Player Embed Code: Download Embed Share Defense Department Officials Testify on Space Force Proposal, Part 1 Defense.gov April 11, 2019 | 01:19:28 Acting Defense Secretary Patrick M. Shanahan; Marine Corps Gen. Joe Dunford, the chairman of the Joint Chiefs of Staff; Air Force Secretary Heather Wilson; and Air Force Gen. John E. Hyten, commander of U.S. Strategic Command, testify on the proposal to establish a Space Force at a hearing of the Senate Armed Services committee, April 11, 2019.Part 1 of 2.