Optical-electronic sensor of spacecraft heat protection ablation
Block diagram and results of tests on gas-dynamic stands are represented to illustrate operation of the continuous ablation sensor, in which color light guides with a diameter of 1 mm are used. It is shown that the application of compensating light filter in the colorless channel makes it possibl...
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| Дата: | 2008 |
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| Формат: | Стаття |
| Мова: | English |
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Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України
2008
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| Назва видання: | Semiconductor Physics Quantum Electronics & Optoelectronics |
| Онлайн доступ: | http://dspace.nbuv.gov.ua/handle/123456789/119057 |
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| Цитувати: | Optical-electronic sensor of spacecraft heat protection ablation / G. Hornostaev // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2008. — Т. 11, № 3. — С. 245-247. — Бібліогр.: 3 назв. — англ. |
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irk-123456789-1190572017-06-04T03:03:22Z Optical-electronic sensor of spacecraft heat protection ablation Hornostaev, G. Block diagram and results of tests on gas-dynamic stands are represented to illustrate operation of the continuous ablation sensor, in which color light guides with a diameter of 1 mm are used. It is shown that the application of compensating light filter in the colorless channel makes it possible to create the meter invariant to external radiant fluxes applied to the heat protection covering surface. 2008 Article Optical-electronic sensor of spacecraft heat protection ablation / G. Hornostaev // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2008. — Т. 11, № 3. — С. 245-247. — Бібліогр.: 3 назв. — англ. 1560-8034 PACS 41.81.Pa http://dspace.nbuv.gov.ua/handle/123456789/119057 en Semiconductor Physics Quantum Electronics & Optoelectronics Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України |
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Block diagram and results of tests on gas-dynamic stands are represented to
illustrate operation of the continuous ablation sensor, in which color light guides with a
diameter of 1 mm are used. It is shown that the application of compensating light filter in
the colorless channel makes it possible to create the meter invariant to external radiant
fluxes applied to the heat protection covering surface. |
| format |
Article |
| author |
Hornostaev, G. |
| spellingShingle |
Hornostaev, G. Optical-electronic sensor of spacecraft heat protection ablation Semiconductor Physics Quantum Electronics & Optoelectronics |
| author_facet |
Hornostaev, G. |
| author_sort |
Hornostaev, G. |
| title |
Optical-electronic sensor of spacecraft heat protection ablation |
| title_short |
Optical-electronic sensor of spacecraft heat protection ablation |
| title_full |
Optical-electronic sensor of spacecraft heat protection ablation |
| title_fullStr |
Optical-electronic sensor of spacecraft heat protection ablation |
| title_full_unstemmed |
Optical-electronic sensor of spacecraft heat protection ablation |
| title_sort |
optical-electronic sensor of spacecraft heat protection ablation |
| publisher |
Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України |
| publishDate |
2008 |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/119057 |
| citation_txt |
Optical-electronic sensor of spacecraft heat protection ablation / G. Hornostaev // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2008. — Т. 11, № 3. — С. 245-247. — Бібліогр.: 3 назв. — англ. |
| series |
Semiconductor Physics Quantum Electronics & Optoelectronics |
| work_keys_str_mv |
AT hornostaevg opticalelectronicsensorofspacecraftheatprotectionablation |
| first_indexed |
2025-07-08T15:09:37Z |
| last_indexed |
2025-07-08T15:09:37Z |
| _version_ |
1837091916838076416 |
| fulltext |
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2008. V. 11, N 3. P. 245-247.
© 2008, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
245
PACS 41.81.Pa
Optical-electronic sensor of spacecraft heat protection ablation
G. Hornostaev
I. Frantsevich Institute for Problems of Materials Science, NAS of Ukraine
3, Krzhizhanovsky str., 03142 Kyiv, Ukraine
E-mail: cosmos@ipms.kiev.ua; phone: (38-044) 424-24-44, fax: (38-044) 424-21-31
Abstract. Block diagram and results of tests on gas-dynamic stands are represented to
illustrate operation of the continuous ablation sensor, in which color light guides with a
diameter of 1 mm are used. It is shown that the application of compensating light filter in
the colorless channel makes it possible to create the meter invariant to external radiant
fluxes applied to the heat protection covering surface.
Keywords: heat protection, ablation, light guide, sensor.
Manuscript received 26.02.08; accepted for publication 20.06.08; published online 15.09.08.
1. Introduction
With the aim to optimize both the thickness and the
weight of heat protection coatings covering the being got
down spacecraft, the latter is supplied with sensors of
ablation of these coatings.
In the analog circuit of sensor measurements [1, 2],
the light transmission of two light guides: color (where
the light transmission depends on the guide length) and
colorless are compared (Fig. 1). The light transmission is
measured by two photoresistors СФЗ-1. An advantage of
the bridge sensor is the independence of the voltage of
midpoint from both the external illumination and the
temperature of the heat protection surface.
2. Substantiation of the principle
of measurement
The results obtained earlier [3] show that both color
glass and photodetector are wide-band. Combined action
of three factors: the spectral energy distribution of the
emission, the spectral sensitivity S(λ) of detector and
( )
143844.1
5
15
1
10991.4
−
λ
−
⎟⎟
⎟
⎠
⎞
⎜⎜
⎜
⎝
⎛
−
λ
⋅
=λλ TedW
color light guide transmission τ(λ) determines the
effective illumination J (Fig. 2):
( ) ( ) ( ) ( ).
