Micrometeroid, orbital debris, and shielding analysis for the Soft X-ray Camera (SXC) of the High Energy Transient Explorer (HETE-2) spacecraft

The High Energy Transient Explorer (HETE-2) is a scientific spacecraft that will carry out a multi-wavelength study to determine the origin and nature of cosmic gamma-ray bursts (GRBs). The Soft X-ray Camera (SXC) is the new science instrument on board the HETE-2 spacecraft and uses a pair of Charge Coupled Devices (CCDs) to detect incoming X-ray in the 0.5-14 keV energy range. Once in Earth orbit, HETE-2 will encounter micrometeoroids and orbital debris. Micrometeoroids are the smallest natural particles in space and orbital debris are any inoperative, manmade objects remaining in Earth orbit. The major concern for CCDs in the SXC is that they are exposed to the micrometeoroids and orbital debris environment. A single impact from these particles may cause the entire failure of the CCD due to an electrical short. The Optical Blocking Filter (OBF) and the Beryllium (Be) shield are two shielding structures that will protect CCDs against particle impacts. The Optical Blocking Filter (OBF) can act as a Whipple shield, which vaporizes or fragments impacting particles. The Be shield is added on the top of only one CCD for additional protection to ensure that at least one CCD is operational. In this thesis, I analyze the micrometeoroids and orbital debris flux environment in order to estimate the number of particles that CCDs will encounter. Then, I calculate the size of particles that cause impact craters which are deep enough to cause a failure of the CCD. In the shielding chapter of this thesis, I discuss how each shield works and analyze its effectiveness in decreasing the significant impact rate on the CCDs. Although HETE-2 will be launched after the November 1999 Leonid meteoroid storm, I analyze the hypothetical impact of such a storm on the SXC.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Aeronautics and Astronautics

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

1999

Author dc:creator

• Pak, Sangwoo, 1974-

Advisor dc:contributor.advisor

• Manuel Martinez-Sanchez.

• Aeronautics and Astronautics

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/50078

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/50078