I'm not impressed. This sounds like a couple of people sitting at a bar saying, "Y'know what would be cool?" without really thinking it
It's nice that they're thinking about the difficulty of transferring fuel between mostly-empty tanks, and wondering about long-term storage of
cryogenic liquid oxygen & hydrogen. They're looking at that problem the wrong way - instead of figuring-out temperature control, simply use fuel
cells to react the two into water, which can be easily stored for years (and generating electricity in the process, which can also be stored by
various means, though in the presence of solar energy only limited by your collector, this is a secondary consideration). When needed, you can use
stored/solar electricity to separate the water back into LOX & LH2.
What they are not thinking about - and this is a real killer - is the fact that, to drop-off the so-call contingency-fuel, they will need to
rendezvous & dock with the storage depot, and this in itself requires a non-trivial amount of fuel. Changing orbits is expensive
in terms of
For example, suppose they had had wanted to establish a contingency fuel depot in lunar orbit during Apollo: It would not have worked because each of
the landing sites required a different orbit to land & take-off. Neither the lander nor the orbiting command/service module had fuel reserve to
switch from one of these orbits to another, and modifying either or both spacecraft to carry that extra fuel would have made them too heavy for the
Saturn V rocket to lift.
Similarly, if you put the depot at one of the Lagrange points, the spacecraft still has to shape an orbit to get there, then match orbits, and then
burn more fuel to leave the depot's orbit and return to Earth. The lunar L4 & L5 point are both as far from the Earth and Moon as the Earth is from
the Moon (they form equilateral triangles). Getting there would require dedicated missions lasting several days. This is much, much more involved
than "Hey, if you don't mind, can you pop by the depot on the way home and drop-off anything you're not using...?"
I don't think that the idea of an orbital depot is a bad one - In fact, if we ever get serious about manned interplanetary space travel, it will be a
necessity - but doing it with so-called contingency fuel from missions to anywhere BUT the depot is not in any way practical.
The article doesn't talk about fueling with respect any of the new propulsion technologies out there, just the old adage of using liquid fuel to
explore the neighborhood.
No matter what propulsion system or energy source you use, you're going to need reaction mass. Newton's Third Law is a bitch.
I'm frustrated with the baby steps.
As someone who watched the greatest space transportation
infrastructure ever built
junked by short-sighted know-nothing luddite political hacks... well, you're preaching to the choir.
* I thoroughly enjoyed the movie "Gravity" - thought it was great, in fact - but its central plot mechanism (using small thrusts to go from Hubble
to ISS to Tiangong) was frankly impossible (almost as much as the Millenium Falcon
doing a U-turn in space). The Space Shuttle itself, with a
cargo bay full of extra maneuvering fuel, would not have had enough fuel to go between the actual orbits of these objects. Even if you could get the
orbits to intersect at the right time, the closing speeds would be hundreds or even thousands of miles-per-hour. The collision... well, it would
pretty much be like the one that starts the whole drama at the beginning of the movie.