Telemetry: the process of recording and transmitting the readings of an instrument.
The telecommunications subsystem provides the interface between the ground station and the satellite and is responsible for transmitting telemetry packets and receiving telecommand packets. It generally consists of antennas and transmitter and receiver circuitry. This transceiver hardware usually contains redundant components in order to ensure communication with the satellite will be possible. Another responsibility of the communications subsystem is the encoding and decoding of packets using the chosen protocol for the mission. Studies done in [14] and [15] show that the most common protocol used in CubeSat mission between 2003 and 2012 was AX.25. This decoding and encoding of communication protocol packets is not to be confused with the decoding and encoding of telecommand and telemetry packets occurring in the command and data handling system.
<aside> ❓ Which team is in charge of this for UTAT? Has the communication protocal between ground and satellite been decided? Will it use this encoding protocol?
@Eesa Aamer’s Answer: Should be an RF task, but the protocol being used might be described in the RF Module’s datasheet? It’s probably buried somewhere in there.
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Inspecting and maintaining the integrity of the on board subsystems is therefore a task that needs to be performed by the OBC. Fault isolation and repair procedures also need to be selected and executed in order to ensure the satellite can continue operating in the presence of damage or faults within a subsystem.
… Telemetry and payload data collected during the orbit also need to be stored in persistent memory for download when a ground station comes into range.
<aside> ❗ I’m guessing this will be housekeeping. This should be a story. Figure out what needs to be checked (ie, temperatures), and how often these need to be checked. What needs to be stored and sent down, what needs to be used to inform the global state variables.
@Eesa Aamer’s Answer: Welcome to Data Budget. I’ll be hopping on this with @Leo Liu because there are several people now asking these questions. Housekeeping data like likely be centered around voltage, current, and temperature readings. Maybe some other niche data collection for certain subsystems.
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The Total Ionizing Dose of electronic equipment is a measure of the amount of radiation a component can withstand before it degrades beyond a reliable state. TID radiation is built up from trapped electrons, trapped protons, and solar flare protons in the device.
A Single Event Effect (SEE) occurs when a charged particle deposits sufficient energy into the device. Common SEEs include the Single Event Upset (SEU) and the Single Event Latchup (SEL). A SEU generally manifests as a bit-flip in memory or a transient pulse in combinational logic. SEUs generally cause undesired effects in the software of a system. On the other hand, a SEL can permanently damage the hardware of a system. A SEL occurs when a charged particle creates a parasitic short circuit within a transistor resulting in excessive current flow. The only way to remove the latchup is to power cycle the device.
<aside> ❓ Which team is in charge of researching these? If this happens, is there a mission that we will pivot to? How do we check that something like this happened?
@Eesa Aamer’s Answer: This would technically be us. Me and @Emily did some introductory research on SEEs and SELs in first year, but we could definitely use some more research on it. Likely this will be another project under the Data Integrity story. We will need some detection methods like checksums along with error-correction algorithms.
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This paper tackles the functionality listed in the Generic Components column.