<sigh> I'm pretty sure even carbon nanotubes aren't strong enough, and good luck growing them 50,000 km long! </sigh> But, as Kim Stanley Robinson pointed out some years ago, it WOULD work on Mars!

Another overly optimistic claim: "Multiple trips up and down an SE can be made in a single day. " Really? Average speed nearly 10,000 kph? No thanks!

The Lofstrom loop is a bit more plausible.