ASAP: SLS/Orion Launch Cadence Poses Safety Risks

Space Launch System in flight. (Credit: NASA)
Space Launch System in flight. (Credit: NASA)

NASA’s Aerospace Safety Advisory Panel (ASAP) believes the projected low flight rates of the Space Launch System (SLS) and Orion crew vehicle will create significant safety challenges for the space agency. The independent safety group also raised questions about the safety of flying astronauts on the system in 2021.

“The ASAP and the Agency remain concerned about risks introduced in the currently scheduled frequency of SLS/Orion launches, ” according to ASAP’s 2014 Annual Report. “The plan indicates a launch about every 2 to 4 years. This would challenge ground crew competency. The skills, procedures, and knowledge of conducting the launch, mission, and recovery are perish-able. The ASAP believes that an extended interval requires the relearning of many lessons and skills, in contrast to Apollo and Shuttle, which had a relatively steady cadence.”

ASAP also expressed concerns about the risks to crew members on the first crewed flight of Orion scheduled for 2021. The report noted that Exploration Mission 2 (EM-2)

will be the first full-up flight test of the new upper stage rocket motor as well as several critical life-support systems, including the Pressure Control System, the Air Revitalization System, and the Fire Detection and Suppression system. NASA has an extensive ground and flight test program planned to exercise these systems extensively before this flight test and to verify their design features. Included in this test program will be microgravity exposure on the ISS.

However, NASA should give careful consideration to the unknowns that may be detected only by actual flight test of safety-critical Orion systems before exposing crew to the flight test regime. If NASA does indeed decide to fly crew on EM-2, the Panel urges NASA to be transparent with all stakeholders and the public on the risks involved, including the rationale supporting why crew are needed on this mission.

ASAP noted that overall risks in programs are higher during early flights than they are over the course of a program. For example, in the space shuttle program

actual risk during early flights was as much as 10 to 100 times greater than the analyses indicated. Early Shuttle astronauts actually faced a 1 in 10 probability of catastrophe on each flight rather than the 1 in 1,000 probability that some analyses had indicated….

Because the perception of external stakeholders is vitally important, NASA’s Office of Communications must be cautious not to create or reinforce inaccurate perceptions of risk….

Download ASAP’s 2014 Annual Report here.