There are so many private space ventures under development these days that it seems like you need a scorecard to keep track of them all. This week, Northrop Grumman Corporation announced that it has completed a feasibility study on a new lunar lander for the Golden Spike Company as part of a plan to send to people to the Moon within ten years at a cost of US$750 million per person.
Golden Spike’s approach is to farm out the development of a lunar lander, lunar space suits, and lunar surface experiment packages to various aerospace companies. Northrop Grumman was given one such commission and it has a definite edge, having built the Apollo Lunar Module and Lunar Module Descent Engines back in the 1960s.
Northrop Grumman looked at 180 lunar lander cases based on options such as orbital loiter, staging, propellants, engines, surface duration and surface cargo. The company confirmed the viability of several concepts, as well as laying down the ground rules for lander development based on automated operations, simplicity and low cost.
The feasibility study looked at propulsion requirements for lunar orbit loitering, landing on the Moon, returning to lunar orbit and rendezvous with the mother ship while taking into account improvements in technology since Apollo. It compared cryogenic fuels, which include liquid hydrogen, and storable fuels, which include hydrazine. It concluded that cryogenics perform better, but storables provide more options and are easier to handle and store over the course of a mission and that storable propellants would reduce risks and costs.
An interesting result of the study was the development of the “Pumpkin” ascent stage concept. If you look at the old Apollo Lunar Module, you’ll notice that the Ascent Stage (which sits on top) is the same size as the Descent Stage. That’s because it was not only used to get the crew back into lunar orbit, but also acted as the living quarters while on the Moon and contained all the controls for landing the craft. With the Pumpkin concept, Northrop Grumman has pared down the ascent stage for the Golden Spike lander to a low-mass globe that's just large enough for two people to squeeze into.
This design eliminates a lot of weight and a lot of problems. Furthermore, the ascent thrusters have been moved from underneath pod and placed on outriggers that can be swung up during liftoff from Earth. All of this adds up to more room available in the descent stage for more propellants. The surface habitat was moved to the descent stage as well. This way, the surface habitat could be divided so that the difficult to control and extremely bothersome lunar dust could be kept (mostly) out and whole craft made to fit inside a five-meter (16.4 ft) wide rocket payload fairing for liftoff.
"This concept has significant operability advantages for surface exploration since the surface habitat can be segmented to isolate lunar dust and provides more space for living and for selecting the most valuable lunar return samples," says Martin McLaughlin, Northrop Grumman's study lead.
Source: Northrop Grumman