Aerospace giant Northrop Grumman (News - Alert) has completed a feasibility study for a commercial lunar lander to be used by the Golden Spike Company to transport astronauts to and from the surface of the moon. The study has, in the words of Northrop's press release, "conceived" a novel, new low-mass ascent staged concept called "Pumpkin."
Northrop's study reviewed Golden Spike's requirements and put together a set of study ground rules and assumptions emphasizing automated operations, simplicity and low cost. It established propulsion requirements for operations to and from the lunar surface, including lunar orbit operations and rendezvous with a crew vehicle to take a two astronaut crew home. A look at new technologies since the completion of the 1970's Apollo program – yes, that's forty years of goodness in computers, materials, and simulation – was done, and the study evaluated 180 lunar landing cases, considering factors including loiter, staging, propellants, engines, surface duration, surface cargo and the technology basis.
Today's release is a long way from building hardware, however. The last task citied "established a pragmatic design trade space for more detailed analysis and development." In other words, Northrop has not been instructed to finalize anything.
Golden Spike had disclosed some details of the study at a press conference held last month at the National Space Symposium in Colorado, highlighting two factors. While cryogenic propellants provide better performance and more options for a 21st century lunar lander, multiple storable propellant options are available and wouldn't require refueling or topping off due to boil-off.
Northrop's conceptual design pares down the ascent module to a "minimalist" pressured pod with a combination descent stage/surface habitat. The two can be packed within a five meter diameter fairing. Using a smaller spherical "Pumpkin" ascent pod with two people and lunar samples packed in provides weight and volume savings for a smaller engine, leaving more unneeded mass on the lunar surface.
Some of that "more" in the descent stages includes integrating a Golden Spike-build leave-behind scientific instruments package. Making the instruments package a part of the descent stage, using its batteries and adding pull-out solar panel for recharging translates to less overall weight since the two items don't need separate batteries while the solar panel provides battery refresh and/or direct power to the descent stage, thereby decreasing the need for more battery capacity if you're simply using stored power.
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Edited by Jamie Epstein