1.2 Requirements
The following requirements are based on the cubesat designing specification standard [1].
Mission Requirements (level 1)
[MSR 1] All parts must remain attached to the FloripaSat during launch, ejection and operation. No additional space debris shall be created.
Compliance with CDS 3.1.2.
[MSR 2] No pyrotechnics shall be used.
Compliance with CDS 3.1.3.
[MSR 3] No energy storage shall exceed 100 watt-hour.
Compliance with CDS 3.1.6.
[MSR 4] FloripaSat materials must satisfy the low out-gassing criterion to prevent contamination of other spacecraft during integration, testing, and launch.
Compliance with CDS 3.1.8.
[MSR 5] FloripaSat must comply with P-POD standard launch system.
Defined by the Launcher (GAUSS).
[MSR 6] As a general guideline, it is advised to limit magnetic field outside the FloripaSat static envelope to 0.5 Gauss above Earth’s magnetic field (Some launch vehicles hold requirements on magnetic field strength. Additionally, strong magnets can interfere with the separation between FloripaSat spacecraft in the same P-POD).
Compliance with CDS 3.1.10.
[MSR 7] FloripaSat must interface with the payloads experiments on orbit.
Defined by the team.
[MSR 8] FloripaSat must comply with orbiter parameters specified by the launch company/vehicles.
Compliance with CDS 3.2.1.
[MSR 9] FloripaSat must operate at Sun-Synchronous orbit: (550 – 600 km).
Compliance by the Launcher (GAUSS).
[MSR 10] CubeSat hazardous materials shall conform to AFSPCMAN 91-710, Volume 3.
Compliance with CDS 3.1.7.
[MSR 11] The CubeSat shall be designed to accommodate ascent venting per ventable volume/area < 2000 inches.
Compliance with CDS 3.1.11.
[MSR 12] The mission must have pre-defined task execution plans based on available power.
Defined by the team.
[MSR 13] Public commands must be well documentend and provided in a public channel for the AMSAT community.
Compliance with AMSAT regards.
[MSR 14] A third party must be able to estabilish communication with the Floripasat only using the availabe public documentation.
Defined by the team.
[MSR 15] All FloripaSat subsystems must comply with the nanosatellite mechanical structure and the CDS mechanical requirements.
Compliance with CDS 3.2.
[MSR 15] CubeSats mission design and hardware shall be in accordance with NPR 8715.6 to limit orbital debris.
Compliance with CDS 3.4.3.
[MSR 16] Any CubeSat component shall re-enter with energy less than 15 Joules.
Compliance with CDS 3.4.3.1.
[MSR 17] Developers will obtain and provide documentation of approval of an orbital debris mitigation plan from the FCC (or NOAA if imager is present).
Compliance with CDS 3.4.3.2.
System Requirements (level 2)
Space System Requirements
[SSR 1] FloripaSat must work in five operating modes: (i) Turned-Off, (ii) Integration and Test, (iii) Safe, (iv) Nominal and (v) Attitude Acquisition.
Necessita-se realizar uma definição dos módulos de operação do satélite.
[SSR 2] FloripaSat must operate in Integration and Test mode during ground tests.
módulo nominal = atividade com todas funcionalidades do satélite. módulo test = módulo de teste da funcionalidade do processo geral sem a aquisição de energia e escalonamento de tarefa.
[SSR 3] In Integration and Test Mode only subsystems that case no human hazards must operate (e.g.:RF transmissions or heating battery).
[SSR 4] FloripaSat must immediately following deployment enter in Safe mode in order to verify all subsystem.
Safe mode necessita ser definido pelo EPS
[SSR 5] During Safe mode FloripaSat only necessary resources must be powered-on.
[SSR 6] During Safe mode the Beacon must transmit “in-the-blind”.
"in-the-blind" = desligado
[SSR 7] FloripaSat must enter in Safe Mode in case of OBDH failure or telecommand request from ground station.
Isto é uma das funcionalidades que o OBDH e TTC que devem decidir..
[SSR 8] After Safe Mode FloripaSat must enter in Attitude Acquisition Mode in order to start spin stabilization.
Confirmar será passivo ou ativo?
[SSR 9] After Attitude Acquisition Mode FloripaSat must enter in Nominal Mode.
Confirmar será passivo ou ativo?
