Mission type | particle science |
---|---|
Operator | USAF |
COSPAR ID | 1968-081A |
SATCAT no. | S03428 |
Spacecraft properties | |
Manufacturer | Northrop |
Launch mass | 204 kg (450 lb) [1] |
Start of mission | |
Launch date | 26 September 1968, 07:37:01 UTC |
Rocket | Titan IIIC |
Launch site | Cape Canaveral LC41 [2] |
Orbital parameters | |
Reference system | Geocentric |
Regime | Geosynchronous |
Perigee altitude | 35,064 km (21,788 mi) [3] |
Apogee altitude | 35,797 km (22,243 mi) [3] |
Inclination | 3.0 ° [4] |
Period | 1,417.9 minutes [4] |
Epoch | 26 November 1968 |
Orbiting Vehicle 2-5 (COSPAR ID: 1968-081A, also known as OV2-5), the third and last satellite of the second series of the United States Air Force's Orbiting Vehicle program, was an American particle science and ionosphere research satellite. Launched 26 September 1968 along with three other satellites, OV2-5 became the first scientific satellite to operate at geosynchronous altitude.
The Orbiting Vehicle satellite program arose from a US Air Force initiative, begun in the early 1960s, to reduce the expense of space research. Through this initiative, satellites would be standardized to improve reliability and cost-efficiency, and where possible, they would fly on test vehicles or be piggybacked with other satellites. In 1961, the Air Force Office of Aerospace Research (OAR) created the Aerospace Research Support Program (ARSP) to request satellite research proposals and choose mission experiments. The USAF Space and Missiles Organization created their own analog of the ARSP called the Space Experiments Support Program (SESP), which sponsored a greater proportion of technological experiments than the ARSP. [5] : 417 Five distinct OV series of standardized satellites were developed under the auspices of these agencies. [5] : 425
The OV2 series of satellites was originally designed as part of the ARENTS (Advanced Research Environmental Test Satellite) program, intended to obtain supporting data for the Vela satellites, which monitored the Earth for violations of the 1963 Partial Test Ban Treaty. Upon the cancellation of ARENTS due to delays in the Centaur rocket stage, the program's hardware (developed by General Dynamics) was repurposed to fly on the Titan III [5] : 422 (initially the A, [6] ultimately the C) booster test launches. [5] : 422 The USAF contracted Northrop to produce these satellites, with William C. Armstrong of Northrop Space Laboratories serving as the program manager. [6]
The first satellite in the OV2 series, OV2-1, was launched 15 October 1965 with a suite of radiation measuring experiments; it was lost when its booster broke up in orbit. [7] The next satellite in the series, OV2-2, was to carry out optical measurements from an altitude of 400 kilometres (250 mi), but the mission was cancelled when the Titan III test schedule was truncated. Instead, OV2-3, with several solar experiments, was scheduled for the next Titan III launch. [5] : 422
OV2-3, along with LES-3, LES-4, and OSCAR 4, was launched on a Titan IIIC on 22 December 1965, but the Transtage carrying the satellites never made its final burn to finalize the geosynchronous orbit. Though the other satellites attached separated and returned data, OV2-3 remained attached and did not operate. [5] OV2-4, which would have left Earth's orbit to conduct measurements, was deleted from the schedule like OV2-2. [5] : 422
OV2-5, originally planned for launch in Spring of 1967, had the largest equipment loadout of the OV2 series. In addition to duplicating OV2-1's radiation detection capabilities, it also could conduct ionospheric radio transmission tests and measure the Lyman-alpha hydrogen emission background. The Titan IIIC launch failure on 26 August 1966 caused the rescheduling of OV2-5's flight for 1968. [5] : 422
The 204 kg (450 lb) [1] OV2-5 was built to the configuration standard to all of the OV2 satellites, with a roughly cubical structure of aluminum honeycomb, .61 m (2.0 ft) in height, and .58 m (1.9 ft) wide. Four 2.3 m (7.5 ft) paddle-like solar panels, each with 20,160 solar cells, were mounted at the four upper corners of the main body. The power system, which included NiCd batteries for night-time operations, provided 63 W of power.
