50
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55
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63
65
67
66
69
68
71
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79
77
78
81
80
83
82
85
84
86
87
88
89
90
91
92
93
95
94
96
97
99
98
01
00
02
03
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09
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11
10
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15
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ATLAS V - Vehicle use: Satellite, Cygnus, CST-100 (future)
American orbital launch vehicle. The Atlas V launch vehicle system uses a standard common core booster, up to five solid rocket boosters, a Centaur upper stage in a single- or dual-engine configuration, and one of several sizes of payload fairings. The current Atlas V 400 and 500 series launch vehicles, placed into service in 2002, are the latest design of the Atlas launch system. United Launch Alliance manufactures and operates the Atlas V launch vehicle to meet commercial and government medium, intermediate, and heavy space lift requirements.
Variant
All variants
Launches
86
Failures
2
Realized
0.98
Predicted
0.97
3/23/2016 - Atlas V (401)
PREMATURE FIRST STAGE ENGINE SHUTDOWN
162nd Atlas V launch
32nd Atlas V 401 launch
Cygnus/OA-6 cargo resupply mission to ISS
The first stage RD-180 engine shutdown six seconds early, requiring the second stage RL-10 engine to burn more than 60 seconds longer than planned to compensate for the first stage under performance. The premature RD-180 shutdown was due to an RD-180 mixture ratio control valve failure which resulted in early liquid oxygen depletion. At approximately T+222 seconds, an unexpected shift in fuel pressure differential across the RD-180 Mixture Ratio Control Valve (MRCV) and a reduction in fuel flow to the combustion chamber caused an oxidizer-rich mixture of propellants and a reduction in first stage performance. The engine supplier implemented a change to the MRCV to prevent recurrence of this anomaly.
SOURCES:
ULA Atlas V OA-6 Anomaly Status
Space Launch Report Falcon 1 Data Sheet
6/15/2007 - Atlas V (401)
PREMATURE SECOND STAGE ENGINE SHUTDOWN
10th Atlas V launch
5th Atlas V 401 launch
The second stage centaur RL-10 engine shut down four seconds early, leaving the payload (NROL30R) in a lower-than-planned orbit. A hydrogen valve on the second stage RL-10 engine failed to close properly during the coast phase between the first and second RL-10 burns. This allowed hydrogen to leak out during the coast phase, leading to fuel depletion and early engine shutdown during the second planned burn. The leaking valve was attributed to extremely cold temperatures experienced during the extended coast phases. A new valve design was implemented on subsequent flights.
SOURCES:
National Reconnaissance Office Press Release
1.00
0.88
0.92
0.86
1.00
0.80
1.00
0.90
1.00
0.67
1.00
0.83
0.97
0.96
0.97
0.96
0.97
0.96
0.97
0.94
0.98
0.96
0.96
0.92
0.98
0.97
0.96
0.93
0.98
0.95
0.95
0.90
0.93
0.88
Realized Rate
Predicted Rate
0.98
0.96
0.98
0.97