GreenCube II
August 22, 2009
Contact: Kristina.Lynch@Dartmouth.edu
Dartmouth
College – Dept. of Physics and Astronomy 6127
Wilder Lab
Hanover, NH 03755 www.dartmouth.edu/~aurora/greencube.html

1.
Mission Manager
2.
Science
3.
Flight Performance
4.
Mechanical
5.
Electrical
6.
Telemetry
7.
References
3.
4.
5.
5.
14.
15.
16.

1.1
General Description:
The undergraduates of the Lynch Rocket Lab, with the help from professors and professionals, are constructing a payload similar to a “CubeSat” developed at California Polytechnic and Stanford Universities. Our group is developing a sensor craft that is effectively three times the size of the typical
CubeSat, giving us more space to meet our science requirement. In June 2008 a prototype payload, which contained only GPS and radio systems, flew on a bursting balloon that reached approximately 90,000 ft. in the air before falling back to earth with a parachute. The total flight took no longer than one hour.
In November of 2008, we conducted a second launch using the actual payload, which flew with the K111 board, thermistors, and a magnetometer.
In August of 2009, we will attempt a third launch. The upcoming launch will differ from previous flights because we will launch two balloons in succession rather than just one.
1.2
Personnel:
August 2009
Kristina Lynch
Robyn Millan
Kevin Rhoads
David Collins
Ralph Gibson
Amanda Slagle ‘12
Phillip Bracikowski
-
-
-
Principal Investigator
- Co – Investigator
- Engineer
Engineer
- Systems/Materials
- Mission Manager
Telemetry/Electronics
- Flight Systems
- Flight Systems
- Logistics/Purchasing
- Subsystems Technician/Checklists
Umair Siddiqui ‘10
Sean Currey ‘11
William Voigt
Julianna Scheiman ‘11
Maxwell Fagin
Ben Feintzeig ‘11
Matt Chong ‘11
November 2008
Kristina Lynch
Robyn Millan
Umair Siddiqui ‘10
- Communications/Videography
- Payload Recovery
-
-
-
-
Payload Recovery
Principal Investigator
Co – Investigator
Flight Systems/Mission Manager

Kevin Rhoads
David Collins
Bill Brown
Dave McGaw
Ralph Gibson
Phillip Bracikowski
Louis Buck ‘10
Julianna Scheiman ‘11
Maxwell Fagin
Tommy Du ‘10
Meghan Mella
June 2008
Dr. Kristina Lynch
Robyn Millan
Kevin Rhoads
David Collins
David McGaw
Bill Brown
Parker Fagrelius
Phil Bracikowski ‘08
Umair Siddiqui ‘10
Claire McKenna ‘10
Julianna Scheiman ‘11
-
-
-
-
-
-
-
–
–
Engineer
Engineer
Communications/Tracking
Communications/Tracking
Systems/Materials
Telemetry/Data Acquisition
Electronic Systems
- Logistics/Assembly/Checklists
- Design Artist/Purchasing
- Recorder/Photographer
- Launch Assistance
– Principal Investigator
– Co-Investigator
– Engineer
– Engineer
– Engineer
– Communications/Tracking
– Mission Manager/Undergraduate
– Telemetry/ Electronics/ Undergraduate
– Flight Systems/ Undergraduate
Undergraduate
Subsystems Technician/ Undergraduate
1.3 Subsystems:
The payload will carry several instruments: a Garmin GPS 15H-W, a
Honeywell HMC-1053 magnetometer, and five PS-series thermistors made by
US Sensor. Our circuitry and interface board will convert the analog inputs of these instruments into digital information, format and send it out as an asynchronous data stream. We hope to keep in constant communication with our payload using an Alinco DR – 135 Radio with either a Tracker2 or an
Alinco EJ41-U TNC.
1.4
Flight
Before launching, we use a program developed by Edge of Space Sciences
(www.eoss.org) to determine the balloon’s probable course due to the current weather. We track our balloon and payload using the GPS information we receive until the payload drops below the horizon of contact with the HAM

receivers. Our payload will have an Emergency Locater Transmitter transmitting on 121.775 for further assistance in tracking.
1.4a
Success Criteria



Minimum:


Collect an altitude vs. velocity profile from at least one payload


Achieve burst altitude of at least 70,000 ft


Land within 30 mi radius of expected landing zone



Comprehensive:

Achieve burst altitude of 90,000 feet


Track payload using GPS for the entirety of the flight


Receive data from the magnetometer and thermistors over the course of the whole flight 
 Produce altitude vs. temperature and altitude vs. velocity profiles for both payloads 
 Collect HD footage of the launch and ascent 

