We will be updating the thermal blanket after DC1. The most up-to-date details on the blanket are contained in this PDF file received from Dave Thompson on Nov. 6, 2003
According to Tom Johnson (GSFC) the design as of Oct. 7, 2002 is:
----------------------- (1) Nextel AF10
Foam
----------------------- (1) Nextel AF10
Foam
----------------------- (1) Nextel AF10
Foam
----------------------- (1) Nextel AF10
Foam
----------------------- (6) Kevlar KM2
| Component | Number in Shield | Thickness each (cm) | Mass per Unit Area each (g/cm2) Areal Density |
Total Thickness (cm) | Total Mass per Unit Area (g/cm2) |
| Nextel AF10 | 4 | 0.0254 | 0.025 | 0.102 | 0.100 |
| Solimide Foam Spacer | 4 | 0.66 | 0.0051 | 2.640 | 0.020 |
| Thermal Blanket | 1 | 0.32 | 0.0368 | 0.320 | 0.037 |
| Kevlar KM2 | 6 | 0.0254 | 0.023 | 0.152 | 0.138 |
| Overall Shield | 3.21 | 0.295 |
Nextel is 62% Al203, 24% Si02, and 14% B2O3
Areal density = 0.025 g/cm2
Thickness = 0.0254 cm
r = 0.025 g/cm2 / 0.0254 cm = 0.984 g/cm3
No details about B2O3 are available, so it is being dropped from the model
Rather we will model Nextel as 70% Al2O3 and 30% Si02
Al2O3 r.l. 4.85 cm r
= 3.97 g/cm3
SiO2 r.l. 12.3 cm r
= 2.2 g/cm3
Normalize densities to find equivalent thickness:
x (0.7 (3.97) + 0.3 (2.2)) = 0.984 g/cm3 ( 0.102 cm)
3.43 x = 0.100
x = 0.1/3.43 = 0.0292 cm
Fractional composition of Al2O3:
Formula Weight: 2(26.98) + 3(15.99) = 101.93
Al: 2(26.98)/101.93 x 100 = 52.9%
O: 3(15.99)/101.93 x 100 = 47.1%
Fractional composition SiO2:
Formula Weight: 28.08 + 2(15.99) = 60.06
Si: 28.08/60.06 x 100 = 46.8%
O: 2(15.99)/60.06 x 100 = 53.2%
Solimide (polyimide) foam based on Kapton (C22H10N2O5)n
Kapton r.l. = 28.6 cm
r kapton = 1.42 g/cm3
Areal density solimide = 0.0051 g/cm2
Solimide r = 0.0051 g/cm2 / 0.66 cm = 0.00773 g/cm3
Calculate equivalent thickness of Kapton:
1.42 g/cm3 (t) = 0.0077 g/cm3 (0.66 cm)
t = 0.00358 cm
Radiation length of each solimide foam layer:
1 - e -(x/X0) = 1 - e -(0.00358/28.6) = 0.00013
Total r.l. of all solimide layers: 0.0005 = 0.05%
Kevlar (C21H15N3O3)n from Dupont Web site
Thermal blanket material is modeled as 0.5 mm Kapton (C22H10N2O5)n
or Mylar C5H4O2
Mylar r.l. 28.7 cm