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SpaceX |OT| Reusable Rockets - To Mars!

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Crispy75

Crispy75

Member
Oct 25, 2017
2,058
Bear in mind that the FAA report was effectively written by SpaceX, to be commented on and modified by all the various agencies, before being signed off. So a lot of the mitigations will already be in the works. I don't think it will be a source of delays. They need to static fire the booster before even thinking about launching, and that will shake a huge number of issues out, I'm sure.

The NASA thing at KSC is weird. They've been planning and building for ages now, with the launch tower well into production off site, yet only now they have concerns? It's either a politically motivated decision, or a rather concerning lack of oversight.
 
Bregor

Bregor

Member
Oct 27, 2017
1,479
Lori Garver's new book "Escaping Gravity" about her role in pushing for commercial space flight is available on Audible:

www.audible.com

Escaping Gravity

Check out this great listen on Audible.com. The inside look at how the battle of the space billionaires began and why it matters, Escaping Gravity is former NASA Deputy Administrator Lori Garver’s firsthand account of how a handful of revolutionaries outmaneuvered the system of pol...
www.audible.com www.audible.com

I think it is going to come out in physical form next week. I've only just started it, but there are already some spicy takes on space politics in it.
 
DieH@rd

DieH@rd

Member
Oct 26, 2017
10,628
Very beastly engines, shame so many of them will be lost to the sea/explosions during the upcoming orbital tests.

If nothing else, excitement is guaranteed.
 
DBT85

DBT85

Resident Thread Mechanic
Member
Oct 26, 2017
16,353
DieH@rd said:
Very beastly engines, shame so many of them will be lost to the sea/explosions during the upcoming orbital tests.

If nothing else, excitement is guaranteed.
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Now someone told me the other day that the new flight plan included an attempt to catch the booster if everything is looking ok to do so. Can;t actually find any mention of it online though.
 
jotun?

jotun?

Member
Oct 28, 2017
4,509
DBT85 said:
Now someone told me the other day that the new flight plan included an attempt to catch the booster if everything is looking ok to do so. Can;t actually find any mention of it online though.
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It's in a recent FCC application

FLIGHT PROFILE
The Starship-Super Heavy test flight will originate from Starbase, TX. The booster stage will
separate and will then perform a partial return and land in the Gulf of Mexico or return to
Starbase and be caught by the launch tower. The orbital Starship spacecraft will continue on its
path to an altitude of approximately 250 km before performing a powered, targeted landing in the
Pacific Ocean.
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bsigg

bsigg

Member
Oct 25, 2017
22,588
Clip of something happening with Booster 7:

youtube.com

✂️ Boom!

32 seconds · Clipped by Bsigg · Original video "SpaceX Tests Super Heavy Booster 7, Results in Explosion and Pad Fire" by NASASpaceflight
youtube.com youtube.com
 
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Crispy75

Crispy75

Member
Oct 25, 2017
2,058
Yikes. Apparently they were doing spin-up tests with all 33 engines. Spinning up the engines requires gaseous methane & oxygen, so they were just squirting a fuel-air mixture everywhere. They should have had sparklers like the shuttle to burn off any excess fuel before it builds up to a dangerous amount...
 
MrKlaw

MrKlaw

Member
Oct 25, 2017
33,141
Is there a general space thread or is this kinda it? Visited the shuttle endeavour in LA this morning and it was pretty incredible. Such a mix of cutting edge tech like the tiles, and really old basic stuff - fabric insulation for the white parts, really basic hinges like you'd use on an old gate or something

If you've been around since the shuttle days though it's quite a sight to just slowly walk around and absorb all the history

They're building a new location next door to display it in launch mode and they have an external tank already so will add the boosters too. Probably a few years out though but I'd love to come back


I really have to go see a Saturn V
 
MrKlaw

MrKlaw

Member
Oct 25, 2017
33,141
The whole thing reminds me of that massive soviet rocket with way too many engines. Assume starship is designed to work with some failed engines but that many surely increases the chances of a failure
 
androvsky

androvsky

Member
Oct 27, 2017
3,523
MrKlaw said:
The whole thing reminds me of that massive soviet rocket with way too many engines. Assume starship is designed to work with some failed engines but that many surely increases the chances of a failure
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The N1 had 30 engines, the Falcon Heavy has 27 and has done well so far. The first version of Raptors had reliability issues, but mainly with restarts. Version 2 is supposed to be a lot better, we're still seeing engine swaps after static fires but not as often as with the earlier prototypes.
 