Locate and recover both payloads after landing

1.4b
Launch Criteria

Surface winds gusting <= 7 knots


Skies <= 1/2 coverage


No precipitation


Acceptable trajectory and landing location verified using BallTrack software from eoss.org

2.1
Goals
2.1a
Short-term goals

Collect and understand data pertaining to gravity waves

2.1b
Long-term goals
Phillip Bracikowski is working on adjusting the GreenCube design such that it will fit on a P-Pod deployer, which is a mechanism that allows
GreenCube-sized objects be cheaply deployed into space from rockets.
When this project, RocketCube, is complete, its long-term applications will

take two forms. First, the CubeSat prototype will be applicable to the
Lynch Rocket Lab’s auroral sounding missions. The Lynch Rocket Lab is interested in the release of approximately eight 10” sub payloads from a main payload rocket to be launched in conjunction with the NSF PFISR radar from Poker Flat Alaska. The 8 sub payloads will be launched together on one main spacecraft. This mission would be for the investigation of the k-spectrum of density irregularities in the auroral ionosphere, which will be measured with plasma density probes.
Second, the CubeSat design will be used Robyn Millan’s laboratory at
Dartmouth College. They will be using the payloads as satellites in lowearth-orbit measurements of relativistic electrons in the radiation belts in order to measure the loss of these particles to Earth's atmosphere.
2.2
Experiments




A magnetometer will be used as an attitude sensor.


Thermistors will be used as stand-in sensors for plasma density probes, but will be used on this flight to monitor the atmospheric temperature outside of our payload in order to help us detect gravity waves.


GPS will be used for position and temporal information and aid in tracking the payload. It provides velocity data for gravity waves.


The computer will convert all analog data from all sensors, of which there will be 7-9, clock and frame and send it out as an Asynchronous data stream to the modem and radio.


The balloon is flown from either Newport, VT or Mt. Washington Regional
Airport. The location and date of the launch is dependent upon winds and weather. In order to determine the flight path of the balloon, we will be using software developed by Edge of Space Sciences. The balloon will ascend to a maximum altitude of between 77,000 and 100,000 ft., ascending approximately 1000 ft/min. before bursting. The payload and accompanying parachute should take just 40 minutes to reach the ground after bursting, and the whole flight shouldn’t last longer than 2 hours.
4.
According to the requirements determined by the CalPoly group, a CubeSat cannot exceed 1 kg. or occupy more than 1000 cm 3 . Our payload is effectively three of these stacked on one another, thus it should not exceed 3 kg. and

3000 cm 3 . Our payload occupies almost exactly 3000 cm 3 of space, and has a mass of 2.0 kgs.
Specifications:
4.1
Box
Mass: kgs
Volume: 3000 cm 3
Materials: Aluminum
Assembly: 6 individual panels and 4 corner rods attached with (24) 3-56 flat head screws.
4.2
Magnetometer
Mass: negligible
Volume: 7.40 x 7.40 x 2.50 mm
Materials: n/a
Assembly: The magnetometer is a Honeywell HMC1053. It has been soldered to a circuit board with an op amp and attached to a sidewall of the main box.
Diagram:

4.3
Thermistors
There will be 6 thermistors with the same mechanical properties in the payload. We will be using the PS502J5 purchased from US
Sensor.
Mass: insignificant
Volume: see diagram
Materials: plastic
Assembly: The thermistors were originally black, but the body of each thermistor has been painted with Sherwin Williams white appliance epoxy to avoid solar heating that would distort temperature readings.
Diagram:
4.4 GPS
We will be using a Garmin 15H-W GPS.
Mass: 14.1 g
Volume: 33.56 mm × 45.85 mm × 8.31 mm
Materials: n/a
Assembly: The GPS is screwed into one of the sidewalls of the CubeSat.
Diagram:

4.5
GPS Antenna GA 25MCX
Mass: n/a
Volume: 2.75" × 2" × .75" with 8ft of cable
Materials: Plastic
Assembly: The antenna is mounted to the outside of one of the endwalls of the CubeSat.
Diagram:
4.6
Radio
A Yaesu VX -3R radio transmitter is used to relay data from the CubeSat to the ground.
Mass: 0.13 kgs
Volume: 1.9” x 3.2” x 0.9”
Materials: n/a
Assembly: The radio with three double A batteries in the FBA-37 battery case is attached inside a sidewall of the CubeSat. The antenna protrudes outside the CubeSat.

