 |
| A Little Joe 5B launch cover from “Hudson” featuring a rubber-stamped cachet, postmarked at Wallops Island with a hand cancel on April 28, 1961. |
Little Joe 5B (LJ-5B) was launched from Wallops Island, Virginia, on April 28, 1961, using a Little Joe launch vehicle and Mercury spacecraft No. 14A. Its principal purpose was to test whether the Mercury spacecraft and its escape system could function properly under the extreme aerodynamic forces—known as maximum dynamic pressure, or max-Q—that could occur during an Atlas launch.
The flight did not proceed exactly as planned. One of the Little Joe's rocket motors failed to ignite on time, causing the vehicle to fly a much lower trajectory than intended. Instead of reaching the planned altitude of roughly 45,000 feet, it reached only about 14,600 feet.
 |
| A Little Joe 5B launch cover from “Hudson” featuring a rubber-stamped cachet, postmarked at Wallops Island with a machine cancel on April 28, 1961. |
Ironically, this deviation produced an even more severe test of the escape system. Because the spacecraft remained in the denser lower atmosphere, it experienced dynamic pressures of approximately 1,920 pounds per square foot, almost twice the planned 990 psf. The abort sequence was initiated at about 33 seconds, and the escape tower, parachutes, and other sequential systems performed successfully.
(Reference from
Little Joe 5B)
