Hacker News Reader

Skylon does have the advantage of burning atmospheric oxygen at low altitudes, meaning it would have a significantly higher payload fraction than the Falcon 9.

View on HN

It's somewhat higher, but not dramatically so. Skylon is projected to be 325 tons loaded with a LEO payload of 15 tons, Falcon 9 Full Thrust a.k.a. Falcon 9 1.2 is 541 tons loaded with a LEO payload of 13-17 tons depending on who you believe. And that's comparing paper hardware with flying hardware. Spacecraft tend to get heavier as they go from paper to reality.

Plus, payload fraction is another thing like SSTO, horizontal takeoff, novel heat shields, and all the rest that are cool but just don't matter except for how they affect the end result. All that matters in the end is how much you can launch, and how much it costs.

>And that's comparing paper hardware with flying hardware. Spacecraft tend to get heavier as they go from paper to reality.

That's the critical point. Skylon is still vaporware, and they've really assumed the best case in published numbers.

According to specs it'll reach 1600 m/s on atmospheric oxygen.

So, afterwards, it needs another 8000 m/s Δv on rocket engines to reach LEO.

Skylon is a neat trick, but it's not magical.

Reply on news.ycombinator.com