Guidance systems are vastly less expensive now, and can take advantage of things like MEMs, fiber laser gyros, and GPS (and, of course, modern computing power).

The tanks on Falcon are welded using Friction Stir Welding, which was invented in the early 1990s.

The landing algorithm for the first stage uses convex optimization algorithms based on interior point methods, which were not available in the 1960s.

However, something very much like an expendable F9 could probably have been built in the 1980s. Simply evolving the Saturn 1B (which was cheaper, per lb of payload to orbit, than the Saturn V) could have easily beaten the Shuttle's economic performance.

I had not heard of Friction Stir Welding previously. Video that demonstrates the technique is here:

https://www.youtube.com/watch?v=aNbQH8XBgxQ

Smarter Every Day has a very interesting video[1] inside the factory of United Launch Alliance in which, among a lot of other things, shows the friction stir welding used in their Atlas Rocket[2]:

[1] https://youtu.be/o0fG_lnVhHw

[2] https://youtu.be/o0fG_lnVhHw?t=1933

This is a great video. Thank you for sharing it.

The gimmick that Eclipse Aircraft (Paul Allen) used to get almost half a billion in investment is they would use FSW instead of rivets.

But that wasn't the main problem with creating a new jet, which has a myriad of other issues before certification.

I'm going to go with SpaceX doesn't have to source from 50 states. It also hasn't had its funding turned off and on.

More generally, SpaceX doesn't have to pay the cost of crossing organizational boundaries. When that happens, unless the parts are standardized and commoditized, then requirements have to be formalized, contracts and costs negotiated. Time and again SpaceX found it was cheaper and faster to just do things themselves rather than buy from traditional aerospace contractors.

"It also hasn't had its funding turned off and on."

That one's a killer. I was once a project manager at an aerospace company developing a new processor chipset for space applications. Our government customer would run out of money near the end of every fiscal year, forcing us to shut down. Then a few months later they would secure funds and ask us to restart. By then most of my staff would have been reassigned to other projects. It was stupidly inefficient and caused costs to balloon.

Yes, mass scale optimization software (CPLEX, GUROBI, XPRESS) is all pretty recent and has completely changed countless industries and saved billions of dollars.

One dimension to this that is often forgotten is that SpaceX does things, though. Of course, many problems are solvable now that everything is more advanced, but putting them to use and creating actual progress for humanity is the real fantastic feat of SpaceX.

yeah, ideas and algorithms are a dime a dozen. turning them into reality is the hard part.

Not to mention CFD modeling - the F1 engines' combustion stability took enormous amount of iterative development and exploding test articles to get right, whereas new engine designs are much closer to working when the first prototypes roll out.

> Simply evolving the Saturn 1B (which was cheaper, per lb of payload to orbit, than the Saturn V) could have easily beaten the Shuttle's economic performance.

I don't know how much it applies, but sometimes evolving something requires switching out components for other ones, which are more expensive. Not everything scales. Marketing isn't the only reason why 50% more capability often costs 100% more. I imagine with rocketry, you're often operating at the edge of the capability for certain materials and approaches.

We have an example of a better component, that is otherwise very similar: the first stage engines of the Saturn IB and the Falcon 9:

H-1: https://en.wikpedia.org/wiki/Rocketdyne_H-1

Merlin: https://en.wikipedia.org/wiki/SpaceX_Merlin

The Merlin has considerably higher specific impulse and thrust/weight ratios. It also has very fast throttling, a necessity for vertical landing. And, it's remarkably cheap (less than $1M per engine). I don't have the figure for the inflation-adjusted cost of the H-1, but I suspect it was much more expensive.

There is a typo in the H-1 link It should be: https://en.wikipedia.org/wiki/Rocketdyne_H-1

> The landing algorithm for the first stage uses convex optimization algorithms based on interior point methods, which were not available in the 1960s.

Is this level of optimisation really needed? I thought most of the landing was having enough fuel margin and then running a PID control algorithm during the landing burn.

