Despite having received millions of dollars in federal government funding, NASA’s small aircraft transportation system (SATS) has been described as “unpromising” by the National Academy of Sciences, which was asked by NASA to review the concept.
NASA’s goals were to “revolutionize aviation” by enabling people “to move, faster and farther, anytime, anywhere” and reduce intercity doorstep-to-destination transportation time by 50 percent in 10 years and 67 percent in 25 years.

The agency envisioned advanced small aircraft flown routinely between the nation’s GA airports while transporting individuals, families and groups of business travelers.
NASA anticipated major advances in avionics, engines, airframes, flight control, manufacturing, com- munications and navigation systems and their application to thousands of small fixed-wing aircraft over the next several decades. It described these advanced aircraft as being safer and easier to operate and much more comfortable, reliable and affordable than current general aviation aircraft.

NASA maintained that the enhancements would make many more of the country’s 5,000 small airports much more practical and available for intercity transportation without requiring large public investments in airport and
ATC infrastructure.

But the academy said there is “little evidence” to suggest that SATS aircraft can be made affordable for use by the general public; SATS has minimal potential to attract users if it does not, as conceived, serve the nation’s major metropolitan areas; SATS promises limited appeal to price-sensitive leisure travelers, who make most intercity trips; infrastructure limitations and environmental concerns at small airports are likely to present large obstacles to SATS deployment; many technical and practical challenges await the development and deployment of SATS technologies; and SATS has the potential for undesirable outcomes.

After being asked by NASA to review the SATS concept, the academy formed a committee with a range of expertise and a balance of perspectives. H. Norman Abramson, executive vice president emeritus of the Southwest Research Institute, chaired the committee, which included 15 members with experience in aircraft engineering and manufacturing, airport management and planning, ATC, aviation safety, economic development, demographics, transportation system planning and travel demand analysis.

The committee met six times during a 16-month period, with all the meetings except the last occurring before September 11. While the group did not have sufficient time to examine the security implications of SATS, it believes that many of the security issues relevant to general aviation would also apply to SATS.

‘Focus on More Achievable Goals’
Overall, the committee urged NASA to abandon the SATS concept and refocus the program on other more achievable goals. “The capabilities and technologies being developed under the SATS program may prove useful in ways that are not now apparent,” the committee said. “Indeed, many system and vehicle configurations not envisioned for the current SATS concept may emerge.”

The group found that the full-scale SATS concept presents a “highly unlikely and potentially undesirable outcome” and it said the system is not likely to emerge as conceived or contribute substantially to satisfying travel demand.

According to the academy, SATS is limited by the affordability of the conceived
vehicles, the lack of demand between origin and destination points proposed in concept, the complex system issues ranging from airspace design and management to safety and environmental effects.

“Moreover, the committee believes that the positing of any such preconceived system, in which a single and definitive vehicle concept is used to guide research and development, could inhibit the evolution of alternative outcomes that may result from technological opportunities and economic and social need,” it said.
But the committee said it “views favorably and endorses much of the technological research and development” contained in the SATS program, as well as the approach of using NASA and other government resources and expertise to leverage and stimulate private-sector investment in aeronautics R&D.

Although the committee does not support public-sector investment in SATS deployment or the use of the SATS concept itself as a guide for making technology development and deployment decisions, it said that the component capabilities and technologies now being pursued under the SATS umbrella can enhance safety and confer other benefits on users of both general and commercial aviation.

The committee urged NASA to join with other government agencies under the lead of the Transportation Department in undertaking “forward-looking studies of civil aviation needs and opportunities” to ensure that they are being addressed “appropriately” through government-funded technology R&D. It said that technological capabilities now being pursued under the SATS program offer the potential to allow more reliable and safe operations during bad weather at more small airports, and to improve the accuracy, timeliness and relevance of the weather, traffic and airport information provided to GA pilots.

The committee also recommended that NASA “prioritize the capabilities and technologies that are now being pursued in the SATS program according to a clearly defined set of civil aviation needs that these capabilities and technologies can help meet.” Such a move, it said, will likely have other positive effects, such as improving the overall utility of small aircraft.