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Earlier quoted context omitted.
I understood it as: better_time = estimated_time * 3; better_cost = estimated_cost * 10;
I missed that - this makes more sense
>29. (von Tiesenhausen's Law of Program Management) To get an accurate estimate of final program requirements, multiply the initial time estimates by pi... I discovered this when my father would come up with some project me and my siblings had to do, such as scrape, sand, prime and paint the house (which thinking back very likely had lead paint). It would inevitably take roughly 3 times longer than he wanted it to ta…
https://en.wikipedia.org/wiki/Hofstadter%27s_law
Hofstadter suggested doubling the scalar and incrementing the units by one. 3 hours -> 6 days, 2 weeks -> 4 months, etc...
This is definitely the wisdom of ages, but some points do show some age. 39. (alternate formulation) The three keys to keeping a new human space program affordable and on schedule: 1) No new launch vehicles. 2) No new launch vehicles. 3) Whatever you do, don't develop any new launch vehicles. Recent SpaceX developments, Starship in particular, put some doubts on this one.
SpaceX never done a human space program, they are purely about making launch vehicles that, after they have seen substantial development, are taken into consideration by NASA for a human space program. Furthermore, Starship is not a launch vehicle in the context of Artemis, it is to be used as a lander. The launcher that will launch humans is still SLS (which fits point 39 perfectly). And SpaceX never was on schedule…
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I mean… yes and no. The Apollo program started in 1961, had the first manned flight in 1968, and landed on the moon in 1969. Gemini started in 1961 and had two people in ‘65. Don’t get me wrong, I’m perpetually impressed by the things SpaceX is doing, but don’t let the fact that the rest of the industry has slowed down significantly convince you that SpaceX is moving faster than anyone ever has before.
For what it's worth, the Apollo program only had one bespoke launch vehicle, the Saturn V. Mercury used the Redstone (for sub-orbital flights) and Atlas, and Gemini the Titan, all of which were developed as ballistic missile platforms.
>39. (alternate formulation) The three keys to keeping a new human space program affordable and on schedule:
> 1) No new launch vehicles.
> 2) No new launch vehicles.
> 3) Whatever you do, don't develop any new launch vehicles.
Given that SpaceX wanted to make a more affordable launch vehicle, they obviously needed to design one. But it certainly didn't make their human space flight programme go faster compared to past endeavours.
>29. (von Tiesenhausen's Law of Program Management) To get an accurate estimate of final program requirements, multiply the initial time estimates by pi... I discovered this when my father would come up with some project me and my siblings had to do, such as scrape, sand, prime and paint the house (which thinking back very likely had lead paint). It would inevitably take roughly 3 times longer than he wanted it to ta…
I knew #36 and have used it in the context of software engineering. But much of the rest is similarly applicable. > #36 Any run-of-the-mill engineer can design something which is elegant. A good engineer designs systems to be efficient. A great engineer designs them to be effective.
Make it work (elegant). Make it right (effective). Make it fast (efficient).
Also with a hint of law 40.
I have a subset of these printed out and tacked to a cork board in my office, and I refer to this website a few times a year. Very, very good stuff. This one in particular was a big influence on me when I moved from engineering to design. It expressed what I'd felt but hadn't put into words. Not just the look, but nearly every aspect of a project is de facto path dependent, so you want to be as far upstream as possib…
This was illustrated in the movie "Galaxy Quest". The aliens saw the humans' TV show about space exploration, and designed a ship that exactly matched the fictional ship depicted. But they never saw a bathroom on the show, so they had to make up their own design...
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"A handful of actual successful designs"? Perhaps we should get the definition clear: a spacecraft in this context is any human-built vehicle flying in space, not just those that carry humans. There are thousands of earth satellites, extra-terrestrial orbiters, landers, rovers, and now even interstellar spacecraft that are very successful. They all needed launch vehicles.
“If you screw up the engineering, somebody dies” does not apply to unmanned spacecraft. In fact, unmanned spacecraft generally operate further away from humans than anything else does. When they go wrong the last thing that’s likely to happen is a human getting hurt.
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Except that requirements cost time to develop, so perfect requirements have significantly more cost than good enough requirements. Also, requirements tend to evolve as customers grow, so requirements will change over time and become less perfect, causing that investment to depreciate.
I agree completely. In the physical goods world, though, it’s not a continuous function. At points along the way, there is a very clear cost step response. Requirements evolving is totally fine and expected, but you need to periodically say “The current set is good enough, let’s build it and ship it”. Trying to do continuous delivery on manufactured items is the road to madness. My general approach to this is to try…