NASA Urged to Limit Flights in 4-Shuttle Fleet to 11 to 13 a Year

NASA should not regularly schedule more than 11 to 13 shuttle launches a year, even with four space shuttles, because of limited resources, a National Research Council panel said Thursday.

In a study requested by Congress and paid for by the National Aeronautics and Space Administration, the research council concluded that eight to 10 flights a year were possible with the current three-shuttle fleet.

The report comes six days after NASA announced its first post-Challenger shuttle launch schedule. Space agency officials said a maximum flight rate of 16 missions a year was possible once a replacement orbiter for Challenger becomes operational in 1991.

No Pressure to Meet Rate

NASA said the flight rate was only a target and that there would be no pressure to meet any given launch rate projection based on scheduling demands.

The research council review panel, however, concluded that 13 flights a year is the reasonable maximum even with four space shuttles, although up to 15 flights could be carried out in a “surge” assuming relatively “simple payloads and flight plans.”

“The number of scheduable orbiters is fewer than the inventory,” the report said. “Reasons include age of hardware, availability of spares, damage or normal wear.

“The panel’s experience suggests that the scheduable orbiter fleet is smaller than the inventory by almost one orbiter. Thus, today the scheduable fleet is only a bit in excess of two.”

In any case, the panel said those flight rates would be possible only if accidents are prevented and improvements are made in shuttle processing facilities, the availability of spare parts and with increases in personnel and training.

Airline Example Offered

The panel suggested that NASA’s shuttle fleet be operated in some ways like an airline manages its jet fleet. It said the space agency should plan for periodic maintenance requirements that could keep an orbiter grounded at any given time.

NASA now is planning five shuttle missions in 1988, with the first post-Challenger launch on Feb. 18, 1988. Nine flights are scheduled for 1989 and 10 in 1990.

The maximum yearly flight rate anticipated after the replacement shuttle becomes operational is 16, the same number of flights planned for 1986 until the Jan. 28 Challenger explosion grounded the shuttle program.

The National Research Council is an operating agency of the National Academy of Science and the National Academy of Engineering, which are private membership organizations that also advise the government.