Apparently yes. See Lars Blackmore's chapter in the 2016 "Frontiers of Engineering" (National Academy Press) (free registration required)

https://www.nap.edu/read/23659/chapter/10

https://www.nap.edu/download/23659

"SpaceX uses CVXGEN (Mattingley and Boyd 2012) to generate customized flight code, which enables very high-speed onboard convex optimization."

This is actually a great example of a true NASA spinoff, btw. Lars Blackmore was at JPL before moving to SpaceX. Landing on Mars and landing a first stage back on Earth aren't the same problem, but they're close enough for the work to transfer.

I believe that the biggest obstacle in SpaceX's "hover slam" landing isn't calculating and controlling the burn but getting sufficiently precise input in time for those calculations. It must be a miracle of sensor fusion.

We had something like an expendable F9 in the 1980s. It’s called Atlas. We used it to launch GPS. We used it during the Shuttle era and we still use it.

> but you have to take into account both more modern technology, as well as the fact that they were able to build off the shoulders of giants.

NASA is currently developing the Space Launch System (SLS) and has spent over $20b with almost nothing to show for it.

https://en.m.wikipedia.org/wiki/Space_Launch_System

To be fair to NASA, I don't think SLS would be nicknamed the senate launch system if it was up to them.

I totally agree. NASA is definitely not incompetent, they are just saddled with bureaucracy and the wrong incentive structure. It's an inherent problem with public institutions, and that's why this public private partnership is so important.

Sure, there are likely many small advantages that add up. For example, 3 flat panels and a few buttons probably weigh less than a metal panel full of dials, allowing for a better payload ratio. That technology wasn't available during the Mercury/Gemini/Shuttle period for any price.

sensors and wiring always weighed more. Of course now the wiring COULD be CANbus or similar in concept instead of individual (heavy) wires. Or move the analog processing and microcontroller to the sensor itself instead of running wires all over the place to a central computer.

Iirc the computers are connected by commodity cat 6e Ethernet.

Do you mean ethernet as the link layer? I ask because I've encountered a number of systems where CAN bus is operated over a cat 6e physical layer.

I can't tell you the answer, but I can definitely say that "cat 6e" is imprecise at best because that's a misnomer rather than an actual standard.

Industry proven technology and easy as heck to replace on-site.

You can't buy company culture either, but that could have been built 40 years ago

Maybe not during Mercury, but definitely during the 70s all the technology was there to build a cheap, reusable rocket and capsule.

The dream was that the shuttle could be that system, but it did not turn out that way. And giving in to the 'sunk cost fallacy' they supported the shuttle for the next 40 years.

Arguably you could say we are 50 years behind where we should be. Unfortunately driving down costs is probably the hardest thing for any government organization to do. Given that there is no competition, no shareholders, no profit motive etc..

Didn't Space X also benefit from NASA launch facilities? I imagine their payroll also includes quite a few NASA trained people too. They certainly aren't doing rocket science from scratch or in a vacuum.

Not too say this isn't a big deal. Just that it's not all Elon and his wunderkind.

Yeah of course, SpaceX would be stupid to not use the resources NASA will make available for them. Honestly, NASA would probably much rather be out of the business of building rockets, so they can focus on the next generation of space experiments. The less money NASA has to spend on hauling stuff into space, the more they can spend on what they put up there.

> NASA would probably much rather be out of the business of building rockets

NASA has never been in the business of building tickets. Mercury went up on Army's Redstone, Gemini on Air Force Titan. Routine launches are on ICBM-derived Atlas and Titan.

Boeing and Douglas built Saturn V, Rockwell built the shuttle orbiter.

SpaceX leases the launch pad and Eastern Range, but those are paid either on a yearly basis, or per use. The NASA/DoD personnel that support the launch are getting paid whether there's a launch or not, because they're needed for any launch from the Cape.

Some are meant to teach, others are meant to do.

NASA and their bureaucracy have been sliding out of the "do" category for some time.

They’ve been doing plenty, but it’s all in unmanned missions.

Furthermore, NASA has always relied heavily on the aerospace/defense industry and related organizations to design and build spacecraft.

Yeah. It is great that Nasa and the US military paved the way, like has happened before (The internet, etc). SpaceX feels like a new era of spaceflight, harnessing so much of the potential that US government created in the previous era.