Transcript 2009 Olin Student Projects

2010 Olin Student Projects
Keith Gendreau
[email protected]
301-286-6188
Fred Huegel
[email protected]
301-286-2285
Kurt Rush
[email protected]
301-286-1196
Bob Baker
[email protected]
301.286.9882
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
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
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
Terrier Mk70
A 1st approximation of complete XACT rocket
X-ray
Concentrators
& Star Tracker
Overall Payload Length: 3.26 m
Payload Diameter: 52 cm*
Payload Mass: 80.2 kg (include ST)
Very Basic XACT
Block Diagram
Rocket
Avionics
System
Unregulated
28 V power
XACT Main
Electronics Node
(XMEN)
Telemetry
Interface
PEB 1
PEB 2
PEB 3
LVPS
Regulated
power
Regulated
power
HK
SRIB
HVPS
IN FLUX..
Will define, but
may be a bit
bigger
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?
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
The World’s First Fully
Controllable Modulated
X-ray Source
LED: Modulate This to
modulate the x-rays.
Optical
Photons
X-ray Photons
Vacuum Flange
Photoelectrons
Electron Target
Photocathode
•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 keV or more
This has evolved to include an
electron multiplier
LED
HV for
Target
(~5-10 kV)
HV for
Electron
Multiplier
(~2-3 kV
1st Magnum Multiplier MXS
Electron
Target HV
Multiplier HV
Be Window
Electron
Target HV
Multiplier HV
Be Window
AMPTEK
Detector
Some 1st Data
Output of
AMPTEK
Detector
Pulses
Modulating
X-ray
Output
Block Diagram
USB
Computer
“Smarts”
LED
Driver
LED
HV
Multiplier
(DC/DC
Converter)
HV Target
(DC/DC
Converter)
Source
(provided
by GSFC
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
House Keeping Items
• LED current (average, max)
• LED temperature (necessary?)
• HV current (or atleast current and
voltage into various DC/DC converters)
“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?
Replace this guy with a
high speed optical
modulator and an
ethernet port.
Replace this guy with a
avalanche photodiode
and an ethernet port..
Replacing the guy wiggling the
mirror
• Voltage Controlled LCD displays (KHz
Speeds?)
• Acoustic Optical Modulators (speeds up
to 100 MHz)
Replacing the guy using his
eye to see the signal on the
receive end
• Avalanche Photo diodes
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
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?
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.
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.