OgTheEnigma

OgTheEnigma

Member
Oct 27, 2017
2,804
Liverpool
MrKlaw said:
The whole thing reminds me of that massive soviet rocket with way too many engines. Assume starship is designed to work with some failed engines but that many surely increases the chances of a failure
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The Falcon Heavy has had 3 perfect launches with 27 engines which is only 3 less engines than the N1. I think the consensus is that the N1 would have still likely failed with less engines, since it had a lot of other design problems.

EDIT: Quora is usually pretty crap, but it's at least given a couple of decent answers in this instance: https://www.quora.com/Why-did-Falco...ed-whereas-the-N1-rocket-of-USSR-with-30-fail
 
DBT85

DBT85

Resident Thread Mechanic
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Oct 26, 2017
16,353
Mad that they've now achieved 151 landings of an orbital rocket.
 
MrKlaw

MrKlaw

Member
Oct 25, 2017
33,141
Tygre said:
And everything nominal on the way down!

That simultaneous side-booster landing will never get old.
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wikipedia says only 3 flights so far with the last in 2019, so this has been the first for 3 years? But yeah something about the landing + synchronised nature is pretty magical
 
Tygre

Tygre

Member
Oct 25, 2017
11,168
Chesire, UK
MrKlaw said:
wikipedia says only 3 flights so far with the last in 2019, so this has been the first for 3 years? But yeah something about the landing + synchronised nature is pretty magical
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Falcon Heavy ended up being way harder of a problem to solve than SpaceX thought it would be (It turns out "just slap three boosters together" is easier said than done) and then once they solved it it turned out the market for this class of lift is pretty small.

When Falcon Heavy development started they were still on Falcon 9 v1.0 with a total liftoff thrust of ~4,000 kN.

By the time of the first Falcon Heavy launch they were running Falcon 9 Block 5 with a total liftoff thrust of ~7,500 kN.

That almost doubling of Falcon 9 performance ate up a lot of the missions that were nominally slated for Falcon Heavy. Falcon Heavy is still a beast with ~15,000 kN of thrust... but it's not quite a Super Heavy like Saturn V was or SLS / Starship will be, and the number of missions that fit in this middle space is just pretty small.
 
DBT85

DBT85

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Oct 26, 2017
16,353
So the latest 14 engine static fire has resulted in them once again digging up the pad under the launch mount to concrete it again.

Reusable rockets. Not reusable launch pads.
 
bsigg

bsigg

Member
Oct 25, 2017
22,588
The Falcon Heavy dual booster separation and boost back is always so cool

And those dual landings will never not be incredible to see.
 
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bsigg

bsigg

Member
Oct 25, 2017
22,588
In other SpaceX news, it seems like we're getting close to first Starship orbital test. The flight license can come kinda whenever so hopefully the fact they're testing a full stack prop load means they're hearing it's soon/within the next few months and they're just confirming everything is working.


View: https://www.youtube.com/watch?v=YdZtQb-9I3c
 
Ether_Snake

Ether_Snake

Banned
Oct 29, 2017
11,306
I still think the tiles are its Achilles' heel. Other than Starship my attention is all on Relativity Space's 3D-printed rocket.
 
m_shortpants

m_shortpants

Member
Oct 25, 2017
11,321
Ether_Snake

Ether_Snake

Banned
Oct 29, 2017
11,306
I might make a Space Exploration OT as I don't think there is enough happening with SpaceX let alone Starship to get enough traction here. I'll use ChatGPT to make it faster, and can make corrections after.