As with the other craft in the OV2 series, experiments were generally mounted outside the cube while satellite systems, including tape recorder, command receiver, and PAM/FM/FM telemetry system, were installed inside. Four small solid rocket motors spun, one on each paddle, were designed to spin the OV2 satellites upon reaching orbit, providing gyroscopic stability. Cold-gas jets maintained this stability, receiving information on the satellite's alignment with respect to the Sun via an onboard solar aspect sensor, and with respect to the local magnetic field via two onboard fluxgate magnetometers. A damper kept the satellite from precessing (wobbling around its spin axis). Passive thermal control kept the satellite from overheating. [5] : 422 OV2-5 was designed for a lifespan of at least one year. [8]
OV2-5 carried 11 experiments, most of which were designed to measure charged particles and magnetic fields around the spacecraft. The satellite also carried the ORBIS-High Ionospheric radio beacon, a VLF receiver, as well as a scanning ultra-violet photometer to measure the Lyman-alpha hydrogen emission background. [5] : 422
OV2-5, along with OV5-2, OV5-4, and LES 6, was successfully launched via Titan IIIC from Cape Canaveral LC41 at 07:37:01 UTC [2] and ultimately delivered to an altitude of 22,000 mi (35,000 km) [8] making it the first ever scientific geosynchronous satellite. Though seven of the 12 experiment appendages failed to deploy, most of the satellite's experiments returned useful data. [5] : 422
Proton energy data collected 2–13 October 1968 in the energy range of 0.060 to 3.3 Mev showed an eight-fold reduction in particle flux between solar storms and quiet periods. Measuring the angle at which protons encountered the satellite also helped refine theoretical models of how the magnetosphere interacts with the flux of charged particles. [9]
OV2-5 was originally released into a geostationary orbit, [8] but as it lacked a system for maintaining an orbit, it gradually slipped into a geosynchronous orbit, [5] : 422 where it and its Transtage still remain (as of June 2021). [4]
The Titan IIIC was an expendable launch system used by the United States Air Force from 1965 until 1982. It was the first Titan booster to feature large solid rocket motors and was planned to be used as a launcher for the Dyna-Soar, though the spaceplane was cancelled before it could fly. The majority of the launcher's payloads were DoD satellites, for military communications and early warning, though one flight (ATS-6) was performed by NASA. The Titan IIIC was launched exclusively from Cape Canaveral while its sibling, the Titan IIID, was launched only from Vandenberg AFB.
Orbiting Vehicle or OV, originally designated SATAR, comprised five disparate series of standardized American satellites operated by the US Air Force, launched between 1965 and 1971. Forty seven satellites were built, of which forty three were launched and thirty seven reached orbit. With the exception of the OV3 series and OV4-3, they were launched as secondary payloads, using excess space on other missions.
OPS 0855, also designated OV4-3, was an American boilerplate Manned Orbiting Laboratory spacecraft launched in 1966. It was flown to demonstrate the launch configuration for future MOL missions. A number of research payloads, designated Manifold, were carried on board, which were intended to operate for 75 days. However, the spacecraft ceased operations after just 30. It was built from a decommissioned HGM-25A Titan I first stage oxidizer tank, bolted to a Transtage. It was part of the MOL and Orbiting Vehicle projects.
The 6555th Aerospace Test Group is an inactive United States Air Force unit. It was last assigned to the Eastern Space and Missile Center and stationed at Patrick Air Force Base, Florida. It was inactivated on 1 October 1990.
OSCAR IV was the fourth amateur radio satellite launched by Project OSCAR and the first targeted for Geostationary orbit on 12 December 1965. The satellite was launched piggyback with three United States Air Force satellites on a Titan IIIC launch vehicle. Due to a booster failure, OSCAR 4 was placed in an unplanned and largely unusable Geostationary transfer orbit; however, OSCAR 4 did facilitate the first direct satellite communication between the United States and the Soviet Union.
Orbiting Vehicle 2-1, the first satellite of the second series of the United States Air Force's Orbiting Vehicle program, was an American life science research satellite. Its purpose was to determine the extent of the threat posed to astronauts by the Van Allen radiation belts. Launched 15 October 1965, the mission resulted in failure when the upper stage of OV2-1's Titan IIIC booster broke up.
Orbiting Vehicle 1-1, was the first satellite in the OV1 series of the United States Air Force's Orbiting Vehicle program. OV1-1 was an American Earth science research satellite designed to measure radiation, micrometeoroid density, and magnetic fields in orbit. Launched 21 January 1965, the mission resulted in failure when, after a successful launch of its Atlas booster, OV1-1's onboard Altair motor failed to fire.
Orbiting Vehicle 1-3, was the second satellite in the OV1 series of the United States Air Force's Orbiting Vehicle program. OV1-3 was an American life science research satellite designed to measure the effects of orbital radiation on the human body. Launched 28 May 1965, the mission resulted in failure when its Atlas booster exploded two minutes after launch.
