[wallace_f]

From '02 - '06 Musk dumped 100MM of his own cash into this, with uncertain outcome. Is it fair to say SpaceX was at least partially an expensive hobby, at some point?

[TeMPOraL]

If by "hobby" you mean "not making you money", then yes - in the same sense as just about like every startup in existence.

If by "hobby" you mean doing something for fun or personal growth, with only vague - if any - expectations of future usefulness, then no. SpaceX was aimed at getting us to Mars from the day 1; it's their entire raison d'être. Musk bootstrapped it with his own cash because he also set this goal - getting humanity to Mars.

If by "hobby" you mean doing something meaningful instead of just making moar money - then sure.

[wallace_f]

I don't know if this is really like every other startup. The amount of money involved and ambitions are far beyond the average startup.

[steve_musk]

From '02-'06 (or even '02-'017) did Musk send anything to another planet/leave Earth orbit? No.

Maybe you could argue the Falcon 1 was an expensive hobby, but interplanetary spaceflight is certainly not.