* 4. ASSEMBLE THE RTG BOOMS.

• This step uses parts printed on Parts Sheet 4 (white card stock).

• Cut out one RTG BOOM. There are four ]-shaped shaded lines at the black end. Slit through the paper along these marks, to create fins which will pop up when the part is folded. Lightly score lengthwise along the two white areas which separate the three trusswork panels. Fold down the two outboard truss panels away from the printed side. The boom takes on a triangular cross-section. The four fins should pop out slightly. Bend them outward a little more.

• Glue the two long black legs together, at the inboard end of the part, white to white. At the black outboard end, wrap the white tab through the notch it meets. This should hold the part together while you apply glue. Fold over the small white tab in the middle, and glue, to hold the part's triangular cross section.

• Optional: Cut a strip of gold-colored foil/paper (such as giftwrap) to fit along the top of the BOOM's trusswork. Glue in place covering the top of the boom, from the inboard end of tab A to the black, finned RTG. Don't cover tab A or the RTG.

• Cut out one RTG NIMS SHIELD. Optionally, cut and glue a piece of gold-colored foil/paper to cover the white side.

• Lightly score along the SHIELD's white line, and fold about 30 degrees, away from the black side.

• Glue the SHIELD's V-shaped notch up onto the bottom of the RTG BOOM's trusswork, at the outboard end of the truss markings (just inboard of the black, finned RTGs). The black side faces inboard. Note: the accompanying image can present an optical illusion. In reality, the bottom of the shield bends toward the outboard end, and it is being viewed from slightly outboard.

  The spacecraft's RTGs are hot. The shields prevent NIMS, which is a science instrument sensitive to infra-red, from "seeing" them.

• Repeat the above steps to make the second RTG BOOM.

• Optional: If you wish to represent Galileo's low-gain communications antenna #2 (LGA2), obtain a straight pin about 4 cm or 1.5 inches in length Stick it into the bottom of an RTG boom, right at the back of the RTG NIMS SHIELD, where the shield meets the truss. It should extend straight down from there. Glue it to the back of the SHIELD. The RTG BOOM which supports LGA2 is designated RTG BOOM 2, and it will be installed on the SPUN BUS near the 2 mark, in a later step.