[SSR 10] Only during Nominal mode FloripaSat must allow tele commands.~~
Durante a missão, ele teria duas funções: Safe e Nominal. Durante o módulo Safe ele não está enviando dados, para níveis de CDS/AMSAT regulation o satélite está desligado.
[SSR 11] FloripaSat must use CSP (Cubesat Space Protocol) as network-layer delivery protocol the ground station to radio.
[SSR 12] During Nominal mode FloripaSat must use CSP to configure the cubesat to operates as (i) Mirror Data Operation or (ii) Processed Data Operation.~~
Isto tem que ser decidido.
[SSR 13] Mirror Data operation must allow TT&C send back incoming data from up-link to earth without any correction or verification.~~
necessário? Trivial não é, mas é um módulo de conhecimento de falha através de uma verificação do dado enviado pela GS
[SSR 14] FloripaSat must have the capability to receive a transmitter shutdown command, as per Federal Communications Commission (FCC) regulation.
é fcc mesmo?
[SSR 15] FloripaSat antennas must wait to deploy and transmit a minimum of 30 minutes after the ejection.
(CDS 3.4.4)
[SSR 16] FloripaSat developers must obtain and provide documentation of proper licenses for use of frequencies. >
[SSR 17] For amateur frequency use, this requires proof of frequency coordination by the International Amateur Radio Union (IARU).
[SSR 18] Developers shall obtain and provide documentation of approval of an orbital debris mitigation plan from the FCC or local agency.
Electrical Power System Module Requirements (EPS) (level 3)
[ER 1] The FloripaSat shall have solar panels as primary source of energy.
[ER 2] The EPS shall control the solar panels in order to maximize the energy harvested.
[ER 3] The EPS shall store the harvested energy in recheargeable batteries.
[ER 4] The EPS shall provide power to all FloripaSat’s subsystems.
[ER 5] The EPS shall have a micro-controller in order to perform all the subsystem designated tasks.
[ER 6] The EPS shall monitor the FloripaSat's batteries measuring its input current, output current, individual cell voltage, temperature and estimating its state of charge.
[ER 7] The EPS shall be able to cut off the power delivering to all subsystems (excepting itself and the beacon transmitter) in case of critical low batteries state of charge scenarios are detected.
[ER 8] The EPS shall be able to control the FloripaSat's batteries temperature, keeping them under apropriate temperature conditions (Temperature operation ranges depends on batteries' model).
[ER 9] The EPS shall have a battery heating system controlled by its micro-controller and apropriated power drivers.
[ER 10] The EPS shall operate the FloripaSat's batteries charge/discharge processes avoiding unbalanced cell conditions.
Compliance with CDS 3.3.8.
[ER 11] The EPS shall have battery cell over-voltage protection.
[ER 12] The EPS shall have battery cell under-voltage protection.
[ER 13] The EPS shall have battery cell over-current protection.
[ER 14] The EPS shall have a step-up converter to charge the batteries from the solar panels.
[ER 15] The EPS shall have an independent circuit to control the solar panels in case the micro-crontroller fails.
[ER 16] The EPS shall comply with the launcher safety requirements. All the FloripaSat's subsystems shall not be powered before or during the launch.
Compliance with CDS 3.3.1 and 3.3.3.
[ER 17] The EPS shall have at least two separation-switches to avoid the system to be powered before/during the launch.
Compliance with CDS 3.3.2.
[ER 18] The EPS shall communicate with other FloripaSat sub-modules.
[ER 19] The EPS microcontroller shall communicate with integrated circuits placed on the EPS PCB.
[ER 20] The EPS shall have UART communication for debugging.
[ER 21] The EPS shall communicate with the beacon microcontroller through UART.
[ER 22] The EPS shall do a housekeeping through I2C protocol in slave mode (OBDH/TT&C).
[ER 23] The EPS shall have seven output power lines in three different voltage levels: (3 x 3.3V, 3 x 5V and batteries voltage).
[ER 24] The EPS shall have one space qualified solar panel mounted on each Cubesat face, totalizing six solar panels.
[ER 25] Every solar panel current and voltage from EPS shall be measured in pairs.
[ER 26] The deployment switch shall be in the actuated state at all times while integrated in the PPOD.
Compliance with CDS 3.3.4.
