The significance of the Starship

4/22/2023: Starship update #6

There's a tweet from Musk that says he has a plan in the works already, and will be ready to launch in one or two months. That seems like "Elon time". It may take a bit longer than he anticipates. The FAA is required to do an investigation, and the government doesn't move quite so fast.

It will be awhile, I suspect.

Meanwhile, what else to say about it? In terms of his architecture to get to the Moon and Mars, I think it's flawed. In particular with respect to the Moon. There are going to be many refueling trips from the ground to the the Starship lunar version while it is in low Earth orbit ( LEO). Why so many? For a rocket with twice the thrust of the Saturn V, why do you need so many refueling trips?

The Saturn V system shed mass as it went along. The less mass you carry around with you, the less fuel you need to get to the next destination along the way. The Starship is carrying a LOT of mass with it. In order to get from LEO to Lunar Orbit, there will have to be a burn. Perhaps there is a better plan than that, but that is what the Saturn V used. There was a burn to get a lunar orbit, then it released a lunar module. The lunar module itself was divided into an upper module and lower one. The lower module powered it down to the surface, and the upper module got it back up in lunar orbit for the return trip. Each time, it shed something it no longer needed, and reduced the propellant mass needed for the next stage of the mission. That's how the Saturn V did it. But not the Starship. They will land the entire thing, and that's going to take a lot of propellant to speed it up and slow it down.

The lunar Starship is already going to be expendable. That means it is already going to be a different bird than the regular Starship. An optimized version could be designed that will get the job done with a lot fewer launches.

But Musk may have different plans. We'll see how those work. Unless the plan is a lot like the one that worked during the Apollo program, there may be a problem.

originally posted on May 7, 2021

It looks like Elon Musk's latest invention will work. One part of it works, at least. The next parts are untested, but the belly flop maneuver will work. But it's not going to be enough.

In my opinion, it is one thing to land a mostly empty Starship on a prepared surface. It is quite another to land it on a place that you have never seen before, such as Mars or even the Moon.

The Starship has a really aggressive maneuver there with that belly flop. Perhaps that is the main reason that it failed so many times before it succeeded. You've got fuel to consider. The belly flop maneuver is on mostly EMPTY tanks. If you go to the Moon, and you want to come back ( I'd think), then you have to land with plenty of fuel still on board.

You'd also have to land on the unprepared surface. The Starship is tall. It can tip over easily. That would not be good if you are on Mars or the Moon.

The Starship's real significance lies not in that it can get to the Moon or Mars. It is in the fact that it can get to LEO cheaply. It is a first step, not a final step. There has to be many steps besides this one.

Maybe it can be modified to land on the Moon. That's a thought.

The way it was done during the Apollo Era was to shed weight as you go. Unneeded pieces that were discarded allowed for less mass that had to be brought back. Less mass can become quite dramatic, and the opposite is also true. Less mass means less fuel. It all translates into much less mass that has to be launched.

If you try to land that big thing on the Moon, you are going to need a LOT of fuel to get there and back. One refueling would probably not be enough. An empty Starship weighs about the same as the Space Shuttle. You need to think about that one.

Refueling has not been demonstrated in space yet. So there you are. It's a possibility if you can get to space cheaply. But the concept isn't completed yet. Lots more needs to be done.

If you can put a lot of stuff into space, you may be able to build an infrastructure up there. That would include the Moon and Mars. Also the places in between. The infrastructure is the next step. The Starship can get it there. That's the signficance.