WASHINGTON — Amid criticism that NASA has strayed from its research and development roots in recent years, a senior agency official told a congressional panel that NASA would be changing the way it invests in advanced technologies.

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Brian Berger is editor in chief of SpaceNews.com and the SpaceNews magazine. He joined SpaceNews.com in 1998, spending his first decade with the publication covering NASA. He was named senior staff writer in 2004, a position he held until being named...