Structure and Mechanism Subsystem
- Main Structure
- Antenna Extension Mechanism
- Membrane Surface Development Mechanism
Perform phase optimization using analysis software called Altair Inspire. Phase optimization is a design method that calculates what shape should be better reduce mass without reduced rigidity. This makes it possible to design light and strong satellites. Although the shape made by phase optimization is very complex, it is possible because of metal laminate.
The dipole antenna is attached to one of the satellite structure surfaces. Before extension, the dipole antenna is rolled up and stored as shown in the figure below. At this time, extension is prevented by connecting to the structure by passing the tegus through the hole at the tip of the antenna. When the antenna is extended, the nichrome wire fuse the tegus.
Connect the membrane edge and the mast, and expand the membrane as the mast extension.
Attempting to assist the expantion using shape memory polymers (SMP).
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Electrical Power Subsystem
- Power Supply System
- Power Storage System
- Power Control Syste
This satellite uses a system that uses solar cells to generate electricity. Solar cells are attached to the sides and membranes of the satellite.
Lithium-ion batteries are installed to secure power when solar power is not available. The surplus electricity obtained from sunlight during sunshine is stored in the battery.
Since solar cells are deteriorated by radioactivity and power generation efficiency is lowered, a margin is provided in advance for the required power. However, if there is too much surplus power before it deteriorates, the battery will heat up and the battery life will be shortened. So we use charge management IC for managing charge and discharge to prevent battery life from being shortened
Communication Subsystem
- Communication Outline
- Satellite Station
- Earth Station
- Budget Calculation
・Transmission of HKD to maintain the satellite health
・Transmission of mission data acquired by satellite-mounted equipment
・Command reception from the earth giving commands to the satellite
2.1 Satellite Station Outline
The radio on board the satellite receives commands from the earth and sends mission data and telemetry data to the earth station.
2.2 Satellite Station Configuration
The equipment and configurations used by the satellite stations are shown below.
| Transmitter | TXE430MFMCW-302A-RU (NISI MUSEN KENKYUSYO) |
| Receiver | TXE430MFMCW-302A-RU (NISI MUSEN KENKYUSYO) |
| TNC Board | laboratory products |
| Antenna | monopole antenna（quenched ribbon steel） |
| Connector | MCX connector |
| Cable | RG-188A/U（teflon cable） |
3.1 Earth Station Outline
In the operation of WASEDA-SAT-ZERO, the purpose is to send and receive FM/CW signals.
The installation location is planned to be Waseda University Building 121. The main equipment is antennas, radios, TNCs, etc.
3.2 Earth Station Configuration
The equipment and configurations used by the earth stations are shown below.
| transceiver | IC-9000 (icom) |
| Network Control Interface | PICNIC (TriState) |
| Azimuth・Elevation Rotator | RC5,ERC5 (Create Design) |
| Antenna | Yagi Antenna |
3.3 Transmit Wave Output Characteristics of Earth Station
The characteristics of each area from the earth station to the satellite station are shown below.
| Station Type | WASEDA Station (tentative) |
| frequency | 430MHz band |
| Bandwidth | 24kHz |
| Radio Wave Model | 24kF2D |
| Transmitter Output | 50W |
| Modulation Speed | 1200bps |
| Modulation Method | FM |
| Polarization Wave | Horizontally Polarized Wave, Circularly Polarized Wave, etc. |
| Earth Station Location | Waseda University Building 121 |
3.4 Earth Station Software
| Satellite orbit simulation, Doppler shift control | Calsat32 |
| TNC | UISS, Sound modem |
| CW signal recorder | audaity |
Link Budget Calculation in English is here.
Command and Data Handling Subsystem
- Outline
- CPU
The data processing system does the following:
・Sensors detect temperature data, attitude data, and strain inside the satellite
・Controlling the LED lighting state of the unfolded membrane surface
・Save data from the sensor in flash memory and send it to the earth station
・others
The RX microcomputer is installed as the main OBC of this satellite. As a countermeasure against the error caused by the single mission once every few months, the sub PIC microcomputer is used and restarted as appropriate.
