Explorer 46
{{Short description|NASA satellite of the Explorer program}}
{{Use American English|date=November 2021}}
{{Use dmy dates|date=November 2021}}
{{Infobox spaceflight
| name = Explorer 46
| names_list = Meteoroid Technology Satellite-A
MTS-A
| image = Explorer-46 MTS-A.jpg
| image_caption = Explorer 46 satellite
| image_size = 300px
| mission_type = Meteroids research
| operator = NASA
| COSPAR_ID = 1972-061A
| SATCAT = 06142
| mission_duration =
| spacecraft = Explorer XLVI
| spacecraft_type = Meteoroid Technology Satellite
| spacecraft_bus = MTS
| manufacturer = Langley Research Center
| launch_mass = {{cvt|90|kg}}
| dimensions =
| power =
| launch_date = 13 August 1972, 15:10 UTC
| launch_rocket = Scout D-1 (S-184C)
| launch_site = Wallops Flight Facility, LA-3A
| launch_contractor = Vought
| entered_service = 13 August 1972
| last_contact =
| deactivated =
| decay_date = 2 November 1979
| orbit_reference = Geocentric orbit{{cite web|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/displayTrajectory.action?id=1972-061A|title=Trajectory: Explorer 46 (MTS) 1972-061A |publisher=NASA|date=28 October 2021|access-date=15 November 2021}} {{PD-notice}}
| orbit_regime = Low Earth orbit
| orbit_periapsis = {{cvt|496|km}}
| orbit_apoapsis = {{cvt|814|km}}
| orbit_inclination = 37.70°
| orbit_period = 97.80 minutes
| apsis = gee
| instruments = Meteoroid Penetration
Meteoroid Penetration Sensors
Meteoroid Velocity Sensors
| programme = Explorer program
| previous_mission = Explorer 45
| next_mission = Explorer 47
}}
Explorer 46, (also Meteoroid Technology Satellite-A or MTS-A), was a NASA satellite launched as part of Explorer program.{{cite web|url=http://www.unoosa.org/oosa/download.do?file_uid=865|title=Letter dated 27 October 1972 from the Permanent Representative of the United States of America to the United Nations addressed to the Secretary-General|work=(72-22115)|publisher=UNOOSA |date=1972-11-08|access-date=22 June 2018|archive-url=https://web.archive.org/web/20150402133320/http://www.unoosa.org/oosa/download.do?file_uid=865|archive-date=2 April 2015|url-status=dead}}
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 {{cvt|701.50|cm}}. 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.{{cite web|url=https://airandspace.si.edu/collection-objects/satellite-explorer-46-meteoroid-technology-satellite-backup/nasm_A19761737000|title=Satellite Explorer 46: Meteoroid Technology Satellite (backup)|publisher=Smithsonian - National Air and Space Museum|date=2007|access-date=15 November 2021}} {{PD-notice}}
Instruments
- Multi-sheet bumper, {{cvt|701.50|cm}} 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.{{cite web|url=http://www.planet4589.org/space/log/launchlog.txt|title=Launch Log|publisher=Jonathan's Space Report|first=Jonathan|last=McDowell|date=21 July 2021|access-date=15 November 2021}}
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.{{cite web|url=https://nssdc.gsfc.nasa.gov/nmc/experiment/display.action?id=1972-061A-01|title=Experiment: Meteoroid Penetration|publisher=NASA|date=28 October 2021|access-date=15 November 2021}} {{PD-notice}}
= 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.{{cite web|url=https://nssdc.gsfc.nasa.gov/nmc/experiment/display.action?id=1972-061A-03|title=Experiment: Meteoroid Penetration Sensors|publisher=NASA|date=28 October 2021|access-date=15 November 2021}} {{PD-notice}}
= 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.{{cite web|url=https://nssdc.gsfc.nasa.gov/nmc/experiment/display.action?id=1972-061A-02 |title=Experiment: Meteoroid Velocity Sensors|publisher=NASA|date=28 October 2021|access-date=15 November 2021}} {{PD-notice}}
Atmospheric entry
Explorer 46 reentered in the atmosphere on 2 November 1979.
See also
{{Portal|Spaceflight}}
References
{{Reflist|30em}}
External links
- [https://airandspace.si.edu/collection-objects/satellite-explorer-46-meteoroid-technology-satellite-backup/nasm_A19761737000 Explorer 46: Meteoroid Technology Satellite (backup)] Smithsonian National Air and Space Museum
{{Explorer program}}
{{Orbital launches in 1972}}