Explorer S-45 (satellite)

Explorer S-45 was a NASA satellite, which was lost in a launch failure in February 1961. The satellite was intended to operate in a highly elliptical orbit, from which it was to have provided data on the shape of the ionosphere,^[1] and on the Earth's magnetic field.^[2] It was part of the Explorer program, and would have been designated Explorer 10 had it reached orbit. A second identical satellite, Explorer S-45A, also failed to achieve orbit when it was launched.^[2]

Explorer S-45

Explorer S-45 satellite before launch
Names	Explorer S-45 NASA S-45
Mission type	Ionospheric research
Operator	NASA
COSPAR ID	EXS-451
Mission duration	Failed to orbit
Spacecraft properties
Spacecraft	Explorer S-45
Spacecraft type	Science Explorer
Bus	S-45
Manufacturer	Goddard Space Flight Center
Launch mass	33.6 kg (74 lb)
Power	Solar cells and batteries
Start of mission
Launch date	25 February 1961, 00:13:16 GMT
Rocket	Juno II (AM-19F)
Launch site	Cape Canaveral, LC-26B
Contractor	Army Ballistic Missile Agency
End of mission
Destroyed	Failed to orbit
Orbital parameters
Reference system	Geocentric orbit (planned)
Regime	Highly elliptical orbit
Perigee altitude	221 km (137 mi)
Apogee altitude	181,100 km (112,500 mi)
Inclination	33.0°
Period	5013.90 minutes
Instruments
Beacon
Explorer program ← Explorer 9 Explorer 10 →

Launch

JUNO II with Explorer S-45 on launch table after gantry pulled back

Explorer S-45 was launched aboard a Juno II launch vehicle, serial number AM-19F. The launch took place from Launch Complex 26B at the Cape Canaveral Air Force Station (CCAFS) at 00:13:16 GMT on 25 February 1961.^[3] The launch vehicle malfunctioned after the second stage separated, and contact with the payload was lost.^[4] The third stages subsequently failed to ignite, resulting in the satellite failing to achieve orbit.^[5]

See also

• Spaceflight portal

• Explorer S-45A
• Explorer program