This observation may already be bleedingly obvious to everyone else, but I feel it is worth explicitly stating:
One of the top priorities of early missions to any destination in the solar system should be to drive down the cost of future missions and increase their safety and reliability as quickly as possible.
While traditionally NASA missions have been of the one-off sortie/expedition variety, if we hope to thoroughly explore our solar neighborhood, and more especially if we want to settle it and bring increasing portions of our solar system into humanity’s economic sphere, following this priority would be a good way of showing that we’re actually serious about it.
I’m no military historian or strategist, but I think using the analogy of a “beachhead” may be appropriate and illustrative. When conducting airborne or amphibious invasions, one of the important goals of the attacking force is to quickly secure the area in a way that enables lower-cost, more reliable transportation of people and material to reinforce the initial beachhead. While the initial forces can use inefficient transport such as paradrops or amphibious landers, the sooner they can secure a port or lagoon or airstrip from enemy operations, the faster they can bring in reinforcements using more efficient means of transportation such as passenger/cargo planes or vessels. In military campaigns, that ability to rapidly reinforce the beachhead can often be a matter of life-and-death.
While space operations may not be quite so dire, there are strong incentives for also trying to quickly transition to more affordable, safe, and efficient means of getting goods and people to and from the destination. The sooner you lower your cost of say delivering objects to the destination, the more exploration/settlement/resource-extraction you can perform with a given amount of money. The sooner you lower your cost of returning material from that destination, the lower the cost of reaching that destination (if you’re producing propellants), and the more competitive you become with shipping material from other locations. Because so much of the cost of human space exploration or settlement is in the transportation of people and goods, the sooner you can lower the transportation cost, the bigger the impact. This is why driving down transportation costs should be such a high priority for early missions to a given destination.
I originally made this first point in the context of Mars missions1, where instead of focusing on sorties, I feel that we can get a much better return on investment by having early Mars missions focus on lowering the costs of future missions by: a) establishing a landing site with good landing pads and navigation aids at a location with good ISRU potential, b) getting as quickly as possible to the ability to produce steady quantities of high-performance fuel and oxidizer (LOX and either Methane or LH2), c) getting a depot/staging base setup in low Mars orbit, and d) getting reusable tankers regularly traveling from the landing site to the depot, stocking it with propellants for future landers and return vehicles.
In this series though, I’d like to focus on some interesting options for pursuing this Beachhead strategy for lunar missions. While I agree with many lunar resource advocates that the Moon can potentially play a significant role in the exploration, settlement, and commerce of the inner solar system, the gear ratio math I discussed in this series’ first blog post suggests that while having highly reusable rocket-powered landers may be a necessary starting point for lunar development, we may need to move beyond the rocket equation to truly unlock the Moon’s potential. Fortunately, unlike most other places of interest in the inner solar system, there are several potentially realistic ways of propellantlessly landing and launching materials and equipment, and eventually people from the Lunar surface. As I mentioned in the first post, most of this series will focus on introducing some of these concepts, and explaining how they might fit into lunar development plans.
Next Up: Intentional Hard Landings
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