[ER 27] In the actuated state, the CubeSat deployment switch shall be at or below the level of the standoff.
Compliance with CDS 3.3.4.1.
[ER 28] If the CubeSat deployment switch toggles from the actuated state and back, the transmission and deployable timers shall reset to t=0.
Compliance with CDS 3.3.5.
[ER 29] All diagnostics and battery charging within the P-POD shall be done while the deployment switch is depressed.
Compliance with CDS 3.3.6.1
[ER 30] The EPS shall have an external connector to charge the batteries.
[ER 31] The CubeSat shall include a RBF pin.
Compliance with CDS 3.3.7.
[ER 32] The RBF pin shall cut all power to the satellite once it is inserted into the satellite.
Compliance with CDS 3.3.7.1.
[ER 33] The RBF pin shall be removed from the CubeSat after integration into the P-POD.
Compliance with CDS 3.3.7.2.
[ER 34] The RBF pin shall protrude no more than 6.5 mm from the rails when it is fully inserted into the satellite.
Compliance with CDS 3.3.7.3.
[ER 35] The EPS shall provide the necessary voltage to deploy the antennas.
[ER 36] The EPS shall monitor the antenna deployment control signal. In case this signal is not asserted after 31 minutes, the EPS shall assert it.
[ER 37] The EPS design shall comply with all testing requirements defined on section (Test Requirements).
1.2.4 On-board data handling Module Requirements (OBDH) (level 3)
[OMR 1] OBDH must be able to detect the ejection mechanism.
To have a start operation condition. Relates to OMR2.
[OMR 2] OBDH must track elapsed time since powered on.
To be able to proper track time and follow CDS guidelines. Relates to OMR 1.
[OMR 3] The OBDH must hibernate for a minimum of 45 minutes after powered on.
Since CDS guidelines.
[OMR 4] The OBDH must interface with the EPS module.
So it can read power level states and operate accordinly. (GR 12)
[OMR 5] OBDH must change its execution mode based on pre-defined schemes based on available power.
Mission goal. (GR 12)
[OMR 6] The OBDH must perform antenna deployment.
OR 22.
[OMR 7] Antena deployment must be deployed only 45 minutes after launch.
Accordingly to CDS guidelines. OR 22. CDS 3.4.5.
[OMR 8] OBDH must not perform any radio communication before 45 minutes after launch.
Accordingly to CDS guidelines. OR 22. CDS 3.4.5.
[OMR 9] The OBDH on-board software must perform CSP data package encoding and decoding.
From recomentation of AMSAT-BR the CSP has a better performance than AX.25, specailly regarding the recovery of corrupted packages.
[OMR 10] The OBDH on-board software must handle telecommands received on the uplink channel.
OR 11
[OMR 11] OBDH must perform measurements of its microcontroller internal temperature and supply voltage.
Failure detection.
[OMR 12] OBDH must log all acquired data in the non-volatile memory, at maximum sample rate provided by the read target.
So the data can be later retrived at full resolution, using specific telecommands.
[OMR 13] OBDH will read the internal temperature and supply voltage of its microcontroller at the sample rate of 1 measurement per second.
Defined by team analysis.
[OMR 14] OBDH will read IMU data at the sample rate of 1 measurement per second.
Defined by team analysis.
[OMR 15] OBDH will read EPS data at the sample rate of 1 measurement per second.
Defined by team analysis.
[OMR 16] OBDH will read Solar Panels sensors at the sample rate of 1 measurement per second.
It Will read gyroscope, temperature and sun sensors. Defined by team analysis.
[OMR 17] OBDH must retreive saved data from non volatile memory at maxium sample provided by the target being read.
Since there is no enough downlink capacity ti transmit data at full sample rate, but the non volatile storage is not so restricted, data will be saved without downsampling, enabling ground teams to retreive it at full resolution for specific time frames.
[OMR 18] OBDH must be able to perform downsampling of the data.
So it can transmit acordingly with the available downlink capacity.
[OMR 19] OBDH must respond to command requests to retreive saved from non volatile memory and respond back to earth segment.
Defined by team analysis.
[OMR 20] Data replied back to earth segment could be at maximum resolution or at downsampled data.
Defined by team analysis.
[OMR 21] OBDH must have a event log in the non volatile memory.
Defined by team analysis.
