Summer Projects Review:Current Status

ADCSADCS calibrated in uniform magnetic field using support hardware to mimic the computer onboard the satellite.

The mV/gauss change is now known:•1-3mV/gauss for the y axis•30-52mV/gauss for the x axis•34-53mV/gauss for the z axis

Pointing variation for the z axis has been calculated, α=2.891° or 0.0505C.

Current passing through the Set/Reset strap on the HMC1053 as its resistance changes due to the ambient temperature has been calculated. This is directly linked to how much power the Set/Reset will draw.

Summer Review6th Aug. 2008

SRCSPACE ACADEMY

1.11amps at 4.5Ω (typical)

Set/Reset circuit on ADCS

Set/Reset strap on HMC1053

50 nanoseconds of peak current (>400mA)

Summer Review6th Aug. 2008

SRCSPACE ACADEMY

• up to 6 solar arrays

• 3 battery charge regulators (BCRs)

• 3 power buses, 2 regulated (3.3V and 5V) and a raw battery bus

• Bus over-current protection

• Battery under-voltage protection; if the battery voltage drops below 6.5V, the output buses are disable until the battery voltage reaches 7.5V

• Telemetry and telecommand via an I2C bus

• Power consumption <0.1W and weight 152.96g

• Estimation of power produced when in sunlight 2.11W (solar array efficiency 17%, AM0 = 1.35kW/m2)

• Battery capacity 1.25Ah

1U CubeSat Electrical Power Supply from Clyde Space

PSU Main Features

Summer Review6th Aug. 2008

SRCSPACE ACADEMY

Current Status• Solar array equivalent circuit and battery simulator connected successfully

• I2C bus has been used successfully

• BCR1 has been damaged – testing has been suspended

Testing of the PSU

Summer Review6th Aug. 2008

SRCSPACE ACADEMY

GOALS

Test flight and dev board Incomplete

Specify physical interfaces Complete

Set up and Software Development Environment Complete

Write ADCS software Incomplete

Fully interface subsystems Incomplete

OBDH

KEY FACTS

Majority of the board runs on 3.3V logic

Board includes +5V and +3.3V VCC power buses

Clock speed of MCU is 7.378 MHz

Power consumption is around 0.01 W

Mass (with physical interfaces) is 90g

Tolerances are -40 to +85°C

Summer Review6th Aug. 2008

SRCSPACE ACADEMY

Summer Review6th Aug. 2008

SRCSPACE ACADEMY

InterfacingPhysical interfaces are via the cubesat kit system bus

Multiplexing and a PowerFET are needed for the ADCS interface.

Transceiver does not plug into the cubesat kit bus.

Modes outlined.

PSU

OBDH

COMS

PAY

SD

CAM

NORMAL OPERATING PROCEEDURE

ADCS

beacon

Summer Review6th Aug. 2008

SRC

Sunlight

Eclipse

Launch

Safe

SPACE ACADEMY