1、Lessons Learned Entry: 1534Lesson Info:a71 Lesson Number: 1534a71 Lesson Date: 2005-04-29a71 Submitting Organization: DFRCa71 Submitted by: Trong BuiSubject: Excessive Slack in the Retention Line of the Main Rocket Recovery Parachute Abstract: The Dryden Aerospike Rocket Test Directors Discretionary
2、 Fund (DDF) project conducted flight research of an aerospike rocket nozzle design using high power amateur rockets. The standard nozzles in these rockets were replaced by the aerospike nozzles and the rockets are then flown with aerospike nozzles only. Two aerospike rockets were flown successfully
3、to altitudes of over 26,000 ft and speeds of over Mach 1.5. The flight data acquired during the flight tests were stored onboard and retrieved after the rockets were recovered. The rockets were recovered using a dual-stage parachute system. The smaller drogue chute comes out at rocket apogee to stab
4、ilize the rocket. The main chute deploys at approximately 2500 ft above ground level to slow the rocket descend for a soft impact on landing. During the first rocket launch, the main chute deployed inadvertently when the drogue chute activated, and the rocket descended on the main chute from apogee.
5、 During the second rocket launch, the main chute bag got outside of the rocket airframe and was entangled with the main chute retention line, preventing main chute deployment and causing the rocket to descend under drogue chute only. Both of these problems were caused by excessive slack in the main
6、parachute retaining line.Description of Driving Event: The main chute bag is retained inside the rocket by the main parachute retention line and the main chutes electronically controlled release device. The drogue chute pulls on the main chute pack when the drogue chute is deployed. The excessive le
7、ngth of the main chute retention line causes the main chute to be pulled out of the rocket airframe when the drogue chute is deployed at apogee during the first rocket launch. During the second rocket launch, the main chute retention line was shortened in an attempt to solve this problem. However, i
8、t still contained enough slack to cause the main chute bag to exit the rocket airframe and become entangled with the retention line, preventing deployment of the main chute.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Lesson(s) Learned: Excessive
9、slack in the main chute retention line can cause inadvertent main chute deployment or main chute bag entanglement.Recommendation(s): Eliminate the need for a main chute retention line. Use a strap that secures the main bag to the electronically controlled main chute release device. Evidence of Recur
10、rence Control Effectiveness: The new main chute retention method was tested successfully during an amateur rocket flight in September, 2004.Documents Related to Lesson: N/AMission Directorate(s): a71 Exploration Systemsa71 Sciencea71 Space Operationsa71 Aeronautics ResearchAdditional Key Phrase(s):
11、a71 Accident Investigationa71 Aircrafta71 Flight Operationsa71 Payloadsa71 Range Operationsa71 Safety & Mission Assurancea71 SpacecraftAdditional Info: Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Approval Info: a71 Approval Date: 2005-08-29a71 Approval Name: Mike Reljaa71 Approval Organization: DFRCa71 Approval Phone Number: 661-276-3621Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
