RockSat 2010Harding Flying Bison RockSat-C Rocket Team

Harding University

Ethan Lilly, Eric Locke,

Darah McDaniel, Ed WilsonJune 22, 2011

Ethan LillySoftware Design

Ethan LillySoftware Design

Darah McDanielFabrication &Spectroscopy

Darah McDanielFabrication &Spectroscopy

Eric LockeElectronics &

Testing

Eric LockeElectronics &

Testing

Edmond WilsonFinances & Logistics

Team Mentor

Edmond WilsonFinances & Logistics

Team Mentor

David StairGraphics & Design

Technician

David StairGraphics & Design

Technician

Team Organization

Mission Overview

The goal of this mission is to measure the absorption spectrum of Earth’s atmosphere as a function of altitude using a mini-spectrometer as a science payload onboard a NASA Terrier-Orion rocket that will reach an altitude of 72 miles, the edge of the atmosphere.

Block Diagram of System

LensLensUV/VIS Spectrometer

UV/VIS Spectrometer

Signal Conditioner for

CCD Array

Signal Conditioner for

CCD Array

Embedded Controller with 2 GB Memory

Embedded Controller with 2 GB Memory

PDPDSignal

Conditioner for Photodiode

Signal Conditioner for

Photodiode

G-SwitchG-SwitchPower

Distribution System

Power Distribution

System

Battery Power Supply

Battery Power Supply RBF

Fiber OpticCable

Atmospheric Spectrometer

Spectrometer

Electrical System• The electrical system is composed of three major circuits.

– G-switch and power supply circuit

– Photodiode amplifier circuit

– Spectrometer signal conditioning circuit

G-switch and Power Circuit

V19 V

D11N4001GP

D21N4001GP

J1Key = SpaceR1

100kΩ

R2

10kΩ R310kΩ

R4

10kΩ

R5

10kΩ

LED1

Q2

2N2222A

Q1MTD6P10E

SD

G

Battery x 2(pos)

V29 V

R7100Ω

G-Switch

Battery (neg)U1NCP1117DT50G

VREFOUT 4VS+3

GND

1

C11.0µF

C20.1µF

5V_out

9V_out

Op-amps

RBS

Photodiode Amplifier Circuit

U1

741

3

2

4

7

6

51

U2

7413

2

4

7

6

51

V10.3 V

V29 V

V39 V

R2

1kΩ

V49 V

V59 V

R1

2kΩ

V_outPhotodiode

Spectrometer Conditioning Circuit

U1

741

3

2

4

7

6

51

U2

741

3

2

4

7

6

51

V19 V

V29 V

R1

10kΩ

R280kΩ

V3

R310kΩ

R4

10kΩ

R510kΩ

R6

10kΩ

VoltageFollower

Non-invertingSummer

Spectrometer Output

Battery

Battery

-1 VVout = (Spectrometer output - 1)

A/D converter input range: 0 to +1.25V

Input: +1.3 to +2.1V Output: +0.3 to +1.1V

Sony ILX511 CCD Linear Array Timing Diagram

Fluorescent Light Spectrum

240 340 440 540 640 740 8400

1000000

2000000

3000000

4000000

5000000

6000000

7000000

8000000

9000000

Wavelength (nm)

Experimental Solar Spectrum

240 340 440 540 640 740 8400

1000000

2000000

3000000

4000000

5000000

6000000

7000000

8000000

9000000

Wavelength (nm)

Water Vapor

Oxygen

Integration With Temple University

– Lessons Learned • Fast A/D conversion is necessary for spectroscopy• Communication between disciplines is key in

problem solving

– Advice for Next Year:• Allow time for overcoming problems and testing• Design everything before building• Test everything several times

– What was the hardest part?• Learning to work with a new microcontroller

Conclusions

- We were able to accomplish this project as a team. This project would be very difficult for any one person to accomplish alone.

- We learned a great deal about carrying out a complete project.

- We are proud of our payload and hope to recover valuable data.

Acknowledgement

• Arkansas Space Grant Consortium

• NASA Workforce Development Scholarship Program

• RockSat-C Program

• Wallops Island Flight Facility