The events on this day in history for our heritage companies are noted below.
The earliest event was in 1957, the latest event was in 1995
Human Spaceflight:
1976 – Design criteria for Shuttle operations at SLC-6/VAFB released to Martin Marietta by NASA
1995 – LANDING: STS-70 (Discovery), KSC
Military and Classified Programs:
NONE
Exploration and Interplanetary Programs:
1962 – LAUNCH FAILURE: Mariner 1, GD Atlas/Lockheed Agena B, LC12, CCAFS
Earth-Monitoring and Civil Weather Satellite programs:
NONE
Commercial Programs:
1976 – LAUNCH: Comstar 2, GD Atlas SLV-3D/Centaur, LC36B, CCAFS
Test, ICBM, FBM programs:
1957 – LAUNCH: Lockheed X-17, LC3, CCAFS
1960 – LAUNCH FAILURE: GD Atlas D, 576-B1, VAFB
1966 – LAUNCH: MM Titan II, 395-B, VAFB
1967 – LAUNCH: GD Atlas/Trident, 576-A3, VAFB
1979 – LAUNCH: Lockheed Trident I C4, SSBN657, ETR
1980 – LAUNCH: Lockheed Trident I C4, SSBN629, ETR
Other:
NONE
The photo today is of the launch of Mariner 1 in 1962, before the failure that resulted in range destruction of the vehicle. Photo Credit: NASA (from the Great Images in NASA History gallery). Here is a write-up about that failure from NASA public sources and posted on Wikipedia:
The launch of Mariner 1 was scheduled for the early morning of July 21, 1962. Several delays caused by trouble in the range safety command system delayed the beginning of the countdown until 11:33 p.m. EST the night before. At 2:20 a.m., just 79 minutes before launch, a blown fuse in the range safety circuits caused the launch to be canceled. Countdown was reset that night and proceeded, with several holds, planned and unplanned, from 11:08 p.m., through the early morning of the next day.
At 9:21:23 a.m. on July 22, 1962, Mariner 1’s Atlas-Agena lifted off from Pad 12. Soon after launch, the booster began drifting northeast of its planned trajectory. Corrective steering commands were sent to the rocket, but the Atlas-Agena instead proceeded further off course, imperiling North Atlantic Ocean shipping and/or inhabited areas in the event of a rocket crash. At 9:26:16 a.m., just six seconds before the Agena second stage was scheduled to separate from the Atlas, at which point destruction of the rocket would be impossible, a range safety office ordered the rocket to self-destruct, which it did.
Cause of the Malfunction:
Because of the gradual rather than sharp deviation from its course, JPL engineers suspected the fault lay in the flight equations loaded into the computer that guided Atlas/Agena from the ground during its ascent.After five days of post-flight analysis, JPL engineers determined what had caused the malfunction on Mariner 1: an error in the guidance computer logic combined with a hardware failure.
The hand-written guidance equations contained the symbol “R” (for “radius”). This “R” should have had a line over it (“R-bar” or R̄), denoting smoothing or averaging of the track data coming from an earlier calculation. But the bar was missing, and so the computer program based on those equations was incorrect. The error was in the original specification, and not in the process of writing the program.
During its ascent, Mariner 1’s booster briefly lost guidance lock with the ground. Because this was a fairly common occurrence, the Atlas-Agena was designed to continue on a preprogrammed course until guidance-lock with the ground resumed. When lock was reestablished, however, the faulty guidance logic caused the program to erroneously report that the “velocity was fluctuating in an erratic and unpredictable manner”, which the program tried to correct for, causing actual erratic behavior, which prompted the range safety officer to destroy the rocket.
The incorrect logic had previously been used successfully for Ranger; it was the combination of the erroneous formula and a hardware fault which led to Mariner’s destruction.
The catastrophic effects of a small error “summed up the whole problem of software reliability” and contributed to the development of the discipline of software engineering.
Subsequent popular accounts of the accident often referred to the erroneous character as a “hyphen” (describing the missing component of the symbol) rather than an “R-bar”; this incorrect mischaracterization was fueled by Arthur C. Clarke’s description of the malfunction as “the most expensive hyphen in history”.
