Explorer 46

Explorer 46
	Explorer 46 satellite
Names	Meteoroid Technology Satellite-A; MTS-A
Mission type	Meteroids research
Operator	NASA
COSPAR ID	1972-061A
SATCAT no.	06142
Spacecraft properties
Spacecraft	Explorer XLVI
Spacecraft type	Meteoroid Technology Satellite
Bus	MTS
Manufacturer	Langley Research Center
Launch mass	90 kg (200 lb)
Start of mission
Launch date	13 August 1972, 15:10 UTC
Rocket	Scout D-1 (S-184C)
Launch site	Wallops Flight Facility, LA-3A
Contractor	Vought
Entered service	13 August 1972
End of mission
Decay date	2 November 1979
Orbital parameters
Reference system	Geocentric orbit
Regime	Low Earth orbit
Perigee altitude	496 km (308 mi)
Apogee altitude	814 km (506 mi)
Inclination	37.70°
Period	97.80 minutes
Instruments
	Meteoroid Penetration; Meteoroid Penetration Sensors; Meteoroid Velocity Sensors
	Explorer program ← Explorer 45 Explorer 47 →

Explorer 46, (also Meteoroid Technology Satellite-A or MTS-A), was a NASA satellite launched as part of Explorer program.^[3]

Mission

Explorer 46 was designed to provide data on the frequency and penetration energy of meteoroids and micrometeoroids in low Earth orbit. Explorer 46 consisted of a hexi-cylindrical bus covered with solar cells. Meteoroid impacts were detected and measured using bumper panels that extended after launch and gave the satellite a windmill-like appearance. The central hub of the satellite carried the velocity and impact experiments. When the bumper targets were extended from the satellite, it had an overall width of 701.50 cm (276.18 in). Twenty meteoroid impacts were recorded by the bumper panels through December 1972. A set of capacitor detectors recorded over two thousand micrometeoroid hits over the same period.^[4]

Instruments

Multi-sheet bumper, 701.50 cm (276.18 in) across, its detectors filled with gas, to register and telemeter loss of pressure;
12 box-shaped velocity detectors at various locations along the spacecraft;
Impact flux detectors, with 64 detectors to assess the population of very small particles.

Launch

Explorer 46 was launched on 13 August 1972, at 15:10 UTC, from Wallops Flight Facility (WFF), with a Scout D-1 Launch vehicle.^[1]

Experiments

Meteoroid Penetration

The objective of this experiment was to measure the meteoroid penetration rates of a bumper-protected target. Penetrations were measured, using 12 2-mil stainless-steel pressure cells located behind 1-mil stainless-steel bumpers. These 12 cells were mounted on 4 bumper panels which extended out from the cylindrical spacecraft body. Due to a malfunction, only two of the four bumper panels deployed.^[5]

Meteoroid Penetration Sensors

This experiment measured meteoroid impacts using a thin film capacitor. Due to a spacecraft malfunction, this experiment had to be turned off two weeks after launch, but it had already recorded 2000 micrometeoroid impacts by that time. It was reactivated in August 1974.^[6]

Meteoroid Velocity Sensors

This experiment measured the velocity of impacting micrometeoroids, using two thin-film capacitors and measuring the time-of-flight between them. Due to difficulties with the spacecraft, this experiment had to be turned off two weeks after launch, but it was turned on again for 1 week in August 1974.^[7]

Atmospheric entry

Explorer 46 reentered in the atmosphere on 2 November 1979.

References

^ ^a ^b McDowell, Jonathan (21 July 2021). "Launch Log". Jonathan's Space Report. Retrieved 15 November 2021.
^ "Trajectory: Explorer 46 (MTS) 1972-061A". NASA. 28 October 2021. Retrieved 15 November 2021. This article incorporates text from this source, which is in the public domain.
^ "Letter dated 27 October 1972 from the Permanent Representative of the United States of America to the United Nations addressed to the Secretary-General". (72-22115). UNOOSA. 8 November 1972. Archived from the original on 2 April 2015. Retrieved 22 June 2018.
^ "Satellite Explorer 46: Meteoroid Technology Satellite (backup)". Smithsonian - National Air and Space Museum. 2007. Retrieved 15 November 2021. This article incorporates text from this source, which is in the public domain.
^ "Experiment: Meteoroid Penetration". NASA. 28 October 2021. Retrieved 15 November 2021. This article incorporates text from this source, which is in the public domain.
^ "Experiment: Meteoroid Penetration Sensors". NASA. 28 October 2021. Retrieved 15 November 2021. This article incorporates text from this source, which is in the public domain.
^ "Experiment: Meteoroid Velocity Sensors". NASA. 28 October 2021. Retrieved 15 November 2021. This article incorporates text from this source, which is in the public domain.