Feasibility of SpaceX Moon landings

A month ago, SpaceX announced that it plans to send two paying customers around the Moon, using a Falcon Heavy and Crew Dragon. The company plans to use a free-return trajectory to send the crew around the Moon and back to Earth, a method which involves only small amounts of propulsion (for course corrections) after the launch. […]

Site-to-site travel on Mars with the ITS

Ever since Elon Musk unveiled his plans to send humans to Mars, one important line of discussion revolves around the logistics of the eventual colony. How will it extract water from the regolith? How will it generate power? What form will the habitats take? And so on, and so on. Today, we will look at […]

Thermal Management Aboard the ITS

Between Elon Musk’s announcement of his architecture to send humans to Mars, and the community questions he answered last week, we now have a much better idea how such a trip will work. This enables intelligent discussion of many possible facets of such a mission, but the one we want to discuss today is heat management. Unlike […]

Why living off the land is essential

As promised, and despite the Amos-6 accident, Elon Musk unveiled SpaceX’s plans to colonize Mars this week at the International Astronautical Congress. The presentation was rich on substance and technical detail (the full talk can be found here), and the community will certainly spend many hours poring over those details in the weeks and months […]

Comparing Upper Stage Rocket Engines

This post follows our comparison of first stage engines, which can be found here. As a reminder, in 2014 Elon Musk said [1]: “Right now, I’d say, engines are our weakest point at SpaceX.” To expand this quote a little: “Right now, I’d say, engines are our weakest point at SpaceX, but they will become […]

Comparing First Stage Rocket Engines

The ideal rocket equation defines the performance of chemical rockets – it looks like this: total change in velocity = exhaust velocity * log (liftoff mass/final mass) So the performance of all rockets, the Falcon 9 included, is mostly defined by just two parameters, the exhaust velocity and the ratio of initial to final mass. […]

What can we learn from SES-9?

SpaceX are launching SES-9 next week [1], and this launch has the potential to tell us a great deal about the capabilities of the new Falcon 9 Full Thrust. Two weeks ago, SpaceX agreed to loft the satellite into a higher orbit than previously planned [2], at the cost of a lower probability of first […]

Explaining the Infeasability of Second Stage Reuse

In an interview in MIT in October 2014 [1], Musk said: “I don’t expect SpaceX’s Falcon line to have a reusable upper stage. With a kerosene based system, the specific impulse isn’t really high enough to do that, and a lot of the missions we do for commercial satellite deployment are geostationary missions. So we’re really going very […]