of space exploration. The memorial was left while the television camera was turned away; he told Mission Control he was doing some cleanup activities around the rover. Scott disclosed the memorial in a post-flight news conference. He also placed a Bible on the control panel of the rover before leaving it for the last time to enter the LM. The EVA lasted 4 hours, 49 minutes and 50 seconds. In total, the two astronauts spent 18 hours outside the LM and collected approximately of lunar samples. Command module activities After the departure of Falcon, Worden in Endeavour executed a burn to take the CSM to a higher orbit. While Falcon was on the Moon, the mission effectively split, Worden and the CSM being assigned their own CAPCOM and flight support team. [[File:Apollo 15 CSM (14412950693).jpg|thumb|left|alt=A spacecraft seen with the Moon in background|Endeavour, with the SIM bay exposed, as seen from the Lunar Module Falcon]] Worden got busy with the tasks that were to occupy him for much of the time he spent in space alone: photography and operating the instruments in the SIM bay. The door to the SIM bay had been explosively jettisoned during the translunar coast. Filling previously-unused space in the service module, the SIM bay contained a gamma-ray spectrometer, mounted on the end of a boom, an X-ray spectrometer and a laser altimeter, which failed part way through the mission. Two cameras, a stellar camera and a metric camera, together comprised the mapping camera, which was complemented by a panoramic camera, derived from spy technology. The altimeter and cameras permitted the exact time and location from which pictures were taken to be determined. Also present were an alpha particle spectrometer, which could be used to detect evidence of lunar volcanism, and a mass spectrometer, also on a boom in the hope it would be unaffected by contamination from the ship. The boom would prove troublesome, as Worden would not always be able to get it to retract.Endeavour was slated to pass over the landing site at the moment of planned landing, but Worden could not see Falcon and did not spot it until a subsequent orbit. He also exercised to avoid muscle atrophy, and Houston kept him up to date on Scott and Irwin's activities on the lunar surface. The panoramic camera did not operate perfectly, but provided enough images that no special adjustment was made. Worden