TransLunar Transportation System
Section 4.2.1.
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Notes on Lunar Transfer Vehicle Design

The LTV is based on a single SPACEHAB module, built by McDonnell Douglas in Huntsville, Alabama. They're already putting together a double SPACEHAB module for STS-77, scheduled to launch in April 1996. We might be able to land a triple module on the moon. (These things come apart like Meccano sets -- the end cones and body of the module are separate units.)

On the end cone of SPACEHAB you'll see a pattern that looks like Mickey Mouse . . .

             ____________  <--- circular end cone is cut off on top
            /            \
           |    O    O    |<--- ~13.5 feet diam x 12 feet long
        ==||     ____     ||==<--- trunnion pin
           |    /    \    |
            \   \____/   / <--- circular hatch
                  ||  <--- keel pin

SPACEHAB Illustration

Figure SPACEHAB Module

You may also download this image in CGM vector graphics format.

The top two circular ports are utility connections, and the big bottom circle is the hatch. The hatch is 54 inches in diameter.

The keel pin is a structural interface to the Orbiter's keel, at the bottom of the payload bay. The trunnion pins fit into trunnions on the Orbiter's payload bay sill.

On top of the SPACEHAB there are two windows arranged diagonally, and two sections for structural attachment of external payloads. The windows are circular and can be replaced by a small scientific airlock.

Adapting SPACEHAB to LTV design

                     small thruster for attitude control
               -------  -----v-
              |:::| O ||O  --   tanks
      hatch  ||---+---||O (     engine    Top View
              | O |:::||O  --   tanks
               -------  -----^-
              SPACEHAB  Propulsion Package

Now, on the end cone opposite the hatch, we attach the LTV's propulsion package. We envision this to be cylindrical, generally conforming to the geometry of the SPACEHAB except not cut off.

On the outside of the shroud surrounding the LTV's engines we put some solar arrays (shiny, deep royal blue) and body-mounted radiators (black stripes, closely spaced). The solar arrays and radiators conform to the geometry of the cylinder. Alternatively, they could be on booms like those on the Salyut and Soyuz and International Space Station. Eventually we'll want booms, to get extra power and cooling for the LTV. We might not do that on the first flight to keep cost and weight under control, but the design will be scarred for it. ("Scarred" means there will be attachment points and connectors for these services to be added later.)

The service module also contains the exterior guidance and navigation equipment. That means small ports (about 3 inches diameter, probably elliptical in shape where they pierce the shell) for the attitude-control thrusters. They'll also have a star tracker, which looks like a box at the apex of a cone; the cone is actually a light shield, about 12 inches long and six inches in diameter at its open end. The cone is flat black; as black as it can get, because its function is to block stray light from getting to the ultra-sensitive star tracker camera. There will be 3 star trackers, which allows the vehicle to get a simultaneous fix in three dimensions. That way they won't have to rotate to sight several starts to determine their attitude.

There should be EVA handrails (bright yellow, 24" long, standing off about 2" from the surface, rounded-rectangle cross section about 1.5" wide by .75" thick) that allow the crew to go EVA and translate along the ouside.

The LTV will also have rendezvous lights and probably attitude indicators so the crew will know what they're looking at when they see it. At least one rendezvous light will be a gimbaled spotlight capable of tracking the approach Ascent Vehicle so they can spot their target over long distances.

TransLunar Transportation System

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