Author Topic: Should ITS have a smaller prototype to ease development?  (Read 13704 times)

Offline Lars-J

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Re: Should ITS have a smaller prototype to ease development?
« Reply #140 on: 03/02/2017 08:47 PM »
At 12m they NEED to have facilities on a barge waterway or at the test/launch site, while at 6m trucking, barging, or flying (in a Super Guppy) a upper stage are all options. I didn't say they were easy, but much more so than a 12m beast. It doesn't have to be as quick as moving a F9 because they would only need 2 or 3 per year, with the stages flying back to CCAFS or Vandy after missions.

It has nothing to do with being quick. Either a road (with overpasses and powerlines) can handle a 6m diameter payload, or it can't. And I'm suggesting that trucking a 6m diameter payload from Hawthorne to McGregor and the launch sites might actually be impossible.

Online spacenut

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Re: Should ITS have a smaller prototype to ease development?
« Reply #141 on: 03/02/2017 09:08 PM »
I was thinking a mini ITS and a booster no larger than 12m to take advantage of the inland waterways.  No way trucking larger than 3.7m dia. is possible via road or even railroad.  On Americas vast inland waterway system 12m dia. is possible.  Any larger than 12 m diameter will either have to go by ship or be built at the launch site only.  Any return ITS or booster will have to be at the launch site only. 

On has to take into consideration existing facilities building ITS.  We do not build planes larger than 747's in America due to the size of existing airports.  Even the large Airbus or Russian transport plane only has a hand full of runways to land and refuel on.  F9/FH can take all of existing land and sea transportation.  At least with our inland waterway system, it opens up a vast area of America one can either launch or land ITS and manufacture the craft and booster if they use the limitations involved. 

Online envy887

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Re: Should ITS have a smaller prototype to ease development?
« Reply #142 on: 03/02/2017 10:53 PM »
At 12m they NEED to have facilities on a barge waterway or at the test/launch site, while at 6m trucking, barging, or flying (in a Super Guppy) a upper stage are all options. I didn't say they were easy, but much more so than a 12m beast. It doesn't have to be as quick as moving a F9 because they would only need 2 or 3 per year, with the stages flying back to CCAFS or Vandy after missions.

It has nothing to do with being quick. Either a road (with overpasses and powerlines) can handle a 6m diameter payload, or it can't. And I'm suggesting that trucking a 6m diameter payload from Hawthorne to McGregor and the launch sites might actually be impossible.

Yeah, I don't think trucking cross-country like F9 would work well, but a combination of trucking, shipping, and maybe flying should work with existing assets.

I'm thinking more like trucking from Hawthorne to the Marina del Rey (Endeavor and ET-94 did a similar trip), then cargo ship to one of the Texas ports, truck inland to McGregor and back, then cargo ship to Port Canaveral. Or lease a Super Guppy or Beluga from LAX to McGregor to Canaveral.

It's not impossible to move a 6 by 25 meter, 20 tonne stage and utilize SpaceX's existing sites. It's quite impossible with a 12m stage, especially the ITS booster.

Offline punder

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Re: Should ITS have a smaller prototype to ease development?
« Reply #143 on: 03/03/2017 06:21 PM »
15t to GTO would be a single launch+return, while 50t would take ~6 refueling launches and be one way (unless refueled on Mars)

Had the distinct feeling I was missing something obvious. Thanks.

Intelligent arguments on both sides. But obviously this has been hashed out inside SpaceX. So I expect they will go for the home run.

On the other hand, they could be keeping an intermediate design close to the vest for political reasons, not wanting to antagonize NASA with an SLS-killer quite yet. On the gripping hand, they just antagonized the heck out of NASA with the MoonDragon announcement.

I just don't know WHAT to think! (classic movie line)

Offline TomH

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Re: Should ITS have a smaller prototype to ease development?
« Reply #144 on: 03/04/2017 12:18 AM »
On the other hand, they could be keeping an intermediate design close to the vest for political reasons, not wanting to antagonize NASA with an SLS-killer

I am not sure they would antagonize NASA as much as a select group of senators.

Offline watermod

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Re: Should ITS have a smaller prototype to ease development?
« Reply #145 on: 03/04/2017 02:46 AM »
I am thinking ITS full size will be required to launch the full LEO and VLEO sat network that SpaceX desires.

12,000 sats... if FH could put up 100 at time that's still too many for their launch rate at all launch sites.   It's going to  take ITS

Offline Jcc

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Re: Should ITS have a smaller prototype to ease development?
« Reply #146 on: 03/04/2017 02:45 PM »
I am thinking ITS full size will be required to launch the full LEO and VLEO sat network that SpaceX desires.

12,000 sats... if FH could put up 100 at time that's still too many for their launch rate at all launch sites.   It's going to  take ITS

I wonder how they will deploy to different orbital planes if they launch 1000 at a time. Possibly the ITS second stage will have many burns to achieve different orbits and deploy groups of sats.

Offline punder

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Re: Should ITS have a smaller prototype to ease development?
« Reply #147 on: 03/04/2017 07:02 PM »
On the other hand, they could be keeping an intermediate design close to the vest for political reasons, not wanting to antagonize NASA with an SLS-killer

I am not sure they would antagonize NASA as much as a select group of senators.

Yes. Sometimes I say "NASA" when I mean the whole federal bureaucracy/congressional vote-protecting/revolving-door-lobbying/not-invented-here complex.

Offline gin455res

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Re: Should ITS have a smaller prototype to ease development?
« Reply #148 on: 05/10/2017 08:19 PM »

How about a merlin-based booster (ITS-lite) with 42 Merlins on the bottom?

What risk would you be trying to retire with this? Would you build it with composite tanks? What role would it play in the 2020's?



Potentially none, but if desired it could be a tank test-bed.

More, the September presentation gave us all a little more freedom to really play with scale and investigate the benefits that it might offer. Elon clearly has.

It could just be a way of capitalising on the Merlin fully.  One large booster only needs one avionics package.  Return to launch site is pretty much proven now, perhaps road transportability is less important?

An upper*-stage with  4 vacuum merlins and a central sea-level merlin (potentially allowing complete reusability). Cost to orbit?

Might squeeze New Glenn and SLS.


[Later, fly a Raptor-based upper-stage with 2 vacuum raptors and a central sea-level raptor


- what is the minimum number of engines needed to mix sea-level and vacuum engines on an upper stage and enable vertical landing; 3,4,5?]?

*Perhaps this might optimise best as a 2nd stage of a 3-stage system.


Could a hypothetical single-stick F-29 be arranged as the picture below:





, have improved average isp by allowing over-expansion in the ring of 8 engines with slightly larger bells?


The outer ring being shut down later in the boost phase.