Speculation thread: intermediate-lift Raptor-derived RLV

[GWH]

In considering the launch costs of ITS vs a miniITS spaceship I think one should look at F9 development and reuse.

SpaceX didn't just slap some legs and grid fins on the F9, land it and reduce the costs of launch through reuse the moment they did that. It's been, and still is, a long journey and many lessons learned in the process.  The block 5 is supposed to get them to the point of rapid and economical booster reuse.  There will be new challenges in upper stage reuse, particularly when there is so much new tech involved in the ITS. See the shuttle orbiter for example.  It will not be easy to get the reflight rates and low refurb of the ITS that makes the per launch cost as low as they want.  There may be a lot of value in learning some of those lessons at a smaller scale.

But to make this argument that the first flight of ITS is going to instantly flip the cost equation on its head is, in my opinion, rubbish.  Just like with F9, it will take a while until they reach that point of operational reusability of a complete new system to reach the cost/flight goals that are projected.

[macpacheco]

In considering the launch costs of ITS vs a miniITS spaceship I think one should look at F9 development and reuse.

SpaceX didn't just slap some legs and grid fins on the F9, land it and reduce the costs of launch through reuse the moment they did that. It's been, and still is, a long journey and many lessons learned in the process.  The block 5 is supposed to get them to the point of rapid and economical booster reuse.  There will be new challenges in upper stage reuse, particularly when there is so much new tech involved in the ITS. See the shuttle orbiter for example.  It will not be easy to get the reflight rates and low refurb of the ITS that makes the per launch cost as low as they want.  There may be a lot of value in learning some of those lessons at a smaller scale.

But to make this argument that the first flight of ITS is going to instantly flip the cost equation on its head is, in my opinion, rubbish.  Just like with F9, it will take a while until they reach that point of operational reusability of a complete new system to reach the cost/flight goals that are projected.

You must assume SpaceX needs to learn things all over again to design a new LV that's fully reusable from the get go.
Rocket design is engineering rather than experimentation. Experimentation is done when there's no / little data. But F9 / FH reuse experience provides a lot of valuable data and experience that makes ITS design far closer to 100% engineering rather than experimentation.
I agree with you that many more lessons will be learned from Block IV and Block V ops, but its very likely mini ITS / ITS construction will only begin 12-24 months after Block V starts flying, which might provide SpaceX around 25 flights worth of Block V flight/re flight.

People insist on thinking they understand SpaceX modus operandi while ignoring Elon Musk's style and track record.
He's as ballsy as they get. He's also a perfectionist. He won't start cutting ITS / mini ITS metal until the design is up to his standards which are quite high.

If you can't put yourself inside E.M.'s head your predictions are very very likely wrong.
My opinion (as well as yours) isn't worth much if you're assuming things will be done they way you like, they will be done like E.M. likes is. Embrace that.

[guckyfan]

People insist on thinking they understand SpaceX modus operandi while ignoring Elon Musk's style and track record.
He's as ballsy as they get. He's also a perfectionist. He won't start cutting ITS / mini ITS metal until the design is up to his standards which are quite high.

In all speculation we need to remember a reusable second stage is announced for end of next year. I can not believe that at this stage they will spend all the needed engineering effort for developing a new Merlin upper stage. I am convinced it will be a Raptor upper stage. Up until that reusable upper stage was announced I liked to speculate but did not believe in a Raptor upper stage for Falcon. But the reusable announcement has changed that.

[macpacheco]

People insist on thinking they understand SpaceX modus operandi while ignoring Elon Musk's style and track record.
He's as ballsy as they get. He's also a perfectionist. He won't start cutting ITS / mini ITS metal until the design is up to his standards which are quite high.

In all speculation we need to remember a reusable second stage is announced for end of next year. I can not believe that at this stage they will spend all the needed engineering effort for developing a new Merlin upper stage. I am convinced it will be a Raptor upper stage. Up until that reusable upper stage was announced I liked to speculate but did not believe in a Raptor upper stage for Falcon. But the reusable announcement has changed that.

