Explosion on a Aerospace Vehicle
The last flight of the Space Shuttle Challenger ended 73 seconds after the launch in an explosive burn of hydrogen and oxygen propellants that destroyed the External Tank and exposed the Orbiter to severe aerodynamic loads that caused complete structural breakup. All seven crew members perished. The two Solid Rocket Boosters flew out of the fireball and were destroyed by the Air Force range safety officer 110 seconds after launch.According to the NASA version (Rogers President Commission): a steady flame coming (combustion gas leak) from the rocket booster impinged on the external tank which eventually failed, after which liquid hydrogen and liquid oxygen burnt in an explosive combustion. There is another analysis by Chirivella: the ignited liquid hydrogen leaking from the external tank caused its structural deterioration and ignited its contents.
Event Date
January 28, 1986
Record Quality Indicator
Region / Country
Event Initiating System
Classification of the Physical Effects
Nature of the Consequences
Cause Comments
The immediate cause of the accident (according to the Rogers Commission)was the failure of the pressure seal in the aft field joint of the right Solid Rocket Booster. The root cause of the failure was a faulty design unacceptably sensitive to a number of factors (effects of temperature, physical dimensions, materials properties, reusability, processing andthe reaction of the joint to dynamic loading).According to another version (Chirivella), the external tank experienced small undetected LH2 leakage ( 1.4 kg/s) which was ignited at early stage from the nearby burning rocket boosters.
Facility Information
Application Type
Application
Specific Application Supply Chain Stage
Components Involved
on-board hydrogen storage, external fuel tanks (liquid and solid fuels)
Storage/Process Medium
Storage/Process Quantity
1575000
Location Type
Location description
Airport and/or Airborne
Operational Condition
Pre-event Summary
In the two external tanks there were 1575 m3 of LH2 and 550 m3 of LOX, which was part of the rocket fuel. The actual pressure was about 0.23 MPa. The potential ignition source was adjacent burning solid fuel rocket boosters. According to NASA, O-ring rubber pressure seal at one of the solid rocket boosters eroded by hot gases after approx. 60 s after lift-off. A steady flame developed which was directed towards the External Tank containing the LH2 and LOX.
Consequences
Number of Injured Persons
1
Lessons Learned
Lessons Learned
Rogers President's Commission issued a series of recommendations to NASA, the first and the most specific one was the redesign and replacement of the Solid Rocket Motor joint and seal.Further, more general recommendations were:1. The review of the whole Shuttle Program Structure2. Bringing qualified astronauts into agency management positions3. To re-design the shuttle safety panel 4. To establish an Office of Safety, Reliability and Quality Assurance5. To improve communication and break management isolation6. To improve the landing safety7. To provide a crew escape system for use during controlled gliding flight8. To establish a flight rate consistent with NASA resources, and to avoid commercial pressure.9. To review and improve installation, test, inspection and maintenance procedures rigorous
Event Nature
Emergency Action
Unknown
Release Type
Release Substance
Release Amount (kg)
1575.00
Ignition Source
Detonation
No
Deflagration
No
High Pressure Explosion
No
High Voltage Explosion
No
Flame Type
Source Category
References
References
The Chapter 4 of President's Commission report
Part of the Chapter XI of President's Commission report, with recommendations
http://science.ksc.nasa.gov/shuttle/missions/51-l/docs/rogers-commissio…
(Accessed September 2020)