Orbiting Vehicle 1-2, launched 5 October 1965, was the third, and first successful, satellite in the OV1 series of the United States Air Force's Orbiting Vehicle program. A radiation measuring satellite designed to conduct research for the planned Manned Orbital Laboratory project, OV1-2 was the first American spacecraft to be placed into orbit on a western trajectory. The satellite stopped functioning in April 1967 after a series of technical problems starting two months after launch.
Orbiting Vehicle 2-3, the second satellite of the second series of the United States Air Force's Orbiting Vehicle program, was an American solar astronomy, geomagnetic and particle science research satellite. Launched 22 December 1965 along with three other satellites, the mission resulted in failure when the spacecraft failed to separate from the upper stage of its Titan IIIC.
Lincoln Experimental Satellite 3, also known as LES-3, was a communications satellite, the third of nine in the Lincoln Experimental Satellite. Launched by the United States Air Force (USAF) on 21 Dec 1965, it was stranded in a Geostationary Transfer Orbit rather than its planned circular high orbit. Despite this, LES-3 returned good data on communications propagation in the UHF band.
Lincoln Experimental Satellite 4, also known as LES-4, was a communications satellite, the fourth of nine in the Lincoln Experimental Satellite, and the first of the series designed for operations at geosynchronous altitudes. Launched by the United States Air Force (USAF) on 21 December 1965, it demonstrated many then-advanced technologies including active use of the military's SHF band to service hundreds of users.
Orbiting Vehicle 1-4, launched 30 Mar 1966, was the fourth, and second successful, satellite in the OV1 series of the United States Air Force's Orbiting Vehicle program. OV1-4 was a long-term bioscience and materials science satellite, designed to return data relevant to long-term human presence in space. Its launch marked the first time two satellites were placed into orbit side-by-side with each other.
Orbiting Vehicle 1-5 was launched 30 Mar 1966, and was the fifth satellite in the OV1 series of the United States Air Force's Orbiting Vehicle program. OV1-5 conducted optical experiments, surveying the Earth in the infrared spectrum to see if water, land, mountains and deserts could be distinguished by their thermal gradients. It was launched concurrently with OV1-4 in the first ever side-by-side satellite orbital deployment.
Orbiting Vehicle 3-1, launched 22 April 1966, was the first satellite in the OV3 series of the United States Air Force's Orbiting Vehicle program. The satellite measured radiation above the Earth, returning useful data for over a year. It is still in orbit as of 1 April 2021.
The Initial Defense Communications Satellite Program or IDCSP was the first United States Department of Defense communications satellite constellation and the first stage of the Defense Communications Satellite Program (DCSP). Launched in five groups by Titan IIIC launch vehicles to near equatorial, subsynchronous orbits between 1966 and 1968, they were intended to be experimental testbeds. They were so successful that, by the time of the launch of the last set of eight satellites, the IDCSP was deemed operational and renamed Initial Defense Satellite Communications System or IDSCS. This system allowed real-time collection of battlefield intelligence during the Vietnam War. A total of 35 IDCSP satellites were launched, 27 successfully.
Orbiting Vehicle 3-4, launched 10 June 1966, was the second satellite to be launched in the OV3 series of the United States Air Force's Orbiting Vehicle program. The satellite measured radiation above the Earth, helping to determine the hazard posed to human spaceflight at typically traveled altitudes. OV3-4 is still in orbit as of 6 June 2021.
Orbiting Vehicle 1-7, launched 14 July 1966, was the sixth satellite launched in the OV1 series of the United States Air Force's Orbiting Vehicle program. OV1-7 was a sky science satellite, designed to return data on charged particles in orbit as well as measurements of solar X-rays and nightglow. Co-launched with OV1-8, the satellite was lost when it failed to detach from its launch rocket.
Orbiting Vehicle 1-8, launched 14 July 1966, was the seventh satellite launched in the OV1 series of the United States Air Force's Orbiting Vehicle program. OV1-8 was designed to test the passive communications utility of an aluminum grid sphere versus a balloon satellite.
Orbiting Vehicle 3-3, launched 4 August 1966, was the third satellite to be launched in the OV3 series of the United States Air Force's Orbiting Vehicle program. The satellite measured charged particles in orbit so that their danger to space-based payloads could be assessed. OV3-3 is still in orbit as of 29 July 2021.