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H.A.S.P. SPARTAN-V Mission Specialist Team: Anthony Cangelosi Chris Nie 1 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. 2 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. 3 HASP SPARTAN-V Design: Image/Design Credit: Jeff Byrne, Structures Team 4 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 5 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 6 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. 7 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 8 Telescope Design 9 Telescope Design 10 Telescope Optical Bench Design: 11 Telescope Optical Bench Design: 12 13 14 15 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. 16 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 17 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. 18 19 20 21 22 Star Candidates (cont.) • Heaviest density of stars expected to be in following constellations: – Aquila – Scutum – Ophiuchus – Hercules 23 Telescope Thermal Considerations: 24 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 25 CCD Thermal Analysis: • Daytime – Radiation from sun • Telescope housing: – Aluminum • High albido • High emissivity 26 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. 27 CCD Thermal Analysis • Night/ Operation time • Heat dissipated from telescope housing to surroundings – Telescope: 1.652 W – CCD: 0.106 W 28 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. 29 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. 30 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. 31 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. 32 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. 33 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. 34 Questions? 35 Appendices: 36 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 37 Original Optical Bench Design: 38 Thermal (Appendix): Change in length due to thermal expansion where: 39 Thermal (Appendix): Heat transfer of conduction where: 40 Thermal (Appendix): Transfer of heat of radiation where: 41 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 42 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 43