Bus Units 1 and 2 (BSU-1/2)
BSU-1 and BSU-2 MLI were the last surfaces to be inspected. At first sight the fluxes for both these surfaces seem unusually high, considering that shielding from the solar arrays was considerable.
All large impacts (greater than 100 µm) have been excised, and are pending chemical analysis.
BSU-1
The peripheral surface of BSU-1 was situated next to the Infra-Red Telescope, and faced about 20 deg; away from the +Y axis of the spacecraft. It contained both SSM and MLI surfaces, thus providing another opportunity to compare both surfaces directly.
Fig. 1 shows an image of BSU-1 taken at Astrotech soon after SFU retrieval. There is a large rectangular area composed of SSM on the top, and two smaller, square areas below. Note the two scuff plates on the left of BSU-1, which probably brought about some flux shielding.
The MLI surrounding the three SSM surfaces are actually divided into three separate blankets, as shown in Fig. 2.
SPR2 stands for "Side Panel R2", SPL2 for "Side Panel L2", and APF for "Access Panel F". These are the three largest MLI blankets on the peripheral face of SFU which contained impacts.
Click on the links below to download high-magnification .jpg images of all the impacts on the selected panels.
BSU-1
BSU1AccessPanelF.zip for impacts in Access Panel F [35 impacts; 3 MB].
BSU1SidePanelL2.zip for impacts in Side Panel L2 [12 impacts; 1 MB].
BSU1SidePanelR2.zip for impacts in Side Panel R2 [33 impacts; 2.8 MB].
Please note that some features are apparently missing. This is because some impact sites were recorded in the preliminary investigation, but were later found to be non-perforating impact craters. There are not enough of these features to provide meaningful flux figures, and so they have been omitted.
BSU-2
BSU2AccessPanelF.zip for impacts in Access Panel F [28 impacts; 2.5 MB].
BSU2SidePanelL2.zip for impacts in Side Panel L2 [13 impacts; 1.1 MB].
BSU2SidePanelR2.zip
for impacts in Side Panel R2 [33 impacts; 2.9 MB].
| BSU-2 MLI Peripheral | ||||
| Blanket | ID | Size (µm) | # layers
penetrated |
Chemistry |
 |
SPR2 SH5 #5 | 28.7 | ||
 |
SPR2 SH4 #27 | 33.4 | ||
 |
SPL2 SH6 #10 | 36.0 | ||
 |
SPL2 SH5 #9 | 45.5 | ||
 |
SPL2 SH5 #6 | 54.1 | ||
| APF SH1 #3 | 54.3 | |||
 |
SPR2 SH4 #23 | 55.3 | ||
| APF SH5 #18 | 57.6 | |||
 |
SPR2 SH7 #18 | 58.9 | ||
| APF SH5 #19 | 60.9 | |||
 |
SPR2 SH4 #32 | 61.2 | ||
 |
SPL2 SH5 #7 | 62.3 | ||
 |
SPL2 SH5 #4 | 64.4 | ||
 |
SPL2 SH5 #5 | 65.4 | ||
| APF SH3 #9 | 65.9 | |||
| APF SH3 #12 | 66.4 | |||
 |
SPR2 SH4 #25 | 68.7 | ||
 |
SPL2 SH5 #8 | 69.2 | ||
 |
SPR2 SH5 #11 | 70.0 | ||
| APF SH1 #4 | 72.4 | |||
 |
SPL2 SH5 #1 | 73.4 | ||
| APF SH5 #21 | 76.5 | |||
 |
SPR2 SH7 #17 | 78.1 | ||
| APF SH5 #33 | 80.5 | |||
| APF SH3 #11 | 89.1 | |||
 |
SPR2 SH4 #24 | 90.5 | ||
 |
SPR2 SH7 #21 | 90.7 | ||
 |
SPL2 SH7 #12 | 90.8 | ||
 |
SPR2 SH4 #30 | 91.9 | ||
| APF SH3 #14 | 92.5 | |||
| APF SH5 #26 | 93.2 | |||
| APF SH3 #13 | 94.0 | |||
 |
SPL2 SH6 #11 | 94.6 | ||
| APF SH5 #31 | 98.5 | |||
| APF SH5 #24 | 98.9 | |||
 |
SPR2 SH7 #20 | 105.5 | ||
