We choose to go to the moon. We choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard, because that goal will serve to organize and measure the best of our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to postpone, and one which we intend to win
Just finished the first half of this book (the part set in the near future). Love the extremely detailed discussions of orbital mechanics and the practicalities of trying to get as many people in to space as possible in a two-year period. Honestly it felt a bit like reading some of the discussions on this forum. I wouldn't be surprised if Neal Stephenson's posting here under some other name. I'm curious what folks think about the science behind some of the plot elements. This would be a fun book to break down and try and figure out how plausible some of the elements are. For example, right at the beginning (MINOR SPOILERS) we are introduced to a near-future version of the ISS that has been attached to an asteroid. Its an iron asteroid at least as big as the station itself. It just seems crazy to me to put it in such a near-earth orbit, as something that big would pose a danger if it deorbited. Plus the delta-v to get it down there would be enormous, and the subsequent extra fuel needed for reboosts would be cost-prohibitive. Stephenson argues the asteroid would actually make it so less reboosts were needed due to less drag coefficient. I'm not so sure about that.
Quote from: sfrank on 06/30/2015 04:29 pmJust finished the first half of this book (the part set in the near future). Love the extremely detailed discussions of orbital mechanics and the practicalities of trying to get as many people in to space as possible in a two-year period. Honestly it felt a bit like reading some of the discussions on this forum. I wouldn't be surprised if Neal Stephenson's posting here under some other name. I'm curious what folks think about the science behind some of the plot elements. This would be a fun book to break down and try and figure out how plausible some of the elements are. For example, right at the beginning (MINOR SPOILERS) we are introduced to a near-future version of the ISS that has been attached to an asteroid. Its an iron asteroid at least as big as the station itself. It just seems crazy to me to put it in such a near-earth orbit, as something that big would pose a danger if it deorbited. Plus the delta-v to get it down there would be enormous, and the subsequent extra fuel needed for reboosts would be cost-prohibitive. Stephenson argues the asteroid would actually make it so less reboosts were needed due to less drag coefficient. I'm not so sure about that.No, if it's about the same cross section as the expanded ISS (and we can expect that within an order of magnitude), then the asteroid would not reduce or increase the amount of propellant needed to fight atmospheric drag, but what it *would* do is slow down the orbital decay process by several orders of magnitude. Instead of "1500kg propellant every month spent on reboost to sustain 400km altitude, or the ISS decays at 5km/month, rising rapidly at lower altitudes", if there was a large asteroid attached it would be "1500kg propellant every month spent on reboost to sustain 400km altitude, or the ISS decays at 100m/month, rising rapidly at lower altitudes".(Numbers are to convey the concept, I don't know the specifics).
Another NSF aspect of the novel is it's take on minimum requirements for backing up civilization and life. It makes a decent case that given biotechnology of a decade or so from now, a very minimal Mars colony could act as a complete backup.
Launches were mostly for the arklets, right? Each arklet was around 15-20 tonnes to be launchable on all the different major launch vehicles, right? Each had a crew of like, 6-8? There were 1500 people chosen. So that implies roughly 200 arklets? I don’t have the book handy, so I’m not sure.This implies like a couple hundred launches per year over 2 years? 100 a year for the arklets, and an equal number for the outfitting and ancillary launches.