Interesting. I wonder why they limited the engines so much. That’s not a full test of the capability of the OLM clamps.
Maybe there will be another static fire at a higher thrust level?
Stunning photos!
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Maybe there will be another static fire at a higher thrust level?
Stunning photos!
Clamps:
TWR at launch: 1.5
Thrust: 17 Mlb
Stack: 11.3 Mlb
Clamp load: 5.7 Mlb
Test Thrust: 7.9 Mlb
B7 full prop: 6.8 Mlb
B7 full CH4: 1.4 Mlb
B7 full O2: 5.4
B7 CH as tested: 0.4 Mlb (1/3 full)
B7 dry: 0.5 Mlb (guess)
B7 as tested: 6.3
Clamp load: 1.6 Mlb, 3.9 Mlb less than launch
Or:
9.1 Mlb less thrust
+ 3 Mlb missing B24
+ 1 Mlb missing CH4
= 5.1 Mlb less clamp load, barely any.
However, I'm guessing they used the crane to validate hold down ability when they tested the stand's support ability.
dhanson865
Well-Known Member
apparently it was half throttle.
50% throttle with 31/33 engines giving 46.97% of nominal thrust seems implied.
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It makes sense to to exercise 100% thrust with full stack - Booster and Starship on top - and 100% fuel on both and with dummy payload weight on Starship.
Static fire was 50% thrust. Launch attempt will be 90%.
Could that tweet from Elon be implying that there won’t be another static fire attempt? Not sure…
dhanson865
Well-Known Member
Beating the Saturn V to be the second most powerful rocket ever, only behind SLS by 5%...
"Oh yeah... and we were at half throttle with 2 engines out..."
S26 was rolled out of the MegaBay and moved to suborbital test stand A, next to S25 on stand B.
S26 has no flaps or heat shield. It seems reasonable to assume that it is the first Starship fuel depot vehicle (I don’t know what SpaceX officially calls that Starship variant) for in-orbit refueling and that it is going to be static fired soon. Exciting times!
S26 has no flaps or heat shield. It seems reasonable to assume that it is the first Starship fuel depot vehicle (I don’t know what SpaceX officially calls that Starship variant) for in-orbit refueling and that it is going to be static fired soon. Exciting times!
Kinda bummed, wanted to see those, thought they'd be cool...
Looks like still on the table for the future according to Shotwell:
"Gwynne Shotwell told reporters last week that SpaceX sold the rigs; 'they were not the right platform.' Still interested in sea-based launch platforms, but the company wants to start flying Starship first and understand it before proceeding."
That certainly sounds like a wise approach. We all know that SpaceX always wants to move forward as fast as possible but they should not get ahead of themselves. With one Stage Zero complete, another one at KSC well along, and a signs of a possible third one at KSC, building two sea-based Stage Zeros right now seems overly ambitious given that there have been no orbital launch attempts, and landings are even farther in the future.
An article with the details:
spacenews.com
SpaceX drops plans to convert oil rigs into launch platforms
SpaceX has abandoned efforts to convert two oil rigs into launch platforms for its Starship vehicle but could develop offshore platforms in the future.
spacenews.com
From that article:
I know that Elon has talked about that kind of launch cadence in the past, but every time I hear it mentioned it blows my mind. I just hope I am around to see it actually happen! I would guess it is at least a decade away.
petit_bateau
Active Member
These semis are relatively standardised designs for floating semi subs.An article with the details:
SpaceX drops plans to convert oil rigs into launch platforms
SpaceX has abandoned efforts to convert two oil rigs into launch platforms for its Starship vehicle but could develop offshore platforms in the future.
We are at peak oil, which is a somewhat bumpy plateau with all sorts of other summits on the ridge, chiefly peak gas and peak liquids.
Arguably we are also at peak offshore oil, gas liquids. Arguably most of the future growth will come from low risk (and low cost) onshore, though we will of course continue to work out the low risk tails from the known offshore plays around the world.
