Transcript Slide 1

H.A.S.P. SPARTAN-V
Mission Specialist Team:
Anthony Cangelosi
Chris Nie
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HASP Background:
• The HASP Platform ascends to 36 km on a zero
pressure NASA balloon for up to 36 hours
carrying 8 small and 4 large payloads.
– SPARTAN-V will be
carried on a large
payload position.
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SPARTAN-V Background
Selective Pointing Apparatus for Research of Turbulence and
Atmospheric Noise Variation
• Mission Statement:
Team SPARTAN-V is working towards the eventual goal of
supporting very precise photometry from balloon-borne telescopes.
This mission focuses on the specific problem of characterizing
atmospheric scintillation and extinction in order to support the
feasibility of observing exo-planets transiting stars from the
stratosphere with a signal to noise ratio of 10^5. To achieve this,
SPARTAN-V will sense platform stability in order to point at a bright
star, and measure that star’s photometric output. In this way,
SPARTAN-V will create a telescopic pointing system capable of
astronomical observing for future payloads.
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HASP SPARTAN-V Design:
Image/Design Credit: Jeff Byrne, Structures Team
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Scientific Mission Objectives:
• The primary scientific goal is to attain a signal
to noise (SNR) ratio of 105:1 by combining a
series of images of a target star over an
extended integration time.
– This is the SNR required to definitively observe an
exo-planet transit in front of its parent star.
– The target star will be between 0 and 4th
magnitude
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Challenges:
• Finding a compact telescope with sufficient
aperture and focal length
• Finding a CCD that is compact, affordable and
provides the best combination of well depth,
quantum efficiency and pixel array size
• Correcting and calibrating for the thermal
environment of 120,000 feet without an active
focusing system.
• Analyzing the data
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Scientific Mission:
• In order to accomplish these goals we will be
building a custom folded refractor telescope
coupled with a QSI 504ME CCD.
– This design takes a standard refractor design and
uses mirrors to fold the beam and shorten the
overall length.
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Telescope Components:
• The telescope frame and component housings
will be machined from aluminum 6061.
• Internal components include:
– 75mm x 400mm focal length primary lens
– 75x75 mm mirror
– 40x40 mm mirror
– QSI 504ME CCD
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Telescope Design
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Telescope Design
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Telescope Optical Bench Design:
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Telescope Optical Bench Design:
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CCD:
• The QSI 504ME is the chosen CCD to
accomplish the science mission:
– 100,000 electron well depth
– 3564x2376 arc second field of view
– High Quantum Efficiency (83% peak)
– One modification is necessary:
• The CCD chip is sealed in a chamber filled with argon
gas at one atmosphere.
• The window will be removed to eliminate the pressure
vessel.
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Exposure Times:
QSI 504 at 70% QE, 100k
well depth
Time To Saturation
[seconds]
Mag 0
Mag 1
Mag 2
Mag 3
Mag 4
10x10 defocus
0.0226
0.0567
0.1423
0.3574
0.8975
Number of frames we will
need to get 10^5 SNR
100k Well Depth (80k
used)
Estimate
Total Integration
Time Including
Readout [minutes]
5x5 defocus
0.0056
0.0142
0.0356
0.0894
0.2244
10x10
34.08583186
35.22285714
38.07792762
45.24700958
63.2485744
10x10 defocus
5x5 defocus
1591.55
4420.97
2000.00
5500.00
5x5
92.18400941
92.96571429
94.92857524
99.85731909
112.2333949
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Star Candidates
• Magnitude 0 to 4
• Must be observable night of launch
(09/06/2010) as well as up to 10 days after.
• Minimal vertical due to pointing restrictions.
• Pitch range from horizon: 50-66 degrees.
• Highest density of viewable stars along part of
galactic plane that is within field of view.
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Star Candidates (cont.)
• Heaviest density of stars expected to be in
following constellations:
– Aquila
– Scutum
– Ophiuchus
– Hercules
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Telescope Thermal Considerations:
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Thermal Telescope Considerations:
• Environment of flight
– Temperature ranges of +70 to -50° C
– Little to no atmosphere; no convection
– Heat transfer will be conduction and radiation
• Total optical tube change in length:
– 0.5796 mm
• Focal Length change:
– 1.7388 mm
• Will be anticipated by using shims based off of
testing and calibration results
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CCD Thermal Analysis:
• Daytime
– Radiation from sun
• Telescope housing:
– Aluminum
• High albido
• High emissivity
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CCD Thermal Analysis:
• Night/ Operation time
• CCD preferred operating
temperature:
– -20° C
• Heat sink (conduction)
– Contact surface:
• 0.044409 meters squared
– Conduction:
• greater than 9 W.
