totm nov 2023 SpaceX Discussion Thread

[Meecrob]

I imagine a lot of falcon 9's landing "inaccuracy" is due to the amount of engines they can fire on landing...or lack thereof. All of this will be computer controlled, and I'm guessing when we see the videos, we will all be thinking there has been an anomaly since the centre engines will be gimballing all over the place...then we will get used to it like the bellyflop hops where we all crapped our pants the first time that one engine shut down on ascent.

[sevenperforce]

2 hours ago, tater said:

I have to say, I still find the idea of it being that precise WRT those loading points... hard to imagine.

Are these what the "tank treads" have become?

Perhaps instead of tank treads they are going with this lego-like rail filled with holes for pegs, that could be actuated to slide back and forth along the top of the chopstick arm.

3 hours ago, tater said:

Having those mounts wrap all the way around the tower does seem cool. However, I'm still a little concerned about the placement of the lift point. 

The cable lift point needs to go through the arm rotation axis, IMO.

[tater]

live in 44

 

Or launch in 44 min... live before

[tater]

 

Music

[Brotoro]

Foggy foggy

fully operational space lasers… ooooooo!

Shut up and take my money.

And we have Liftoff!

Max Q

MECO

[Brotoro]

Toasty waffles deployed

Entry burn

[tater]

Landed

 

[Brotoro]

Booster Landed! Never gets old.

[tater]

Making it look routine.

Given the accuracy of F9 on a wobbly ASDS, and the no-hover nature of F9 landings, maybe they can do better than I imagine with SH?

I mean they must have some confidence.

[tater]

 

 

[Beccab]

The second falcon 9 reused 10 times!

[tater]

 

Live in 37 hours, lol.

 

[RCgothic]

I'm about an episode and a half into the Netflix documentary so far and I'm struggling to hold it together. Inspiration 4 is really awesome!

[tater]

1 hour ago, RCgothic said:

I'm about an episode and a half into the Netflix documentary so far and I'm struggling to hold it together. Inspiration 4 is really awesome!

Yeah, the show is pretty well done, and the crew are all just decent humans.

[JoeSchmuckatelli]

13 hours ago, tater said:

I have to say, I still find the idea of it being that precise WRT those loading points... hard to imagine.

The whole 'catch a rocket' thing is pretty bonkers.  Especially without landing legs.  That's just plain nuts.

....aaaaand yet, if anyone can do it (even if it takes a few tries) SX just might be the group to pull it off.

My fear is that they're spending so much money trying to do this stuff, that they overcommit to one idea that ends up being a dead end (wasted effort) or destroy the stuff they've built in the first or third attempt.  Everyone says, routinely, "Space is Hard" - but its also expensive.

Starlink should give them an instant boost and a lot of ongoing revenue... but it will take a while to refill the coffers of money already spent on Starlink itself.  Can't imagine that each individual satellite costs only a few hundred dollars.

Edited September 14, 2021 by JoeSchmuckatelli

[tater]

Or maybe they end up adding legs back in. (keep removing parts til you have to add some back)

It's interesting to remember that landing on the launch mount was part of the initial concept (which I thought was nuts back then, as well).

[Beccab]

Not sure if this was posted yet when we heard of the FCC, but some info on the S20 landing point rough target from our usual reddit insider:
"Just over 62 miles NW of the Kauai island, Approx Lat/Long 22.834, -160.343. Water depth 15,500 ft to the bottom. No artificial reef unfortunately"

[tater]

 

5 minutes ago, Beccab said:

Water depth 15,500 ft to the bottom. No artificial reef unfortunately

ITAR-compliant disposal?

[MKI]

1 hour ago, JoeSchmuckatelli said:

Everyone says, routinely, "Space is Hard" - but its also expensive.

Space is always hard, but it doesn't have to be expensive to figure it out.

 

10 hours ago, tater said:

Given the accuracy of F9 on a wobbly ASDS, and the no-hover nature of F9 landings, maybe they can do better than I imagine with SH?

I'd put a Falcon 9 booster landing as being harder than a SH landing.

1. Merlin's can't throttle deep, so they essentially must perform a suicide burn. SH will be able to hover into an exact position without any problem.

2. Most Falcon 9's end up landing on a moving target in the ocean. 

3. Due to essentially having 0 weight restrictions on the catcher arms, compared to weight restrictions on carrying landing legs through the flight, there isn't really anything stopping SpaceX from making the arms more "cushiony" than a Falcon 9 landing legs. This also drastically saves weight, increasing flight performance

 

I think the hover part is the key feature that will make a SH landing extremely accurate. Catching a booster seems insane because the only ones landing boosters are already doing it in a harder environment. If the techniques where reversed, and SpaceX was doing Super Heavy landings  and were thinking about landing using the Falcon 9's approach, it wouldn't make as much sense since a Falcon 9 landing is harder. 