I would call it a recoverable upper stage rather than a reusable one. A first step. Precisely where SX needs to experiment with techniques.

[JamesH65]

People insist on thinking they understand SpaceX modus operandi while ignoring Elon Musk's style and track record.
He's as ballsy as they get. He's also a perfectionist. He won't start cutting ITS / mini ITS metal until the design is up to his standards which are quite high.

In all speculation we need to remember a reusable second stage is announced for end of next year.

No not really. They said they hope to do something that may or may not be a reusable second stage, hopefully maybe by the end of next year.

I can not believe that at this stage they will spend all the needed engineering effort for developing a new Merlin upper stage. I am convinced it will be a Raptor upper stage. Up until that reusable upper stage was announced I liked to speculate but did not believe in a Raptor upper stage for Falcon. But the reusable announcement has changed that.

I don't think there is any evidence at all to support a Raptor U/S. Not to say it won't happen, just that there is nothing to indicate that it will. If nothing else, the cost to infrastructure to support it will be pretty high. Will the Raptor even be ready by end of next year?

[hkultala]

People insist on thinking they understand SpaceX modus operandi while ignoring Elon Musk's style and track record.
He's as ballsy as they get. He's also a perfectionist. He won't start cutting ITS / mini ITS metal until the design is up to his standards which are quite high.

No, the only reason he's not cutting ITS metal is because it's made of carbon fiber, not metal.

Related to his perfectionism, exactly the opposite. He knows that the best way to get something done is to start experimenting, get your hands dirty. And they ALREADY both made and broke one ITS tank.

[spacenut]

I still think a Mini-ITS/BFR should be built to be able to take advantage of pad 39A at 12 million lbs thrust or less.  More than Saturn, but less than a full blown 28 million they have been speculating for the BFR.  ITS or Mini ITS would be sized to fit this 12 million lb thrust rocket.  That way SpaceX can take advantage of the existing pad and infrastructure.  Same with transportation infrastructure. 

[macpacheco]

No, the only reason he's not cutting ITS metal is because it's made of carbon fiber, not metal.

Related to his perfectionism, exactly the opposite. He knows that the best way to get something done is to start experimenting, get your hands dirty. And they ALREADY both made and broke one ITS tank.

F9 Block II easily took at least an extra year to fly because Musk demanded M1D engines had to had the margins to fly 100 times, several things on the F9 Block II were very overdesigned because of reuse, although they knew they wouldn't be recovering and reflying Block II for a while.

And now SX already has a line of rockets flying, generating revenue, certified with USAF.

The earlier you fix issues the cheaper the fix is to implement.

The full ITS set (1 booster, 1 tanker, 1 spaceship) is expected to cost over half a billion USD.
I'd say even Elon Musk isn't going to build the first one in a hurry. The man has a degree in economics. He's aggressive but certainly not stupid.
If its a mini ITS that might be able to launch from LC39A at a reasonable cost of upgrades, that's one thing, but if its the full size ITS, I don't think your argument holds water.

[spacenut]

One of the reasons I believe a "Raptor 9" based rocket would be beneficial is not only taking advantage of existing infrastructure, but the following.

Say a 7m diameter Raptor 9 is built.  A 7 meter upper stage could also be built to be reusable, based on ITS design, only smaller about half scale.

A Raptor 9 would generate about 6 million lbs thrust.  This would get an expendable version payload to 80-90 tons.  Ok you make the entire rocket reusable and you can match Falcon heavy expendable.  Falcon heavy, according to Musk, is "hard".  A single stick rocket would be easier?  Probably. 

This rocket could do moon and Mars, with extensive building of an in space infrastructure to use fuel depots, SEP tugs, among other things. 

Sure you only can get about 30-40 tons of payload to Mars, maybe more, but that is doable sooner.  With SEP tugs and fuel depots, even more payload may could be landed. 

This rocket would compete, (with various upper stages) with SLS and New Glenn, and be more capable.  Falcon Heavy would not be needed. 

Shear cost is another reason to take advantage of existing infrastructure.  Pads 39A or B could either be used to launch without building a new launch facility. 

