www'goshenhs'orgdeptscience

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Goshen High School NASA SLI Rocket Team Critical
Design Review

• www.goshenhs.org/dept/science
• February 1, 2005

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Mission Objectives

• The rocket achieves an altitude of one mile
• All Recovery Systems Work Correctly
• IR Sensors Collect Usable and Meaningful Data
  about water vapor concentration in the atmosphere
• No Major System Failures Occur

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Organizational Chart
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The Vehicle

• The diagram above shows the RockSim image of our
  rocket. This design is based on last years SLI
  rocket. Our rocket this year will be built from
  2.56 fiber glassed airframe and be slightly
  shorter and considerably less massive than last
  years rocket.

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Design and Construction

• Our rocket is being constructed using 2.56
  tubing that has been strengthened with fiberglass
  and epoxy.

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Systems OverviewPropulsion

• We are planning to use Cesseroni Pro 38
  reloadable motors, with the size depending on the
  final mass of the rocket and the thrust
  requirements to reach the target one mile
  altitude.
• We anticipate practice flights with I205
• and I285 motors and plan on a final flight with
  a J330.

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System OverviewRecovery

• We will be using the Public Missiles Ltd.
  Co-Pilot Altimeter. The Co-Pilot will deploy the
  drogue chute and payload at apogee and the main
  chute at 500ft AGL.

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System OverviewRecovery

• A Perfect Flite Minitimer3 is installed next
  to the Co-pilot and will serve as a backup for
  the copilot, to ensure drogue and payload
  parachute deployment.

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System OverviewRecovery

• We will use RockSim 7.0 to determine the
  appropriate chute size.
• We want the rate of descent to be between 10 and
  20 ft/s, 20 ft/s being the maximum tolerable rate
  of descent this is due to the significant value
  of the payload.

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System OverviewRadio Tracking System

• Our rocket will contain 2 radio beacons.
• An Adept T400 in the launch vehicle.
• A 147 MHz beacon in the payload.

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System OverviewData Collection

• Our rocket will contain one AED Electronics RDAS
  unit for data collection.

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Testing

• We have built an Aerotech Tomahawk kit which we
  have flown using an Aerotech F50 and plan to fly
  it again using a G80 to test the recovery and
  prototype payload systems.
• We will be flying our main rocket several times
  at local launches to make final component and
  system tests.

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This chart shows data gathered from an IR and a
visible light sensor on our prototype payload,
when exposed to sunlight. The sensors were moved
in a manner that attempted to simulate the
swinging motion of the payload as it would have
moved while descending under the parachute.
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Flight Checklist
At School Assemble nose cone Shock cord
parachute folded Prep e-match with payload bay
ejection charge Drill Pro 38 delay grain to
desired delay Load motor in aluminum casing Make
sure launch rail is clean At Launch Site Before
assembly check Co-Pilot Battery Fresh 9.4V
alkaline battery Check radio beacon battery
12.1v Set up launch rail Load rocket on rail Turn
on Co-Pilot arm Turn on radio beacons Turn on
radio receivers
At Launch Site (cont.) Make sure signal is
present Load igniter Connect igniter to
ignition system Check sky for aircraft Members
should be 100 ft away from rocket Members in
surrounding area for rocket recovery Countdown
5 count Launch rocket Use radio beacon for
recovery Turn off radio beacon Turn off
Co-Pilot Load all materials return to school
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Flight Checklist (cont.)
At School Unload materials Retrieve data Analyze
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Safety and Failure Analysis

• Potential failures include
• Loss of Rocket Engine Misfires
• Airframe failure Recovery Failures

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Safety Risk Plot
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Risk Plot Cont.
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Payload Objective

• The objective of this payload is to measure the
  absorption of near IR radiation in the wavelength
  region close to 900 nm. This region has
  significant water vapor absorption, which will
  allow us to see the effect of water vapor on IR
  absorption as the payload descends.

R-DAS in center, sensors on end, kevlar cord will
be attached to the parachute.
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Payload Educational Value

• 50 of the water vapor in the atmosphere is
  located in the first mile. Over the distance of
  one mile, we should be able to measure a
  difference in the absorption of solar radiation
  by water vapor. Measurements will be made with a
  detector (Sharp PD49PI ) that has a maximum
  sensitivity in the 900 1000 nm region of the
  near IR. We are expecting to see a 10 change in
  IR signal strength over the whole of our flight,
  more or less depending on the humidity.

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Payload Integration
We plan to locate the payload in the top section
of the rocket and plan to attach the payload
section to the nosecone via screws. The IR and
visible light sensors will be located at the base
of the nosecone / payload section, so that it
will point at the sky during descent. This
arrangement will allow the sensors to best obtain
data. Above the sensors (when rocket is vertical
on the pad) will be other flight electronics such
as the radio beacon, thermocouple temperature
board, and the R-DAS. All of these electronics
will be built into a plywood frame, which will
allow easy access and setup of the payload. The
payload section of the rocket will descend under
its own parachute, separately from the main
portion of the rocket.
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Payload Electronics

• Infrared Sensors - Inexpensive photodiodes
• Sharp PD49PI with peak sensitivity at 1 micron
  (900-1050 nm)
• Sensor output recorded by RDAS
• Visible Light Sensor
• a. Sharp BS120 with peak sensitivity at 560
  nanometers
• Sensor output recorded by RDAS
• A LM324 Quad Op-Amp serves to amplify the signal
  from the sensors so that it can be recorded by
  the RDAS
• Thermocouple - to measure air temperature

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Payload Testing

• Currently, we are testing the payload using an
  Aerotech Tomahawk.
• Testing has included work with different light
  sources.

This chart shows the data gathered from the new
payload sensors, which will be used for
collecting data on the flight to an altitude of
one mile.
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Payload Safety Risks
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Activity Plan

• Build an Aerotech 1.9 Tomahawk kit (done)
• Fly Aerotech Tomahawk on a F50-9 motor payload
  prototype. (done) The sky was uniformly overcast
  so no useable data was collected. It was good
  experience for this years group.
• Fly the Tomahawk on a G80-7 motor with full
  payload prototype
• Build 2.56 model with a design similar to last
  years project. We plan to build a slightly
  smaller rocket than last year and a less massive
  payload so that the one mile target altitude can
  be reached with a smaller motor, such as a J330
  (38 mm).
• Fly the 2.56 model at Three Oaks, MI and/or
  locally at the Elkhart County Fairgrounds with a
  special FAA waiver.
• Analyze the data. Publish the data in a physics
  or rocket magazine if it is scientifically
  interesting.

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Summary

• There is still a lot of work to do with the
  construction and testing of our new rocket. The
  rocket has been designed and we are now in the
  process of constructing it. The payload has been
  assembled, tested, and is fully operational. We
  would like to have another practice flight of our
  Tomahawk rocket to experience launching and
  analyzing the data. Because all of the SLI
  members from last years project were seniors, we
  are using their reports and design as a guide for
  our own rocket and working to build an experience
  base to insure mission success.