The Gravity Gradient Stabilization Experiment (GGSE-4) was a technology satellite launched in 1967. This was ostensibly the fourth in a series that developed designs and deployment techniques later applied to the NOSS/Whitecloud reconnaissance satellites.
GGSE-4 was launched by the U.S. Airforce from Vandenberg Air Force Base atop a Thor Agena-D rocket.[1] GGSE-4 remained operational from 1967 through 1972.[2]
It is alleged that the real name of GGSE-4 was POPPY 5B or POPPY 5b and that it was a U.S. National Reconnaissance Office satellite designed to collect signals intelligence;[3] POPPY 5B was part of a 7-satellite mission. A partial subset of information about POPPY was declassified in 2005.[4]
Other sources say that GGSE-4 weighed only 10 pounds but that it was attached to the much larger Poppy 5, which would have weighed 85 kg and featured an 18-meter boom.[5] It is further alleged that GGSE-4's mass is not at all like GGSE-1's mass and that GGSE'4 weighs 85 kg.[6]
On,[7] GGSE-4 was expected to pass as closely as 12 meters [8] from IRAS, another un-deorbited satellite left aloft. IRAS was launched in 1983 and abandoned after a 10-month mission. The 14.7-kilometer per second pass[9] had an estimated risk of collision of 5%. Further complications arose from the fact that GGSE-4 was outfitted with an 18 meter long stabilization boom that was in an unknown orientation and may have struck the satellite even if the spacecraft's main body did not.[10] Initial observations from amateur astronomers seemed to indicate that both satellites had survived the pass, with the California-based debris tracking organization LeoLabs later confirming that they had detected no new tracked debris following the incident.[11]
Gravity Gradient Stabilization Experiment (GGSE-1)