Author Topic: Should ITS have a smaller prototype to ease development?  (Read 30038 times)

Online 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.

Offline 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. 

Offline 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.

Offline TrevorMonty

From development point of view, booster and its launch facilities are most expensive item. If ITS operates from DSG at EML1(or similar location) and never returns to earth then there is no need for large booster. ITS could be delivered to LEO empty as SSTO or with help of smaller booster and refuelled for its initial trip to DSG. The ITS is sized to support passengers for months yet it is being used to carry them for few days on the highest DV section of journery.

Use smaller vehicles that are optimized for earth - DSG trip. These would require are considerable smaller booster.

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Online Robotbeat

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Re: Should ITS have a smaller prototype to ease development?
« Reply #150 on: 06/03/2017 08:02 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
At 3000 satellites per year, that's only 30 launches. 40 launches is often considered the bare minimum for full reuse to make economic sense. So an ITS of approximately FH-level of capability would be fine for the Constellation. More might make sense for Mars, but FH is just about right for the Constellation.
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Offline Ludus

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Re: Should ITS have a smaller prototype to ease development?
« Reply #151 on: 06/03/2017 08:45 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
At 3000 satellites per year, that's only 30 launches. 40 launches is often considered the bare minimum for full reuse to make economic sense. So an ITS of approximately FH-level of capability would be fine for the Constellation. More might make sense for Mars, but FH is just about right for the Constellation.

That's with the first generation of  smallsats. If they start in 2019 that generation will be ready for replacement in the mid 2020s about when ITS would be available to launch the 2.0 sats. With ITS the new generation could be 10X the mass as well as some multiple improved from advancing technology. Every indication is that global internet demand will still be rising fast enough to absorb rapidly scaling up capacity. This seems like the sort of thing that benefits from just scaling it up. More power, more antennas, more processing capacity on top of technology advance.

Offline Peter.Colin

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Re: Should ITS have a smaller prototype to ease development?
« Reply #152 on: 07/09/2017 12:19 PM »
I think they should make a mini "satellite launching ITS"!
This should have no front window but an opening and closing satellite bay.

- In this way the FH second stage is reusable (for heavier payloads it can be re-fueled by a mini tanker to be able to land)
- The basic architecture can be tested, while earning money.
- The BFR and life support systems can be developed later.
- You could practice landing on Earth and on Mars.

« Last Edit: 07/09/2017 12:24 PM by Peter.Colin »

Offline Joris

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Re: Should ITS have a smaller prototype to ease development?
« Reply #153 on: 07/09/2017 12:27 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.

SpaceX needs to figure out a way to build something of ITS in Alabama, the current SLS yearly budget would go towards ITS in a heartbeat.
JIMO would have been the first proper spaceship.

Offline spacenut

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Re: Should ITS have a smaller prototype to ease development?
« Reply #154 on: 07/09/2017 12:39 PM »
I've advocated building a booster that can take advantage of the existing Saturn V infrastructure, the existing inland and intercoastal waterways of America.  That limits the size to 12m maximum diameter.  That limits the booster thrust to 12 million lbs (Nova of the 1960's was to go to the moon with 8 F-1 engines).  Now the ITS spacecraft would have to be downsized to fit the booster.  This would at least get us to Mars, or have a huge satellite booster. 

Like someone said a full size ITS empty and only partly fueled can get to LEO, then be filled and fueled with smaller rockets.  It would require a downsized booster. 

Problem with the huge ITS system.  You would either have to launch on a sea platform, or go through an environmental nightmare to build the launch site on land or coast somewhere.  Lots of people live near the coasts.  Noise, sea turtles, etc, to deal with.  The cape is already built.  Unless they can build a launch site at Boca Chica.

If the sub-scale ITS or BFR can be built wide enough, and if a new launch site can be built, the BFR could be stretched like F9 and add more engines to whatever maximum amount of engines the diameter can take. 

I do think a sub-scale booster, with a reusable 2nd stage could take a 3rd stage to launch large or groups of GSO birds. 

Since Musk said the FH was "hard", a wide enough booster should be built that can later be stretched for more payload, but use existing facilities to begin without going to a 3 core superheavy.  At first, I thought a big rocket taking advantage of pads 39 for moon centric or a flags and footprints to Mars, then go with a 3 core heavy for the BFS or ITS.  But, after all the delays and waiting for FH, it seems logical to make a wide short rocket to begin with, then stretch like they did with F9 as either more engines are added or they are made to produce more thrust like Merlins.  So a big single core, but wide, then stretch as new facilities are built.  Just my outside opinion based on what they did with F9. 
« Last Edit: 07/10/2017 01:55 AM by spacenut »

https://twitter.com/Robotbeat/status/884140192705204224

mm what about this tweet?
It has been retwitted by people who are usually well-informed

"SpaceX in the next 1.5yrs: Falcon Heavy, Dragon Crew, highly reusable F9 (most reused), constellation demosats, Grasshopper-like ITS tests"

Offline cletus

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Re: Should ITS have a smaller prototype to ease development?
« Reply #156 on: 07/19/2017 06:00 PM »
Elon Musk confirms ITS will be smaller than announced last year (but still big): http://forum.nasaspaceflight.com/index.php?topic=42615.msg1703908#msg1703908

(Source: ISS R&D 2017 Conference livestream )
« Last Edit: 07/19/2017 06:03 PM by cletus »

Offline Lar

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Re: Should ITS have a smaller prototype to ease development?
« Reply #157 on: 07/19/2017 06:05 PM »
to the question in the topic:  Yes.

Mars architecture:

"Yes, I see ISC in Adelaide as a good time to do the updated version of the Mars architecture. It's evolved quite a bit since the last talk.  The key thing to figure out is how do you pay for all of that to go to Mars. It's super expensive. And I kind of think that if we downsize to Mars vehicle, make it capable of doing Earth orbit activity as well as Mars activity, then maybe we could pay for it using money for Earth orbit activities. That's one of the key elements of the new architecture. It's similar to what was at ISC; it's a little bit smaller but still big. But I think this one has a shot at being real on the economic front."
"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk
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Offline redliox

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Re: Should ITS have a smaller prototype to ease development?
« Reply #158 on: 07/19/2017 06:35 PM »
Elon Musk confirms ITS will be smaller than announced last year (but still big): http://forum.nasaspaceflight.com/index.php?topic=42615.msg1703908#msg1703908

(Source: ISS R&D 2017 Conference livestream )
to the question in the topic:  Yes.

Mars architecture:

"Yes, I see ISC in Adelaide as a good time to do the updated version of the Mars architecture. It's evolved quite a bit since the last talk.  The key thing to figure out is how do you pay for all of that to go to Mars. It's super expensive. And I kind of think that if we downsize to Mars vehicle, make it capable of doing Earth orbit activity as well as Mars activity, then maybe we could pay for it using money for Earth orbit activities. That's one of the key elements of the new architecture. It's similar to what was at ISC; it's a little bit smaller but still big. But I think this one has a shot at being real on the economic front."

The prophecy has come true  8)

I wasn't able to see the conference livestream.  How small will the subscale vehicle be in comparison to ITS?  Dragon 2 is almost small enough to fit into the space shuttle cargo bay whereas ITS would be slightly taller/longer and chunkier than the whole space shuttle; that's a fairly broad range (I say wearing my Captain Obvious uniform).
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Online Lars-J

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Re: Should ITS have a smaller prototype to ease development?
« Reply #159 on: 07/19/2017 06:47 PM »
There was no mention of a scale for the smaller ITS system.

Tags: Space X ITS