[OMR 22] OBDH must record into the event log warnings or errors generated during its operation.
Defined by team analysis.
[OMR 23] OBDH must respond to telecomands to retreive the stored record logs.
Defined by team analysis.
[OMR 24] OBDH must know the pre-defined expected maximum time that each task should run.
Defined by team analysis.
[OMR 25] OBDH must reset a task execution if it exceed its pre-defined maximum execution time.
Failure treatment defined by tem analysis.
[OMR 26] OBDH must perform a complete system reboot if its main cycle exceeds the maximum expected execution time.
Failure treatment defined by tem analysis.
[OMR 27] OBDH must be able to authenticate public and restricted commands.
To enable OMR 28 implementation.(GR 14)
[OMR 28] OBDH public commands must not interfere in any way with Floripasat normal and expected operation, except the critical hibernate command.
To enable public access to the cubesat, without compromising its mission plan.
[OMR 29] OBDH must obey to a public command that can put the whole cubesat in hibernation for 24 hours.
Compliance with AMSAT/IARU regulations.
[OMR 30] OBDH must be able to restore by itself from the hibernation mode after 24 hours.
So OMR 29 can be implementated, without permatently cancelling the satellite operation.
[OMR 31] OBDH must perform a complete system reset after restoring the hibernation mode.
Defined by team analysis to treat unknown effects from outside radiation. ( e.g bitflip).
[OMR 32] OBDH must record to event log when it enters the hibernation mode.
Defined by team analysis.
[OMR 33] OBDH must reset the its timers if deployment switch toggles from actuated state and back.
Compliance with CDS 3.3.5.
Telemetry, Tracking and Command requirements (TT&C) (level 3)
[TMR 1] The Floripasat shall have a physical device to inhibit radio frequency (RF) transmission.
Compliance with CDS 3.3.9. The use of three independent inhibits is highly recommended and can reduce required documentation and analysis.
[TMR 2] The CubeSat will have the RF power output to the transmitting antenna input no greater than 1.5W.
Compliance with CDS 3.3.9.1.
[TMR 3] The CubeSat will have the RF power output to the transmitting antenna input no less than 1.0 W.
Defined by team analysis, considering the link budged details.
[TMR 4] Operators will obtain and provide documentation of proper licenses for use of radio frequencies.
Compliance with IARU regulation.
[TMR 5] CubeSats will comply with their country’s radio license agreements and restrictions
Compliance with CDS and Brazilian legislation.
[TMR 6] No CubeSats shall generate or transmit any RF signal from the time of integration into the PPOD through 45 minutes after on-orbit deployment from the P-POD.
Compliance with CDS.
[TMR 7] TT&C shall transmit and receive on the frequency of 437.50 Mhz.
Defined by the team, based on available spectrum alocation to Amateur communication.
[TMR 8] TT&C shall modulate and demodulate information using GFSK.
Defined by the team.
[TMR 9] TT&C Beacon must transmit periodic beacon messages at interval of 10 minutes, except when in hibertating or shutdown mode.
Allows groundstations to track and recevie satellite data even if telecommand was not sent to the satellite.
[TMR 10] TT&C Beacon periodic message transmission interval can be decreated to one message per minute, upon telecommand request.
[TMR 11] TT&C must receive telecommands from groundstations and demodulate them.
[TMR 12] TT&C must interface with OBDH, exchanging encoded raw data received or to be transmitted.
[TMR 13] TT&C must modulate raw data received from OBDH using GFSK, prior to transmission, and demodulate received data and forward raw data to OBDH.
Signal modulation will be done using radio transceiver hardware.
[TMR 14] TT&C shall transmit and receive data at a baudrate of 1200 bps.
Defined by the team, based on link budget analysis.
1.2.6 Mechanical requirements
[MR 1] The RBF pin and all CubeSat umbilical connectors shall be within the designated Access Port locations, green shaded areas shown in Appendix B of the CDS document.
Compliance with CDS 3.3.6.
[MR 2] CubeSats are cube shaped picosatellites with dimensions and features outlined in the CubeSat Specification Drawing.
Compliance with CDS 3.3.6.
[MR 3] The CubeSat shall use the coordinate system as defined in Appendix B [X] for the appropriate size. The CubeSat coordinate system will match the P-POD coordinate system while integrated into the P-POD. The origin of the CubeSat coordinate system is located at the geometric center of the CubeSat.