Once off-peak the liquidity in the relevant engineering design and manufacturing to construct these semi-submersibles will rapidly dissipate and be hard to re-assemble. Whilst the rigs themselves may have an economic lifetime of (say) 20-years in a single usage pattern, they will not have that same economic lifetime if they are to be significantly converted in a safe and cost-effective manner to another usage. You only have to inspect a 10-year-old semi to understand what I mean.
SpaceX might want to do (say) a dozen launches a day per rig. That is only a launch per rig every 2-hours. Not so difficult for stack - tank - and go. You only need a few rigs to do that at a rate of (say) thity or so per fleet per day (ex-Terra). That would be 11,000 per year ........ of which quite a few would be tankers, but sheesh ...
The point being that whilst SpaceX may conside these are disposable items, and that may be a fair assessment of the market now, that may not be the case in the future.
Different littorals have different rquirements. some may lend themselves to relatively easily assembled offshore islands of dredged sands in <50m water depth. Others may require floaters in >80m water depths. (The intermediate bit in 50-80m using jackups is I think not of interest). The floaters required for 20MW wind are a world apart from these O&G floaters.
Maybe enough littoral desert coast is the way to do this. There is a lot of Chile, Peru, Namibia, Morocco, Australia. Maybe Texas even. All sorts of offshore islands.
Imagine the size of the onshore GSE tank farm required to support that many Starship launches per day. I can’t quite wrap my head around it.
petit_bateau
Active Member
As a comparison it is instructive to look at large scale LNG liquefaction plants which gives a feel for the size of the cryogenic problem. I appreciate that the long term goal for SpaceX is to get renewable methane (CH4) but for now taking hydrocarbon CH4 will be what they are doing. There is also the need to get liquid oxygen (LOX) so for comparison purposes it is worth summing both the CH4 + LOX
"the LNG market typically differentiated between small- to mid-scale production facilities and world-scale plants. Whereas the small- to mid-scale segment usually produces up to 0.5 million tonnes per annum (mtpa), world-class plants have liquefaction capacities of anywhere between 3.5 and almost 8 mtpa."
If you want to read more widely try also
World LNG Report 2022 | IGU
This 13th edition of the IGU World LNG report has become one of the most anticipated, in light of another, even more eventful year for the LNG sector. The 2022 report is out at a time when LNG is more vital than ever to secure and reliable functioning of energy systems around the world. It is...
www.igu.org
Anyway popping those numbers into a spreadsheet it looks like a typical very large 2-train LNG plant can do about 22,000 tons/day of cryogenic liquid gas. So to get to a launch cadence of 12 per day that would require a 4-train plant.
Now it would be possible to put that in an offshore floating vessel such as Shell has done with the Prelude FLNG that only (!) does 3.6 mt/yr and still weighs in at 600,000 t when fully loaded, more than five times the displacement of a Nimitz-class aircraft carrier. It is the world's largest floating liquefied natural gas platform as well as the largest offshore facility ever constructed. But far better/easier/safer to put that on a very large piece of coastal flat deserted land where you can avoid a lot of the problems of going to a floater.
So a good equivalent would be Bintulu LNG which is the 21mt/yr exemplar for a very-large facility - note train sizes have increased over the years hence this being a 9-train.
And if you are going to build on such a large piece of empty coastal land you might as well put the launch & recovery pads somewhere within sensible pieline distance. An artificial island in shallow water offshore (say <30m water depth) would seem to be the better way to go for a series of offshore pads that are sufficiently segregated from each other, and from the onshore LNG/LOX plant
Again to get a feel for that, here is a shot of Bintulu - a good planning guesstimate would be a 10km x 10km chunk of empty coastline, with space nearby for a fairly large township to provide the workforce.
Nice view of S25 and S26 on their suborbital launch pads with B7 in the background.
A single engine spin prime test was conducted. Speculation is that it was to test the start sequence of the engine that failed to start during the recent full static fire attempt. In this image you can just make out the escaping gas below the booster.
Need to correct my post: S25 is on suborbital pad A which is used for cryo testing before engine installation, according to the latest NSF video.
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