Elon Musk, CEO Spacex, gave a keynote to a roomful of aerospace engineers at the AIAA/AMSE/SAE/ASEE Joint Propulsion Conference in San Diego on August, 2011
SpaceX’s first two priorities are to have a successful Dragon docking with the International Space Station (ISS) in December, followed by “convincing NRO and the Air Force we’re a good thing.”
Later this year or early next year, Musk expected to unveil a “super high efficiency” staged combustion engine.
The company’s Falcon Heavy rocket, to be flight demonstrated in late 2012 or early 2013, could deliver 10 to 15 metric tons to Mars, but Musk wants a vehicle capable of 50 metric tons and fully reusable. If Falcon Heavy could be made fully reusable, costs to LEO could be low as $50 to $100 a pound.
“Ultimately, the thing that is super important in the grand scale of history is, are we on a path to becoming a multi-planet species or not?” Musk said during his keynote address, according to PC Magazine. “If we’re not, that’s not a very bright future. We’ll just be hanging out on Earth until some eventual calamity claims us.”
Spacex has had discussions with NASA to use Falcon Heavy for “big missions” to Mars and the outer solar system, with one notational mission going out 150 to 200 astronomical units (AU) “past Pluto and stuff.”
Two technology areas Musk didn’t like were lifting bodies/wings and nuclear rockets.
On the former, he said he was a “vertical takeoff, vertical landing” type guy and eschewed wings since they had to be tailored for each planet’s atmosphere and were useless on airless bodies such as the Moon.
Drawbacks to nuclear power included the need for shielding (heavy), water (heavy), and public objections against launching nuclear fuel on a rocket. “It’s a tricky thing getting a reactor up there with a ton of uranium,” Musk said and went on to say while nuclear power would be useful for Mars or lunar operations, he implied that some assembly (i.e., mining and processing fuel off planet) would be required.
Spacex Efforts at Reusability
SpaceX needs to develop and operate “fully reusable, rapidly reusable space transport,” Musk stated. “It wouldn’t be a good car if you had to change the tires on it every time you drove it or could only drive it once a week.”
Only 0.3 percent of the cost of a Falcon 9 launch is propellant. Being able to fully reuse all the parts of the launch system could significantly drive down the cost of launches.
What success has SpaceX had in reusability? “It’s sucked,” Musk stated bluntly. “It’s super damn hard. SpaceX has learned a lot by flying and recovering Dragon, but the engineers can’t give that level of protecting to the first and second stages of the Falcon 9.”
Constructing a “suit of armor” even for the first stage has been harder than anticipated. “It comes in at a pretty steep angle, the forces are very high,” Musk said. “It’s belly flopping on the atmosphere, something has to be done to shed velocity.”
One solution being looked at is restarting the engines to slow down the first stage, but the fuel to do that has to be weighed against payload loss to orbit, increased structural margins for recovery, and better thermal shielding. “It’s a tough trade,” he said. “We have something on paper that closes. We’ll have to see if that is a reality as well.”