Team ZephyrCritical Design Review

Joseph Sheehey, Huy Le, Andrew Zizzi, Alex Morrow, Sam Evans, Logan Wright

October 14, 2008

Mission Overview

• The BalloonSat Zephyr shall ascend to an altitude of approximately 31,000 meters and perform measurements on internal and external temperature, relative humidity, and ambient sky brightness between the ranges of 380 nm to 740 nm and 875 nm to 980 nm. The science of this mission exists to better understand the optimal wavelength range high altitude observatories should utilize.

• Hypothesis– Infrared and UV ambient light will increase with altitude– Visible spectrum light will decrease with altitude

Objective Requirements• BalloonSat Zephyr shall not exceed one kilogram in mass and shall

be completed by October 30, 2008. The cost of materials not including those provided by Space Grant shall not exceed $150.

• The BalloonSat shall measure ambient sky brightness in watts/meter2 using LED photometers throughout the ascent of the flight and record this data on HOBO dataloggers.

• The BalloonSat shall fly a powered resistance heater during the entire flight.

• The Canon A570IS shall be programmed to take images every ten seconds during the ascent of the balloon.

• BalloonSat Zephyr shall fly a HOBO with an internal relative humidity and internal temperature probe as well as an external temperature probe that shall protrude from the foamcore structure to provide an accurate reading.

• Team Zephyr shall approximate ascent and descent rates during the flight by comparing recorded external temperature data to known atmospheric temperature profiles.

System Requirements• BalloonSat Zephyr shall be constructed from lightweight foam composite

material and shall be manufactured in a simple process that is capable of withstanding the forces experienced during flight so that it can fly again.

• The BalloonSat shall fly ten different colors of LEDs covering the aforementioned wavelength ranges. There shall be five LEDs of each color that are wired in series with a known resistance and connected to a HOBO data logger voltage input channel. The three four-channel HOBOs shall be programmed to record voltage levels for each LED string at simultaneous ten second intervals.

• The heater shall be powered by three nine-volt batteries from immediately before takeoff until retrieval.

• All images from the Canon A570IS shall be stored on a two GB SD memory card. The firmware of the camera shall be programmed to take an image every ten seconds after the camera has been turned on until the memory card is full.

• The temperature and relative humidity HOBO shall be programmed to take and record data readings every ten seconds from launch until retrieval.

• Team Zephyr shall compare temperature data from the HOBO to recorded atmospheric temperature profiles with respect to time to determine the average ascent and descent rates of the BalloonSat.

Design

• One-directional diode in LED produces a current when hit by a photon of correct wavelength

• Power = V2/R

• Area = 5(ALED) = 98.2 mm2

• Intensity = P/A = Watts/meter2

• Voltage varies with intensity and resistance varies with temperature

Experiment Hardware

• Parts

• Ten to fifteen LEDs of each color (spares included for testing and backup)

• Electrical wire

• Straws

• Four 4-channel HOBOs

• Temperature independent resistors

Design Drawings

Design Drawings

Functional Block Diagram

BudgetComponent Mass Price Part Number Vendor Name

Structure 145g $0.00 - Space Grant

Camera 222g $0.00 Canon A570 IS Space Grant

HOBO 29g $0.00 H08-007-02 Space Grant

HOBO (3) 90g (~29g ea.) $0.00 H08-006-04 Space Grant

Heater 15g $0.00 - Space Grant

9V Batteries (3) 140g (~46g ea) $0.00 - Space Grant

Camera Filter 15g $11.40 MISL40.5 B&H Photo Video

Wiring 100g - - -

LED's (5 of each color are flight, the rest are backup,) Mass is for Flight Hardware only

IR (10) 1.5g (~.3g ea) $12.40 RL5-IR2730 SuperBrightLEDs

Red (15) 1.5g (~.3g ea) $7.85 RL5-R12120 SuperBrightLEDs

Orange (15) 1.5g (~.3g ea) $4.10 RL5-O4030 SuperBrightLEDs

Yellow (15) 1.5g (~.3g ea) $7.85 RL5-Y12120 SuperBrightLEDs

Green (15) 1.5g (~.3g ea) $8.60 RL5-G16120 SuperBrightLEDs

Aqua (15) 1.5g (~.3g ea) $7.85 RL5-A7032 SuperBrightLEDs

Blue (15) 1.5g (~.3g ea) $8.60 RL5-B12120 SuperBrightLEDs

Violet (15) 1.5g (~.3g ea) $13.40 RL5-V1015 SuperBrightLEDs

Ultraviolet (15) 1.5g (~.3g ea) $14.40 RL5-UV1230 SuperBrightLEDs

White (15) 1.5g (~.3g ea) $10.20 RL5-W15120 SuperBrightLEDs

Totals 771g $106.65

Schedule

• Major Deadlines– October 18th Whip Test– October 25th and 26th Final Construction and

Experiment Integration– October 30th - Cold Test– November 4th – Mission Simulation– November 14th – Final Weigh-in and

BalloonSat Turn-in– November 15th - Launch

Test Plan

• Drop Test – October 9th– Completed

• Stair Test – October 9th– Completed

• Whip Test – October 18th• Light Intensity Test – October 30th

– To calibrate LEDs

• Cold Test – October 30th– Examine change in resistance with respect to temperature– Determine timing interval for camera measurements– Test thermal subsystem

Biggest Worries

• Finishing Integration on Time

• Wiring of LED Photometers surviving flight Forces