Design of optical-electronic sensor for ablation of spacecraft heat protection
Results of designing and studying the characteristics of the fiber-optic sensor for the ablation of the low-sublimating heat protection which intended for the use on the being got down module of article “Mars-5” are represented. The originality of development consists of guarantee for continuous...
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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 |
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| Цитувати: | Design of optical-electronic sensor for ablation of spacecraft heat protection / G. Hornostaev, V. Pasichny, Yu. Lytvynenko // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2008. — Т. 11, № 2. — С. 159-162. — Бібліогр.: 2 назв. — англ. |
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irk-123456789-1188612017-06-01T03:05:15Z Design of optical-electronic sensor for ablation of spacecraft heat protection Hornostaev, G. Pasichny, V. Lytvynenko, Yu. Results of designing and studying the characteristics of the fiber-optic sensor for the ablation of the low-sublimating heat protection which intended for the use on the being got down module of article “Mars-5” are represented. The originality of development consists of guarantee for continuous measurement of the instantaneous value of thickness of heat protective coating of the article during its descent. Achieving this goal is ensured by the application of two light-guide sensors, one of which is made from color glass-light filter. 2008 Article Design of optical-electronic sensor for ablation of spacecraft heat protection / G. Hornostaev, V. Pasichny, Yu. Lytvynenko // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2008. — Т. 11, № 2. — С. 159-162. — Бібліогр.: 2 назв. — англ. 1560-8034 PACS 41.81.Pa http://dspace.nbuv.gov.ua/handle/123456789/118861 en Semiconductor Physics Quantum Electronics & Optoelectronics Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine |
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English |
| description |
Results of designing and studying the characteristics of the fiber-optic sensor
for the ablation of the low-sublimating heat protection which intended for the use on the
being got down module of article “Mars-5” are represented. The originality of
development consists of guarantee for continuous measurement of the instantaneous
value of thickness of heat protective coating of the article during its descent. Achieving
this goal is ensured by the application of two light-guide sensors, one of which is made
from color glass-light filter. |
| format |
Article |
| author |
Hornostaev, G. Pasichny, V. Lytvynenko, Yu. |
| spellingShingle |
Hornostaev, G. Pasichny, V. Lytvynenko, Yu. Design of optical-electronic sensor for ablation of spacecraft heat protection Semiconductor Physics Quantum Electronics & Optoelectronics |
| author_facet |
Hornostaev, G. Pasichny, V. Lytvynenko, Yu. |
| author_sort |
Hornostaev, G. |
| title |
Design of optical-electronic sensor for ablation of spacecraft heat protection |
| title_short |
Design of optical-electronic sensor for ablation of spacecraft heat protection |
| title_full |
Design of optical-electronic sensor for ablation of spacecraft heat protection |
| title_fullStr |
Design of optical-electronic sensor for ablation of spacecraft heat protection |
| title_full_unstemmed |
Design of optical-electronic sensor for ablation of spacecraft heat protection |
| title_sort |
design of optical-electronic sensor for ablation of spacecraft heat protection |
| publisher |
Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України |
| publishDate |
2008 |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/118861 |
| citation_txt |
Design of optical-electronic sensor for ablation of spacecraft heat protection / G. Hornostaev, V. Pasichny, Yu. Lytvynenko // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2008. — Т. 11, № 2. — С. 159-162. — Бібліогр.: 2 назв. — англ. |
| series |
Semiconductor Physics Quantum Electronics & Optoelectronics |
| work_keys_str_mv |
AT hornostaevg designofopticalelectronicsensorforablationofspacecraftheatprotection AT pasichnyv designofopticalelectronicsensorforablationofspacecraftheatprotection AT lytvynenkoyu designofopticalelectronicsensorforablationofspacecraftheatprotection |
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2025-07-08T14:47:49Z |
| last_indexed |
2025-07-08T14:47:49Z |
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1837090546414256128 |
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Semiconductor Physics, Quantum Electronics & Optoelectronics, 2008. V. 11, N 2. P. 159-162.
