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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]

#801

Post by edm0nd »

api wrote: post #311
blackeyeblitzar wrote: post #229

Earlier quoted context omitted.

When Musk first proposed this, I thought he was crazy. It seemed like something a school boy would draw up. Now I think this will become routine and forgettable after a few more successes. Is there a word for that - something out of fiction becoming mundane?

I thought it was plausible given the accuracy of F9 landings, though I still wonder how it will work at scale if one failure destroys the landing site. That could ruin the cost benefits. Where his vision hit a lot of speed bumps is second stage reusability. Starship is a beautiful second stage to throw in the ocean. They’ll probably get it landing but the heat tiles will require a lot of refurbishment between flights…

iirc they plan on making multiple launch sites so one getting damaged wont grind operations to a halt.

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

#802

Post by irrational »

ls612 wrote: post #580
iknowstuff wrote: post #555

Earlier quoted context omitted.

correct me if I’m wrong but I don’t think the second stage is meant to be caught. It will have legs to land on Earth/Mars without any landing infrastructure.

It is expected to land astronauts on the Moon as well this decade, which will certainly require legs.

Or have the tower on the moon catch it.

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

#804

Post by askvictor »

syncsynchalt wrote: post #718
kedv wrote: post #705

Earlier quoted context omitted.

Why is SpaceX choosing to land the booster on the Mechazilla arms instead of performing a soft ground landing like the Falcon 9 booster?

1) legs are heavy 2) empty rockets are stronger in tension than compression the scale of Superheavy is such that the above two items are making the arms scheme make sense. The number of engines also gives this rocket the ability to hover, which probably makes the scheme easier to pull off.

> 2) empty rockets are stronger in tension than compression

True, but wouldn't the deceleration burn be putting much more compression onto the near-empty rocket than the landing?

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

#805

Post by oceanplexian »

norman784 wrote: post #767
Isamu wrote: post #531

Earlier quoted context omitted.

I imagine that they will be their own first customer - putting Starlink satellites into orbit while they are gaining confidence in the reliability of the system for external customers. They have to prove out the landing of the second stage, either with another catch or with landing gear, which they need for the lunar lander anyway.

If Im not mistaken, they already delivered a payload in one of the previous flights, because they cut the transmission for a while and didn’t show the payload bay like one previous flight.

I’m not sure they are, if only because of the altitude. They only took Starship up to 200km, Starlink are nearly double that so while they do have thrusters that’s quite the distance.

Starship is not really in a true orbit, I forget the exact terminology but the trajectory is designed to re-enter regardless of what happens with the the flight.

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

#806

Post by jessriedel »

shellfishgene wrote: post #535
pj_mukh wrote: post #392

Earlier quoted context omitted.

I know the control algorithms are the mind-blowing part here but, does anyone have any literature about how the Rocket localized itself with respect to the chopstick arms? It must've been some combination of GPS and Radar pings to the arms? And then the onboard IMU to make sure it hits it straight.

From the control point of view, isn't this exactly the same as F9 landing on a pad, except the pad is virtual, floating in between the chopsticks and the ground? Or course one difference is that the approach needs to be from the correct direction.

A major difference is that F9 (landing on a wide flat pad) had a quite wide acceptable horizontal error, 10 meters or more, whereas I think this (landing between two chopsticks) needs like ~1 meter accuracy in the radial direction.

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

#807

Post by bottlepalm »

thisisthenewme wrote: post #722
atleastoptimal wrote: post #711

Why can only Elon do stuff like this and not BlueOrigin or the hundreds of other aerospace startups? Does he just have a 1/100000000 combination of intelligence, tenacity, and directionality that can't be matched by anyone, even those trying to emulate him as closely as possible?

Why do we think its Elon 'doing' this? Just curious, since it could just as well be that its the engineers and other leaders who could be the differentiator.

Because it's Elon who said "ok, build it." There's no one else except him with that power and/or the guts. Even landing a rocket the government had given up on, and no company was even trying until he did. People were calling the 'chopstick' landing system a dumb idea until today.

It's not like engineers don't come up with wild ideas all the time to their leadership, but is the leadership good enough to understand the good ideas from bad ones? Take the risk, spend billions to actually execute?

Elon has enough of a physics/engineering background to ask the right questions, understand the trades engineers put in front of him, and make the risk/reward calculation to make the right decisions the ends up winning.

To get what SpaceX has you need strong technical leadership all the way up the chain. Many companies don't. Their CEOs are experts in legal, PR, finance, etc... They make poor technical decisions.

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

#808

Post by irjustin »

lutorm wrote: post #551
foobarian wrote: post #235

Earlier quoted context omitted.

Even without the catch step, I always feel like their boosters are coming down way too fast way too late, with engines reigniting startlingly close to surface. Never ceases to surprise me.

Every moment your engines are burning at anything less than maximum thrust, you are wasting fuel. You want to relight as late as possible with as high thrust as possible for maximum efficiency. But that it actually works is nuts.

PEDANTIC - max efficiency isn't necessarily tuned to max thrust.

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

#809

Post by bottlepalm »

slimebot80 wrote: post #694

The SpaceX engineers did a great job, as did NASA. The media needs to stop blindly attributing this to "Elon Musk". He did well taking the risks NASA was not allowed to take at the start. But these days he is toxic to the media and toxic to reporting, so for that reason alone the media could smarted up a little. Well done SpaceX and NASA engineers.

Elon is the guy who said, "that is the craziest idea I've ever heard, here's billions, let's build it"

It's 100% Musk that this happened, literally no one else would have done it. Everyone thought it was dumb until today. No company, no government or sci fi movie for that matter had even thought of it in the first place.

SpaceX engineers given the green light by Musk, not NASA, made it a reality. That's not to say Elon didn't make many decisions along the way in the design and development of both Starship, the launch towers and everything else.

The point is, Elon deserves a hell of a lot of credit along with everyone else. Everyone has their part to play in the success of the mission.

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

#810

Post by jve »

syncsynchalt wrote: post #718
kedv wrote: post #705

Earlier quoted context omitted.

Why is SpaceX choosing to land the booster on the Mechazilla arms instead of performing a soft ground landing like the Falcon 9 booster?

1) legs are heavy 2) empty rockets are stronger in tension than compression the scale of Superheavy is such that the above two items are making the arms scheme make sense. The number of engines also gives this rocket the ability to hover, which probably makes the scheme easier to pull off.

3) rapid reuse by landing on launch tower
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