Lunar Module Ascent Engine Cover Shield Assembly.

The Lunar Module was a crowded space, and the ascent engine sported this cover during final ground assembly and checkout (photo in context below).

It is an aluminum plate, anodized a striking red color, measures 23″ in diameter, and engraved with “Caution Step With Care,” and “Remove Before Flight,” as well as two lines of instructions near the top. Part numbers on pads on the reverse side have been evenly worn, probably from use. Cover is signed in silver ink by James Lovell, Rusty Schweickart, Dave Scott, John Young, Buzz Aldrin, and Edgar Mitchell, each adding their missions under their signatures.