Will the MUCH Bigger Falcon Eat the SLS?

Yes! Well…provided NASA’s Space Launch System (SLS) is still a thing when Big Falcon Rocket (BFR) becomes a thing, which might be a while yet.

Also, I should clarify something from the start, the development timelines that Falcon Heavy and the Space Launch System demonstrated have had no respectable schedule reliability and there is no reason to believe that SLS or Big Falcon Rocket will improve on that record and every reason to assume that they won’t. However, I don’t want to keep saying, “projected” this and “projected” that throughout this blog entry. I’ll just say upfront that the numbers I will use here the projected timelines claimed by relevant experts according to various sources today. Also, the projected capabilities of these systems are fairly solid for Falcon 9 and Falcon Heavy, as they are at the end of their development cycle. Those of SLS were probably pretty much set in stone at design time and are based largely on a very well-known engine from the Space Shuttle era, and so are also fairly solid. The Big Falcon Rocket is a cutting-edge system reflecting some ideas that might not pan out in the end, some problems that have yet to be fully solved, and a new engine design that will improve from its base over repeated use and refinement. Therefore, BFR’s performance numbers will likely be quite fluid for a while.

Having said all that, the #dearMoon mission for BFR is their next goal after rolling out Commercial Crew and establishing Falcon Heavy with the Air Force. But Yusaku Maezawa’s ride will not likely be its first flight nor its first trip to the Moon. In fact, it should probably launch several robotic missions, and crewed LEO missions, before it can be expected to take a bunch of artists on a Moon tour. Elon announced a projected date for that flight as occurring in 2023, which you should consider to be a very aggressive goal.

SLS has been in development for a long time now, and will begin its flights in 2020, and isn’t currently expected to fly very frequently because of its high cost. Yet, some NASA representatives have said repeatedly that SLS is real and the SpaceX Heavy Lift Vehicle (HLV) is not. They stopped saying that this February when a SpaceX Falcon Heavy lofted a car out to Mars orbit…taking it off of the list of paper rockets that it had been sharing with SLS. Falcon Heavy, with current Block 5 technology, carries nearly as much capacity as the earliest version of SLS will, but not later versions. Its payload fairing is far too small to compete with SLS on the total dimensions of payloads that can be lifted. Also its fuel, rocket-grade kerosene, is not as efficient in space as the liquid hydrogen that SLS uses, so it’s performance drops off for interplanetary missions. Still, it will always be viewed as nearly SLS capable by those who don’t care to look at those other details. That’s important. Also it is still far from dollar for dollar less capable in the eyes of most folks.

BFR is a different bird entirely from Falcon 9, Falcon Heavy (FH), or SLS. In capabilities, BFR will have a slightly larger diameter than SLS, a slightly higher payload capacity than SLS Block 1 and slightly less than SLS Block 1B amd Block 2 as currently designed. Still, they are so close in capability that such a droll comparison descends into an unnecessarily complicated game of hair-splitting when their expected differences in cost and availability are taken into account.

Money is the main enabler for doing things in space, so doing more for less means doing more much more frequently and for a wider list of payloads and industries. This goes for both Commercial and Government projects, but far more for the Commercial ones which also happen to fly far more missions anyway. For both, greater cost means fewer missions and thus slower launch cadence, a higher percentage of overhead costs, less public interest and a greater perception of waste. Depending on who you talk to, SLS will cost between $500M and $1B per launch. Falcon Heavy, by comparison, when launched fully expandable like SLS, costs only $150M per launch. BFR will never be used expendibly, but each unit is projected to cost $335M to build if you want a basis for comparison there. Bottom line…SpaceX thinks that, due to full reusability, they can fly the BFR for an astonishingly low $7M per launch! With reusability, the much smaller Falcon Heavy can’t even come close to that at $90M! Nothing currently flying can!

There exists a powerful triumvirate at work…a mutual back-scratching club between the military procurement industry that builds SLS, certain powerful Congress persons and certain parties within NASA. These people have gotten together and arranged things nicely so that SLS doesn’t have to ever compete in any serious way with Falcon Heavy. So, it might actually survive the $500M to $90M price difference between them.

Currently, both SLS and BFR are paper rockets. So, the one remaining issue between them left to discuss is time. Therefore, let’s now look at their current development and flight timelines.