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CCD Thermal Analysis
• Night/ Operation
time
• Heat dissipated from
telescope housing to
surroundings
– Telescope: 1.652 W
– CCD: 0.106 W
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Testing and Calibration:
• Telescope:
– Focus calibration and component alignment will
be done during the build process using a three
line resolution test.
• A back lit pattern of “slits” is observed with the
telescope through a calumniating lens which will allow
for the optical bench to be properly aligned and
calibrated.
– CCD characterization will begin upon its arrival
and will be accomplished primarily during the
machining phase.
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Testing and Calibration:
Focusing for Flight:
• Using a pinhole LED with known output we will:
– Find the focus point at room temperature at a 10 x 10
defocus.
– Vary the temperature to create plot of number of
pixels in defocus vs. temperature.
– Calculate a function from the defocus data to
determine the defocus needed at flight temperatures.
– Using these results we will cool the telescope to flight
temperature and test the defocus stability.
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Testing and Calibration
• Flux calculations for integration times
– Attain 10 x 10 defocus at arbitrary temperature
(likely room temperature)
– Calculate flux of known light source (LED).
• Find how much light energy falls on aperture
– Vary time periods of exposure to find number of
pixel counts received.
– Determine the pattern on the CCD
• The images will be shaped like doughnuts with the ring
saturating well before the center.
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Testing and Calibration
• CCD temperature dependencies
– Measure dark current of CCD at different
temperatures.
• Each photo will have to have its unique dark current
subtracted from it during data analysis.
– Test CCD heat sink
• Measure the temperature of the CCD while in casing
during operation at different environment
temperatures and compare results with static thermal
test of CCD without heat sink.
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Post Flight Analysis:
• The science data will consist of at least 2,000
images.
– Since conditions will vary during the total
integration time of 30 to 80 minutes; each image
should be individually analyzed or evaluated
before combining.
– Also, depending on the varying star location,
focus, and temperature conditions in each image;
stacking the images may not be possible.
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Post Flight Analysis Continued:
• In order to analyze the data either IDL or IRAF
should be used.
– Both are used by astronomers to analyze images
(arrays of counts).
– Both are available on campus
• Provided the images cannot be stacked:
– First reduce each image
• Subtract the dark noise and background
– Sum the counts for the target star
– Combine the counts, background and dark noise from
all the images and calculate the total SNR.
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Questions?
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Appendices:
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Flux Calculations:
Flux Calculations:
75mm
units
1.2000E-08
[erg/(cm^2 *sec * Ang)]
3.6000E-12
[erg]/photon
Converting to Photons
with average wavelength
of 5500 angstroms
3333.333333
[photons/(cm^2 *sec *Ang)]
Across a 3000 Angstrom
band
1.0000E+07
[photons/(cm^2 *sec)]
4.4179E+08
[photons/sec]
3.9761E+08
[photons/sec]
2.7833E+08
[photons/sec]
Average Flux over R,V,B
bands for a Magnitude 0
Star:
Energy Per Photon (5500
A)
Aperture Light gathering
power
10% loss due to optics
70% quantum efficiency of
CCD
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Original Optical Bench Design:
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Thermal (Appendix):
Change in length due to thermal
expansion where:
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Thermal (Appendix):
Heat transfer of conduction where:
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Thermal (Appendix):
Transfer of heat of radiation where:
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Build Schedule:
25-Mar
27-Mar
3-Apr
10-Apr
17-Apr
24-Apr
1-May
8-May
15-May
17-May
22-May
24-May
29-May
5-Jun
6-Jun
1-Jul
Design and 1/2 of 75mm Mirror Mount
Finish 75mm Mirror Mount
40mm Mirror Mount
Barlow Mount
Symposium
Build CCD Mount
Finish Building Bench/Begin assembly
Finish Assembly/ Align Parts
Finish Assembly/install HASP integration parts/light weight/modify CCD
Mission Simulation
Have telescope ready for Thermal Vacuum Test
Thermal Vacuum Test
Begin testing and calibration phase
Flight Simulation Testing
Complete any further calibrations required
Have Optical System fully calibrated for flight and integrated into platform for
last time
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Budget:
Item
75mm Primary
Lens
75x75mm Mirror
40x40mm Mirror
Orion 2x
Ultrascopic 3element Barlow
Lens
QSI 504ME
1.25 inch
nosepiece
Supplier
Edmund
Optics
Edmund
Optics
Edmund
Optics
Product
Ident
Cost
Mass
In Stock as of
3/19
p45-419
$159.00
Yes
p45-339
$139.00
Yes
p63-167
$59.50
Yes
$93.95
Yes
Orion
Optics
Quantum
Scientific
Imaging
Quantum
Scientific
Imaging
$2,500.00
Total:
$49.00
$500.45
950g
Special Order
Other
Notes:
Donated
Special Order
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