Boston University

Daniel Taylor Nima BadizadeganR. Terry Black Pantelis Thomadis

Mission 1: Communications

• Determine packet loss in near-space environment– Measuring rate of packet loss

at varying altitudes

• Proof of concept for status beacon– Status beacon will begin

when BUSAT is launched, contains vital status information

– Important part of communications system

Mission 2: Magnetometer

• Testing magnetometer in different thermal environments

• Determine three orthogonal magnetic field vectors

• Determine how well the magnetometer will work near radio and power systems– Large source of interference

SHOT II / UN-7 Connection

• Communications system test– Packet loss– Near space environment– Proof of concept for beacon

• Magnetometer– Thermal testing– Stored data can be used for calibration in the

future– Same setup as on BUSAT

SHOT II Design – Block Diagram

SHOT II Design – Software

• No software needed for radio– Beacon set up automatically

• Microcontroller software:– Read data from Magnetometer every 42 seconds– Data stored in EEPROM (512 bytes total)– 113 data points per axis

SHOT II Design – Mechanical

SHOT II Test Procedure

• Chase balloon around with handheld Yagi antenna– Receive and record any packets received from the

beacon, can be checked for error rate• Magnetometer records data automatically

– One sample every 62 sec– EEPROM can be read when the payload is

recovered

Expected Data

• Magnetometer: 113 data points for each axis– Data comparable to IGRF data– Should indicate that magnetometer correctly

reads magnetic field (with error) over large temperature range

• Communications: packet loss data– Able to decode and read packets on the ground– Low packet loss (75% received)

Test Results• Structural Tests

– Payload survived all tests with minimal damage

• Functional Tests– Testing completed with

expected results– Successfully retrieved

magnetometer data– Communications received

80% of packets transmitted