DESTINATION MOON: A History of the Lunar Orbiter Program
Prelude to Mission II
[245] At the time of launch of Lunar Orbiter I the status of the other spacecraft was as follows. Spacecraft 5, the second flight spacecraft, was in storage at Cape Kennedy. Its photo subsystem was due to be delivered at KSC on September 4, 1966. Spacecraft C, a ground-test spacecraft, was at JPL for display purposes, and no further work was planned for it. Spacecraft 1, also a ground-test spacecraft, [246] was at Boeing in Seattle. It had completed formal testing and was being used as a flight-test unit. During Mission I Boeing used it to duplicate problems encountered on Lunar Orbiter I as an aid to their resolution. Spacecraft 2 was also at Boeing, awaiting its photography subsystem so that it could begin mission simulation tests. Spacecraft 3, the fifth flight spacecraft, was in the clean room at Boeing waiting for various hardware components to be installed. Major testing of this spacecraft was due to begin on November 7. Spacecraft 6, the third flight spacecraft, was scheduled for preshipment review on August 19 followed by shipment to Cape Kennedy on August 20. Spacecraft 6 would then serve as a back-up for the second flight spacecraft. Finally, Spacecraft 7, the fourth flight spacecraft, was in storage at Boeing awaiting preenvironmental flight checkout, scheduled to begin on August 29.35
The second Lunar Orbiter mission had run into difficulties during May 1966, six months before the tentative November launch date for Lunar Orbiter II. On May 20 NASA and Boeing program officials conducted a preshipment review of Spacecraft 5 at the Boeing Company. This spacecraft was to serve as back-up for the first mission and was to be launched on the second mission in the event that all went as planned [247] on the first. After reviewing the history of Spacecraft 5, NASA's review team refused permission to ship it to Cape Kennedy facilities without further testing.36 The Boeing Lunar Orbiter Program officials objected to this, but the history of Spacecraft 5 revealed a need to overcome inadequate operations of important equipment.
Having been subjected to the same tests as Spacecraft 4, Spacecraft 5 was considered ready for shipment with one major exception. The camera thermal door had failed to open during thermal vacuum testing. The other thermal vacuum tests were completed, save for this one. Again it was attempted. The thermal vacuum chamber was pressurized and the command for the door to open was sent. Again it remained closed. Next the operation of the thermal door was visually observed, and after some of the thermal insulation had been pulled loose the door operated correctly through several cycles. The door and its motor mechanisms were then removed from the spacecraft for special thermal vacuum tests.37
Boeing officials wanted to ship the spacecraft to Cape Kennedy without the door while it underwent further tests. [248] Once the cause of failure was isolated, it could be corrected, and the door could be reinstalled at the Cape. NASA officials declined this suggestion because of the long history of development troubles with the door mechanism. Nevertheless, Boeing officials still wanted to ship the spacecraft, saying that they would be merely effecting a transfer from Boeing-Seattle to Boeing-Florida. Boeing's major reason was the delivery deadline for the second flight spacecraft: June 22. A contract incentive depended upon meeting this date. However, NASA officials still disagreed with Boeing's line of reasoning and insisted that the facts were clear. The spacecraft had failed a specified test. It was necessary to retest the whole spacecraft. Reluctantly Boeing management accepted this verdict and issued instructions to return the spacecraft to the test chamber on May 21.38