JUMPSEAT (AFP-711)

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Look out for a forthcoming article on these satellites by Blackstar & writing partner. He’s posted about it over on NSF, so as we don’t have an existing thread I thought I would start one in preparation.

Jumpseat (satellite) - Wikipedia

en.m.wikipedia.org en.m.wikipedia.org
 
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Here’s the first part.


Big bird, little bird: chasing Soviet anti-ballistic missile radars in the 1960s
by Dwayne A. Day
Monday, December 14, 2020

The second bus-sized HEXAGON photo-reconnaissance satellite roared off its California launch pad in January 1972. Inside of its payload shroud atop the Titan III rocket, the HEXAGON looked somewhat like a train locomotive, and tucked along one of its slab sides was a small rectangular box about the size of a suitcase. After the HEXAGON reached its proper orbit and stabilized itself, circling the Earth over its poles, the box detached, pushed off by springs. It started spinning, and then fired a small rocket motor that boosted its orbit a bit higher than the big bird that had delivered it into space. The small satellite began unfolding like an origami crane spreading out, deploying solar panels and numerous antennas, most of them pointed down at the Earth.

The satellite was named MABELI, and once its antennas were open, MABELI began hunting for radar signals.

MABELI stood for “Main beam TIVOLI.” TIVOLI had been a predecessor satellite, and it stood for “Technical Intelligence Vehicle Orbital Life Indefinite,” which only made a little bit of sense and may have been an inside joke to its designers, who often gave the satellites and their payloads irreverent names, sometimes naming them after movie stars or puns or even their coworkers. Three TIVOLI satellites had flown by 1971, and now MABELI was following on, continuing the mission of listening for signals from Soviet anti-ballistic missile (ABM) radars, a mission that had perplexed American intelligence analysts for much of the 1960s. It had been one part of an often-heated debate over whether the Soviet Union was developing an anti-ballistic missile system, and whether the United States needed one as well.
 
As I don’t do FB I don’t know how to get the accompanying image onto this forum.

NRO Facebook page:

POPPY was the successor to GRAB, the nation's 1st ELINT satellite. Developed by the Naval Research Lab, POPPY was designed to detect land based radar emitters and support ocean surveillance, making great contributions to the nation's security during a perilous era. ️ #tbt
 
Here’s the second part.



From TACSAT to JUMPSEAT: Hughes and the top secret Gyrostat satellite gamble
by Dwayne A. Day and Nicholas W. Watkins
Monday, December 21, 2020

Starting in August 1968, the secretive National Reconnaissance Office began launching new intelligence satellites into much higher orbits to accomplish their missions. The first was the CANYON series of communications intelligence satellites, followed in 1970 by the first of the RHYOLITE telemetry interception satellites. In spring 1971, the NRO launched a new and enigmatic satellite named JUMPSEAT, which has remained perhaps the most mysterious of these high-orbit satellites. Each of these satellites pushed the state of the art in terms of payloads, antennas, and satellite design. But JUMPSEAT represented a concerted effort by a civil and commercial satellite designer to break into the top-secret world of satellite intelligence by leveraging a new technology and a military contract to demonstrate that it could perform the mission of both detecting signals from the ground, and spotting missile launches with an infrared telescope.

By the late 1960s, the Space Systems Division of Hughes Aircraft Company was already a dominant force in satellite communications, having developed the first geosynchronous orbit communications satellite, Syncom 2 in 1963, and its commercial successor, Intelsat I, better known as Early Bird, in 1965. In early 1969, another new Hughes technology, the Gyrostat, made its space debut. This time it was on the tactical communications satellite, or TACSAT, one of the first geostationary military comsats. The Gyrostat was a damping system which prevented satellites from inevitably spinning around their longest axis. By allowing “long and thin” satellites, the Gyrostat maximized the use of shroud space on the Titan IIIC launcher, enabling TACSAT to be nearly eight meters long and three meters in diameter. TACSAT was a spinning cylinder with a large antenna “farm” on its top, and at over half a ton in mass, and with over 200 watts of power to the UHF antenna array, it has long been known to be a pioneer and record-breaker among comsats. Newly revealed information is, however, only now showing how TACSAT gave Hughes the knowledge and skills to successfully compete for several other key military and intelligence satellite contracts over the next few years, including the JUMPSEAT signals intelligence (SIGINT) and Satellite Data System (SDS) data-relay satellites. The new information also confirms the long-rumored dual role of JUMPSEAT in carrying both signals intelligence (SIGINT) and infrared missile detection payloads, though some puzzles remain.
 

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