 | |
| Mission type | Earth science |
|---|---|
| Operator | USAF |
| COSPAR ID | 1969-025 |
| SATCATno. | S03823 |
| Spacecraft properties | |
| Manufacturer | General Dynamics |
| Launch mass | 142 kg (313 lb) |
| Start of mission | |
| Launch date | 18 March 1969 (1969-03-18) UTC |
| Rocket | Atlas F |
| Launch site | Vandenberg 576-A-2[1] |
| End of mission | |
| Decay date | 5 March 1970 |
| Orbital parameters | |
| Regime | Low Earth Orbit |
| Eccentricity | 0.00484 |
| Perigee altitude | 397.00 km (246.68 mi) |
| Apogee altitude | 463.00 km (287.69 mi) |
| Inclination | 99.100° |
| Period | 93.2 minutes[2] |
| Epoch | 18 March 1969 07:41:00 UTC |
Orbiting Vehicle 1–17 (also known asOV1-17)[1] was solar radiation satellite, part of a quadruple payload launch on 18 March 1969. Part of theOV1 series ofUSAF satellites, using standardized designs and sent to orbit on decommissionedAtlasICBMs to reduce development and launching costs, OV1-17 was launched viaAtlas F along withOV1-18,OV1-19, andOV1-17A. Its primary purpose was to measure the effects of the Earth's ionosphere on detection, control, communications, and tracking systems in space. Because its stabilization system failed to deploy, and because of the abbreviated data sets, the flight yielded relatively few scientific results. Still, 11 papers were published using OV1-17 data.
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.[3]: 417 Five distinct OV series of standardized satellites were developed under the auspices of these agencies.[3]: 421 : 425
The OV1 program, managed by Lt. Col. Clyde Northcott Jr.[4] was an evolution of the 2.7 m "Scientific Passenger Pods" (SPP), which, starting on 2 October 1961, rode piggyback on suborbital Atlas missile tests and conducted scientific experiments during their short time in space. General Dynamics received a $2 million contract on 13 September 1963 to build a new version of the SPP (called the Atlas Retained Structure (ARS)) that would carry a self-orbiting satellite. Once the Atlas missile and ARS reached apogee, the satellite inside would be deployed and thrust itself into orbit. In addition to the orbital SPP, General Dynamics would create six of these satellites, each to be 3.66 m (12.0 ft) long with a diameter of .762 m (2 ft 6.0 in), able to carry a 136 kg (300 lb) payload into a circular 805 km (500 mi) orbit.
Dubbed "Satellite for Aerospace Research" (SATAR), the series of satellites was originally to be launched from theEastern Test Range on Atlas missions testing experimental Advanced Ballistic Re-Entry System (ABRES) nosecones. However, in 1964, the Air Force transferred ABRES launches to theWestern Test Range causing a year's delay for the program. Moreover, because WTR launches would be into polar orbit as opposed to the low-inclination orbits typical of ETR launches, less mass could be lofted into orbit using the same thrust, and the mass of the SATAR satellites had to be reduced.[3]: 417
Prior to the quadruple launch of which OV1-17 was a part, there had been 16 satellites in the OV1 series, the first orbited on January 21, 1965. AfterOV1-1, the last ABRES test launch, OV1-2 through 12 were launched on decommissionedAtlas DICBMs, with the exception ofOV1-6, launched via theTitan IIIC tasked for theManned Orbiting Laboratory test flight.OV1-13 andOV1-14 were the first to be launched on a decommissionedAtlas F.[3]: 418, 420
The Orbiting Vehicle program was succeeded by theSpace Test Program, managed by theSpace Missile Organization's Space Experiments Support Program, which had absorbed the ARSP in 1968, and OV1-17 was launched under its auspices.[3]: 421, 425–426 The OV1 program ultimately comprised 22 missions, the last flying on 19 September 1971.[3]: 421
OV1-17, like the rest of the OV1 satellite series, consisted of a cylindrical experiment housing capped with flattened cones on both ends[5] containing 5000 solar cells producing 22watts of power. Continuing the design trend started withOV1-7, the solar cells were flat rather than curved, as had been in the case with the first six OV1 satellites.[3]: 420 Two .46 m (1 ft 6 in) antennae for transmitting telemetry and receiving commands extended from the sides of the spacecraft. 12 helium-pressurizedhydrogen peroxide thrusters provided attitude control.[3]: 418
Unlike most of the prior satellites in the OV1 series, OV1-17 was not spin-stabilized, but was supposed to maintain its attitude through Vertistat, agravity-gradient stabilization system consisting of three 15.5 m (51 ft)-long horizontal booms forming a 'y' and two 19 m (62 ft)-long vertical booms.[2] This system was demonstrated unsuccessfully onOV1-7 andOV1-86, but successfully onOV1-10.[3]: 420
OV1-17's primary purpose was to measure the effects of the Earth's ionosphere on detection, control, communications, and tracking systems in space,[3]: 421 Its suite of 12 experiments included three crystal spectrometers for detecting solar X-rays, a large deployable dish antenna for measuring radio interference, and an electron spectrometer developed byLockheed for detecting auroral electrons (in conjunction withATS-5 using a similar experiment). Further instruments were to measure ion densities, gamma radiation, and the energy spectra of electrons and protons, while the booms themselves would measure electric fields.[3]: 421
The satellite also carried a meteor trail calibration beacon to see if such trails could be used to relay radio messages. A pane of 14[2]cadmium sulfide solar cells and a set of thermal control coatings were mounted to determine performance and radiation resistance.[3]: 421
OV1-17 was launched fromVandenberg's 576-A-2 launch pad along with OV1-18, OV1-19, and OV1-17A (housed in OV1-17's propulsion module) on an Atlas F rocket on 18 March 1969 at around 7:47:35 UTC[1] into an orbit that took it from 463 km (288 mi) above the Earth to minimum397.00 km (246.68 mi).[2] Once in orbit, the propulsion module separated to become its own satellite.[6]
The Vertistat on OV1-17 failed to deploy properly, as had happened on previous flights, causing the spacecraft to tumble, which rendered four of the seven environmental experiments useless. Moreover, the three remaining aerospace experiments only received useful data for relatively short time periods, limiting results.[7]
The satellite reentered the atmosphere on 5 March 1970.[2]
Despite the failure of the Vertistat system, OV1-17 collected data on extremely-low frequency radio propagation, horizon dayglow, nightglow, high-energy solar protons, magnetospheric ions, electric fields, gamma radiation, and the energy spectra of electrons and protons,[3]: 421 and 11 papers were published based on OV1-17 data.[8]