Interface Control Document

GreenCube II

Lynch Rocket Lab – Dartmouth College

August 22, 2009

Contact: Kristina.Lynch@Dartmouth.edu Dartmouth College – Dept. of Physics and

Astronomy 6127 Wilder LabHanover, NH 03755

www.dartmouth.edu/~aurora/greencube.html

Contents:

1. Mission Manager 3.

2. Science 4.

3. Flight Performance 5.

4. Mechanical 5.

5. Electrical14.

6. Telemetry15.

7. References16.

1. Mission Manager:

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 - Principal InvestigatorRobyn Millan - Co – InvestigatorKevin Rhoads - EngineerDavid Collins - EngineerRalph Gibson - Systems/MaterialsAmanda Slagle ‘12 - Mission ManagerPhillip Bracikowski - Telemetry/ElectronicsUmair Siddiqui ‘10 - Flight SystemsSean Currey ‘11 - Flight SystemsWilliam Voigt - Logistics/PurchasingJulianna Scheiman ‘11 - Subsystems Technician/ChecklistsMaxwell Fagin - Communications/VideographyBen Feintzeig ‘11 - Payload Recovery Matt Chong ‘11 - Payload Recovery

November 2008

Kristina Lynch - Principal InvestigatorRobyn Millan - Co – InvestigatorUmair Siddiqui ‘10 - Flight Systems/Mission Manager

Kevin Rhoads - EngineerDavid Collins - EngineerBill Brown - Communications/TrackingDave McGaw - Communications/TrackingRalph Gibson - Systems/MaterialsPhillip Bracikowski - Telemetry/Data AcquisitionLouis Buck ‘10 - Electronic SystemsJulianna Scheiman ‘11 - Logistics/Assembly/ChecklistsMaxwell Fagin - Design Artist/PurchasingTommy Du ‘10 - Recorder/PhotographerMeghan Mella - Launch Assistance

June 2008

Dr. Kristina Lynch – Principal InvestigatorRobyn Millan – Co-InvestigatorKevin Rhoads – EngineerDavid Collins – EngineerDavid McGaw – EngineerBill Brown – Communications/TrackingParker Fagrelius – Mission Manager/Undergraduate

Phil Bracikowski ‘08 –Telemetry/ Electronics/ Undergraduate

Umair Siddiqui ‘10 – Flight Systems/ UndergraduateClaire McKenna ‘10 – Undergraduate

Julianna Scheiman ‘11 –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 Science:

2.1 Goals

2.1aShort-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 low-earth-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.

3 Flight performance:

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. Mechanical:

According to the requirements determined by the CalPoly group, a CubeSat cannot exceed 1 kg. or occupy more than 1000 cm3. Our payload is effectively three of these stacked on one another, thus it should not exceed 3 kg. and 3000 cm3. Our payload occupies

almost exactly 3000 cm3 of space, and has a mass of 2.0 kgs.

Specifications:

4.1 Box

Mass: kgsVolume: 3000 cm3

Materials: AluminumAssembly: 6 individual panels and 4 corner rods attached with

(24) 3-56 flat head screws.

4.2 Magnetometer

Mass: negligibleVolume: 7.40 x 7.40 x 2.50 mmMaterials: n/aAssembly:

Diagram:

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.

4.3 Thermistors

There will be 6 thermistors with the same mechanical propertiesin the payload. We will be using the PS502J5 purchased from US Sensor.

Mass: insignificantVolume: see diagramMaterials: plasticAssembly: 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 gVolume: 33.56 mm × 45.85 mm × 8.31 mmMaterials: n/a

Assembly:The GPS is screwed into one of the sidewalls of the CubeSat.

Diagram:

4.5 GPS Antenna GA 25MCXMass:n/aVolume: 2.75" × 2" × .75" with 8ft of cable Materials: PlasticAssembly: 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 kgsVolume: 1.9” x 3.2” x 0.9”Materials: n/aAssembly: 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.

Diagram:

4.7 Batteries

Mass: 250.1 gramsVolume: 128 cubic cmMaterials: Lithium ion batteries, plastic packagingAssembly: 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 gramsVolume: 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 m3

Materials: LatexAssembly: 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: 0.71 kgsVolume: n/aMaterials: rip-stop nylonAssembly: 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:

Balloon

Parachute

Payloads

5. Electrical:

Electrical system data is given below:

Systems: Voltage PowerMagnetometer +/-12 n/aThermistors +12 n/aGarmin GPS 15H-W +8.0 – 40.0 280 – 459 mW

ComputerConvert +28 to +/- 12 & n/a+5

5.1 MagnetometerThe 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.

6. Telemetry

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 StationsEach 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 TNCEach ground station will use a Tracker2 T2-135 or an Alinco EJ41-U TNC.

EJ 41-U T2-135

6.1b AntennaThe antenna used for each ground station is an MFJ-1728B 2/6 meter dual band mobile antenna.6.1c ComputerEach 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 PowerEach radio is powered by a fresh 12V car battery.

7. References:

Link to Cubesat Design Specification –

http://cubesat.atl.calpoly.edu/pages/documents/develo

pers.php Images –

http://the-rocketman.com/chutes.html#chute%20specs

http://www.universal-radio.com/catalog/ht/3003.jpg&i

mgrefurl

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