ISIS (satellite)

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ISIS 1 /ISIS-A
OperatorCSA / NASA
COSPAR ID1969-009A
SATCAT no.03669
Spacecraft properties
ManufacturerRCA Victor
Launch mass241.0 kilograms (531.3 lb)
Start of mission
Launch date30 January 1969, 06:43:00 (1969-01-30UTC06:43Z) UTC
RocketDelta E1 485/D65
Launch siteVandenberg SLC-2E
Orbital parameters
Reference systemGeocentric
RegimeLEO
Eccentricity0.017475
Perigee578 kilometres (359 mi)
Apogee3,526 kilometres (2,191 mi)
Inclination82.42º
Period128.42 minutes
ISIS 2 (ISIS-B)
OperatorCSA / NASA
COSPAR ID1971-024A
SATCAT no.05104
Spacecraft properties
ManufacturerRCA Victor
Launch mass264.0 kilograms (582.0 lb)
Start of mission
Launch date01 April 1971, 02:53:00 (1971-04-01UTC02:53Z) UTC
RocketDelta E1
Launch siteVandenberg SLC-2E
Orbital parameters
Reference systemGeocentric
RegimeLEO
Eccentricity0.0045
Perigee1,358 kilometres (844 mi)
Apogee1,458 kilometres (906 mi)
Inclination88.1º
Period113.6 minutes

ISIS 1 and 2 ("International Satellites for Ionospheric Studies") were the third and fourth in a series of Canadian satellites launched to study the ionosphere. After the success of Canada's Alouette 1, Canada and the United States jointly sent up three more satellites in the ISIS program. The first was named Alouette 2 (after originally being named ISIS-X). As was the case for the Alouette satellites, RCA Victor of Montreal was the prime contractor for both ISIS 1 and 2.

There was a final satellite scheduled for construction, but when the government's focus shifted towards communications satellites, it was cancelled in 1969.

ISIS 1[edit]

ISIS 1 (1969-009A) was launched at 6h46 UTC on January 30, 1969 by a Delta rocket at the Western test range at Vandenberg AFB in California. Canada stopped using ISIS 1 on March 13, 1984 but Japan was authorized to keep on using it and did so until 1990.

Unlike the Alouette satellites the ISIS had complex navigational equipment and a tape recorder to record some experiments when they were out of communications range and play back the results when the satellites came over Canada again. Some other experiments were not recorded but data was sent in over several stations around the globe. In total it conducted 10 experiments.

ISIS 2[edit]

ISIS 2 (1971-024A) was launched at 2h57 UTC on April 1, 1971 on a Delta rocket also from the Western test range at Vandenberg AFB in California. Due to budget constraints, the design of ISIS 2 was largely similar to that of ISIS I. The main difference was the addition of two experiments designed to study atmospheric optical emissions. This allowed images to be taken for the first time of an entire Aurora Borealis as seen from above.

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