Pivot to BFR

[wannamoonbase]

I believe that SpaceX can ‘pivot’ to BFR, with the following caveats.


1) That FH Flys successfully
2) The improve on reuse turn around time and costs
3) That no one takes the 2022 date seriously.

They’ll get Raptor certified
The BFR is ‘just’ twice the size of the FH with only 4 engines more
The BFR is a single body booster, easier than FH

How much time and money, those are the big questions.

[Eric Hedman]

Blue's business model is being a hobby project for a billionaire.

I suspect he has every intention of turning Blue into a profitable business.  Now that his factory is getting close to completion, I think you will see Blue Origin starting to move faster.  And I do believe his plans are pushing Elon Musk to move faster to stay ahead.  Five years from now, hopefully SpacesX and Blue Origin will be slugging it out for dominance of he launch market.

[AncientU]

...
Are there any past historical precedents that can be referenced for comparison?
Is this the best way forward, or are we likely to see some compromises in what pans out? If so, in what ways?

The US Navy made such a pivot with its submarine force.  After experimenting with reactor-powered subs, termed Fleet Nuclear Submarines, basically a WWII diesel sub with a reactor and steam propulsion plant, and testing the Albacore hull design, they stopped all diesel sub production and completely went nuclear with the Scorpion class attack subs, and soon the GW class boomers.  One individual with vision lead that transition, H.G Rickover.

At that pivot, all other subs in the world became obsolete.

[MATTBLAK]

A man who knows Sub history! I like that  (got dozens of books about submarines).

[Jim]

At that pivot, all other subs in the world became obsolete.

which is not true

[Oberon_Command]

The US Navy made such a pivot with its submarine force.  After experimenting with reactor-powered subs, termed Fleet Nuclear Submarines, basically a WWII diesel sub with a reactor and steam propulsion plant, and testing the Albacore hull design, they stopped all diesel sub production and completely went nuclear with the Scorpion class attack subs, and soon the GW class boomers.  One individual with vision lead that transition, H.G Rickover.

Skipjack-class. Scorpion was a Skipjack-class submarine.

[John Alan]

At that pivot, all other subs in the world became obsolete.

which is not true

Agreed... 
The German 212 class is known to be a good modern non nuclear sub...
https://en.wikipedia.org/wiki/Type_212_submarine

In 2013, while on the way to participate in naval exercises in U.S. waters, the German Navy's U-32 established a new record for non-nuclear submarines with 18 days in submerged transit without snorkelling.[16] It also got through all the defences of a U.S. carrier strike group, unseen, and shot green simulation torpedos at the carrier.[17]

Assuming it's 20 knot top speed is all you want out of a sub... 

Anyway... Pivot to BFR... Topic...

[sanman]

Will SpaceX have to upsize their organization significantly - even if only temporarily - in order to be able execute this pivot to BFR? Or is Musk hoping to be able to avoid that altogether by drawing down F9 production?

Isn't it safer to just borrow more and upsize temporarily, in order to meet the demands and challenges of this transition more reliably? It's not like SpaceX is still living back in the Falcon-1 days.

[ranger84]

Overall I think this pivot is exciting, but what worries me is I don't see NASA allowing astronauts to fly on something that can only land propulsively and I heard no mention of A LAS. I can see a lot of new exciting things BFR can do but I don't see how it can replace the Dragon2 in the commercial crew missions anytime soon, unless NASA changes dramatically.

[IainMcClatchie]

STP-2 requires a number of inclination and altitude changes with multiple payloads, I rather doubt F9 could do it - even expendable. And F9 definitely can't throw Dragon 2 around the Moon. And it can't compete for most DoD direct to GSO missions.

Also, the F9 upper stage is woefully undersized for BFR; you would end up wasting almost all of the booster's potential while getting about the same payload as FH. Classic LEGO rocket.

SpaceX piggybacked the first stage re-entry and landing tests on the back of a bunch of paid customer flights.  That was genius.  They managed to convince their customers to accept a switch to a higher performance vehicle, thinner margins on the engines, big legs on the booster than could have deployed during launch, subcooled propellants that did eventually burn one customer's payload.  This was a great sales job and a fabulous way to get a bunch of data that would otherwise cost billions of dollars (really out of reach).

SpaceX can kill itself if some of these gambles go wrong.  Alternatively, it can manage risk and get to the same goal with more certainty.

You can look at Falcon Heavy as a complicated way to boost a F9 upper stage to a higher energy separation.  BFR is less complex way to do the same thing -- yes, 31 vs 27 engines, but one rather than three separations, one rather than three landings, and a far simpler load path from engines to separation.  It doesn't matter that the upper stage wastes lots of the BFR potential.  BFR will cost less to operate that the two boosters and core of the Falcon Heavy.

Once the design team can transition away from BFR, they can move on to designing something that takes better advantage of it.  In the meantime the ops folks will get years of experience with BFR on someone else's dime.  They will get experience with upper stage re-entry, on someone else's dime.  SpaceX can slap horribly mass-inefficient gas/gas methalox tankage and thrusters on the upper stage to practice upper stage landings, and their customers will pay for the bulk of it.

Consider each stage of the Falcon 9 as a separate vehicle.  There is a huge amount of engineering work in each of these things, and this work is amortized over a puny number of instances.  That makes the amortized engineering in each vehicle the dominant fraction of the cost.

Rocket interfaces are far more complex than LEGO interfaces.  Interface commonality is even more work.  I'm suggesting that an adaptor that lets a BFR boost a F9US may require substantially less engineering than a new Raptor based upper stage.  And, it decouples the schedule for BFR from the BFS schedule, and lets SpaceX retire the F9 booster before retiring Dragon.