Another way to think about it is we have been doing mid-are refueling for decades and no one bats an eye and that has 2 aerodynamic vehicles flown into exact position for long periods of time. 

 

 

Also didn't see anything for the Starlink launch, too many clouds where we ended up. A family friend who was elsewhere got a good view though as they had a break in the clouds. Will have to try to catch the next launch from their place instead next time haha.

 

Edited September 14, 2021 by MKI

[JoeSchmuckatelli]

28 minutes ago, Beccab said:

No artificial reef unfortunately

Well - not one dive-able by tourists.  But stuff like that does tend to collect life on the bottom.

Quote

Victor Vescovo, who led the expedition and piloted the sub, said: “The wreck is so deep so there's very little oxygen down there, and while there is a little bit of contamination from marine life, it's remarkably well intact except for the damage it took from the furious fight.”

USS Johnston: Sub dives to deepest-known shipwreck - BBC News

 

[Beccab]

2 minutes ago, JoeSchmuckatelli said:

Well - not one dive-able by tourists.  But stuff like that does tend to collect life on the bottom.

USS Johnston: Sub dives to deepest-known shipwreck - BBC News

 

I've always been curious, have there ever been people who dived to a rocket stage?

[mikegarrison]

10 minutes ago, Beccab said:

I've always been curious, have there ever been people who dived to a rocket stage?

There have been salvage expeditions that pulled them up.

21 minutes ago, MKI said:

Another way to think about it is we have been doing mid-are refueling for decades and no one bats an eye and that has 2 aerodynamic vehicles flown into exact position for long periods of time.

There is a fair amount of play in that system. The Navy-style system uses a flexible hose, and the AF-style system uses a boom that is actively guided into position. And both systems allow the two airplanes some relative movement.

[JoeSchmuckatelli]

17 minutes ago, Beccab said:

I've always been curious, have there ever been people who dived to a rocket stage?

I don't think so.  At least not intentionally - the people who run these deep sea excursions to sunken ships or waste fields have other priorities (historical, treasure, ecological) and the rocket stage is both fairly tiny and not worth the trip.  I've seen deep sea footage of waste fields off the California Coast, and a bunch of shipwrecks - but never anything like that.

Best hope would have been something related to Shuttle

 

 

Quote

 

one claim to fame I always hear, is that during her tenure with the US Navy, she had recovered the black boxes from the Space Shuttle Challenger disaster in 1986. This story was widely circulated, and even published in a 2017 article in Scuba Diving Magazine. Except there is one little problem - the space shuttle Challenger was not equipped with black boxes.

The real name of what's commonly known as a 'black box' is actually a 'flight data recorder,' and the purpose of these devices is to provide voice recordings from the flight deck, as well as data recordings from an aircraft when it's in flight. In the unlikely event of an aircraft accident, the data recorders aid investigators in reconstructing an accurate account of the incident.

 

Black boxes are used on aircraft, not spacecraft.

 

What did the Kittiwake do? (divetech.com)

 

 

Okay - ignoring what I wrote above... From the quote and article cited:  "Naval Sea Systems Command Report on the Salvage of the Space Shuttle Challenger Wreckage sitting in my inbox. This was the complete report from the US Navy, published in 1988 about their recovery efforts. "

 

However - I've not seen any reports of dives that looked at their utility as an artificial reef.

 

Edited September 14, 2021 by JoeSchmuckatelli

[mikegarrison]

2 hours ago, tater said:

Or maybe they end up adding legs back in. (keep removing parts til you have to add some back)

It's interesting to remember that landing on the launch mount was part of the initial concept (which I thought was nuts back then, as well).

IMO, they are being driven by what I think is an unreasonable requirement. The vision is to land, refuel and take off again. It's hard to imagine they really have a need for that kind of cadence, even considering the need for multiple refueling flights in close succession. But that's what seems to be driving them to the "land on the launchpad" solution.

Aggressive design goals are fine -- you'll never hit goals you don't aim for -- but if they compromise meeting the more basic requirements, they can turn into problems.

[JoeSchmuckatelli]

17 minutes ago, mikegarrison said:

if they compromise meeting the more basic requirements, they can turn into problems

Ain't that the truth!

...

Booster hasn't even had a hop, much less a test flight.