This rocket with the ability to launch the Constellation by carrying 20-30 or more satellites in one launch.  Cost to launch a large single stick shouldn't be more than Falcon Heavy is to be, so launch costs would drop. 

This rocket would be in the range of payload and capabilities of the old "Direct" rocket, at about half the price. 

It could fill and nich and still get us to Mars with refueling.  So, it may take 3 times as many launches as a full blown ITS, but should cost less than half to get going.   

[guckyfan]

I think the remark FH is "hard" gets interpreted wrong. Sure the design was hard. But like Tom Mueller said about Merlin 1D, the design was hard. Now that it is designed, building and flying it is no longer hard. The same will apply for FH. FH will be replaced, but not earlier than phasing out the whole Falcon family, IMO.

[AncientU]

One of the reasons I believe a "Raptor 9" based rocket would be beneficial is not only taking advantage of existing infrastructure, but the following.

Say a 7m diameter Raptor 9 is built.  A 7 meter upper stage could also be built to be reusable, based on ITS design, only smaller about half scale.

A Raptor 9 would generate about 6 million lbs thrust.  This would get an expendable version payload to 80-90 tons.  Ok you make the entire rocket reusable and you can match Falcon heavy expendable.  Falcon heavy, according to Musk, is "hard".  A single stick rocket would be easier?  Probably. 

This rocket could do moon and Mars, with extensive building of an in space infrastructure to use fuel depots, SEP tugs, among other things. 

Sure you only can get about 30-40 tons of payload to Mars, maybe more, but that is doable sooner.  With SEP tugs and fuel depots, even more payload may could be landed. 

This rocket would compete, (with various upper stages) with SLS and New Glenn, and be more capable.  Falcon Heavy would not be needed. 

Shear cost is another reason to take advantage of existing infrastructure.  Pads 39A or B could either be used to launch without building a new launch facility. 

This rocket with the ability to launch the Constellation by carrying 20-30 or more satellites in one launch.  Cost to launch a large single stick shouldn't be more than Falcon Heavy is to be, so launch costs would drop. 

This rocket would be in the range of payload and capabilities of the old "Direct" rocket, at about half the price. 

It could fill and nich and still get us to Mars with refueling.  So, it may take 3 times as many launches as a full blown ITS, but should cost less than half to get going.   

If you are going to build a completely new rocket to take advantage of existing infrastructure, why just go incrementally better than FH?  So you've obsoleted your own rocket... not a reason to celebrate.

New intermediate-sized Raptor rocket should maximize capability of LC-39A and B.  Build a 12+Mlbf booster (19 engines in three ring -- 1-6-12 -- hex pattern  would be my choice) with both a conventional second stage and fairing, plus a follow-on mini-ITS spaceship second stage.  Core diameter would be around 9m (8-10).  Reusable booster mode payload would be around 200t.

Probably could find a few uses... everything you said x 2.  And obsolete someone else's rocket.

[guckyfan]

If you are going to build a completely new rocket to take advantage of existing infrastructure, why just go incrementally better than FH?  So you've obsoleted your own rocket... not a reason to celebrate.

FH covers almost the entire need for lifting in cislunar space. No need to build a bigger rocket than this. Except for the ITS which can take care of everything too large for the smaller vehicle.

New intermediate-sized Raptor rocket should maximize capability of LC-39A and B.  Build a 12+Mlbf booster (19 engines in three ring -- 1-6-12 -- hex pattern  would be my choice) with both a conventional second stage and fairing, plus a follow-on mini-ITS spaceship second stage.  Core diameter would be around 9m (8-10).  Reusable booster mode payload would be around 200t.

Probably could find a few uses... everything you said x 2.  And obsolete someone else's rocket.

This would be a rocket oversized for most launchs. They are already developing an oversized rocket, why another?

