Author Topic: 9m ITS Development Updates and Discussion Thread  (Read 109023 times)

Online vaporcobra

Elon Musk has revealed in a response on Twitter that the subscale ITS with a diameter of 9m could still be developed in SpaceX's current factories. No mention of pads or test facilities.
https://twitter.com/elonmusk/status/888813713800785923

This probably warrants a new, 9m-focused updates and discussion thread.

Full disclosure/shameless self-promotion: I wrote the retweeted Teslarati article that led to the above reply. (It's by far the worst I've written, but can't choose which articles get retweeted by Musk  :()
« Last Edit: 07/22/2017 09:51 PM by vaporcobra »

Offline M.E.T.

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Re: 9m ITS Development Updates and Discussion Thread
« Reply #1 on: 07/22/2017 08:24 PM »
Great. Thanks for the new thread.

Now eagerly waiting for someone to model that for us to see what type of performance such a Raptor based vehicle could deliver - both reusably and in expendable format. Also, what diamater "ITS" could such a booster send to LEO? Would it be large enough to comfortably carry astronauts to Mars, and house them for a 2 year period in space and on the Martian surface before returning?

EDIT

The above got me thinking, is the ITS diameter also limited by the 9m maximum? If so, the "flairing" shape of the current ITS, which is wider than the booster itself, will not be possible, limiting the ship to the booster diameter, I would guess.
« Last Edit: 07/22/2017 08:27 PM by M.E.T. »

Offline DJPledger

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Re: 9m ITS Development Updates and Discussion Thread
« Reply #2 on: 07/22/2017 08:25 PM »
Dev. costs for 9m dia. ITS system should be much lower than for the previous 12m dia. one as it will make full use of existing manufacturing and launch facilities. Building new manufacturing and launch facilities is very expensive.

Offline IanThePineapple

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Re: 9m ITS Development Updates and Discussion Thread
« Reply #3 on: 07/22/2017 08:28 PM »
Sooo will this finally be a Falcon X/XX? ;)
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Offline DJPledger

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Re: 9m ITS Development Updates and Discussion Thread
« Reply #4 on: 07/22/2017 08:37 PM »
Sooo will this finally be a Falcon X/XX? ;)

Nope, the 9m dia. ITS system will be a completely different architecture to the old Falcon X/XX design studies.

Offline tater

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Re: 9m ITS Development Updates and Discussion Thread
« Reply #5 on: 07/22/2017 08:39 PM »
Much of the ITS "flaring" was the landing gear wing/pods. Seems like those can be attached after the core is made.

Offline MikeAtkinson

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Re: 9m ITS Development Updates and Discussion Thread
« Reply #6 on: 07/22/2017 08:44 PM »
The above got me thinking, is the ITS diameter also limited by the 9m maximum? If so, the "flairing" shape of the current ITS, which is wider than the booster itself, will not be possible, limiting the ship to the booster diameter, I would guess.

Suggest that the stakes (is that what we should call them?) can be added at the launch site just as the landing legs are now.

Offline Barrie

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Re: 9m ITS Development Updates and Discussion Thread
« Reply #7 on: 07/22/2017 09:03 PM »
Suggest that the stakes (is that what we should call them?) can be added at the launch site just as the landing legs are now.

You mean strakes?

Offline MikeAtkinson

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Re: 9m ITS Development Updates and Discussion Thread
« Reply #8 on: 07/22/2017 09:25 PM »
Suggest that the stakes (is that what we should call them?) can be added at the launch site just as the landing legs are now.

You mean strakes?

Yes, stupid spelling correction changed strakes to stakes.

Offline CTC

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Re: 9m ITS Development Updates and Discussion Thread
« Reply #9 on: 07/22/2017 09:28 PM »
Since we know the use of existing factory and launch pad, how will SpaceX transport it between the two? Road, train or water still seem very difficult for 9m diameter booster.
Airlift it similar to Energia/Buran booster?

Offline TomH

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Re: 9m ITS Development Updates and Discussion Thread
« Reply #10 on: 07/22/2017 09:43 PM »
Since we know the use of existing factory and launch pad, how will SpaceX transport it between the two? Road, train or water still seem very difficult for 9m diameter booster. Airlift it similar to Energia/Buran booster?

The answer is located here, but L2 membership is required.
« Last Edit: 07/22/2017 09:44 PM by TomH »

Offline M.E.T.

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Re: 9m ITS Development Updates and Discussion Thread
« Reply #11 on: 07/22/2017 09:56 PM »
Since we know the use of existing factory and launch pad, how will SpaceX transport it between the two? Road, train or water still seem very difficult for 9m diameter booster. Airlift it similar to Energia/Buran booster?

The answer is located here, but L2 membership is required.

Wow. That's quite a long Hyperloop Elon is talking about there.

Just kidding. I have no clue what is hidded behind the impenetrable L2 veil.