For those who didn't see it, I love Stoke Space's approach to a reusable 2nd stage

View: https://youtu.be/EY8nbSwjtEY

And Relativity Space is going doing a launch of its 3D printed rocket soon, like next week or so.
 
bsigg

bsigg

Member
Oct 25, 2017
22,588
Bregor said:
Where did you hear that? There current sources I've seen are mentioning the 10th, 11th and 12th.
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It says it in the tweet. Wet dress rehearsal next week which includes the maritime warning that are active until the 12th, and then a launch about a week later assuming they get the FAA flight license. That puts us around 4/18 - 4/20.
 
androvsky

androvsky

Member
Oct 27, 2017
3,523
bsigg said:

View: https://twitter.com/SpaceX/status/1644044484026716160

Oh my god, it's happening

Also, they're aiming for a 4/20 launch. I hate Elon so much.
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If it helps any they're almost certain to miss it.

Bregor said:
Where did you hear that? There current sources I've seen are mentioning the 10th, 11th and 12th.
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I've seen people assume those dates are basically for dress rehearsal of marine keep-outs and regulatory filings, since Brownsville isn't used to dealing with rocket launches. It'd be great if it's that soon, if only to not be a giant meme.
 
MrKlaw

MrKlaw

Member
Oct 25, 2017
33,141
why the tiles? feels like going back to the traditional heat shield approach and they're prone to failure/expensive/slows recycling for launches. No way for them to slow approach like coming into a earth orbit before a controlled reentry, and using engines to slow entry speed like the Falcon 9?

Presumably they're expecting fireworks its been so long and so relatively few iterations vs falcon they can't expect a landing if they achieve orbit (the orbit part might be doable if its empty for a test flight there might be enough spare dT to compensate for issues)
 
DBT85

DBT85

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Oct 26, 2017
16,353
MrKlaw said:
why the tiles? feels like going back to the traditional heat shield approach and they're prone to failure/expensive/slows recycling for launches. No way for them to slow approach like coming into a earth orbit before a controlled reentry, and using engines to slow entry speed like the Falcon 9?

Presumably they're expecting fireworks its been so long and so relatively few iterations vs falcon they can't expect a landing if they achieve orbit (the orbit part might be doable if its empty for a test flight there might be enough spare dT to compensate for issues)
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The vast majority of the tiles are identical so can be swapped out. The shuttle I believe they were all unique.

Falcon is only coming back from a short hop up and so can, like Booster, just burn fuel to slow down, it's speed is actually quite low conpared to orbital velocities. The Starship itself would be hitting the atmosphere at a substantially higher speed, using fuel to slow that down is simply a waste of energy. The fuel costs to lug around tiles are way way lower than the fuel costs to try and slow down from just orbit not even including the fuel costs needed to carry that extra fuel everywhere, let alone return from the moon or mars which would be faster still.
 
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Crispy75

Crispy75

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Oct 25, 2017
2,058
Yeah the tiles are the most concerning element for me. Right now they're using a very similar material to the shuttle, which is fragile, and most importantly loves to soak up water. This is bad news because any trapped water will boil away in vacuum, the expanding vapour cracking the tile on the way out. Given that the shuttle (and starship) can spend days or weeks exposed to the elements before launch, it's impossible to keep them dry. The shuttle didn't need all its tiles replacing every flight (as is commonly believed) but it did need to be thoroughly dried and then each tile had to be injected with a waterproofing agent. This would burn out during re-entry and so had to be re-applied, by hand, tile by tile, before every flight.

Starship's current heat sheld will have the same issues. Right now it's not too big a deal as each launch will be a completely fresh ship. But in the long term, they will have to use something else. That will take time to develop, but it's critical for achieving the flight rates they're aiming for.
 
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