SpaceX had a presentation last night about the latest news on their Starship/Super Heavy reusable rocket.
To get everyone up to speed:
Three years ago, SpaceX announced their plans for an extremely heavy launch vehicle that could put 300 tons into low Earth orbit reusably. Since then they have scaled down their plans slightly, due to budget and timeframe constraints, but they have converged on a design that should put 100-150 tons into orbit reusably. It consists of a two stage vehicle, larger than the vaunted Saturn V, with the first stage landing similarly to SpaceX’s current boosters and the second using a new system with a kind of aerobrake maneuvering system.
It’s difficult to overstate the importance to space flight if they can pull this off. Their goal is for the craft to be nearly as reusable as a commercial aircraft, with the costs approaching a small factor of the fuel/propellant costs. Despite the large size, the propellant should cost under a million bucks for a full flight. That’s only $10/kg. Flight costs of $100/kg do not seem unreasonable, which puts the system at a tenth the cost of SpaceX’s own Falcon Heavy system, which was already the cheapest around.
A very significant design change along the way was the switch to stainless steel for the main structure. Despite seeming like an old and obsolete material, stainless has a few key advantages here. First, it actually becomes stronger than even carbon fiber at cryogenic temperatures. Second, it stays strong even at high temperature–such as those of orbital reentry. It remains structural even when red hot. And finally, it’s cheap. So cheap that SpaceX can build a bunch of prototypes and not worry if they blow up or otherwise fail.
About a month ago, SpaceX performed their Starhopper test. It’s a simple test article that went up about 500 feet, demonstrating their stainless steel construction technique, their new Raptor engine, and their control systems. The test was a total success.
Their next test will be a full sized version of the upper stage, called Starship. They’re aiming for a 20 km height, which will allow some testing of their reentry systems. They’ll probably go higher than that eventually, but to get to orbit they need the first stage (the Super Heavy booster).
Speaking of reentry: you may notice from the picture above that Starship has four wings. Each of these wings (really, aerobrakes, since they aren’t airfoils) can fold at the base using powerful motors. The craft will steer by folding the aerobrakes in and out, a bit like a skydiver tucking his arms and legs in to orient. It does this to maintain a controllable descent through the atmosphere. Once it nearly reaches the ground, it does a flip and lands on its tail under rocket power.
You may also notice that the ship is very shiny, which of course comes from its stainless steel construction. Give it a very classic sci-fi vibe.
SpaceX still hasn’t said too much about their Mars plans aside from the launch system. They’ll need to work on that, but I hope that once they get the thing flying, NASA will have no choice but to adopt it for their plans, and they’ll be able to work together on it. We’ll see.
And for anyone not interested in Mars at all, or even space, this craft will have one very tangible near-term benefit: the launch of SpaceX’s Starlink internet service. This requires *thousands *of satellites in orbit, and although the first batches are being launched on the Falcon 9, it pretty much requires Starship to complete the constellation. Starlink will enable gigabit internet for virtually everyone on Earth, no matter how remote.