[spacenut]

A 12 million lb thrust or lower would take advantage of existing infrastructure.  Give us a big rocket to match or exceed SLS at a lower cost.  Allow for a Mini-ITS which would give us 50 tons or 50 people to Mars instead of 100.  Allow us to get there quicker as no new infrastructure would have to be built (except at Boca Chica maybe).  This rocket could become a workhorse for moon as well as Mars missions.  Multiple satellite launcher.  Deep space probe launcher. 

The width of railroad tracks haven't changed since the 1880's when they standardized the track nationwide.  Engines have increased in size as well as railcars.  Why not build a rocket to take advantage of infrastructure built to handle the Nova rocket of the 1960's that was never built.  Same with highways.  Trucks have gotten larger but not the highway widths.  Two pads can already handle 12 million lbs.  Existing barges in the inland waterways of America can handle 10-12m maximum diameter.  Don't know the maximum length. 

With the BFR/ITS, the factory will be limited to near the pad.  Due to the massive power of this rocket, a huge radius would need to also be clear for each launch.  The Cape has this but at 12 million lbs.  The Mini-BFR factory and the Mini-ITS factory could be built anywere along the inland or intercoastal waterway, like in states that are more manufacturing friendly and have less regulations than California, and are also nearer potential launch locations and LNG facilities. 

Again taking advantage of existing infrastructure from factory to transportation to launch site has to be a cost consideration, not just the biggest rocket you can build on paper, but as big as you can reasonably build cost wise and still get to Mars. 

[macpacheco]

If you are going to build a completely new rocket to take advantage of existing infrastructure, why just go incrementally better than FH?  So you've obsoleted your own rocket... not a reason to celebrate.

New intermediate-sized Raptor rocket should maximize capability of LC-39A and B.  Build a 12+Mlbf booster (19 engines in three ring -- 1-6-12 -- hex pattern  would be my choice) with both a conventional second stage and fairing, plus a follow-on mini-ITS spaceship second stage.  Core diameter would be around 9m (8-10).  Reusable booster mode payload would be around 200t.

Probably could find a few uses... everything you said x 2.  And obsolete someone else's rocket.

Raptor's better ISP and double T:W are huge benefits, both for upper stable and booster.

Just as importantly F9 and FH were designed aiming for re-use but they couldn't take reuse for granted.
Designing a rocket from the ground up for reuse allows such things as much more expensive but lighter carbon composite structures, giving up on road transport.
Its funny the list has been enumerated over a dozen times by several people, but some guys have locked their thought process in a path that doesn't actually make sense.

The fundamental FACT is F9 with upper stage expendability is a very capable rocket that can handle the vast majority of SpaceX manifest.
Designing a Raptor upper stage will deliver more performance, but at what fabrication cost vs F9 upper stage ?
SpaceX stated main upper stage reuse path involves putting same fuel vacuum and SL engines on the upper stage, there's not enough room to do that with road transport limits.
So if you open your mind to the give and take of:
1 - The end game is ITS and ITS style reuse
2 - Raptor is already being tested, for nearly 6 months, Raptor is a very real rocket engine !
3 - Raptor is designed for perhaps 100 mission firings per refurb, 10x as many as M1D (key, key, key issue) Just the refurb savings on the booster already shoots down your idea !
4 - In the short run, F9 as is can handle the manifest economically, with FH handling the balance
5 - There's a lot of economical benefit on a larger rocket that can deliver a handful of GEO satellites at a time to a far more convenient orbit than today. Don't loose sight that most of SpaceX's current revenue is toward GEO launches
6 - A fully reusable SLS sized booster will... KILL SLS ! There's a chance SpaceX can finally be recognized as the path to the Mars, the Moon, the outer planets. What if SpaceX started getting a US$ 1 billion / yr subsidy to build the full sized ITS ? (Ok, I'm probably dreaming)
7 - A mini ITS / Raptor 9 rocket would actually have the lifting and payload bay/fairing size to deliver perhaps even 3x as many CommX satellites per launch.

And you're blatantly ignoring the FACT that SpaceX / Elon Musk doesn't think small. Yep, you're thinking way too small. You're idea doesn't fit SpaceX  M.O.

