Cubesats To Pocketqubes: Opportunities And Challenges
Stefano Speretta
Challenge the future 1 Content
• Introduction • Satellite classes: differences and similarities • Delfi-PQ: our new developments • Development strategy: a new way to look at space systems
Challenge the future 2 Introduction
Facts about CubeSats • Clearly defined form factor (10cm cubes) • Mass: ~1kg per unit • Modular approach to build a bigger spacecraft
Source: NASA nasa.gov Source: JPL jpl.nasa.gov
Challenge the future 3 Introduction
CubeSats have become a standard for low cost systems • Cheap deployment system • Modular approach • Simple to scale to a bigger size
Source: ISIS www.isispace.nl
Challenge the future 4 Introduction
Is it possible to make satellites even cheaper?
Challenge the future 5 Introduction
PocketQubes are becoming a widespread possibility • Smaller form factor (10cm -> 5cm) • Mass: ~100g • Modular approach to build a bigger spacecraft
Source: University of Alaska Fairbanks Source: Stuart McAndrew
Challenge the future 6 Challenge the future 7 Comparison between satellite classes
Comparison based on a single unit
CubeSat PocketQube Side Area Volume
Challenge the future 8 Comparison between satellite classes
Comparison based on a single unit
CubeSat PocketQube Solar Power Inertia Magnetic Moment
Challenge the future 9 Comparison between satellite classes
• Is the satellite size sufficient to guarantee proper tracking? • What is the minimum cross-section for tracking? • Are TLEs available for PocketQubes? • Are the TLEs updated often enough for tracking? • Do PocketQubes require more time to be acquired after deployment?
Challenge the future 10 Tracking PocketQubes
• Only one launch so far included PocketQubes • Dnepr-19 on November 21st 2013 • 31 satellites were launched • 23 satellites deployed from the rocket deck • 8 satellites deployed by a micro-satellite (UNISAT-5) • 4 PocketQubes • Deployment happened 49 minutes after deployment from the rocket
Challenge the future 11 Tracking PocketQubes
• WREN • 1P
• 50$-Sat • 1.5P
• BeakerSat • 2.5P
• QubeScout • 2.5P
Challenge the future 12 Tracking PocketQubes
Challenge the future 13 Tracking PocketQubes
QubeScout CubeSats: • 1U WREN • 2U • 3U
50$-Sat BeakerSat
DubaiSat-2
Challenge the future 14 Tracking PocketQubes
QubeScout CubeSats: • 1U • 3U
BeakerSat WREN
50$-Sat
Challenge the future 15 Tracking PocketQubes
Challenge the future 16 Tracking PocketQubes
Challenge the future 17 Tracking PocketQubes
• Satellite size seems compatible with current NORAD tracking capabilities • These satellites seem not be a threat for other space assets • Not more than CubeSats are… • So…
Challenge the future 18 Delfi-PQ
• PocketQube • Mass < 500 g • 50 mm x 50 mm x 178 mm • Power ~1 W orbit average Delfi-PQ is a picosatellite demonstrating a reliable core bus platform and at least one advanced subsystem or payload. • Reliable core platform • power, data, communication, thermal and structure • Demonstrating advanced subsystems and payloads With key candidates: • Attitude Determination and Control • Micro propulsion • Payload Instruments • Iterative development approach (as opposed to waterfall/V-model)
Challenge the future 19 Communication
• Radio based on COTS radio SoC • Key candidate: Mbed SX1276 • 100 mW (+20 dBm) RF output • Bit-rate up to 300 kbit/s • Different modulation schemes • Ground station at TU Delft • Potential cooperation with ISIS BV for a small GS network in Delft
Challenge the future 20 Thermal Analysis
Cases Tmax S.P. Tmin S.P. Tmax PCBs Tmin PCBs [ºC] [ºC] [ºC] [ºC] Reference 30.7 -11.3 27.3 20.8 Hot 33.0 9.0 33.9 33.4 Cold 30.2 -13.2 26.2 19.2 Tumbling 19.8 -10.8 27.3 20.8 Nadir 26.0 -13.3 23.8 17.6 Top/bottom 33.0 -13.3 33.9 17.6 ±10ºC 43.0 -23.3 43.9 7.6 margin
Challenge the future 21 Structural Design (1)
Challenge the future 22 Structural Design (2)
Challenge the future 23 PQ-9 supported Spacecraft Architecture
Advanced OBC Subsystem set 1
EPS
Payload set 1 COMMS
Advanced Subsystem set 2 or Payload set 2
Challenge the future 24 PQ9 Interface
V_BUS1 V_BUS2 • 9-pin Lean minimal design V_BUS3 SDA • Breakouts for V_BUS4 o Debug SCL o Kill switch o Battery charging
1 2 3 4 5 6 7 8 9
RESET GND
Pin Signal Function
1 SCL I2C clock 2 RESET System reset (active low ?) 3 SDA I2C data 4 GND Ground 5 V_BUS1 Power line ( OBC and COMMS) 6 V_BUS2 Power line (Advanced subsystem set 1) 7 V_BUS3 Power line (Payload set 1) 8 V_BUS4 Power line (Advanced subsystem set 2/Payload set 2) 9 GND Ground
Challenge the future 25 PQ9 Interface on PCB
Dimensions in mm
Challenge the future 26 Electrical Power Subsystem
Challenge the future 27 Onboard Computer (1/2)
Requirements: Options:
• Highest power efficiency in • TI MSP432 (32-bit ARM Cortex M4F ) o 95uA/MHz active 4.56 mA@48MhZ available COTS o Software development support by Microcontroller ENERGIA IDE o TI MSP432P401R Launchpad o Up to 4 I2C, 8 SPI, 4 UART • Software development support
from the open source • ATSAMD21G18 (32-Bit ARM Cortex M0+) community o 25 mA@48MhZ (approx.) o Software development support by Arduino IDE • Commercially available in a o Arduino Zero board development board o SPI/TWI support • ATMEGA328 (AVR 8bit MCU) o 0.2mA/MHz active 4 mA@20MhZ • Support for I2C/SPI/UART o Software development support by communication protocols Arduino IDE o Arduino Nano board o 2 SPI/TWI support
Challenge the future 28 Onboard Computer (2/2)
PQ9 interface I2C
Real Time MSP432P401R Micro
Clock SPI (TI MCU) SPI SD Card (Storage) I2C
MPU-9250 (IMU)
Challenge the future 29 Development Strategy
Delfi Satellite Program
• Hands-On Education • Technology Demonstration • Platform Research & Development • Public Outreach
Challenge the future 30 Development Strategy
Delfi Satellite Program
• Stop using the V-model approach • Traditional in the space industry • Proved non optimal for short missions • Embrace an agile development method • Similar to software Agile and SCRUM methodologies • Iterative design approach • Continuous integration of new solutions • Better approach for incremental engineering • Becoming widespread also in industry (ex. Planet Labs)
Challenge the future 31 Questions?
www.delfispace.nl https://twitter.com/delfispace
Stefano Speretta [email protected]
Challenge the future 32