusa…

I’ve read that a shuttle refit after landing was so expensive and time consuming to render it useless…. Feel free to correct if wrong.

The turnaround time for Shuttle was 2-3 months, while building a brand new rocket takes like 1-2 years. Although for the cost of Shuttle, we could have built a whole bunch of expendable rockets, pipelined with a regular launch cadence, and probably also gotten some cost savings through economies of scale.

Re: Starship Flight 5: Launch and booster catch [video]

#984

Post by mncharity »

mncharity wrote: post #900
dmix wrote: post #17

Video of the catch > Mechazilla has caught the Super Heavy booster! https://x.com/spacex/status/1845442658397049011

A phone video[1] from Mexico, with nice plume refraction of the Sun. [1] https://x.com/Cosmo_556/status/1845554958604657051

Erratum: Not Mexico. I echoed a repost without sanity checking the perspective - sorry about that.

Re: Starship Flight 5: Launch and booster catch [video]

#986

Post by tempfile »

55555 wrote: post #819
asadotzler wrote: post #659

Earlier quoted context omitted.

Everyone gets this wrong, cost is not price. SpaceX themselves launch Starlinks at about $1,200/kg but they charge customers closer to $12,000/kg. Do the math. Costs coming down are increases in SpaceX profits, not decreases in customer prices.

Over the extremely long term in competitive industries, prices asymptote at ~costs. So it's still a generally useful measure, and in ~all cases, it's at least a directional indicator.

Why would the extremely long term be a useful measure, when we have no way to know how long that will take to happen, and no way to know what will happen in the meantime to disrupt it?

Re: Starship Flight 5: Launch and booster catch [video]

#987

Post by was_a_dev »

mhandley wrote: post #877
ChuckMcM wrote: post #516

Pretty impressive. The engineering team at SpaceX is really something. Some thoughts; The 'chopsticks catch' was amazing to watch. Seems like it adds a lot of risk and clearly the booster needs additional fire suppression systems :-) perhaps the tower could mount something that sprays the booster like the barges have for the F9 boosters. The heatshield held out for a much longer time, the asymmetric heating on the fl…

As to whether catching the booster adds risk - I'm not sure it does. First, to the extent the booster is out of position in the x (sideways) direction, the chopsticks can move to accomodate error. But actually I think this dimension is the easiest of the three, as the booster has plenty to time to null any error in this dimension. In the y direction (direction of travel towards the tower), the rails on the chopsticks…

The most challenging axis in my opinion is the roll axis of Super Heavy, if there is a roll angle error, the pins could not sit properly on the chopsticks and the whole booster slides off.

Re: Starship Flight 5: Launch and booster catch [video]

#989

Post by starspangled »

pclmulqdq wrote: post #375
dotnet00 wrote: post #60

Earlier quoted context omitted.

They previously threw around a number of around $1M per flight, as mostly fuel costs. Also, while 150t is the target payload capacity, the current test vehicles are closer to 50t in payload capacity, there are revisions in the pipeline based on data from these test flights which will bring it up to 150t.

None of the vehicles have demonstrated any payload capacity yet. 50 tons is the on-paper capacity only, and seems quite high given how little fuel is left when the bring an empty starship to orbital altitude. I assume that as the engines and launch procedures get more efficient, they will start being able to bring stuff to orbit (and quite a bit of stuff, too).

They have, they brought up 10 tonnes on the test before last to do a prop transfer test for NASA.

Re: Starship Flight 5: Launch and booster catch [video]

#990

Post by didgeoridoo »

was_a_dev wrote: post #987
mhandley wrote: post #877

Earlier quoted context omitted.

As to whether catching the booster adds risk - I'm not sure it does. First, to the extent the booster is out of position in the x (sideways) direction, the chopsticks can move to accomodate error. But actually I think this dimension is the easiest of the three, as the booster has plenty to time to null any error in this dimension. In the y direction (direction of travel towards the tower), the rails on the chopsticks…

The most challenging axis in my opinion is the roll axis of Super Heavy, if there is a roll angle error, the pins could not sit properly on the chopsticks and the whole booster slides off.

Just slap a buncha RCS on there, maybe a reaction wheel or two, and presto.

Source: Kerbal Space Program

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