View source for ISIS (satellite)

{{Short description|Satellites studying Earth's inosphere}}
{{About|Canadian satellites launched to study Earth's ionosphere|international studies of infarct survival|International Studies of Infarct Survival}}
{{Infobox spaceflight
| name                  = ISIS 1 /ISIS-A
| image                 =
| image_caption         =

| mission_type          =
| operator              = [[Canadian Space Agency|CSA]]{{\}}[[NASA]]
| COSPAR_ID             = 1969-009A
| SATCAT                = 03669
| mission_duration      =

| spacecraft_type       =
| manufacturer          = RCA Victor
| dry_mass              =
| launch_mass           = {{convert|241.0|kg}}
| power                 =

| launch_date           = {{start-date|30 January 1969, 06:43:00|timezone=yes}}&nbsp;UTC
| launch_rocket         = [[Delta (rocket family)|Delta E1]] 485/D65
| launch_site           = [[Vandenberg Air Force Base|Vandenberg]] [[Vandenberg AFB Space Launch Complex 2|SLC-2E]]
| launch_contractor     =

| landing_date          =

| orbit_epoch           =
| orbit_reference       = [[geocentric orbit|Geocentric]]
| orbit_regime          = [[Low Earth orbit|LEO]]
| orbit_eccentricity    = 0.017475
| orbit_periapsis       = {{convert|578|km|mi}}
| orbit_apoapsis        = {{convert|3526|km|mi}}
| orbit_inclination     = 82.42º
| orbit_period          = 128.42 minutes
| apsis                 = gee
}}

{{Infobox spaceflight
| name                  = ISIS 2 (ISIS-B)
| image                 =
| image_caption         =

| mission_type          =
| operator              = [[Canadian Space Agency|CSA]]{{\}}[[NASA]]
| COSPAR_ID             = 1971-024A
| SATCAT                = 05104
| mission_duration      =

| spacecraft_type       =
| manufacturer          = RCA Victor
| dry_mass              =
| launch_mass           = {{convert|264.0|kg}}
| power                 =

| launch_date           = {{start-date|01 April 1971, 02:53:00|timezone=yes}}&nbsp;UTC
| launch_rocket         = [[Delta (rocket family)|Delta E1]] 
| launch_site           = [[Vandenberg Air Force Base|Vandenberg]] [[Vandenberg AFB Space Launch Complex 2|SLC-2E]]
| launch_contractor     =

| landing_date          =
| landing_site          =

| orbit_epoch           =
| orbit_reference       = [[geocentric orbit|Geocentric]]
| orbit_regime          = [[Low Earth orbit|LEO]]
| orbit_eccentricity    = 0.0045
| orbit_periapsis       = {{convert|1358|km|mi}}
| orbit_apoapsis        = {{convert|1458|km|mi}}
| orbit_inclination     = 88.1º
| orbit_period          = 113.6 minutes
| apsis                 = gee
}}

'''ISIS 1 and 2''' ("'''International Satellites for Ionospheric Studies'''") were the third and fourth in a series of Canadian [[satellite]]s launched to study the [[ionosphere]] over one complete [[solar cycle]]. 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 Ltd. of [[Montreal]] was the prime contractor for both ISIS 1 and 2.<ref name=":0">{{Cite web|last=Agency|first=Canadian Space|date=2000-06-16|title=Building on the Success of Alouette with ISIS I and II|url=https://www.asc-csa.gc.ca/eng/satellites/isis.asp|access-date=2021-04-09|website=www.asc-csa.gc.ca}}</ref>

A third satellite, ISIS 3, was scheduled for construction, but when the government's focus shifted toward communications satellites, it was cancelled in 1969. The funds were instead used to produce the [[Communications Technology Satellite]] (also known as Hermes), which was launched in 1976.<ref>{{Cite web|date=2012-09-06|title=Alouette 1 – Celebrating 50 Years of Canada in Space|url=https://spaceq.ca/alouette_1_celebrating_50_years_of_canada_in_space/|access-date=2021-04-09|website=SpaceQ|language=en-US}}</ref>

