NSSDCA ID: 1972-061A-01
Mission Name: Meteoroid Technology SatelliteThe objective of this experiment was to measure the meteoroid penetration rates of a bumper-protected target. Penetrations were measured, using 2-mil stainless-steel pressure cells located behind 1-mil stainless-steel bumpers. These were mounted on 4 bumper panel arrays which extended out from the cylindrical spacecraft body. Due to a malfunction, only two of the four bumper wings deployed.
The Bumper Penetration Experiment consisted of 96 long narrow (5.03 cm x 3.2 meters) pressure cells surrounded on both sides by thin layers of bumper material. Each pressure cell comprised compressed helium sealed between two 0.005 cm (0.002 in) thick 21-6-9 stainless steel (Nitronic 40) walls, with a switch that would trip if the pressure fell below 96000 Pa. Mounted in front and back of the cell, set off by 1.25 cm (0.5 in), were the 0.0025 cm (0.001 in) thick 21-6-9 stainless steel bumpers. Any particle hitting the bumper with enough energy to penetrate the bumper and then the pressure cell would result in the pressure cell losing gas and tripping the pressure switch, recording a hit.
Because the impact could come from either side, the pressure cell had an exposed area of 0.322 square meters (3.47 square feet). The actual effective area of any cell would be between 76% and 92% of the total area depending on its location. Eight pressure cells were mounted together along their long edges about a cm apart to form one panel, 48.3 cm (19 in) wide by 3.2 meters (10.5 ft) long. The twelve panels thus formed were mounted on the spacecraft in groups of three around the axis to form four "wings" separated by 90 degrees. The three panels on each wing extended together 3.2 meters from the spacecraft, and were oriented so that two were parallel to the spacecraft axis along the 48.3 cm width, and one was situated between them with the width perpendicular to the spacecraft axis, forming a cross section looking like a plus sign with the top and bottom extended. The 96 sensors gave a total surface area of 30.9 square meters (333 square feet), and an effective area of 26.6 square meters (286 square feet).
The bumper panels were collapsable sheets, with the bumpers held out from the detectors by leaf springs on deployment. In launch configuration, the panels were rolled into cylinders, each one attached to a reservoir of pressurized gas. They are deployed by releasing a clamp, unrolled with a motorized boom, and rigidized by the gas. Two of the wings on opposite sides of the spacecraft failed to deploy fully (it is estimated they opened to about half their length), so the data received from two of the four wings, or 6 of the 12 panels, was not easily interpretable. About 20 impacts were recorded on all panels through December 1972, and after one year 31 of the 96 cells had been punctured. Over the total 899 day duration of the experiment, until final interrogation on 29 January 1975, 53 cells lost their pressure.
Questions and comments about this experiment can be directed to: Dr. David R. Williams
Name | Role | Original Affiliation | |
---|---|---|---|
Dr. William H. Kinard | Other Investigator | NASA Langley Research Center | w.h.kinard@larc.nasa.gov |
Mr. Donald H. Humes | Principal Investigator | NASA Langley Research Center | d.h.humes@larc.nasa.gov |