SpaceX

SpaceX

Making Commercial Spaceflight a Reality

Erik Seedhouse, Springer Praxis 2013, BeavertonLib 629.4 SEE

Like most Praxis books, informative, opinionated, and rough around the edges.

Opinions about technology schedules are shaped to encourage funding, not provide timetables. If every technology schedule is equally optimistic (typically 2 to 3 times), they mesh, and cost overruns are paid for by accumulation of unexpected revenues.

As I write this, !SoaceX is undergoing 10% layoffs, and is years behind the schedules in this book. That said, they astounded me by actually landing and reusing first stage boosters, and by launching a Falcon Heavy with 27 engines that did not blow up. Indeed, they haven't yet blown up a mature Merlin; I hope that none of the laid-off engineers are the ones that knew how to achieve this miracle. If they were laid off, I hope they teach their techniques to other rocket companies.

Elon Musk is the messiah of our times, until he makes a big mistake and is crucified for that. I hope that happens long after Dragon Crew capsules become the main ISS "commuter bus", and long before Red Dragon crashes astronauts and their fecal bacteria on Mars. Mars is a terrible place to colonize (the asteroids are better), but it may be the source of exotic biological knowledge that could save planet Earth, and help colonize useful places in the solar system.

• p096 fig 6.10 Dragon approach and docking trajectories to ISS (from !SpaceX, in miles); phasing at 200 km distance, communication zone 28 km distance, Keep Out sphere at 200 meters. Approach and docking takes hours.
  • ISS is very fragile and vulnerable; very slow rendezvous is safer. A small, armored space station terminal hanging from a 200 meter tether might be safer and quicker to use, with precisely timed launch. Radial acceleration at the bottom of the tether, 0.8 mm/s²; the apogee of a slightly faster orbit below ISS with a perigee about 1.4 km below ISS radius. Tether climb energy 70 microjoules per kilogram; a watch battery could lift tonnes. A two minute transit might require 5 joules per kilogram for acceleration.
• p102 Table 6.4 Renzezvous timeline, 187 minutes mission elapsed time.

• p102 Table 6.5 Dragon C2 cargo manifest; bags of rations, including low sodium meals.

• p104 GNC == Guidance Navigation Controller

• p128 Sierra Nevada Dream Chaser dead link 2019 January 18

• p131 ATK Liberty, an Ariane core stacked on an ATK solid. And what is the point?
• p165 "Now obviously, we can't point to past examples of private industries developing space" ... Er, uh, comsats?
• p175 Appendix II - applying for a laaunch and re-entry license. Paperwork and meetings with the FAA. A launch loop can't afford FAA meetings every 45 seconds, so this will presumably be streamlined someday

• p178 SpaceX DragonLab fact sheet

• What is the curved cut on the dragon cargo capsule cone?