HALO jumps are used to enter hostile territory undetected when threats to both Airmen and aircraft are expected.
Comet ISON Survives Sun Impact
Continuing a history of surprising behavior, material from Comet ISON appeared on the other side of the sun on the evening on Nov. 28, 2013, despite not having been seen in observations during its closest approach to the sun. This movie shows Comet ISON orbiting around the sun -- represented by the white circle -- and covers Nov. 27, 2013, 3:30 p.m. EST, to Nov. 29, 2013, 8:30 a.m. EST. ISON looks smaller as it streams away, but scientists believe its nucleus may still be intact.