Reductions in Astronaut Corps May Be Too Deep Says NRC

The National Research Council (NRC) today released a study assessing how large the NASA astronaut corps should be now that the space shuttle program has ended. It concluded that NASA may be cutting the size of the corps too deeply and supports retaining the T-38 training aircraft used by the astronauts.

Noting that the size of the astronaut corps has diminished from almost 150 people in 2000 to 61 in May 2011, the report cites the many uncertainties that must be taken into account when rightsizing the corps: “Viewed as a supply chain, astronaut selection and training are very sensitive to critical shortfalls because of the long lead times and long recovery time between missions, and because astronauts, trained for specific roles and missions, cannot be easily interchanged.”

Thus, it concluded that “the currently projected minimum target size for the active Astronaut Corps poses a risk to the U.S. investment in human spaceflight capabilities” because it does not take into account “unexpected increases in attrition, or commercial, exploration, and new mission development tasks.”

The NRC specifically recommended that NASA factor in a higher “reserve” when determining the number of NASA astronauts that are needed.

NASA uses a theoretical model to determine the “minimum manifest requirements,” or how many astronauts it needs. The model is based on the number of astronauts who are in a post-flight reconditioning period, plus the number on-orbit, plus program spaceflight opportunities with a 5-year rotation. It then adds a reserve factor, which in the past was 50 percent, but recently was lowered to 25 percent for budgetary reasons, according to the report.

That model does not include “real-world constraints,” however, such as needed skill mix, medical disqualification, or the desired pairing of inexperienced and experienced astronauts, the NRC concluded. Nor does it take into account “new sources of uncertainty” such as a “relatively new medical condition” — papilledema, a swelling of the optic disk – afflicting astronauts returning from long duration missions. Thus, the NRC recommends that NASA return to a higher reserve factor when calculating the number of astronauts needed, though it did not specify what level should be used.

The committee also reviewed the need for NASA to retain astronaut training and simulation facilities and aircraft. One particularly controversial topic is whether the fleet of T-38N aircraft in which the astronauts train is still needed for what NASA calls spaceflight readiness training (SFRT). The NRC concluded that the aircraft should be retained because they teach critical decision-making skills in an operational environment:

“High-performance aircraft provide conditions including crew disorientation and rapid fluctuation in G-forces, under which the flight crew must carry out complex tasks in a stressful and potentially life-threatening environment. This combination of unique environments, demand for rapid, critical decision making, and historical evidence convinced the committee that SFRT provides experienced-based training that cannot be duplicated by current, or to the best of the committee’s knowledge, projected alternative techniques or technologies.”

The NRC committee was co-chaired by Fred Gregory and Joe Rothenberg. Gregory is a former astronaut and former NASA Deputy Administrator. Rothenberg is a former NASA Associate Administrator for Space Flight and former Director of NASA’s Goddard Space Flight Center.