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The baseline spacecraft design for the Artemis Project Reference Mission is the Vertical Landing Configuration. You can see the original cartoons of this configuration in ASI 9600001 and ASI 9600002; and a much more elegant rendering by Vik Olliver in ASI 9700002 at the right. We're putting the most study into this configuration, core-drilling the design to find out what works, what doesn't, and what it will take to get these things built and flown.
The concept of the Vertical Landing configuration gets a bit complicated, so in December 1995 I made a cartoon in a little QuickTime movie, ASI 9500026, to show how the initial exploration base deploys after it lands on the moon. It's a big file, 888K, so use this link with caution.
The Vertical Landing configuration has grown away from the Integrated Stages Option (see ASI 940007) that it was originally based on. "Integrated Stages" meant that the Ascent Stage was actually part of the Descent Stage. (The nomenclature dates back to the 1980s, when I was fiddling with all sorts of ways to build a moonbase.) I did that to save weight; but over the course of 1995 and 1996, we decided to abandon the idea. We want to use cryogenic fuels for the Descent Stage, to get the higher specific impulse; but we want to use hypergolics on the Ascent Stage to maximize reliability. That means different engines for descent and ascent.
When we decided to use different engines for the Ascent Stage, we were free to relocate it. In Vik Olliver's rendering above, you'll see the Ascent Stage mounted alongside the descent engines. We're thinking of having the crew ride in the Ascent Stage even during the descent to the moon. With the Ascent Stage mounted side-saddle and the crew aboard it, we have an emergency abort capability almost all the way down to the surface. We might lose the habitat, but at least we can save the crew!
This configuration gives us an option of using the Ascent Stage engines during the initial descent to the moon. I don't know whether having the ascent engines already lit will add any safety margin to our abort capability -- hypergolic rockets fire up really fast, even from a cold start. So currently we're not planning to light the ascent engines until the crew really wants to get back up to the orbiting Lunar Transfer Vehicle.
We're also considering the Horizontal Landing Configuration shown in ASI 9600105. It has certain advantages over the Vertical Landing Configuration, but we don't yet know if it really decreases weight or cost or adds reliability. Nobody has run any numbers yet, but the structure for the horizontal configuration actually looks heavier than the vertical configuration.
Looking into the future from January 1997, my best guess is that by the time we open the first tavern on the moon, we will have tried out spacecraft resembling both these configurations and eleventy dozen other things.
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