Ranger 3 (nonfiction)
Ranger 3 was a space exploration mission conducted by NASA to study the Moon.
The Ranger 3 robotic spacecraft was launched January 26, 1962 as part of the Ranger program. Due to a series of malfunctions, the spacecraft missed the Moon by 22,000 mi (35,000 km) and entered a heliocentric orbit.
The Ranger 3 space probe was designed to transmit pictures of the lunar surface during a period of 10 minutes of flight prior to impacting on the Moon, to rough-land a seismometer capsule on the Moon, to collect gamma-ray data in flight, to study radar reflectivity of the lunar surface, and to continue testing of the Ranger program for development of lunar and interplanetary spacecraft.
Sporadic tracking of the probe continued until January 31 when the attitude control thrusters exhausted their propellant supply, at which point the mission was officially terminated.
Liftoff took place at 3:30 PM EST on January 26, a mere hour and 15 minutes before the launch window closed, after which Ranger 3 could not have been launched for another month.
Around 140 seconds after liftoff, the guidance officer reported that he had lost his link on the Atlas. The antenna on the booster used to receive guidance commands had ceased operating and the autopilot system reverted to its built-in backup program, but unfortunately this lacked the same precision as the ground guidance and the Atlas's staging and engine cutoff did not occur on schedule. The engines also over-accelerated and imparted excessive velocity into the Agena and probe, so that it entered a higher-than-planned parking orbit. Even worse, equipment at a Florida tracking station malfunctioned and picked up Ranger 3's orbital parameters 5 minutes late. Meanwhile, the Agena restarted and sent the probe out of Earth orbit, but another error in its guidance program resulted in a further erroneous trajectory. This ensured that the spacecraft reached the Moon 14 hours early and missed it by 36,793 kilometers (22,862 miles) on 28 January.
Although impact with the Moon was no longer possible, Ranger 3 could still be used for deep-space studies. Commands were issued to unfurl the camera boom and on the 28th, a fixed-up computer program was uploaded. But midway through this maneuver, the probe's signal strength began to weaken and the computer system completely failed. The TV camera transmitted images, but as the antenna was now pointed away from Earth, they were extremely weak and noisy. It was possible to see the reference crosses on the camera lens, illuminated by reflected sunlight from the probe's chassis, but the Moon was not visible. With the computer dead, Ranger 3 became completely unresponsive to any ground commands and the earth and sun sensors were rendered useless. The gyroscopes continued to maneuver the probe and ground controllers momentarily reacquired a lock on the antenna, but without stable attitude control, they could not hold it steady. As they were unaware of the computer failure, they continued sending commands to Ranger 3 in vain. Sporadic tracking of the probe continued until January 31 when the attitude control thrusters exhausted their propellant supply, at which point the mission was officially terminated.
In the News
Fiction cross-reference
Nonfiction cross-reference
External links:
- Ranger 3 @ Wikipedia