2
1
λλλτλ= ∫
λ
λ
dSWJ
Here λ1 and λ2 are minimum and maximum
wavelengths that correspond to the range of the detector
sensitivity. A close agreement of spectral characteristics
of color light guide and detector occurs. This makes it
possible to do measurements in the narrow fixed spectral
range.
3. Numerical calculations of the effective illumination
Calculation by the numerical integration method is made
for the photoresistor СФЗ-1 as well as the color light
guides with various lengths of neutral grey glass NG-3
(Fig. 3). The color temperature of the emitter is of 1273-
2273 K. Step of the integration dλ = 25 nm, the spectral
range λ = 675-1200 nm, the single section of light guide
is of 5 mm.
With a change in the length of color light guide to
the value of Λr, the photoresistivity changes by e times.
The estimation of the length Λr is accomplished
according to the amplitude characteristic of the
photodetector
lg R = h – clg J,
where: R is the value of photoresistance located under
the color light guide, c = Λt / Λr , h = const, Λt is
determined from Fig. 3. With a change in the length of
color light guide to the value Λt , its light transmission τ
changes by e times.
With the change of the temperature of emitter the
constant value Λt remains. A constant relationship
between the illumination in the color channel of the
specific length and in the colorless channel (with the
zero length of the color light guide) also remains.
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2008. V. 11, N 3. P. 245-247.
© 2008, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
246
Fig. 1. Bridge scheme of the sensor: 1, 2 – color and colorless
light guides; R0 – photoresistance, which is located under the
colorless light guide.
Fig. 2. Factors that influence on the effective illumination: τ is
the transmission of glass NG-3 with the thickness 10 mm, W –
radiant energy with the color temperature 1750 °С, S – relative
light sensitivity of СФЗ-1.
4. Construction of photodetector part
For the bridge to be invariant to the illumination, it is
necessary to establish compensator (light filter) between
the colorless light guide and photodetector. This ensures
the light transmission equal to the light transmission of
the color light guide of the standard length.
Approximately, it is possible to accept
EU
2
1
= ,
( )212 2
1 LLLL −+= .
Here: L1, L2 are the initial and finite lengths of the
color light guide; E – supply voltage; U – voltage of the
midpoint of potentiometer; L – certain standard length of
the light guide: (L1 > L > L2). The compensator is
divided by two parts: the filter of coarse adjustment (of
the glass NG-2 with the length 10 mm) and glass post
with the black segment. It is possible to change the value
of the photo resistance R0 located under the colorless
light guide (Table) by means of detector rotation.
Table. Data on flow control with the aid of the compensator
of the fine adjustment.
Mark of the glass
post
Painting the side
surface R0, кOhm
BC White 7 – 500
BC Black 14 – 2000
NС White 88 – 1500
NС Black 62 – 1500
5. Stand tests
To check the correctness of calculations of the parameter
Λr, the measurement of Teflon-4 ablation with the aid of
the color light guides of the glass NG-3 was carried out.
The inspection of the value of removal is achieved with
the aid of the filming. Tests were performed using two
gas-dynamic stands (IPMS NAS of Ukraine, Kyiv and
SRI TP, Moscow).
Results of measurements (Fig. 4) showed that the
composition of medium and its thermodynamic
parameters do not influence on the value of the
parameter Λr = 3.85 mm. This value corresponds to the
results of calculation illustrated in Fig. 3.
Fig. 3. Effective illumination of photoresistor СФ3-1
calculated in dependence on the length L of the light guide
made of the glass NG-3 at various color temperatures T of the
illuminator: 1 – Λr = 3.975 mm, T = 2273 К; 2 – Λr = 3.65 mm,
T = 2023 К; 3 – Λr = 4.40 mm, T = 1773 К; 4 – Λr = 3.78 mm,
T = 1523 К; 5 – Λr = 3.90 mm, T = 1273 К; 6 – average values.
Fig. 4. Change in the value of the photoresistance located under
the color light guide with the diameter 1 mm and the length
15 mm made of glass NG-3 in the process of Teflon-4 ablation
on two gas-dynamic stands (L is the instantaneous value of the
color light guide length): 1 – q = 12 МW/m2, Р = 2.3⋅105 Pа, Т =
2600 К; 2 – q = 16 МW/m2; Р = 5.5⋅105 Pa, Т = 5500 К.
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2008. V. 11, N 3. P. 245-247.
© 2008, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
247
6. Conclusions
1. It is proved by both the calculation way and the
experiment on two gas-dynamic stands that the constant
of the length of color light guide is stable under varied
illumination conditions (Λr = 3.85 mm). It is necessary
to introduce compensating light filter into the colorless
channel. Its transmission (in the maximum of the band of
the spectral sensitivity of detector) must be close to the
transmission of the color light guide which shortened to
half the thickness of the removed layer.
2. The results of measurements of the removal of
heat protection material Teflon-4 obtained by the light-
guide sensor and filming coincide with the accuracy
≤10 %.
References
1. G.F. Hornostaev, Fiber-optic sensors and the
prospect for their use in the space program of
Ukraine // Kosmіchna nauka і tekhnologіya 2(3/4),
p. 88-94 (1996) (in Russian).
2. G.F. Hornostaev, V.V. Pasichny and G.V. Tka-
chenko, Method of measurement by radiant
component of heat flux on the surface of ceramic
heat protection // Kosmіchna nauka і tekhnologіya
12(2/3), p. 98-102 (2006) (in Russian).
3. G.F. Hornostaev, V.V. Pasichny and G.V. Tka-
chenko, Methods of the control of operating
characteristics of heat protection by the fiber-optic
sensors // Kosmіchna nauka і tekhnologіya 13(3),
p. 12-18 (2007) (in Russian).
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