© 2008, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
159
PACS 41.81.Pa
Design of optical-electronic sensor
for ablation of spacecraft heat protection
G. Hornostaev, V. Pasichny and Yu. Lytvynenko*
I. Frantsevich Institute for Problems of Materials Science, NAS of Ukraine
3, Krzhizhanovsky str., 03142 Kyiv, Ukraine
*E-mail: yurimlyt@mail.ru; phone: (38 044) 424-24-44, fax: (38 044) 424-21-31
Abstract. Results of designing and studying the characteristics of the fiber-optic sensor
for the ablation of the low-sublimating heat protection which intended for the use on the
being got down module of article “Mars-5” are represented. The originality of
development consists of guarantee for continuous measurement of the instantaneous
value of thickness of heat protective coating of the article during its descent. Achieving
this goal is ensured by the application of two light-guide sensors, one of which is made
from color glass-light filter.
Keywords: heat protection, ablation, sensor, light guide.
Manuscript received 07.02.08; accepted for publication 15.05.08; published online 30.06.08.
1. Introduction
The large volume of developments for the creation of the
optical-electronic means for monitoring the operating
characteristics of the heat-proof materials used at the
being got down spacecraft was carried out in the
Institute for Problems of Materials Science, NAS of
Ukraine.
This paper presents the first part of the studies
devoted to the creation of a sensor for the continuous
measurements of the thickness value for the ablated low-
sublimating materials used at the being got down module
“Mars-5” (customer is SIU “Energy”, Russia [1, 2]).
These problems were posed with the development
of the optical sensor of ablation on the basis of the
measurement of the length of color light guide:
1) to ensure the independence of the sensor indi-
cations from both the external illumination and
temperature of the being destroyed surface of heat-proof
material;
2) to ensure the average accuracy of the order of
several percentages when the length of the color light
guide is being measured.
Light guides from the color glass were made in KS
Scientific Research Institute, St.-Petersburg according to
the technical task of Institute for Problems of Materials
Science, NAS of Ukraine.
The first problem is solved by the way of using the
bridge measuring circuit of voltage by two photo-
detectors, one of which is illuminated through the
transparent while the second through the color light
guide. The instrument must measure not the absolute
illumination, but only relation of the illumination of
photodetectors in both the transparent and color
channels. The second problem is solved by the correct
selection of photodetectors, material of light guides and
by the filtration of input noise.
2. Procedure of measurement
of the heat protection removal
It is necessary to introduce the characteristic named as
the length constant Λ of a color light guide. Its light
transmission is changed by e times with a change in the
length of the light guide on the value Λt while the photo-
resistance illuminated through the light guide is changed
also by e times with a change in the length of the light
guide by the value Λp. We should measure a change ∆ of
the length of color light guide. If the resistance is
measured with the accuracy of 3-5 %, then it is obvious
that the minimum value of resistance under the entire
light guide must also composes 3-5 % of the value of
resistance under the light guide, which was burnt by the
value ∆.
Consequently, the value of removal must exceed
the length constant Λp from 3.5 (e –3.5 = 0.03) to 3 times
(e –3 = 0.05). At a distance ∆ = 2 Λp, instead of the
exponential dependence of resistance on the length of
light guide, it is possible to use the gross linear
approximation, in which the deviation of exponential
curve from the straight line does not exceed 10 % of the
value ∆. For the practical use, it is necessary to select the
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2008. V. 11, N 2. P. 159-162.
© 2008, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
160
color light guides, in which 2 or 3 length constants are
placed in the assigned thickness of the layer of the heat
protection removal.
The section of the light guide with the length of lr
remains after combustion yet. In order that the photo-
detectors under the transparent and color light guides
would work in the same photoresistance range (so that a
constant relation of resistances remains with this relation
of the illuminations), it is necessary to compensate their
illuminations introducing an additional filter into the
channel of the transparent light guide. The compensating
filter is selected in such a manner that its transmission
would be equal to the transmission of the color light
guide, which had burnt to have the length (lr + 0.5 ∆).
