SOLRAD 10
Mission type | Heliophysics |
---|---|
Operator | NASA |
COSPAR ID | 1971-058A[1] |
SATCAT no. | 5317 |
Spacecraft properties | |
Manufacturer | Naval Research Laboratory |
Launch mass | 260 kilograms (570 lb) |
Start of mission | |
Launch date | July 8, 1971, 22:58 Scout B S177C | UTC
Launch site | Wallops LA-3A[2] |
End of mission | |
Decay date | 15 December 1979[3] |
Orbital parameters | |
Reference system | Geocentric |
Regime | Low Earth |
Eccentricity | 0.0006626[4] |
Perigee altitude | 204 kilometers (127 mi)[4] |
Apogee altitude | 213 kilometers (132 mi)[4] |
Inclination | 51.0598°[4] |
RAAN | 328.0487°[4] |
Argument of perigee | 235.3867°[4] |
Mean anomaly | 124.4027°[4] |
Mean motion | 16.23884333[4] |
Epoch | 13 December 1979[4] |
Revolution no. | 46942[4] |
Solrad 11A → |
Solrad 10, also known Explorer 44, NRL-PL 165 and Explorer SE-C, was one of the SOLRAD series designed to provide continuous coverage of
Launch
Solrad 10 was launched on 8 July 1971 from
It launched from Wallops Island,[8] Virginia, into a 436 × 630 km (271 × 391 mi) orbit. The plane of rotation shifted about 1°/day so that a stellar detector mounted to point radially outward from the axis scanned the celestial sphere. Data from all detectors were stored in a 54-kbs core memory and telemetered on command to the United States Naval Research Laboratory (NRL) tracking station at Blossom Point, Maryland. Data were also transmitted in real time at 137.71-MHz and were shared with the international scientific community through Committee on Space Research (COSPAR). Expected lifetime was 3 years.[5]
Spacecraft
Solrad 10 was a 12-sided cylinder that measured 76 centimetres (30 in) in diameter and 58 centimetres (23 in) in height. Four symmetrically placed 17.8 by 53.3 centimetres (7.0 in × 21.0 in)
Experiment
All-Sky X-Ray Survey
This experiment was designed to map the sources of X-ray emission in the sky in the 0.5 - 15-A region. The detector, mounted on the side of the spacecraft, was a large-area proportional counter mounted to point radially outward from the spin axis, which pointed continually toward the sun. The detector window was made of 1/8-mil-thick mylar with an effective area of 100-cm2. The gas filler was a mixture of 0.45 argon, 0.45 xenon, and 0.10 carbon dioxide maintained at 4 lb/cm2. A collimator limited the field of view to 8°, full width at half maximum (FWHM) in a plane containing the spin axis and 1° in the plane perpendicular to the spin axis. Charged particle information was provided by proportional counters mounted on three sides of the X-ray detector. Aspect information was provided by a blue-sensitive photomultiplier capable of detecting all fourth-magnitude and not fifth-magnitude stars. The resolution of the aspect system and the accuracy with which the experiment could locate X-ray sources was better than ± 0.25°. The detector was connected to a 400-channel pulse time analyzer which was synchronized with the spin period to give a 2° spatial resolution in the spin direction. The whole celestial sphere was surveyed every 6 months. Due to the low altitude of the satellite, there was a high charged-particle count at all times. This background limited the usefulness of the data, and no results from this experiment were published.[9]
Solar Radiation Detectors
This experiment was designed to monitor the solar X-ray flux in eight bands and the solar UV flux in five bands as part of a long-term project to observe solar X-ray and UV activity with sets of standardized sensors over an entire solar cycle. The X-ray bands observed were 0.08 to 0.8 A, 0.1 to 1.6 A, 0.5 to 3 A, 1 to 5 A, 1 to 8 A, 8 to 16 A, 1 to 20 A, and 44 to 60 A. All the detectors for these bands, with the exception of that for the 0.08- to 0.8-A band, were ionization chambers fitted with a variety of window material (beryllium, aluminum, and Mylar) of various thicknesses and filled with several different gases (krypton, argon, nitrogen, Carbon tetrachloride, and xenon) at various pressures. The 0.08- to 0.8-A band had as a detector a cesium iodide (CSI) (Na) scintillating crystal surrounded by a plastic scintillating material viewed by a single photomultiplier. This detector was designed to collect data on the very high-energy solar X-ray emission observed only during solar flares. The UV bands observed were 170 to 500 A, 170 to 700 A, 1080 to 1350 A, 1225 to 1350 A, and 1450 to 1600 A. The two shorter wavelength bands had lithium fluoride, photosensitive surfaces protected by aluminum, aluminum oxide, and carbon windows for detectors, while the remaining bands had ion chambers with windows composed of lithium fluoride, calcium fluoride, or silicon dioxide, and various gas filters (nitric oxide or triethylamine 8). Some of the solar detectors were protected from charged particles by cone-shaped aluminum collimators. The data were transmitted over two telemetry systems in one of three forms—stored data, real-time digital (PCM) data, and real-time analog data. Telemetry system 1 (TM 1) used a PAM/PCM/FM/PM transmitter that operated at 137.710 MHz with a radiated power of 250 MW. Under normal operating conditions, TM 1 continuously transmitted analog and PCM real-time data, although the real-time digital PCM was the primary real-time transmission format. Telemetry system 2 (TM 2) used a PCM/PM transmitter that operated at 136.38-MHz with a radiated power of 250 MW. TM 2 transmitted stored data (up to one data sample a minute for 14.25 hours) on command.[10]
Atmospheric entry
Explorer 44 (SOLRAD 10) returned to the atmosphere, disintegrating on 15 December 1980,[11] or December 15, 1979.[3]
See also
- Solrad 9
References
- ^ a b c d "Solrad 10". NSSDCA. NASA Goddard Space Flight Center. Retrieved June 19, 2018. This article incorporates text from this source, which is in the public domain.
- ^ a b McDowell, Jonathan. "Launch Log". Jonathan's Space Page. Retrieved June 19, 2018.
- ^ a b "EXPLORER 44 (SOLRAD-10)". n2yo.com. Retrieved June 19, 2018.
- ^ a b c d e f g h i j Peat, Chris. "Solrad 10 - Orbit". Heavens-Above GmbH. Retrieved June 19, 2018.
- ^ a b "Display: Explorer 44 (SOLRAD 10) 1971-058A". NASA. October 28, 2021. Retrieved November 14, 2021. This article incorporates text from this source, which is in the public domain.
- ^ "Display: Explorer 37 (SOLRAD 9) 1968-017A". NASA. October 28, 2021. Retrieved November 13, 2021. This article incorporates text from this source, which is in the public domain.
- ^ Wade, Mark (2017). "Solrad". Encyclopedia Astronautica. Archived from the original on December 28, 2016. Retrieved June 19, 2018.
- ^ "Launch Log". Jonathan's Space Report. July 21, 2021. Retrieved November 14, 2021.
- ^ "Experiment: All-Sky X-Ray Survey". NASA. October 28, 2021. Retrieved November 14, 2021. This article incorporates text from this source, which is in the public domain.
- ^ "Experiment: Solar Radiation Detectors". NASA. October 28, 2021. Retrieved November 14, 2021. This article incorporates text from this source, which is in the public domain.
- ^ "Trajectory: Explorer 44 (SOLRAD 10) 1971-058A". NASA. October 28, 2021. Retrieved November 14, 2021. This article incorporates text from this source, which is in the public domain.
External links
- SOLRAD/GRAB Archived 2018-06-20 at the Naval Research Laboratory