WASHINGTON — Former NASA Administrator Mike Griffin — not his successor Charles Bolden — will testify Sept. 15 before the House Science and Technology Committee on options for the future of U.S. manned spaceflight outlined in a summary report by a blue-ribbon panel.

Bolden originally was slated to testify alongside Norman Augustine, who led the review. But the House Science and Technology Committee released a revised witness list Sept. 10 that did not include Bolden, and added Griffin and retired U.S. Navy Vice Adm. Joe Dyer, chairman of NASA’s Aerospace Safety Advisory Panel.

Augustine’s panel was tasked by the White House in May with determining options for the future of NASA’s manned spaceflight program.

Formally known as the Review of U.S. Human Space Flight Plans Committee, the group delivered a summary report to White House and NASA officials Sept. 8. The study concluded that NASA’s current manned space exploration program, dubbed Constellation, is not sustainable and that absent additional funding, no viable options for manned exploration beyond low Earth orbit exist.

Griffin helped design and develop the Constellation program as NASA chief under former U.S. President George W. Bush.

“It is clarifying to see a formal recognition by the Commission that, based upon budgetary considerations, ‘the human spaceflight program appears to be on an unsustainable trajectory,’” Griffin, now a professor at the University of Alabama Huntsville, wrote to friends and colleagues in a Sept. 9 e-mail obtained by Space News.

Griffin, however, went on to blast the Augustine committee for failing to render a “clear-eyed, independent assessment of the progress and the status of Constellation[.]”