 |
SPR2 SH5 #1 | 112.2 | ||
| APF SH1 #1 | 113.8 | |||
| APF SH7 #34 | 115.1 | |||
 |
SPR2 SH5 #6 | 116.0 | ||
| APF SH5 #25 | 116.1 | |||
 |
SPR2 SH5 #12 | 121.3 | ||
 |
SPR2 SH4 #29 | 140.9 | ||
 |
SPR2 SH4 #28 | 148.4 | ||
 |
SPR2 SH6 #15 | 153.6 | ||
| APF SH3 #7 | 154.5 | |||
 |
SPR2 SH5 #9 | 167.1 | ||
 |
SPR2 SH6 #13 | 169.0 | ||
| APF SH5 #29 | 169.6 | |||
| APF SH5 #30 | 170.1 | |||
| APF SH5 #28 | 170.7 | |||
| APF SH3 #10 | 174.6 | |||
| APF SH3 #17 | 174.8 | |||
 |
SPL2 SH5 #2 | 189.3 | ||
| APF SH3 #15 | 186.7 | |||
 |
SPL2 SH5 #3 | 189.4 | ||
 |
SPR2 SH6 #14 | 189.5 | ||
| APF SH2 #5 | 202.0 | |||
 |
SPR2 SH5 #2 | 210.0 | ||
 |
SPR2 SH5 #3 | 236.8 | ||
| APF SH3 #16 | 238.7 | |||
| APF SH3 #8 | 271.4 | |||
| APF SH3 #6 | 272.4 | |||
| APF SH5 #20 | 289.5 | |||
| APF SH2 #1 | 290.0 | |||
| APF SH5 #23 | 520.5 | |||
| BSU-2 MLI Peripheral | ||||
| Blanket | ID | Size (µm) | # layers
penetrated |
Chemistry |
 |
SPR2 SH4 #21 | 38.4 | ||
 |
SPR2 SH5 #13 | 39.1 | ||
 |
SPL2 SH6 #10 | 45.9 | ||
 |
SPR2 SH6 #28 | 47.1 | ||
 |
SPR2 SH5 #14 | 48.7 | ||
 |
APF SH2 #3 | 51.5 | ||
 |
APF SH6 #28 | 52.8 | ||
 |
SPR2 SH5 #19 | 54.2 | ||
 |
SPR2 SH5 #18 | 54.8 | ||
 |
SPL2 SH5 #6 | 55.0 | ||
 |
SPR2 SH7 #33 | 56.0 | ||
 |
SPL2 SH5 #8 | 59.8 | ||
 |
SPR2 SH5 #15 | 64.1 | ||
 |
APF SH3 #14 | 67.6 | ||
 |
SPL2 SH5 #7 | 68.1 | ||
 |
SPL2 SH5 #5 | 69.3 | ||
 |
SPL2 SH5 #4 | 70.6 | ||
 |
APF SH5 #24 | 70.9 | ||
 |
SPL2 SH5 #1 | 71.7 | ||
 |
SPR2 SH6 #27 | 73.7 | ||
 |
SPL2 SH5 #9 | 75.3 | ||
 |
APF SH3 #19 | 75.8 | ||
 |
SPR2 SH6 #30 | 77.7 | ||
 |
SPL2 SH6 #11 | 77.7 | ||
 |
APF SH3 #15 | 78.0 | ||
 |
APF SH6 #26 | 83.8 | ||
 |
SPR2 SH4 #12 | 86.7 | ||
 |
SPR2 SH4 #9 | 88.6 | ||
 |
APF SH2 #2 | 91.3 | ||
 |
SPR2 SH4 #1 | 92.1 | ||
 |
SPL2 SH7 #13 | 93.0 | ||
 |
SPR2 SH6 #25 | 93.1 | ||
 |
APF SH2 #9 | 95.7 | ||
 |
SPR2 SH4 #10 | 97.6 | ||
 |
SPR2 SH4 #22 | 103.0 | ||
 |
APF SH2 #5 | 111.5 | ||
 |
APF SH4 #20 | 112.6 | ||
 |
SPR2 SH4 #8 | 115.1 | ||
 |
SPR2 SH4 #6 | 118.6 | ||
 |
APF SH2 #7 | 120.2 | ||
 |
SPR2 SH4 #20 | 122.9 | ||
 |
SPR2 SH5 #16 | 126.6 | ||
 |
SPR2 SH7 #31 | 128.0 | ||
 |
APF SH6 #25 | 135.5 | ||
 |
APF SH5 #22 | 139.5 | ||
 |
SPL2 SH7 #12 | 143.8 | ||
 |
SPR2 SH4 #7 | 148.7 | ||
 |
SPR2 SH4 #3 | 148.9 | ||
 |
APF SH3 #13 | 154.8 | ||
 |
SPR2 SH4 #4 | 157.8 | ||
 |
SPR2 SH6 #26 | 168.9 | ||
 |
APF SH2 #8 | 170.8 | ||
 |
APF SH2 #11 | 172.0 | ||
 |
APF SH2 #10 | 173.6 | ||
 |
APF SH1 #1 | 175.9 | ||
 |
APF SH3 #18 | 176.3 | ||
 |
SPL2 SH5 #2 | 179.6 | ||
 |
APF SH3 #12 | 179.7 | ||
 |
SPR2 SH4 #5 | 187.0 | ||
 |
SPL2 SH5 #3 | 187.1 | ||
 |
SPR2 SH6 #29 | 189.8 | ||
 |
APF SH5 #23 | 204.8 | ||
 |
SPR2 SH4 #11 | 210.3 | ||
 |
SPR2 SH6 #24 | 211.5 | ||
 |
APF SH5 #21 | 231.1 | ||
 |
SPR2 SH7 #32 | 236.2 | ||
 |
APF SH2 #4 | 248.4 | ||
 |
APF SH2 #6 | 254.6 | ||
 |
APF SH3 #16 | 260.6 | ||
 |
APF SH3 #17 | 273.7 | ||
 |
SPR2 SH5 #17 | 340.7 | ||
 |
APF SH6 #27 | 381.3 | ||
 |
SPR2 SH4 #2 | 484.8 | ||
 |
SPR2 SH6 #23 | 639.5 | ||
| BSU-2 | Scuff plates | IRTS | SEM | EFFU | 2DHV | Solar arrays |