Sunday, August 29, 2021

Starships and Stay-ships, Moonbases and Mars-bases, Fun...Profit?

NASA hopes to return to the moon by 2024 (the Artemis Program) and chose SpaceX’s Starship for use as its lunar lander (designated HLS – Human Landing System). The Starship is powered by three ingredients: liquid methane, liquid oxygen, and an electric car magnet and human dynamo named Elon Musk. Musk plans a kind of million man migration to Mars (which will include other genders – I used “man” to keep the alliteration rolling). For Elon, going to the moon is a little like Coca-Cola deciding to produce apple juice because it’s got spare capacity at its bottling plant. In fact, Elon has started so many different projects in the last few years that I have to wonder about his attention span.

Nasa’s HLS choice caused chagrin in the World’s Richest Guy, Amazon founder Jeff Bezos, whose moon lander floundered. Bezos’ space launch start-up, Blue Origin,  joined established aerospace contractors to submit a competing bid. Upon losing, he immediately mobilized an army of lawyers and lobbyists to put a stop to the SpaceX contract. They argue that spending 3 billion dollars on Elon Musk’s more capable lander is nuts when you can spend ten billion on their much less capable one (this being established DC tradition and the only one congress holds sacred). Now, I won’t claim to be an astronaut, but this effort to squash the upstart start-up gives me hope that their lunar lander will work. After all, if SpaceX fails, it will fail quickly, given the promised pace of Starship development. Then Blue Origin, with its pocket-sized politicians, could pick up the pieces and profit. 

Starship ranks as the world’s most powerful rocket. Mated with its first stage “super-heavy” booster, it is taller than the Statue of Liberty atop her pedestal. The Lunar-lander portion alone is as tall as a 17 story building (minus the thirteenth floor, of course). Both the booster and the starship will be reusable – and SpaceX intends to build a lot of Starships in a variety of configurations (it’s a “cheaper by the dozen” kinda deal). The lunar-lander could carry 100+ tons of cargo to the surface with ample pressurized living space for the astronauts. They, and the cargo, can descend from the Starship penthouse to the lunar surface by way of an elevator – down, please. The possibilities here are enough to boggle even a stubbornly un-boggled mind, such as my own.


Given the possibilities, the project, as originally envisioned by NASA, seems rather unambitious. The contract covers one “roundtrip moon-trip” for four Astronauts, with hopefully more to follow at a rather sluggish pace. Artemis is somewhat more capable than the Apollo program from fifty years ago. This expensive turkey is unlikely to survive in the congressional slaughterhouse for long. What is needed is something much more inspiring that can mobilize public support. Allow me to offer a few suggestions, a not-so-little dream project for Mr. Musk to pursue while I indulge in my afternoon naps.


Initially, it will start with three dedicated Starship lunar-landers for the moonbase. Ship number one and two will have their retro-rockets mounted around the top of the ship to minimize the kick-up of lunar dust during landing (as is currently conceived). The first lander is maximized for cargo and the second for astronauts. Both will land on the moon upright. After unloading the cargo from the carrier, the astronauts will prepare a long and narrow pad for starship three (the pad might be packed lunar soil covered by a tarp).


Starship number three will be a “stay-ship,” built with its small retro-rockets along its side, rather than around the top, so it can land lengthwise. After it is secured in place, this ship’s engines and fuel tanks will be removed, allowing the entire volume of the ship to be used as a lunar base (the Starship is nine meters in diameter and 50 meters long – I’m using metric measurements since it has left the U.S.). It would be designed and built on Planet Earth with this end in mind. The Stayship can carry much of the required supplies for this transformation in its cargo bay. The powerful raptor engines – configured for operation in a vacuum – will be repurposed to power space “tow motors.” At some point, these will go into lunar orbit with containers full of “exports” and return with containers full of “imports,” after a careful rendezvous with the cargo ship. The removed fuel tanks of the “stay-ship” will be used to store methane and oxygen to fuel the space tugs. Oxygen is rather abundant on the moon, molecularly bound with iron, for instance. Oxygen is also found in the moon-water that clings as ice to the dark side of craters, but moon-water might be a bit too precious to use as a fuel source. Methane, the fuel used by starships, appears rather rarer. 


At some point, the “astronaut” starship will return to Earth orbit with some or all of the astronauts. It will then move cargo and personnel back and forth from Earth orbit to Lunar orbit. The space “tow motors” will pick up supplies in lunar orbit and deliver them to the surface. A space-based warehouse might be called for (perhaps parked at a Lagrange Point, where the interplay of the gravitational fields of the earth and moon will keep it in a stable orbit between the earth and the moon).


Additional “stay-ships” will land at the moonbase and have their guts removed. These ships will be equipped to make solar panels, smelt metals, and produce glass and ceramics for future base expansion. Aluminum and steel production on the moon could provide structural material for a ship bound for Mars but built on the moon. The stored guts of the stay-ships can be used for the Mars ships. These “Mars” ships will only travel in a vacuum or through an extremely thin Martian atmosphere, so they can be designed with this fact in mind. Liquid oxygen can be made on the moon. Perhaps supply ships could fill up with liquid oxygen in lunar orbit and leave liquid methane for the moon. With luck, trapped subsurface gases might be found on the moon (methane, CO, CO2, ammonia). 


At some point, the starship that was maximized for cargo and waited patiently on the lunar surface can be refueled and join the second starship in trips to Earth and back (or head to Mars).


So, two of the first products for lunar export could be rockets and LOX. The moon’s “comparative advantage” in trade might be its one-sixth of earth’s gravity. It could provide a port for large nuclear-powered ships to move about the solar system mining asteroids. If these ships came close to earth we’d hear those “what if it crashes in my neighborhood” scares that accompany such discussions.


This plan would require a larger “up-front” investment but could yield a lunar base that pays for its ongoing operation and might even provide a good return on the initial investment.  That will mean more opportunity for Blue Origin, Boeing, and other interested parties, so they should get their lobbyist to work on something more “inspiring,” rather than more costly.