4.7
Diagram:
Batteries
Mass: 250.1 grams
Volume: 128 cubic cm
Materials: Lithium ion batteries, plastic packaging
Assembly: The main battery pack is made in house of 16 Energizer lithium ion double A batteries soldered in series to obtain a voltage of 24-
28V for the computer. It is sealed in plastic packaging and tied to the inside of the CubeSat. To power the radio, 3 double A batteries are used in the FBA-37 battery case that is an accessory to the VX-3R radio.
4.8 TNC
A Tracker 2 ot2m is used to help transmit the data coming out of the computer.
Mass: 10 grams
Volume: 4.2 x 3.2”
Materials: n/a
Assembly: The tracker 2 is fixed to a inside wall of the CubeSat.
It is taken out of its original encasing and left as just a circuit board.

Diagram:
4.9
Balloon:
A Kaymont KCL 1200 sounding balloon is used to carry the payload. The two balloons are filled with a total of 6 tanks of BL300 helium ordered from
Airgas.
Mass: 1200 gr.
Volume: 2.99
Materials: Latex m 3
Assembly: The balloon is tied shut, and tied to the top of the flight train.
Diagram: n/a
4.10 Parachute:
A Rocketman 8-ft diameter parachute is used to slow the descent of the payload after balloon burst.
Mass:
Volume:
0.71 kgs n/a
Materials: rip-stop nylon
Assembly: The chute is tied on the bottom end to the payloads, and

at the top to the balloon.
Diagram:
4.11 Cameras:
Each balloon will be equipped with a camera to capture video of the launch and flight. The first camera is a side looking FlipVideo HD, and the other is a downward looking Panisonic miniDV SD.
Assembly: The Flip Video camera uses a custom battery pack to allow
2+ hours of recording.

The total flight train is assembled as shown below:

Electrical system data is given below:
Systems:
Magnetometer
Thermistors
Garmin GPS 15H-W
Computer
Voltage
+/-12
+12
+8.0 – 40.0
Power n/a n/a
Convert +28 to +/- 12 & n/a
+5
280 – 459 mW
5.1 Magnetometer
The magnetometer is connected to a preamp as shown in the following diagram. The six inputs are the positive and negative voltage outputs from each axis of the magnetometer.
The magnetometer is powered by +/-2.1V, which is obtained by passing +/-12V through 10k resistors.

5.2 Thermistors
The thermistors are attached to our circuit as follows:
In this diagram, R3 is the thermistor. It is set up as part of a voltage divider with
R1 (5.1 M ohms) in order to output a voltage between 0 and 5V when given a 12V input. The resistance of the thermistors increases exponentially as temperature decreases, so resistance is very low at room temperature. R2 (15k ohms) is added in series with the thermistor to increase the total resistance enough to give a nonzero reading at room temperature.
Each GreenCube box contains a Yaesu VX-3R radio which hopefully will be used to maintain constant communication between the payloads and the teams on the ground. One radio will transmit on the frequency 144.330 and the other on
144.430. The radios are each connected to a Tracker2 TNC which is programmed to transmit GPS data once every 5 seconds. Magnetometer and thermistor readings will be transmitted as often as they are received by the TNC, which is once every 10 seconds.
6.1 Ground Stations
Each ground station consists of a computer connected to two Alinco
DR-135 mobile radios, each with a built-in TNC that is connected to an antenna. Two radios are necessary for each ground station because each payload will be transmitting on a different frequency. There are two ground stations – one each for the launch and recovery teams.
6.1a TNC
Each ground station will use a Tracker2 T2-135 or an Alinco EJ41-U
TNC.

EJ 41-U T2-135
6.1b Antenna
The antenna used for each ground station is an MFJ-1728B 2/6 meter dual band mobile antenna.
6.1c Computer
Each mobile radio is connected to a Dell PC through an RS-232 serial cable. We will use the software program RealTerm to observe and record the data received by each radio. Each computer also contains the file otwincfg.exe, which is used to program the Tracker2 modems.
6.1d Power
Each radio is powered by a fresh 12V car battery.
Link to Cubesat Design Specification – http://cubesat.atl.calpoly.edu/pages/documents/developers.php
Images – http://the-rocketman.com/chutes.html#chute%20specs http://www.universal-radio.com/catalog/ht/3003.jpg&imgrefurl http://www.magneticsensors.com/pictures_comp.html
http://www.manventureoutpost.com/marine/images/cw/25238.gif
http://www.ussensor.com/prod_inter_std_a.htm
http://ecx.images-amazon.com/images/I/31mz1qlqGPL._SL500_AA280_.jpg
http://www.universal-radio.com/CATALOG/fm_txvrs/2014lrg.jpg

http://www.argentdata.com/images/opentracker-t2-135.jpg
http://www.emsi.se/webshop/images/opentracker-ot2m-board.jpg&imgrefurl