The matching of materials is executed for the thickness
of the removal layer of approximately 10 mm with the
use of photoresistance СФЗ-1.
Transmission of the compensating filter is
( )[ ]prF l Λ∆+=τ /5.0exp .
The photosensitivity is defined as the value
reversed to the energy of the luminous flux which is
necessary for maintaining the constant value of photo-
resistance. The spectral sensitivity can be calculated
from both the spectral effectiveness curve for the
emissions of equal power and the dependence of the
photoresistance on the power, which was measured for
one of the wavelengths.
3. Studying the energy characteristic
of the detector СФЗ-1
The measurements of photoresistor with the strong light
fluxes were carried out under the conditions of the
concentration of the light beam from illuminator by a
parabolic lens into the focal spot with a diameter of
4 mm. СФЗ-1 characteristic in the average range of
illumination was obtained in the monochromatic green
as well in the visible light, whereas the IR part of the
spectrum was cut off by the light filter SZS-28, at high
illumination in the red and infrared regions of the
spectrum (red filter) (Fig. 1). The illumination mea-
surements were carried out by both the selenium photo-
cell F-102 and the microammeter M-95.
The neutral grey filters NG-6, NG-8, NG-9, NG-10
with the identical absorption spectrum in the IR range
but with different density were used for the work in the
red – infrared regions. The following values were used
for the calculations: the maximum of sensitivity of the
selenium photocell of 556 nm; the energy flux of
1 lm/m2 at the light wavelength λ = 556 nm are equal to
1.46×10–7 W/cm2; the photosensitivity of the selenium
photocell at the wavelength λ = 510 nm is 92 % of the
maximum; photosensitivity СФЗ-1 at the wavelength λ =
510 nm is equal to 2.5 % of the peak one. The data about
the luminous flux are reduced to the peak of spectral
sensitivity of СФЗ-1 (λ = 720 nm).
Fig. 1. Energy characteristics of СФЗ-1: R – resistance, Ohm;
J – flux density, mW/cm2.
4. Study of the СФЗ-1 spectral efficiency
The optical part of the spectrophotometer СФ-4 has been
used as the luminous source with the following changes:
1) the quartz-halogen lamp КГЛ-12-100 with a
power of 100 W is established in the illuminator. The
lamp is delivered by the current of 8 A, with the voltage
of 12.0 V from the rectifier stabilized by ferroresonant
stabilizer C-0.5;
2) the glass lens with the focal length 60 mm,
which forms in the focus the vividly illuminated square
field with the size of 4×4 mm is established in the output
window of instrument.
The adjustment of the wavelength scale was carried
out with the aid of the monochromatic ray of helium-
neon laser ЛГ-52 with the wavelength 632.8 nm. The
absolute energy of the luminous flux was measured at
the wavelength 556 nm (where the flux of 4.07×
×1015 quantum/(s·m2) corresponds to illumination of
1 lx) by the luxmeter of Ю-16. The radiated power is
0.17 mW at this wavelength. The relative measurements
of the radiated power described below make it possible
to estimate the power with values to 2 mW in the
infrared region.
The bolometer based on thermistors MMT-1 was
used as the receiver of radiant energy. Measuring
illuminated thermistor was smoked while the second
thermistor, which compensated the changes of the
general temperature of building, was closed with white
screen. A change in the resistance under the radiant
heating from the monochromator is small and consists of
about 0.05-0.3 % of nominal. For the voltage
amplification the operational amplifier whose output was
measured by millivoltmeter is used.
The correction for convection drift was introduced
as follows: output voltage U0 before the opening the lock
of monochromator was measured, then the voltage U1 in
t1 = 30 s after beginning the illumination was measured.
At once the lock was shut and after the time t2 (1.0 min)
the voltage U2 with the unlighted bolometer was
measured. The signal can be expressed as
U = U1 – (U2 – U0) t1/(t1 + t2).
