As a Systems Engineering exercise, an in a sincere attempt to plan ahead, it occurred to me that I had not really considered a top-down set of requirements for a robust interplanetary mission. And what I mean by “robust” is a mission using technology that allows for reusability across multiple destinations, with the ability to chart courses to those destinations as the ship’s operator determines them. Essentially, such a mission and the ship needed would be akin to the kind seen in the sci-fi exploits of a person’s favorite space opera.
In this case, though, it’s not sci-fi: I intend to make it real.
So, first things first, what’s the mission?
For travel extents, let’s bound it to, say, the Oort Cloud. Without going to an interstellar range, that’s pretty far, and gives a lot of margin for range to places in the Sol System that we’d be likely to go. We’ll look up what that distance is later.
Do we want to land on the destinations? I’d say that’s a yes. How is landing defined? Do we land the whole ship, or are there separate landing vessels? Regardless of that as-yet-unanswered question, do we land with thruster pointing, like the lunar landers, or do we glide in? I think that gliding/flying in is best as a baseline landing mode, but for destinations without an atmosphere a thrust-balance platform would need to be included, too.
How quickly do we want to go from place to place? That’s a hard one. It would be beautiful if we could plot a course to the Moon, or Mars, or even to the Asteroid belt or beyond, and get there within a week. This, of course, means going very fast. Enormously so. That means copious power, stupendous propulsion, and relatively high fuel stores. Again, the numbers for these factors will take some time to develop.
Then we need to ponder life support. The many factors leading into an ECLSS design closure touch on power, oxygen and other breathing gasses, food, water, heating, and waste handling. I’m sure that I’m leaving out other considerations, so I’ll have to think about it.
What about the crew? I think that’s not too hard to tease out. A captain, a second in command, ship’s engineer, a medical officer, and a research lead. That’s five people minimum to account for food, water, air, living space, and of course, duty stations. I would expect the crew to be cross-trained to help each other, but it seems like some duplication of standing crew duties might make some sense, too. It would also make sense to have some excess capacity for passengers, as well.
All of the above really leads to a lot of work yet to define the mission formally, and to develop a Conops to build a Systems structure upon. I’ll be back soon with the products of those steps.