Offline Peter.Colin

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Re: 9m ITS Development Updates and Discussion Thread
« Reply #12 on: 07/22/2017 09:58 PM »
A 9 meter core would either be

1/6/12 = 19 Raptor engines

Or

1/6/14 = 21 Raptor engines

Since the original plan was 1/6/14/21= 42

21 Raptor engines for a 9 meter core is most likely.
« Last Edit: 07/22/2017 09:59 PM by Peter.Colin »

Offline UberNobody

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Re: 9m ITS Development Updates and Discussion Thread
« Reply #13 on: 07/22/2017 10:03 PM »
I get a maximum of 21 engines as well, or about 14.4mlbf.  I suspect Raptor won't be quite as powerful in its initial implementation, so ITS-21 is in the ballpark of 39A capability.  It's hard to imagine using sub scale raptor on the booster, but it might be useful on the spaceship.

Now that I think about it, if SpaceX starts with spaceship suborbital tests, using sub scale raptor might speed things up a bit.  Musk has already talked about increasing the expansion ratio to 150 on the sub scale engine, perfect for doing suborbital tests with a 9m BFS...
« Last Edit: 07/22/2017 10:08 PM by UberNobody »

Offline tater

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Re: 9m ITS Development Updates and Discussion Thread
« Reply #14 on: 07/22/2017 10:05 PM »
Would they use scaled versions, or full sized?

What about the spacecraft? Scaled to 6 vac and 3regular, or 3 vac and 3 at the full ~4m and ~2m sizes?

Offline M.E.T.

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Re: 9m ITS Development Updates and Discussion Thread
« Reply #15 on: 07/22/2017 10:08 PM »
Would they use scaled versions, or full sized?

What about the spacecraft? Scaled to 6 vac and 3regular, or 3 vac and 3 at the full ~4m and ~2m sizes?

With a sub scale Raptor roughly equivalent to a Merlin in thrust, that would give a 21 engine ITSy less thrust than a Falcon Heavy. Of course, it might well be much more efficient in its single core configuration than the FH is with three cores.

Offline AncientU

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Re: 9m ITS Development Updates and Discussion Thread
« Reply #16 on: 07/22/2017 10:13 PM »
Would they use scaled versions, or full sized?

What about the spacecraft? Scaled to 6 vac and 3regular, or 3 vac and 3 at the full ~4m and ~2m sizes?

With a sub scale Raptor roughly equivalent to a Merlin in thrust, that would give a 21 engine ITSy less thrust than a Falcon Heavy. Of course, it might well be much more efficient in its single core configuration than the FH is with three cores.

I'd go with the subscale on the spaceship (so that some full vacuum engines could be employed) and the full scale on the booster(19 engines, 1-6-12 hex packing, 12-13Mlbf total).  This configuration would allow the ship to do exactly what the full scale ship is targeted for, but at smaller scale. Would be perfect vehicle to begin Mars infrastructure development from existing facilities.
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Offline Coastal Ron

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Re: 9m ITS Development Updates and Discussion Thread
« Reply #17 on: 07/22/2017 10:32 PM »
Since we know the use of existing factory and launch pad, how will SpaceX transport it between the two? Road, train or water still seem very difficult for 9m diameter booster.
Airlift it similar to Energia/Buran booster?

Airlift is likely out because the SpaceX factory is next to a general aviation airport whose only runway is just 4,956 ft in length, which is about half the length needed for an Antonov An-225 Mriya.

I think instead we can look to the experience of the Shuttle Endeavour and it's External Tank (ET), where both of those traveled 16 miles inland on surface streets from either the Los Angeles International Airport (Shuttle) or the Marina del Rey harbor (the ET) to the California Science Center.

SpaceX may have already surveyed possible routes to the LAX airport or the harbor in order to ensure that if they built a 9m diameter ITS at their Hawthorne facility that it wouldn't end up as a permanent exhibit there...  :o
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

Offline Jim

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Re: 9m ITS Development Updates and Discussion Thread
« Reply #18 on: 07/22/2017 10:34 PM »
The ET was a one time only and not something that would  be regular

Offline Peter.Colin

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Re: 9m ITS Development Updates and Discussion Thread
« Reply #19 on: 07/22/2017 10:38 PM »
I get a maximum of 21 engines as well, or about 14.4mlbf.  I suspect Raptor won't be quite as powerful in its initial implementation, so ITS-21 is in the ballpark of 39A capability.  It's hard to imagine using sub scale raptor on the booster, but it might be useful on the spaceship.

Now that I think about it, if SpaceX starts with spaceship suborbital tests, using sub scale raptor might speed things up a bit.  Musk has already talked about increasing the expansion ratio to 150 on the sub scale engine, perfect for doing suborbital tests with a 9m BFS...

Using sub scale Raptors on the booster might speed things up also and could make the 9 meter design to the original 42 engines again?
42 sub scale engines is maybe better than 21 full scale engines, so that the future full scale ITS is "just" a dimensional upgrade.
Gimballing center 7 engines vs outer double ring engines remains the same.
« Last Edit: 07/22/2017 10:42 PM by Peter.Colin »

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