WASHINGTON — The National Transportation Safety Board (NTSB) announced that it will hold a public hearing July 28 to determine the most likely cause of the fatal SpaceShipTwo accident last October.

The meeting will be held at NTSB’s conference center here starting at 9:30 a.m. Eastern. The purpose of the meeting, according to the July 23 announcement, is “to determine the probable cause” of the Oct. 31 accident, which the NTSB has been investigating in cooperation with the Federal Aviation Administration’s Office of Commercial Space Transportation and other agencies.

NTSB investigators said in the days after the accident that the vehicle’s co-pilot, killed in the accident, appeared to prematurely unlock the feathering mechanism that raises the vehicle’s tail for reentry. That created an aerodynamic instability and, seconds later, the vehicle broke apart in mid-air. The vehicle’s pilot survived the accident with minor injuries.

The NTSB has made no formal statements on the accident investigation since mid-November, when it announced it had interviewed the surviving pilot. In comments at a meeting of the National Research Council’s Aeronautics and Space Engineering Board here April 22, NTSB Chairman Christopher Hart suggested the lack of automation in the SpaceShipTwo cockpit may have played a role in the accident.

“It depends so much on humans doing the right thing under some fairly challenging circumstances, i.e., being in a three-g environment, wearing gloves, flicking switches,” Hart said at the meeting. “I don’t think it’s very well understood because we just don’t have that much experience with it.”

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...