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2008. V. 11, N 2. P. 159-162.
© 2008, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
161
Fig. 2. Dependence of the potential U of the bolometer on the
equal energy width δ of the monochromator slot for the
different wavelengths of the emission: 1.0 (1), 1.25 (2), 1.5 (3),
0.9 (4), 0.8 (5), 1.75 (6), 0.7 (7), 0.6 (8), 0.5 µm (9).
The dependence of the radiation power on the
width of the monochromator slot was obtained for
9 wavelengths (Fig. 2). Dependence between the
logarithms of both the width of slot and the output
voltage is strictly linear: the average coefficient of linear
correlation is equal to 99.84. The average inclination of
the dependence composes of 2.118 (Table). The
obtained linear dependences can be used for the
calculation of the slot width by the method of the least
squares; so that the radiation power is retained at the
level of unity with λ = 500 nm for the maximum
disclosure of the slot (2 mm).
The dependence of the equal energy width of slot
on the wavelength is shown in Fig. 3. The radiation
power in the blue spectral region was insufficient to
obtain the dependence described above. With the
completely opened slot, the powers for λ = 450 nm and
425 nm were equal, respectively, 45 and 37 % of the
emission with the wavelength of 500 nm. Extrapolation
for 475 and 400 nm gives estimations which respect of
66 and 28 %. After establishing both the wavelength
with a step of 25 nm and the appropriate width of slot for
the flow of a constant power the lock was opened.
Table. The coefficient of linear correlation β and the
inclination α of the dependence of the logarithm for the
equal energy width δ of the monochromator slot on the
output voltage U for various wavelengths λ.
λ,
nm 600 700 800 900 1000 1250 1500 1750
β 99.79 99.89 99.94 99.84 99.98 99.57 99.74 99.88
α 2.129 2.084 2.129 2.036 2.109 2.246 2.146 2.063
δ,
mm 1.291 0.964 0.863 0.699 0.490 0.553 0.603 0.899
Fig. 3. Calculated equal energy width δ of the monochromator
slot for the different wavelengths λ of emission.
In Fig. 4a, the values of the СФЗ-1 photodetector in
the flow of equal power are shown for the different
wavelengths, that is the curve of the spectral efficiency.
According to the amplitude characteristic of the detector
(Fig. 4b), we find a relative illumination which cor-
responds to the measured value of resistance. This
relative illumination characterizes photosensitivity. The
peak photosensitivity is accepted as 1.
5. The selection of glass for the color light guide
In accordance with the measured spectral characteristics
of the photodetector СФЗ-1, the glass must have a
passband within the range 700 to 800 nm. The length
constant for the thickness of the removal layer of 10 mm
must comprise from 3 to 5 mm. From the formula of the
transmission coefficient of color glass
( ) 1
10
−−λ=τ Dlk ,
where l is the length of color light filter, mm; kλ is the
decimal absorption coefficient for the layer of 1 mm;
Fig. 4. The spectral sensitivity of the photodetector СФЗ-1: a –
resistance R and photosensitivity S with the equal energy
illumination; b – the amplitude characteristic of the photo-
detector, J – flux density.
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2008. V. 11, N 2. P. 159-162.
© 2008, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
162
D is a correction for reflection (value of the order of 0.04
for larger quantity of glasses), we find the absorption
coefficient:
kλ = (1g e + D)/Λt .
With the value τ = l / е and l = 3–5 mm, the ne-
cessary value of kλ composes of 0.160–0.095, respec-
tively. According to State All-Union Standard (USSR)
9411-60 to the color glasses the NG-3 glass has the color
optical characteristics which close to assigned ones.
6. Conclusions
The amplitude characteristic and spectral sensitivity of
photodetector СФЗ-1 are investigated; the selection of
the material of a color light guide is substantiated; initial
data for creating the sensor of continuous ablation are
obtained (results of its tests will be represented in the
following paper).
References
1. 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 Ukrainian).
2. 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 Ukrainian).
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