Tag Archives: SpaceX

The rocket equation is obvious, but

This is from 2012. I've never read it before, but I picked it up as a reference in the Integrating PM and SE book that I'm reading: Andrew Chaikin, Is SpaceX Changing the Rocket Equation?, Air and Space Magazine (January 2012).

You read something like that and—you get a little jealous. The article itself, eight years later, is almost quaint. Falcon 9 works. Dragon just dropped off passengers at the International Space Station for the first time. The notes about rocket engine redundancy are now, hundreds of rocket engines later, obvious. Same thing with fasteners and stage diameters—it's so obvious that you should reduce the number of things that you (a) need to design or build and (b) that you need to design interfaces for and (c) have to learn how to use. Painfully obvious. I don't know about the economics of rocket stage reuse (I would be happy to believe—send references this way, etc.) but the economics of multi-application of components and equipment is just so obvious. And building things in-house? Yessir—obvious. In retrospect. For the rest of us.

How many things exist in your day-to-day life and your day-to-day work that are besotted with obvious things that should be abandoned or changed. There's nothing that is that needs to always be. Everything is contingent. Everyone is winging it. Even the best things were designed by people who did the best the could with the resources they had with the time that was available—nothing is optimal.


I remember having an interview with SpaceX sometime around the time of this article—something for a range safety job, I think, which would have been related to my very first gig at Orbital working on Kinetic Energy Interceptor, which means I was still listing... I have to look this up because I don't remember... AFSPCMAN 91-710 on my resume. I only remember talking to the recruiter because I had to step out of Brookline Booksmith into the freezingass cold of Massachusetts winter to answer classic interview questions such as "what was your GPA?", which I answered grumpily because it's a stupid question when you've been out of school for a few years, but also I didn't have a job at the time so maybe I should have just played the game. I don't know. Years later I had another interview where I was asked by the interviewer to explain why I was a rock star, which I also pointed out was a stupid question. It is a stupid question—hey, sorry, I played the bass guitar, you might confuse us for wallpaper—but, again, what happens if you play the game?


SpaceX didn't change the rocket equation. Delta-V is Delta-V—yesterday, today, tomorrow. Exit velocity, initial mass, final mass.

The physics is simple.

However.

Here we are.

For now.

Articles like this one are an envypill for me—eat it up.


We invited Elon Musk to come to the University of Illinois for SpaceVision2005. He flew to Champaign, gave the talk, flew back out—bing bang boom. I didn't see the presentation. I fired all our conference staff for that hour and sent them into the talk, then watched the tables outside myself. I've got to bug people who went there, see if they remember, 15 years ago, what it was all about—see if any of their trajectories were altered by the event.