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Starship's Third Flight Test [video]

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Re: Starship's Third Flight Test [video]

#271

Earlier quoted context omitted.

Grid fins aren't drag devices. They are control surfaces. As long as they are oriented so the fins are aligned with the airflow, they have no effect on orientation. The benefit of not folding them in is one less part that can fail. There might be a slight reduction in drag by folding them in, but not much and apparently not worth it.

The side edge of the grid fin may have more surface area than edge on.

Not sure they can turn that far.

Re: Starship's Third Flight Test [video]

#272

The test is essentially a success at this point. Starship can take payload to orbit and open/close the payload doors. The remaining things are icing on the cake. They can refine re-usability while flying payloads.

Big things they still need to hit are soft splashdown of both stages because recovery and reuse are critical to the economics of Starship. From the stream it looks like they had barely any engines light during the landing burn and I could see several missing tiles on the second stage. Way fewer were missing though which is a bonus, last time they were visibly missing a lot of tiles even before they lost the stage.

Re: Starship's Third Flight Test [video]

#273
post #242

Earlier quoted context omitted.

No, most rocket engines have quite limited amount of throttle capability and run near maximum thrust until cutoff. The rocket yaws and pitches in the first seconds of flight while the vehicle is still subsonic, then flies a gravity turn trajectory at zero angle of attack (facing the direction of travel) at near maximum thrust. Any errors accumulated during early part of the flight will be corrected by adjusting the t…

Thank you. Yes, I figured that real life engines could not throttle enough for the maneuver as stated. I am familiar with the gravity turn, but I just don't see how energy can be added continuously, uniformly right up to a circular orbit. But I've not really put much effort into trying to understand that, I'll start looking more at real life pitch angles at various altitudes. Maybe I just need to start that gravity t…

In vanilla KSP1 with a reasonable orbital launcher, fly up to 1000m altitude and tap D on your keyboard 1 to 10 times. Then hands off until 2nd stage and then throttle down to avoid overshooting the apoapsis.

Finding the correct number of key taps to get the right pitch angle is the key. The throttle can only help so much.

Re: Starship's Third Flight Test [video]

#274
post #60
post #16

Earlier quoted context omitted.

What’s grifty about nasa space flight? They’re a private news org that does incredible coverage of SpaceX and spends funds doing as such. They’re mostly donation driven but they don’t solicit them really. They just thank folks that do on their livestream. Their forums are an absolute goldmine of knowledge if you take a look and it is an incredibly friendly community.

Whenever I've seen them (not sure which specific ones) they've been either 1) Whining about donations (and shoutouts every few seconds) 2) Whining about the cost of cameras (I remember one of the early exploding and the commentator spent the next 10 minutes going on about his expensive cameras) Yes they are funded by begging, that's not something I'm interested in listening too. I've seen US TV occasionally, I find i…

The official SpaceX hosts often don't mention when something goes wrong or looks bad. For example, they didn't comment on the ongoing tumbling of the ship. Of course they want to present themselves in the best possible light. Other streamers are more independent, they do point out those things.

Re: Starship's Third Flight Test [video]

#275
post #258

Earlier quoted context omitted.

Here's a fun thought, how many Starship launches would it take to put the equivalent mass of the ISS up in the same orbit?

The ISS weighs ~420 metric tons. That is 2-3 expendable launches or 3-4 reusable ones.

for comparison, building the ISS took 40 assembly flights [0] (36 of them from the Space Shuttle)

[0] https://en.m.wikipedia.org/wiki/Assembly_of_the_Internationa...

Re: Starship's Third Flight Test [video]

#277
post #116

T+37: Seems a little turny-aroundy in orbit there and a bit "small-pieces-falling-offy" Still, good job getting it there T+43: seems to be turning around a bit too much for something thats got heat shields on one side and is about to re-enter T+45: flaps moved, maybe that is supposed to get it the right way round, I get it now - it uses the flaps to orient for re-entry T+46: the little bits of debris must be tiles co…

>T+46: the little bits of debris must be tiles coming off Seemed like ice to me, which itself can be it a problem. The vehicle didn't seem very stable even before this point so I'm wondering if we're getting ice build up on the cold gas thrusters which changed the control dynamics keeping the ship from flying stably.

Right after the engine cut-offs for the second stage from the first burn you can see at least one tile missing and during the burn before that I also saw some dark flecks fly off.

It certainly looked like there was either a fairly continuous firing of the cold gas thrusters, a stream from the second stage engines, or some atmospheric effects from being in such a low orbit.

Re: Starship's Third Flight Test [video]

#278

Earlier quoted context omitted.

The side edge of the grid fin may have more surface area than edge on.

Not sure they can turn that far.

I'm saying if you could fold the grid fin, the surface area presented may be as high or higher than the surface area presented when unfolded.

Re: Starship's Third Flight Test [video]

#279

Did anyone notice at around T+30:16 the cargo door was almost shut when it looked like it popped out of place. Then the view suddenly switched to an external camera. Am I wrong?

Yeah, seems like something that needed to be closed even if it were on the cool side of the reentry.

Re: Starship's Third Flight Test [video]

#280

Earlier quoted context omitted.

The ISS weighs ~420 metric tons. That is 2-3 expendable launches or 3-4 reusable ones.

Jesus Christ, that really puts it into perspective what a game changer starship is

Now do the same calculation in units of hubble space telescope and james webb space telescope masses.

Then look at expected reusable launch cost and figure out how many HSTs or JWSTs we could have put in orbit for the same cost.

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