This is not the only hurdle. You can have an airport right next to a major city, with hundreds of arrivals and departures each day.
The same cannot be said for a Starship spaceport. Due to very loud launch, sonic booms on landing [0], and the danger of dropping a Starship onto populated areas, it would likely need to be offshore. That requires a boat, so now boarding a Starship involves thinking about sea states, taking a ferry ride on each side, and more.
Starship is super cool, but point to point Starship is a bit of a fantasy when you start to get to the nitty gritty.
110dB 20km from the origin? That is a serious WTF right there if that number is accurate. If my quick estimate is correct that would mean that the sonic boom is deadly to anything within a few 100m around the booster. Even 110dB is skirting the border to permanent hearing damage from a single exposure.
It could be possible for a couple routes where launch and final approaches could be done over water. It'd need some shallow seas, so platforms could be anchored to the bottom, as well as some high-speed rail and some veeeeery long rail bridges connecting the spaceport to land.
A quick look at ocean depth maps points to friendly continental platforms around the East US, China, a lot of Australia and New Zealand, and most of South America.
It'd be a massive effort, but not completely impossible. To get to Brazil to see my family, I'd probably need to first go to Southwest Ireland before boarding a suborbital flight to Rio, so it'd be 2 hours of rail, then 20 or so minutes of suborbital, then another hour flying to São Paulo (which is not on the coast). Still beats flying through Lisbon, Amsterdam or Paris.
Hear, hear. Rapid dragon air-launched Superheavy with two-way radial symmetry switchblade wings for engine-forward horizontal landing. Make it a big-ass glider biplane with big Dragon in its tail for cargos. No sketchy flops or balancing act, Cg forward of CoL all the way from retro burn to touchdown. Capsule escape available down to 500 feet or there abouts.
And that suborbital spaceflight is effectively off the table for anyone with a heart condition. There's a reason why you see all those warnings on rollercoasters even when the dangerous part lasts <1s. Now let's subject someone to minutes of it.
That's akin to saying that it seems fundamentally impossible to make landing rockets safe which, in fact, is exactly what Boeing/Lockheed were saying when SpaceX was first revolutionizing that space as well.
I’m not aware of any rocket landing safe enough for human use. NASA nixed the idea of propulsive landing for Dragon 2 for this reason. It’s extremely difficult to make safe, since just about any reasonable engine configuration means guaranteed death if a single engine fails at a critical moment. Compare with modern airliners where an engine can fail at any point in flight and the plane can land safely.
You're right; I meant to refute the following point:
NASA nixed the idea of propulsive landing for Dragon 2 for this reason (safety)
It wasn't because of safety, but because it would have needed tests, development and certification (for a new type of landing) while already having an established method (splashing into the sea).
> NASA nixed the idea of propulsive landing for Dragon 2 for this reason.
That is completely false. First of all, NASA didn't nix it, they just didn't make it a priority as it had little value from their perspective.
The reason it was not done is that para-shouts have to be in the design anyway for abort situations, so that was fixed.
So for SpaceX, the question was to likely delay the program, and take on a whole lot of extra engineering work that they were not actually getting paid for, remember fixed price contract.
They were only going to work on it if they really thought they needed it for something like Red Dragon. And then they could still add it later.
And one of the primary reason SpaceX thought that its to hard, is that they landing feet would have to have gone threw the heat shield. That would have made the whole heat-shield design massively more complex.
He said it was the difficulty in proving the safety. There's an informative article here. [1]
NASA likes parachutes because they've always used parachutes. SpaceX likes retropulsive landings because Mars is their goal, and Mars' atmosphere isn't dense enough for parachutes. It's also safer for the crew in nominal operation and enables a much higher degree of rapid reuse, relative to NASA's traditional operation of taking a salt water bath in the ocean.
So they could go through the [very reasonable] extensive costs and testing involved in proving the safety of the retropulsive landings, or just go old school, strap a few parachutes on and work on getting crew to the ISS (which was the goal at the time). They chose the latter and with the plan of getting back to retropulsive landings later, which they also did. Parachutes remain the main landing mechanism for the Crew Dragon, but it now also has retropulsive landing capabilities to be used in case of a chute failure.
This is not the only hurdle. You can have an airport right next to a major city, with hundreds of arrivals and departures each day.
The same cannot be said for a Starship spaceport. Due to very loud launch, sonic booms on landing [0], and the danger of dropping a Starship onto populated areas, it would likely need to be offshore. That requires a boat, so now boarding a Starship involves thinking about sea states, taking a ferry ride on each side, and more.
Starship is super cool, but point to point Starship is a bit of a fantasy when you start to get to the nitty gritty.
[0] https://www.nasaspaceflight.com/2024/11/starships-sound-stud... (TL;DR: Super Heavy's sonic booms are 110 dB when standing 20 km from the booster.)