[spacenut]

Maybe not, but it is more practical and can be done sooner rather than later.  We still need the raptor engines, not matter what rocket they are used on.  I know this is a speculation thread, but no infrastructure exists for the proposed BFR/ITS yet.  That will take 3-5 years to build and maybe an extra billion.  2 years to modify pad 39 they already have maybe and probably a couple hundred million.  They could even use the McCloud facility in Louisana to build and intermediate lift of 12 million lbs or less or anywhere else for that matter.  LNG can be either shipped in or piped into the Cape.  A pipeline company might even build the pipeline into the cape from an existing pipeline just for the sale of the gas, and maybe even the LNG facility.  Before I retired from my gas company a pipeline for natural gas was being laid under the Gulf from Louisiana to Tampa for power generation.  From this pipeline alone LNG could be made during off peak hours at a power plant. 

Also, if the intermediate 10-12 million lb thrust Raptor derived vehicle is built, it would be less costly than SLS for the same or larger payload, putting SLS out of business.  This rocket could be built within 5 years, not 10 for BFR/ITS.  Also, Musk might need another influx of capital to get this big project up and running.  With an intermediate Raptor derived rocket, he could begin on his own. 

For practical purposes, I think large SEP tugs should be built to carry non perishable and non human cargo to Mars.  A Mini ITS system could be left at Mars and not return to earth to dock and bring down the SEP cargo to Mars, SEP could then return to Earth for more cargo.  The intermediate vehicle can launch the SEP tugs, cargo and propellant on a continuous bases to Mars.  Mini-ITS would bring people and several used and Mars transport between Mars and high Mars orbit.  SEP tugs could use argon from Mars or Earth to refuel since Mars atmosphere had quite a bit of argon.  Or they could use an oxygen supplied SEP tug with excess oxygen created in methane production on Mars to supply the fleet of Mini-ITS. 

 

[philw1776]

Again taking advantage of existing infrastructure from factory to transportation to launch site has to be a cost consideration, not just the biggest rocket you can build on paper, but as big as you can reasonably build cost wise and still get to Mars.

That was a major factor when SpaceX was sending new cores to FL for every launch and even sending flight proven cores back to Texas for static firings then back to FL.  An ITS will be transported once, from the nearby factory and then used many tens of times plus without further transportation.
I don't see how a wide 12 million LB rocket uses existing transportation.

[dror]

One of the reasons I believe a "Raptor 9" based rocket would be beneficial is not only taking advantage of existing infrastructure, but the following.

Say a 7m diameter Raptor 9 is built.  A 7 meter upper stage could also be built to be reusable, based on ITS design, only smaller about half scale.

A Raptor 9 would generate about 6 million lbs thrust.  This would get an expendable version payload to 80-90 tons.  Ok you make the entire rocket reusable and you can match Falcon heavy expendable.  Falcon heavy, according to Musk, is "hard".  A single stick rocket would be easier?  Probably. 

This rocket could do moon and Mars, with extensive building of an in space infrastructure to use fuel depots, SEP tugs, among other things. 

Sure you only can get about 30-40 tons of payload to Mars, maybe more, but that is doable sooner.  With SEP tugs and fuel depots, even more payload may could be landed. 

This rocket would compete, (with various upper stages) with SLS and New Glenn, and be more capable.  Falcon Heavy would not be needed. 

Shear cost is another reason to take advantage of existing infrastructure.  Pads 39A or B could either be used to launch without building a new launch facility. 

This rocket with the ability to launch the Constellation by carrying 20-30 or more satellites in one launch.  Cost to launch a large single stick shouldn't be more than Falcon Heavy is to be, so launch costs would drop. 

This rocket would be in the range of payload and capabilities of the old "Direct" rocket, at about half the price. 

It could fill and nich and still get us to Mars with refueling.  So, it may take 3 times as many launches as a full blown ITS, but should cost less than half to get going.   

If you are going to build a completely new rocket to take advantage of existing infrastructure, why just go incrementally better than FH?  So you've obsoleted your own rocket... not a reason to celebrate.

