parker%NRL-CSS@sri-unix.UUCP (04/26/84)
From: Alan Parker <parker@NRL-CSS> They are not mounted on the ET because they cost big bucks and the ET is lost after launch. To build them to be recovered would probably add cost and weight. Remember, the main point of the Shuttle was for as much as possible to be resusable and for time between launches to be minimized. -Alan