Compliance with CDS 3.3.6.
[MR 4] No components on the green and yellow shaded sides shall exceed 6.5 mm normal to the surface.
Compliance with CDS 3.3.6.
[MR 5] Deployables shall be constrained by the CubeSat, not the P-POD (Deployer).
Compliance with CDS 3.3.6.
[MR 6] Rails shall have a minimum width of 8.5mm.
Compliance with CDS 3.3.6.
[MR 7] Rails will have a surface roughness less than 1.6 µm.
Compliance with CDS 3.3.6.
[MR 8] The edges of the rails will be rounded to a radius of at least 1 mm.
Compliance with CDS 3.3.6.
[MR 9] The ends of the rails on the +/- Z face shall have a minimum surface area of 6.5 mm x 6.5 mm contact area for neighboring CubeSat rails.
Compliance with CDS 3.3.6.
[MR 10] At least 75% of the rail will be in contact with the P-POD rails. 25% of the rails may be recessed and no part of the rails will exceed the specification.
Compliance with CDS 3.3.6.
[MR 11] The maximum mass of a 1U CubeSat shall be 1.33 kg.
Compliance with CDS 3.3.6.
[MR 12] The CubeSat center of gravity shall be located within 2 cm from its geometric center in the X and Y direction.
Compliance with CDS 3.3.6.
[MR 13] The 1U CubeSat center of gravity shall be located within 2 cm from its geometric center in the Z direction.
Compliance with CDS 3.3.6.
[MR 14] Aluminum 7075, 6061, 5005, and/or 5052 will be used for both the main CubeSat structure and the rails.
Compliance with CDS 3.3.6.
[MR 15] The CubeSat rails and standoff, which contact the P-POD rails and adjacent CubeSat standoffs, shall be hard anodized aluminum to prevent any cold welding within the PPOD.
Compliance with CDS 3.3.6.
[MR 16] The RBF pin shall be removed from the CubeSat after integration into the P-POD.
Compliance with CDS 3.3.7.2.
[MR 17] The RBF pin shall protrude no more than 6.5 mm from the rails when it is fully inserted into the satellite.
Compliance with CDS 3.3.7.3.
Attitude Determination and Control System (ADCS) (level 3)
[ADR 1] To be define.
Payload Requirements
[PR 1] To be define.
Ground Station Requirements (level 2)
[GSGR 1] The ground station must be able to identify the beacon transmitted by the FloripaSat.
[GSGR 2] The ground station must be able to communicate with the FloripaSat through the TT&C via CSP (Cubesat Space Protocol).
[GSGR 3] The ground station must demodulate the beacon from the FloripaSat.
[GSGR 4] The ground station must decode the beacon from the FloripaSat.
[GSOR 5] The ground station must demodulate and decode the information TT&C from the FloripaSat.
[GSOR 6] The ground station must decode the information TT&C from the FloripaSat.
[GSOR 7] The ground station must to encode TT&C information to transmit to the FloripaSat.
[GSOR 8] The ground station should modulate GFSK
[GSOR 9] The ground station should demodulate GFSK.
[GSOR 10] The ground station should encode information in CSP (Cubesat Space Protocol) frames.
[GSOR 11] The ground station must decode the information in CSP (Cubesat Space Protocol) frames.
[GSOR 12] The card acquisition, scheduling, transmission and reception is the USRP B210.
[GSOR 13] The beacon should operate on a 435-438 MHz band.
[GSOR 14] The telemetry must operate on a 435-438 MHz band.
[GSOR 15] The remote control must operate on a 435-438 MHz band.
[GSOR 16] The ground station must send data at a rate of 1200 bps.
Test Integration Requirements (level 2)
[TR 1] FloripaSat must allow random vibration testing.
Compliance with CDS.
[TR 2] FloripaSat must allow thermal vacuum bakeout to ensure outgassing of components.
Compliance with CDS.
[TR 3] FloripaSat must allow shock testing as defined by launch provider.
Compliance with CDS.
[TR 4] FloripaSat must allow visual inspection.
Compliance with CDS.
[TR 5] FloripaSat must be approved in Qualification, Protoflight and acceptance testing.
Compliance with CDS.