"A tachyon would need to have negative mass, wouldn't it?"

Yeah, it occurred to me that might've been an undue assumption, but I was already committed to the message...

A Moonbase in 1999 (minus the waste dump) was a reasonable prospect. Interstellar flight in 1997? Not even in my wildest 11-year old dreams in 1965...

And not again since 1972...what sucks is that our spaceflight technology doesn't at least resemble that of '2001' by now.

Said the man with his own personal computer, connected to a world-wide network...

You're correct that if there are hostile ETs out there, it likely won't be for material reasons or energy, but our history shows that that isn't the only reason wars are fought. The possibility still exists for some sort of social, philosophical or religious motivation, and/or a psychology we don't understand...

"Wouldnt it make more sense and cost less money to build a helium scrubber to connect to the International space station and pull the helium out of the thermosphere where it is most abundant? "

"...we didn't go to the moon because it was profitable."

Ow!

If you're looking for the He3 isotope of helium as part of nuclear fusion fuel, be advised that to obtain one ton of the stuff, you need to process 100 million tons of Lunar regolith. This isn't remotely worth considering, until you have working commercial fusion reactors to use the stuff. Otherwise, it's like…

The Moon has way more surface area, and way more time to collect.

"So say we aaaAHHHHHH....!"

"I say we need to have our population growth problems solved before we can think seriously about space colonization. "

What was that about my bosom...?

What was that about my bosom?

Not surprised at this. Seriously overdue, if true...

You, my friend, need to read David Brin's Uplift Universe stories, especially 'Startide Rising, and 'The Uplift War.'

Looks like Emma Peel and John Steed landed on that same square for the same reason. It just sounds cool...

Basically, the 'hotter' the fuel, the higher its exhaust velocity, and that's what matters in rocket performance, assuming the thrust is the same. That temperature doesn't necessarily have to be achieved by chemical reactions. You could deliver the energy via a distant laser. Nuclear rockets work by running the stuff…

Almost true in Iran, as we speak...