2010 Olin Student Projects

1. 2010 Olin Student Projects Keith Gendreau Keith.c.gendreau@nasa.gov 301-286-6188 Fred Huegel frederick.g.huegel@nasa.gov 301-286-2285 Kurt Rush Kurt.d.rush@nasa.gov 301-286-1196 Bob Baker Robert.g.baker@nasa.gov 301.286.9882

2. 2009 Student Projects with contacts • XACT Sounding Rocket Low Voltage Power Supply Point Design • Keith Gendreau, Kurt Rush, Fred Huegel, Bob Baker • Modulated X-ray Source Controller • Keith Gendreau

3. Project #1, XACT Low Voltage Power Supply Point Design • We are in the initial phases of designing and building a suborbital rocket payload to do astrophysics • The detectors and command & data handling units need regulated low voltage power derived from “28 Volts” from Rocket battery • Do a point design of a Low Voltage Power Supply (LVPS) and build a prototype • Take Electrical and mechanical requirements of LVPS • Include basic housekeeping functions • Build a command tester

4. XACT Payload and Rocket Nose Cone & Recovery System X-ray Polarimeters, Electronics, & MXS Telemetry and ACS Systems Aft Cone & Door Optical Bench Black Brant VC X-ray Concentrators & Star Tracker Terrier Mk70 Overall Payload Length: 3.26 m Payload Diameter: 52 cm* Payload Mass: 80.2 kg (include ST) A 1st approximation of complete XACT rocket

5. Very Basic XACT Block Diagram PEB 1 XACT Main Electronics Node (XMEN) Rocket Avionics System Regulated power PEB 2 PEB 3 LVPS Unregulated 28 V power Regulated power HK Telemetry Interface SRIB HVPS

6. IN FLUX.. Will define, but may be a bit bigger

7. Other details • We will soon specify connectors for the power output and HK address and data • HK should include actual voltages and currents and some temperatures of items which may get warm • Look in digikey and elsewhere for cheap, but robust converters and parts.. • Some specify shock and vibration ratings • Can you make a USB based card that would allow us to query for HK?

8. Olin student Project #2: Modulated X-ray Source Controller • Our new modulated X-ray source uses UV light to generate photoelectrons which are accelerated into high voltage targets to make X-rays • We like to have absolute control of the X-ray flux, which is driven by absolute control of the UV light (from LEDs) • Olin student project: build an X-ray source electronics box which • provides HV • Drives UV LED with arbitrary flux output • Measures currents, temperatures • Is USB controlled with PC or mac software

9. The World’s First Fully Controllable Modulated X-ray Source • Characteristics: • Rugged- no moving parts or fragile filaments- perfect for space flight. • Modulates x-rays at same rate that one can modulate an LED • Major NASA Uses: • Timing Calibration • A “flagged” in-flight Gain Calibration Source: Have calibration photons only when you want them and increase your sensitivity by reducing the background associated with the calibration photons

10. This has evolved to include an electron multiplier LED HV for Target (~5-10 kV) HV for Electron Multiplier (~2-3 kV

11. 1st Magnum Multiplier MXS Electron Target HV Multiplier HV Be Window Electron Target HV Multiplier HV Be Window AMPTEK Detector

12. Some 1st Data Output of AMPTEK Detector Pulses Modulating X-ray Output

13. Block Diagram LED Computer LED Driver Source (provided by GSFC USB HV Multiplier (DC/DC Converter) “Smarts” HV Target (DC/DC Converter)

14. Commands from computer • HV target voltage (0-10 kV) • Use EMCO Q series dc/dc converter with a dac and transistor follower • HV multiplier voltage (0-3 kV) • Use EMCO Q series dc/dc converter with a dac and transistor follower • Arbitrary LED flux as a function of time • Asci file? • Pulsed LED flux • Frequency, duty cycle or width, amplitude • Query for housekeeping

15. House Keeping Items • LED current (average, max) • LED temperature (necessary?) • HV current (or atleast current and voltage into various DC/DC converters)

16. “i-Heliograph” • Can we make a low power data transmitter to send “lots” of data from the moon to the earth using a 19th century idea enhanced with 21st century technology? • How does such a system compare to laser communication?

18. Replace this guy with a avalanche photodiode and an ethernet port.. Replace this guy with a high speed optical modulator and an ethernet port.

19. Replacing the guy wiggling the mirror • Voltage Controlled LCD displays (KHz Speeds?) • Acoustic Optical Modulators (speeds up to 100 MHz)

20. Replacing the guy using his eye to see the signal on the receive end • Avalanche Photo diodes

21. There should be a power savings compared to Laser Comm • Lasers are ~10% efficient on producing optical output from electricity it gathers from ~25% efficient solar cells. • Total efficiency from sun = 0.25 * 0.1 = 2.5% • Mirrors are ~90% reflective

22. Other factors in comparison • Mass to moon • Do solar cells and power system with Laser weigh more than a mirror and heliostat? • Reliability • Solar panels, motors, AOMs… • Is dust an issue?

23. 2009 Olin Job • Build a Heliostat to capture the sun • Pipe the light from the Heliostat through either an accoustic optical modulator or a LCD retarder • Build a simple pulse frequency modulator to drive the AOM or LCD retarder • Build a demodulator to read the output of an APD • Predict performance and compare to Laser Comm.

24. GSFC will provide • A telescope base to make a heliostat • An AOM to modulate light • A Circuit design to produce a FM Pulse train • A Telescope for the receive end • An APD (maybe dual use the one for the MCA project) • The demodulator design.