NTSB · Safety Recommendation
Safety Recommendation A-93-103
Recommendation
THE NTSB RECOMMENDS THAT THE ORBITAL SCIENCES CORPORATION: REQUIRE, AS PART OF ELV LAUNCH PLANNING DOCUMENTATION: FOR LAUNCHES FROM REMOTE SITES OR AIRCRAFT, A PLAN TO ASSURE THAT ESSENTIAL COMMUNICATIONS INTERRUPTIONS RESULTING FROM ANTENNA PATTERNS ARE IMPROBABLE. PRACTICAL CONSIDERATION SHOULD BE GIVEN FOR TOLERABLE INTERRUPTIONS THAT MAY BE ASSOCIATED WITH TRANSIENT CONDITIONS SUCH AS AIRCRAFT MANEUVERS.
Safety Issue and Context
ON FEBRUARY 9, 1993, ABOUT 0930 EASTERN STANDARD TIME, THE LAUNCH SEQUENCE FOR AN ORBITAL SCIENCES CORPORATION (OSC) PEGASUS EXPENDABLE LAUNCH VEHICLE (ELV) WAS ABORTED BY THE NATIONAL AERONAUTICS AND SPACE ADMINISTRATION (NASA) RANGE SAFETY OFFICERS, IN ACCORDANCE WITH A PREVIOUSLY ESTABLISHED LAUNCH CONSTRAINT. SEVERAL SECONDS LATER, THE LAUNCH SEQUENCE WAS REINITIATED BY THE OSC TEST CONDUCTOR, AND THE MISSILE SEPARATED UNEVENTFULLY FROM ITS CARRIER AIRCRAFT. THE IGNITION AND STAGING OF THE PEGASUS AND ITS SUBSEQUENT DEPLOYMENT OF TWO SATELLITES INTO LOW EARTH ORBIT WERE ALSO UNEVENTFUL. THERE WERE NO INJURIES TO PERSONNEL INVOLVED IN THE MISSION AND NO DAMAGE TO MISSION ASSETS.
Response History
May 9, 1994 · NTSB Correspondence · Orbital Sciences Corporation
THE BOARD NOTES THAT THE OSC HAS IMPLEMENTED A DIRECT UHF VOICE LINK BETWEEN THE B-52 CARRIER AIRCRAFT PILOT & THE WESTERN RANGE CONTROL OFFICER & RANGE SAFETY OFFICER. THIS UHF VOICE LINK PERMITS A VERY RAPID RESPONSE CAPABILITY TO CONVEY INSTRUCTIONS TO THE CARRIER AIRCRAFT IF NECESSARY. BASED ON THIS INFO, THE BOARD CLASSIFIES A-93-103 "CLOSED--ACCEPTABLE ACTION."