Direct Imaging Black Holes from LEO
Ref Bari | Ben & Luke Update
Partner Satellite to BHEX
Stand-alone Satellite
Pathfinder Mission
Partner Satellite to BHEX
Stand-alone Satellite
Pathfinder Mission
Supplement (u,v) coverage at 86 GHz
Enable parameter estimation of Sgr A*/M87
Achieve Space-Space VLBI
Pathfinder Mission
Partner Satellite to BHEX
Stand-alone Satellite
Supplement (u,v) coverage at 86 GHz
Enable parameter estimation of Sgr A*/M87
Achieve Space-Space VLBI
Supplement (u,v) coverage at 86 GHz
Enable parameter estimation of Sgr A*/M87
Achieve Space-Space VLBI
Survey of >25 AGN+BH Targets @86 GHz
Enable Population Modeling of SMBHs
Enable real-time imaging of dynamical accretion disk around Sgr A*
Enable multi-messenger gravitational astronomy w/ LIGO + LISA
Partner Satellite to BHEX
Stand-alone Satellite
Pathfinder Mission
Supplement (u,v) coverage at 86 GHz
Enable parameter estimation of Sgr A*/M87
Achieve Space-Space VLBI
Supplement (u,v) coverage at 86 GHz
Enable parameter estimation of Sgr A*/M87
Achieve Space-Space VLBI
Survey of >25 AGN+BH Targets @86 GHz
Enable Population Modeling of SMBHs
Enable real-time imaging of dynamical accretion disk around Sgr A*
Enable multi-messenger gravitational astronomy w/ LIGO + LISA
Enable low-cost Space-Ground & Space-Space VLBI
Sub-milli arcsecond angular resolution
Dual short and long baseline lengths
Rapid coverage of (u,v) plane
Decreased signal loss from LEO
Decreased radiation environment in LEO vs. MEO
Sub-milli arcsecond angular resolution
Dual short and long baseline lengths
Rapid coverage of (u,v) plane
Decreased signal loss from LEO
Decreased radiation environment in LEO vs. MEO
Prospects of Detecting a Jet in Sagittarius A* with VLBI (Chavez et. al., ApJ 2024)
Sub-milli arcsecond angular resolution:
Dual short and long baseline lengths
Rapid coverage of (u,v) plane
Decreased signal loss from LEO
Decreased radiation environment in LEO vs. MEO
Sub-milli arcsecond angular resolution:
Dual short and long baseline lengths
Rapid coverage of (u,v) plane
Decreased signal loss from LEO
Decreased radiation environment in LEO vs. MEO
Sub-milli arcsecond angular resolution:
Dual short and long baseline lengths
Rapid coverage of (u,v) plane
Decreased signal loss from LEO
Decreased radiation environment in LEO vs. MEO
Metrics and Motivations for Earth–Space VLBI: Time-resolving Sgr A* with the Event Horizon Telescope (Palumbo et. al., ApJ 2019)
Sub-milli arcsecond angular resolution:
Dual short and long baseline lengths
Rapid coverage of (u,v) plane
Decreased signal loss from LEO
Decreased radiation environment in LEO vs. MEO
Metrics and Motivations for Earth–Space VLBI: Time-resolving Sgr A* with the Event Horizon Telescope (Palumbo et. al., ApJ 2019)
Sub-milli arcsecond angular resolution:
Dual short and long baseline lengths
Rapid coverage of (u,v) plane
Multifrequency Black Hole Imaging for the Next-generation Event Horizon Telescope (Chael et. al., 2023, ApJ)
Sub-milli arcsecond angular resolution:
Dual short and long baseline lengths
Rapid coverage of (u,v) plane
Decreased signal loss from LEO
Decreased radiation environment in LEO vs. MEO
Sub-milli arcsecond angular resolution
Dual short and long baseline lengths
Rapid coverage of (u,v) plane
Decreased signal loss from LEO
Decreased radiation environment in LEO vs. MEO
Sub-milli arcsecond angular resolution
Dual short and long baseline lengths
Rapid coverage of (u,v) plane
Decreased signal loss from LEO
Decreased radiation environment in LEO vs. MEO
Maximum data transmission rate (in bits per second); How fast can you send data from BHEX Mini to the earth?
Sub-milli arcsecond angular resolution
Dual short and long baseline lengths
Rapid coverage of (u,v) plane
Decreased signal loss from LEO
Decreased radiation environment in LEO vs. MEO
Power of Transmitted Signal: Strength of downlink signal in Watts (i.e., shouting louder to be heard further away!)
Sub-milli arcsecond angular resolution
Dual short and long baseline lengths
Rapid coverage of (u,v) plane
Decreased signal loss from LEO
Decreased radiation environment in LEO vs. MEO
Transmitter Gain: How well-focused your signal is when it leaves the satellite
(i.e., shouting into a megaphone instead of into the wind)
Sub-milli arcsecond angular resolution
Dual short and long baseline lengths
Rapid coverage of (u,v) plane
Decreased signal loss from LEO
Decreased radiation environment in LEO vs. MEO
Receiver Gain: How effectively the ground station collects and concentrates the incoming signal (i.e., ALMA's big dish listening to our incoming signal)
Received Power: How strong is the signal once it hits the ground receiver? (after traveling through empty space)
Sub-milli arcsecond angular resolution
Dual short and long baseline lengths
Rapid coverage of (u,v) plane
Decreased signal loss from LEO
Decreased radiation environment in LEO vs. MEO
Receiver Gain: How effectively the ground station collects and concentrates the incoming signal (i.e., ALMA's big dish listening to our incoming signal)
Distance: How much distance did the signal travel through free space? (LEO vs. MEO!)
Sub-milli arcsecond angular resolution
Dual short and long baseline lengths
Rapid coverage of (u,v) plane
Decreased signal loss from LEO
Decreased radiation environment in LEO vs. MEO
Receiver Gain: How effectively the ground station collects and concentrates the incoming signal (i.e., ALMA's big dish listening to our incoming signal)
Sub-milli arcsecond angular resolution
Dual short and long baseline lengths
Rapid coverage of (u,v) plane
Decreased radiation environment in LEO vs. MEO
Sub-milli arcsecond angular resolution
Dual short and long baseline lengths
Rapid coverage of (u,v) plane
Decreased signal loss from LEO
Decreased radiation environment in LEO vs. MEO
Decreased ISM scattering at LEO than MEO
Decreased ISM scattering at LEO than MEO
Orbit design for mitigating interstellar scattering effects in Earth-space VLBI observations of Sgr A* (Aditya Tamar, Ben Hudson, Daniel C.M. Palumbo, A&A, 2025)
Decreased ISM scattering at LEO than MEO
Intrinsic Gaussian Source
Decreased ISM scattering at LEO than MEO
ISM Scattering
Decreased ISM scattering at LEO than MEO
BHEX Mini Visibility Amplitude Advantage
Regardless of Source Flux Density!
Decreased ISM scattering at LEO than MEO
Antenna
Receiver
Cryocooler
Solar Panels
Ultra-Stable Oscillator
Ultra-Stable Oscillator
Phase Error
Ultra-Stable Oscillator
Ultra-Stable Oscillator
Allan Deviation
ABRACON SMD OCXO
Digital Backend
Original Analog Radio Signal
Sample the Signal every Unit Interval
Nyquist-Shannon Sampling Theorem
Retain only the samples and record the sign of the voltage for each sample
Reconstruct the original signal
Quantization Efficiency: how much of the analog SNR is retained after digitization
SNR: Signal to Noise Ratio
Data Generation Rate: In Bits per Second
Cross-Correlation
Phy
Eng
Fund