New intermediate-sized Raptor rocket should maximize capability of LC-39A and B.  Build a 12+Mlbf booster (19 engines in three ring -- 1-6-12 -- hex pattern  would be my choice) with both a conventional second stage and fairing, plus a follow-on mini-ITS spaceship second stage.  Core diameter would be around 9m (8-10).  Reusable booster mode payload would be around 200t.

Probably could find a few uses... everything you said x 2.  And obsolete someone else's rocket.

Now, you see where this leads?
This is, as guckyfan suggested, a very Big FR.
I agree these are very reasonable advantages, and I too think this is a more logical size for the BFR, but it will only push the full size further away.
An intermediate vehicle needs to serve the later design, not compete with it.
It needs to be drastically simpler in order to remove 'design roadblocks', to make the impossible possible.

Sevenperforce's design is just that-
You start with a spaceship that lanches on FH, develope all hardware and architecture on smaller scale and realistic budjet and timescale while being usefull.
IF necessary, then move on to an improved booster and develope the needed hardware, again, on smaller scale.
Only then you move on to a big freaking rocket, with your development process sped up.

On that note, I do think that 4 meters is too small for the spaceship which needs to be at least as big as a a F9 fairing.

[spacenut]

12m would use existing barge transportation on rivers and the inter-coastal waterway.  The VAB and pads 39A and 39B were designed for 12m Nova rocket to replace Saturn V.  Nova was to have 8 F1 engines and develop 12 million lbs thrust which is what the pads and the VAB were designed to handle. 

I do not think the existing barge and inter-coastal waterway can handle anything larger than 12m due to bridges and standard barge sizes.  15m ITS will require ALL new infrastructure.  Transportation from factory to launch pad, and launch pad itself, as well as distance for the shock wave of the blast off.   The cape offers this from the old Saturn pads.  The VAB could be used for assembly and the old Saturn transporter could be used for ITS because ITS is liquid fueled, thus will be lighter than solids.   

[macpacheco]

Think about how large a rocket that would still cost less per launch than F9, as long as:
F9 booster requires a little refurb each launch, a lot of refurb every 10 launches and must be rebuild/thrown away every 100 launches.
F9 upper stage is still thrown away except when launched on a FH with very little payload but FH launches incur 3x faster usage of boosters.

Meanwhile a very large rocket consumes far more O2 and CH4, but those are both very cheap, the booster flies 100x between refurbs, 1000x total, the upper stage flies say 20x between refurbs and 100x total. The cost to build the launch stack and refurb should still dominate.

Even a rocket with SLS size expendable performance could be cheaper or at least similar cost per launch with F9.
It both casts a shadow over SLS, but also directly replaces all FH launches and could also replace the vast majority of F9 launches.

I also suggest thinking about launch pad congestion if the predicted launch volume materializes.
F9/FH are stepping stones onto large raptor rockets, they are not going to hang around once mini ITS is flying and its certified with NASA/USAF.

[gospacex]

I also suggest thinking about launch pad congestion if the predicted launch volume materializes.
F9/FH are stepping stones onto large raptor rockets, they are not going to hang around once mini ITS is flying and its certified with NASA/USAF.

Wrong.
F9/FH is the only thing which makes SpaceX money at the moment. They are "cash cows".

Whatever new rocket SpaceX builds, it definitely will need some pad modifications - which means pad downtime, which means "cash cows" stop generating money. Which means only one pad at a time should undergo modifications - to keep other pads launching "cash cows". Which means they *are* going to hang around for years even when a new, better SpaceX rocket exists.

And if the new rocket is so large that it needs a new or radically modified pad, the effect is even more pronounced, since now "cash cows" can't launch from it. If any problem grounds new rocket, no money gets generated by this shiny new tech, *and* "old" tech can't launch either!

The above considerations might even result in SpaceX opting to build new pads, not modify existing ones.

Apart from pads, new rocket potentially experiencing problems (such as launch mishaps) is another reason why F9/FH will not be removed from service at once. They will be old, well-known and reliable, if somewhat less efficient, money makers for the company.