== ISIS 1 ==
ISIS 1 ('''1969-009A''') was launched at 6h43 [[UTC]]<ref>{{cite web|title=ISIS 1 Launch Information|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/displayTrajectory.action?id=1969-009A|publisher=NASA NSSDCA|access-date=December 18, 2022}}</ref> on January 30, 1969, by a [[Delta rocket]] at the Western test range at [[Vandenberg AFB]] in [[California]].<ref>{{Cite web|title=NASA NSSDCA - Spacecraft Details -ISIS 1|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1969-009A|access-date=2021-04-09|website=NASA Space Science Data Coordinated Archive}}</ref>

Unlike the Alouette satellites, 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.<ref name=":0" /> 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 ==
ISIS 2 ('''1971-024A''') was launched at 2h53 [[UTC]]<ref>{{cite web|title=ISIS 2 Launch Information|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/displayTrajectory.action?id=1971-024A|publisher=NASA NSSDCA|access-date=December 18, 2022}}</ref> on April 1, 1971, on a [[Delta rocket]] also from the Western test range at [[Vandenberg AFB]] in [[California]].<ref>{{Cite web|title=NASA NSSDCA - Spacecraft Details - ISIS 2|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1971-024A|access-date=2021-04-09|website=NASA Space Science Data Coordinated Archive}}</ref> 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, including a [[photometer]]. This allowed images to be taken for the first time of an [[Aurora (astronomy)|Aurora Borealis]] as seen from above.<ref name=ucalg>{{Cite web|date=2021-03-29|title=ISIS-II space mission launched University of Calgary's international reputation for auroral research|url=https://science.ucalgary.ca/news/isis-ii-space-mission-launched-university-calgarys-international-reputation-auroral-research|access-date=2021-04-09|website=University of Calgary|language=en}}</ref>  [[James Gosling]] wrote some of the software to analyze data from ISIS 2, as a high school student working for the [[University of Calgary]] physics department.<ref name=ucalg /><ref>{{cite web |url=https://archive.computerhistory.org/resources/access/text/2019/10/102781080-05-01-acc.pdf |title=Oral History of James Gosling, part 1 of 2 |publisher=Computer History Museum |date=March 15, 2019 |author1=James Gosling |author2=Hansen Hsu |author3=Marc Weber |id=Catalog number 102781080 |pages=23–24}}</ref>

On March 13, 1984, both ISIS 1 and ISIS 2 were loaned to Japan's Communications Research Laboratory, which continued to operate the satellites until 1990, when they were shut down due to deterioration of battery capacity.<ref>{{Cite web|title=Alouette/ISIS: How it all Began|url=https://www.ieee.ca/millennium/alouette/alouette_franklin.html|access-date=2021-04-09|website=www.ieee.ca}}</ref>

== See also ==
* [[Polar wind]]
* [[Alouette 1]]
* [[Alouette 2]]

{{Portal|Spaceflight}}

== External links ==
* [http://www.asc-csa.gc.ca/eng/satellites/isis.asp ISIS program from the Canadian Space Agency]
* [http://friendsofcrc.ca/Projects/ISIS/isis.html ISIS Satellite program]
* [https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1969-009A ISIS-I] at NSSDC (1969-009A)
* [https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1971-024A ISIS-II] at NSSDC (1971-024A)

== References ==
{{Reflist}}{{Canadian Space Agency}}{{Orbital launches in 1969}}
{{Orbital launches in 1971}}

[[Category:Satellites orbiting Earth]]
[[Category:Satellites of Canada]]
[[Category:Spacecraft launched in 1969|ISIS 1]]
[[Category:Spacecraft launched in 1971|ISIS 2]]
[[Category:Geospace monitoring satellites]]