SpaceX plans begin hop tests of a prototype of BFR next year in 2019. The new engine it will use, the Raptor, burns Methane and has already been in testing. Given the routine schedule slippage of SpaceX projects however, 2020 might be more a reasonable expectation. These hop tests will attract a lot of attention, are necessary to prepare for BFR reusability, and will take place in the shadow of the very busy crewed and uncrewed Falcon 9 (F9), and ramping uncrewed FH launch schedules. The first stages of the Block 5 FH and F9 rockets are supposed to be 10x reusable and this will add credence and authority to the BFR hop tests. Even though BFR won’t be a full rocket nor an orbital launcher, blog articles like this one, written by many others out there besides myself, which compare the cost and capabilities of SLS with SpaceX rockets will receive ever-increasing Google search attention with each orbital hop test! I have already seen this. WordPress provides very detailed reports on it. —9/21/2019 Update: Oops, type-o here, I meant to say BFR’s hopper (now called “Star Hopper”) would be sub-orbital, not BFR/Starship…and the above prediction about blog article hits here with every hop came true BTW—

SLS will fly its first full on test flight in June of 2020. This date has shifted many times as a result of several design and quality control setbacks. This flight is referred to here and elsewhere as EM-1 and it will fly without a serious interplanetary propulsion stage. It will carry the Orion crewed spacecraft, without crew aboard, on a loop around the Moon, and will also deploy 13 CubeSats. I promise that the launch and flight will be important, beneficial, and epic. However, nothing else SLS related will fly in space until then. Remember that; it is an important. The last SLS/Orion related flight was EFT-1 when the Orion capsule went on a short flight aboard a Delta Heavy (another excessively expensive launcher). This flight occurred on December 5th, 2014 . Do you remember it? I had to look up the date on Wikipedia and it seemed to me to be a great deal longer ago. Rockets are Rock Stars, and like Rock Stars they must perform or they are quickly forgotten.

The SLS EM-2 mission cannot launch at all until 2022 because the Interplanetary upper stage (aka. the Interim Cryogenic Propulsion Stage (ICPS)), and the flying of crew on the Orion capsule, will require launchpad upgrades that are not projected to be completed until then. This mission, called EM-2, will be a Moon loop with a small crew.

The next SLS launch, the uncrewed Europa Clipper mission, is planned for 2024 if it does not get canceled. Not everyone is happy with it and many think the cost of launching it on SLS wil unnecessarily add too much to the mission.

All SLS launches after that through 2030, 9 launches in all, are then earmarked for the planned cislunar space station and to support the use of that station for the in-space construction of an Interplanetary spacecraft to take Orion to Mars and other places in the Solar System. This project is called the Lunar Orbital Platform-Gateway (LOP-G). The tenth launch of SLS/Orion will ride the LOG to Mars. Between now and then, the above mentioned Interplanetary launcher, the Delta Heavy (half the capacity of Falcon Heavy for $350 M / launch), will be cancelled and unavailable. So when NASA or anyone else wants to launch something out of Earth orbit, like Mars probes and landers, for the next decade, who they gonna call? Why SpaceX of course…or one of their upcoming competitors.

BFR will be on an everramping development and testing schedule leading up to #dearMoon, projected for 2023. Expect this to be the apex demonstration/test flight and for it to go into full service and begin replacing the F9, FH, and anything else that can’t measure up to it. However, I cannot stress enough that this rocket is not mostly a derivative product like Falcon Heavy. It is a totally new and still fluid design with some highly optimistic technology challenges to overcome. The orbiter component of this system is in several important ways a space plane. Such things are very hard to do and have notoriously caused many unforeseen challenges and horrible timeline creep for other companies. Even a shameless SpaceX fan like myself cannot expect SpaceX to hit anywhere near their schedule target. I will be shocked to a heart attack if do.


Frequent Falcon 9 and Falcon Heavy flights will make it increasingly difficult for the languishing SLS to maintain its support in Congress. When BFR (or something else like it) starts flying, SLS will have only slightly higher lift capacity than BFR, but a staggering price difference. SLS cannot survive any further delays because we can only afford to fly the pig once a year, and BFR will be capable of taking over the SLS mission profile. Every year that SLS doesn’t launch brings it one year closer to the 1:71 cost ratio between it and BFR. That price difference means that even if SLS survives Falcon Heavy, when Big Falcon Rockets fly repeatedly and reliably then the SLS program will fly into a wall. Nobody, not even Congress, will put up with that price difference.

Many future jobs will arise from the constantly expanding future of space exploration that will be empowered by the lower launch prices available through fixed-price Commercial contracts. Many jobs also rely on SLS, but those workers don’t need the Space Launch System to actually launch to get paid from year to year. This acts like an anchor in the mud of human progress. Folks can see more rockets flying from Fixed Price contracting. It brings about more rapid innovation, is more visible, exciting, and gets more done for a wider industry. If you work on the SLS and will retire soon, hang in there. If not, then you should make a move that will benefit you and your family and that will find your established in a more stable situation 5-10 years from now.

~ by Bill Housley on September 20, 2018.

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