Last weekend I spent Saturday at Apollocon, Houston’s leading sf/f convention. As usual, it was held at the Doubletree near IAH, so my three-year-old son had an exciting moment when a jumbo jet went loud and low overhead on takeoff. A fine hotel, free cookies on checkin, and passable service for drinks and meals in the bar.
In addition to spending time with old friends and sampling some excellent Scotches, I attended two memorable presentations.
The first, by astronaut Stan Love, was about the engineering difficulties faced in planning a manned mission to Mars. The velocity change required to get to Mars and back (~48,000 mph) isn’t much greater than that achieved by the Apollo moon landings (~42,000 mph), which sounds feasible, but… given that chemical rockets today are about as good as they are likely to get, the only way to get to and from Mars is by using transfer orbits, which only work when leaving a planet during particular launch windows. A manned Mars mission would take 32 months and require schlepping 100 tons of crew, capsule, air, water, food, spare parts, etc. out and back. If we assume the same payload/fuel ratio as the Apollo moon missions, we would need roughly the mass of an aircraft carrier on the launch pad. This is well beyond feasible, at least today.
The second, by NASA scientist Paul Abell, discussed near Earth asteroids. Since a meteor impact killed the dinosaurs, the need to understand and track these objects is acute. Over 9000 are known, with more constantly being discovered. The ongoing discoveries are mostly of small ones, less than 100 meters in diameter, which doesn’t sound bad–but the Tunguska event, which leveled a thousand square miles of forest, was probably caused by a 50-meter object bursting at high altitude. For asteroid detection and deflection, it doesn’t help that some have very low albedos, and are thus difficult to see; and others are rubble piles (literally, collections of rocks held together by mutual gravity) which can’t be moved to a different, Earth-avoiding orbit by strapping a rocket onto it.
Finally, in one of those moments that only happens when conversing with other people who share your passions, while talking with Amy Sisson and Delilah Mitchell Peeler, for the first time I really realized a common thread in a lot of the work of Octavia Butler. In a lot of her stories, the notionally more powerful character (e.g., Doro in Wild Seed, Rufus in Kindred) turns out to be dependent on a less powerful one (e.g., Anyanwu and Dana, respectively). An interesting thought about Butler’s work and human relationships in general.