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by JPLeRouzic 4 days ago
I am a big fan of SpaceX, they are amazing engineers and scientists!

But when I watch such videos I can't suppress thinking that is not the way access to space should be. I still (I am 69) think that the way forward is with planes that could take off and landing on runways.

2 comments

Spaceplanes have a nice visual aesthetic, but absent something much more energy-dense than chemical fuel, they'd still need to be multi-stage, e.g. https://en.wikipedia.org/wiki/Northrop_Grumman_Pegasus#/medi...

My current fantasy for space access is an orbital ring: https://en.wikipedia.org/wiki/Orbital_ring

A fantasy for all the same reasons as putting up a million data centre satellites (it's roughly the same size project), but somewhat more useful as it turns space from one of the most expensive and difficult places to go, to a long-distance high-speed rail line.

> *Orbital rings*

I love megastructures, but I think it will take us a thousand years before we possess them (as a species).

> *Higher energy density than chemical fuel*

That’s true, but it’s a general problem that applies to rockets too as Tsiolkovsky recognized back in 1896!

A burning Starship in the Indian Ocean doesn't look like either as vision of the future, but rather like an ugly cyberpunk dream.

Agreed on Starship.

Orbital rings… I think are more like a century or two. Physical possibility and affordability will I think take only 25-100 years[0], the rest being politics getting to the point nobody shoots it up.

[0] if you believe Alphabet's estimates about how fast SpaceX can reduce costs, estimated in the context of orbital data centers, it would only take 10.

I think this is overoptimistic, as the Alphabet paper assumed 370,000 tons[1] getting launched as the process for reducing costs, and I think Musk runs out of other people's money before that point.

[1] https://arxiv.org/pdf/2511.19468

Looking at the return trajectory for the space shuttle helps you understand the difficulties in combining aero-flight with rocketry using the same control surfaces.
I am not convinced this is a huge roadblock because the US and Chinese armies still use them.