So if it's possible to put an adaptor on the BFR that allows it to lift a Falcon 9 upper stage, that may be a good idea.  It really comes down to whether the F9US can be used as is, or if it will need substantial engineering to make it work up there.

[Coastal Ron]

Overall I think this pivot is exciting, but what worries me is I don't see NASA allowing astronauts to fly on something that can only land propulsively and I heard no mention of A LAS. I can see a lot of new exciting things BFR can do but I don't see how it can replace the Dragon2 in the commercial crew missions anytime soon, unless NASA changes dramatically.

Propulsive landing is going to take a while to get comfortable with, but we are many years away from NASA having to be concerned with that option - and they would still have the Boeing Dreamliner to rely upon.

[DreamyPickle]

Dragon 2 propulsive landing was cancelled because it was too much work to qualify the system and prove that it can work safely. I guess he proposed DragonFly program was not enough?

The BFS however can hold a lot more fuel and can fly around and simulate the final stages of descent and landing many times. We'll get to see it perform plenty of aerial acrobatics and this should satisfy crew safety requirements for landing.

Lacking an abort system could be a problem. Regulations might force them to add something before they can legally fly passengers.

[Coastal Ron]

Lacking an abort system could be a problem. Regulations might force them to add something before they can legally fly passengers.

Commercial airliners have never had "abort" systems for the passengers, so I'm not sure why this would be any different.

The first people flying on point-to-point rockets like this will also be OK with signing a "informed consent" form.

[MATTBLAK]

Dragon 2 was cancelled because it was too much work to qualify the system and prove that it can work safely. I guess he proposed DragonFly program was not enough?

The BFS however can hold a lot more fuel and can fly around and simulate the final stages of descent and landing many times. We'll get to see it perform plenty of aerial acrobatics and this should satisfy crew safety requirements for landing.

Lacking an abort system could be a problem. Regulations might force them to add something before they can legally fly passengers.

Dragon 2 cancelled?! Are you saying that SpaceX will no longer have a Commercial Crew Astronaut vehicle for ISS? I don't think that's going to happen.

[DreamyPickle]

Dragon 2 cancelled?! Are you saying that SpaceX will no longer have a Commercial Crew Astronaut vehicle for ISS? I don't think that's going to happen.

Sorry, I just meant the propulsive landing part.

[DOCinCT]

Will SpaceX have to upsize their organization significantly - even if only temporarily - in order to be able execute this pivot to BFR? Or is Musk hoping to be able to avoid that altogether by drawing down F9 production?

Isn't it safer to just borrow more and upsize temporarily, in order to meet the demands and challenges of this transition more reliably? It's not like SpaceX is still living back in the Falcon-1 days.

I would think some production staff will move from Merlin to Raptor assembly lines, since the skill sets are similar.  One would assume the manufacture of the engine assemblies, plumbing etc. is the same skill set as well.
The carbon fiber production staff, assuming there is staff, would have to be greatly expanded, most likely from new hires (with retraining the tank assembly people when Falcon production ramps down). 

[hamerad]

Wouldn't it be possible if they do run into issues with BFR to slow instead of just halt F9 production by reducing number of F9 in production from 5 to 1?

This would still give them the benefit of shifting staff onto BFR with the added safety net of having a few more F9 around to keep up with demand.

[guckyfan]

I think this is way overrated. The switch will be gradual.

Very soon they switch much of their development capability to BFR.

Early next year the F9 first stage production facility will start building block 5. End of next year they know exactly how much effort they need for servicing them and how many flights they can do with only servicing. They will also have a good understanding if they would be able to do a major refurbishment to continue flying a core beyond 10 or 12 uses. At that time they can determine how many first stages they need in stock and can probably terminate production of first stages, mothballing the production line.

They will keep producing second stages in a separate production facility as long as they are needed.

In parallel they phase out production of SL Merlin and introduce Raptor.

By that time they will know with high confidence when they will be able to fly BFR. At no time there is a major risk. Worst case they have to reactivate F9 production.

[IainMcClatchie]

Suppose for a moment that you are Gywnne Shotwell.  It's late 2018, you've recovered a few F9 Block 5 boosters, and the Raptor team hasn't had a RUD on the test stand in six months.  Fairing capture and reuse are just starting.
 You are certain that the BFR that you build will be reused at least ten times. 

How big a BFR do you want to build?

Does it really matter if it has 31 or 42 Raptors? You already have the 12 meter tooling -- you built that when you built the test tank.  Fuel is still a small part of your launch costs, and you don't have to fill the BFR tanks completely when you launch.  There is pretty much no difference in moving a 9 vs 12 meter rocket, neither one is going down a California freeway.

I think they should build the full-size BFR.  They can leave off some engines and partially fill the tanks if they want to save a few bucks.  The launch cradle, recovery cradle, vertical integration cranes, setbacks for noise and safety, these can all be sized for the full BFR.

[speedevil]

<snip>
Does it really matter if it has 31 or 42 Raptors? You already have the 12 meter tooling -- you built that when you built the test tank.  Fuel is still a small part of your launch costs, and you don't have to fill the BFR tanks completely when you launch. 

You don't have the tooling - test tooling capable of laying up one 12m tank is not going to be capable of holding, transporting, moving, outfitting multiple 12m BFR stages.
(well, unless they've managed to make it not leak over months, and they were insane and spent at least a large slice of a billion, and have a building we don't know of)