BVEX
Balloon-borne VLBI Experiment
Demonstrating stratospheric VLBI correlation at 22 GHz
Pioneering the first-ever VLBI correlation between a balloon-borne telescope in the stratosphere and ground-based radio observatories.
Mission Overview
BVEX represents a groundbreaking advancement in radio astronomy, operating in the stratosphere above 99% of Earth's atmosphere to achieve unprecedented angular resolution through balloon-ground VLBI correlation.
Mission Status
BVEX was successfully launched on August 29th, 2025, from Timmins, Ontario in association with CNES and CSA STRATOS program, but unfortunately did not reach the stratosphere due to a balloon leak. While the science objectives were not fulfilled during this flight, we are preparing to re-launch a much improved BVEX system in the near future.
Principal Mission Goals
- Demonstrate sub-millimeter positional stability
- Achieve meter-level 3D position accuracy for VLBI correlation
- Characterize stratospheric phase stability at 22 GHz
- Generate interference fringes with ground-based telescopes
System Architecture
Interactive diagram showing the distributed computing architecture with real-time control systems operating across ground stations and balloon-borne flight computers.
Ground
Sagittarius
Ophiuchus
Click on any subsystem block to navigate to its detailed section below
System Components
Detailed overview of the key systems that enable BVEX's groundbreaking VLBI capabilities.
BCP - Sagittarius
Primary DevelopmentComplete C-based flight control software managing all subsystems on the Sagittarius flight computer, including the RFSoC spectrometer, VLBI backend, timing system, GPS, PR59, position tracking, and heater control. I developed the UDP client-server architecture enabling communication with the Ophiuchus flight computer and ground station command interface.
- Dual flight computer UDP communication protocol
- Ground station command interface with real-time telemetry
- Multi-layer safety systems with watchdog protection
RFSoC Backend System
Primary DevelopmentThe RFSoC 4x2 FPGA system implements multiple signal processing pipelines for spectroscopy and VLBI operations. I developed the complete FPGA control system, spectral analysis algorithms, and high-speed data acquisition.
- AMD-Xilinx XCZU48DR RFSoC Gen3 control
- 5 GSPS sampling with 14-bit to 2-bit requantization
- Coarse spectrometer (960 kHz bin resolution)
- Fine 120 kHz spectrometer for water line detection
- VLBI 100 GbE link for high-speed data packet capture
VLBI Data Storage
Primary DevelopmentHigh-speed data recording system handling continuous 100 Gbps data streams from the RFSoC. I developed the complete storage optimization algorithms, real-time recording system, and data integrity verification.
- 12 GB/s sustained write performance
- 16 TB storage capacity (6 hours at full rate)
- Automatic file rotation and redundant verification
Timing System
Primary DevelopmentPrecision timing chain essential for VLBI correlation, maintaining phase coherence across the observation. I integrated the OCXO reference, GPS timing, and TICC phase measurements for picosecond-level accuracy.
- 60 picosecond timing resolution
- 7×10⁻¹¹ Allan deviation at 1s
- GPS-disciplined OCXO with TICC monitoring
Housekeeping System
CollaborativeComprehensive health monitoring infrastructure collecting data from 84+ analog channels distributed across the payload. Developed collaboratively with Rafael Costa and Terry Yang, featuring LabJack integration and real-time telemetry.
- 20+ temperature sensors with ±0.01°C precision
- Real-time power monitoring (0.1A resolution)
- Environmental sensors and safety limits
Power Breakout Board (PBoB)
CollaborativeCritical power distribution system enabling remote operation of all BVEX subsystems. Developed collaboratively with Terry Yang, providing intelligent power management and monitoring with LabJack-based control and current sensing capabilities.
- 10 individually switched power channels (28V input)
- Remote power cycling capability via ground station
- Real-time current monitoring with shunt sense resistors
- Overcurrent protection and brownout detection
Position Tracking System
CollaborativeDistributed network of high-precision MEMS sensors characterizing mechanical vibrations and pointing stability. Developed in collaboration with Rafael Costa and Aarchi Shah for sub-millimeter position tracking.
- 3x ADXL355 accelerometers (±8g, 1000 Hz)
- 1x SPI single-axis gyroscope (1000 Hz)
- 1x 3-axis I2C gyroscope (1000 Hz)
- 20 μm RMS position resolution
Heater Control System
Direct ContributionDistributed heating system maintaining operational temperatures for critical components during passage through the -60°C tropopause. Developed control algorithms and integration with Rafael Costa.
- 5x Kapton heater circuits (20W each)
- PID temperature control with safety limits
- Solid-state relays with thermal protection
PR59 TEC Control System
Primary DevelopmentPrecision thermoelectric cooler (TEC) control system for pressure vessel thermal management. I developed the complete control electronics, feedback algorithms, and integration with the PBoB power system.
- Thermoelectric cooling control for pressure vessel
- Temperature feedback with ±0.1°C precision
- Integration with housekeeping telemetry
OCXO Timing Reference
Primary DevelopmentOven-controlled crystal oscillator providing the ultra-stable 10 MHz reference for VLBI operations. I designed the thermal control system, distribution amplifiers, and integration with the timing chain.
- 10 MHz ultra-stable reference (7×10⁻¹¹ Allan deviation)
- Oven temperature control (±0.01°C stability)
- Distribution to RFSoC and timing systems
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