BHEX Mini
Direct Imaging Black Holes from LEO
Ref Bari, Brown University
- 🎯 Introduction
- 🔭 Event Horizon Telescope
- 📻 BHEX (Black Hole Explorer Satellite)
- 🕰️ BHEX Mini
- 🕒 BHEX Mini Timeline
- 💰Funding Deadlines
BHEX Mini
- 🎯 Introduction
- 🔭 Event Horizon Telescope
- 📻 BHEX (Black Hole Explorer Satellite)
- 🕰️ BHEX Mini
- 🕒 BHEX Mini Timeline
- 💰Funding Deadlines
BHEX Mini
Ref Bari
Physics MS, Brown
-
Analysis of Binary Black Holes via Neural Networks (under Prof. Brendan Keith, Brown)
-
Funded under NSF Neural DynAMO Grant
-
-
“Nitrogen Outgassing from Water Worlds” (R.Bari et. al., under review, The Astrophysical Journal 2025)
-
“Reflection from Relativistic Light Sails” (R. Bari, The Astronomical Journal 2024)
-
“Simulating the Action Principle in Optics” (R. Bari, The Physics Teacher 2023)
-
Spin Qubit CNN Researcher at the Meriles Condensed Matter Lab
-
“A Path Integral Derivation of Hawking Radiation” (MS Thesis)
Binary Black Holes
Physics MS, Brown
-
Analysis of Binary Black Holes via Neural Networks (Prof. Brendan Keith, Brown)
Highly Eccentric Orbit
Gravitational Wave
Loss Function
Plane
(p,e)
Brown Space Engineering
Spaceflight Heritage
EQUiSat
SBUDNIC
PVDX
Spaceflight Heritage
SBUDNIC
PVDX
- 1U CubeSat (1.3 kg, 10x10x10 cm)
- Payload: High-Power LED Array + LiFePO4 Batteries (<6 kg)
- ADCS: Passive Magnetic Atitude Control System
- Power Generated: 1.3W (Top+Bottom Panels) & .7W (Side)
-
Total Cost: $5000
- All components built in-house at Brown Engineering Lab
EQUiSat
- 3U CubeSat (3 kg, 30x10x10 cm)
- Payload: Ham Radio Transceiver, 2 Cameras, Arduino Nano
- ADCS: Spring-Loaded + Aerodynamic Drag Sail
- Power Generated: 1.3W (Top+Bottom Panels) & .7W (Side)
-
Total Cost: $10,000
- 3D-Printed Components at BDW
- 3U CubeSat (~6 kg, 30x10x10 cm)
- Payload: Perovskite Solar Panels + Robotic Arm + Digital Display
- ADCS: Magnetorquers
-
Total Cost: ~$30,000
- 3D-Printed Components at BDW
- CUBECOM S-Band Transceiver ($10,000)
Spaceflight Heritage
SBUDNIC
PVDX
EQUiSat
BHEX Mini
- 🎯 Introduction
- 🔭 Event Horizon Telescope
- 📻 BHEX (Black Hole Explorer Satellite)
- 🕰️ BHEX Mini
- 🕒 BHEX Mini Timeline
- 💰Funding Deadlines
BHEX Mini
Black Hole (M87)
Black Holes: An Intro
BHEX
EHT
LIGO
Penrose
Ghez
Einstein
Schwarschild
Oppenheimer
Kerr
Hawking
Event Horizon Telescope
(2019)
Event Horizon Telescope (EHT)
Event Horizon Telescope
(2019)
Event Horizon Telescope (EHT)
- 🎯 Introduction
- 🔭 Event Horizon Telescope
- 📻 BHEX (Black Hole Explorer Satellite)
- 🕰️ BHEX Mini
- 🕒 BHEX Mini Timeline
- 💰Funding Deadlines
BHEX Mini
Event Horizon Telescope
(2019)
Event Horizon Telescope (EHT)
Black Holes: An Intro
(2031)
Black Hole Explorer Satellite (BHEX) Mission
Imaging a Black Hole
(The black hole explorer: Motivation and vision, Johnson et. al., 2024)
- 🎯 Introduction
- 🔭 Event Horizon Telescope
- 📻 BHEX (Black Hole Explorer Satellite)
- 🕰️ BHEX Mini
- 🕒 BHEX Mini Timeline
- 💰Funding Deadlines
BHEX Mini
Spaceflight Heritage
EQUiSat
SBUDNIC
PVDX
Spaceflight Heritage
SBUDNIC
PVDX
EQUiSat
BHEX Mini
\text{MEO} (20000 \text{ km})
\text{LEO} (400 \text{ km})
BHEX Mini
Imaging a Black Hole
BHEX Mini
BHEX Mini
BHEX Mini
BHEX Mini
- Email BHEX Team
Jan 2025
BHEX Mini
- Email BHEX Team
Jan 2025
BHEX Mini
- Email BHEX Team
Jan 2025
BHEX Mini
- Email BHEX Team
Jan 2025
Feb 2025
- Literature Review
BHEX Mini
- Email BHEX Team
Jan 2025
Feb 2025
Mar 2025
- Literature Review
- Advised against pursuing BHEX Mini by Prof. Rick Fleeter
- Submit to Rhode Island Space Grant
BHEX Mini
- Email BHEX Team
Jan 2025
Feb 2025
Mar 2025
- Literature Review
- Advised against pursuing BHEX Mini by Prof. Rick Fleeter
- Submit to Rhode Island Space Grant
BHEX Mini
- Email BHEX Team
Jan 2025
Feb 2025
Mar 2025
- Literature Review
- Advised against pursuing BHEX Mini by Prof. Rick Fleeter
- Submit to Rhode Island Space Grant
BHEX Mini
- Email BHEX Team
Jan 2025
Feb 2025
Mar 2025
- Literature Review
- Advised against pursuing BHEX Mini by Prof. Rick Fleeter
- Submit to Rhode Island Space Grant
BHEX Mini
- Email BHEX Team
Jan 2025
Feb 2025
Mar 2025
- Literature Review
- Advised against pursuing BHEX Mini by Prof. Rick Fleeter
- Submit to Rhode Island Space Grant
BHEX Mini
- Email BHEX Team
Jan 2025
Feb 2025
Mar 2025
- Literature Review
- Advised against pursuing BHEX Mini by Prof. Rick Fleeter
- Submit to Rhode Island Space Grant
BHEX Mini
- Email BHEX Team
Jan 2025
Feb 2025
Mar 2025
- Literature Review
- Advised against pursuing BHEX Mini by Prof. Rick Fleeter
- Submit to Rhode Island Space Grant
BHEX Mini
- Email BHEX Team
Jan 2025
Feb 2025
Mar 2025
- Literature Review
- Advised against pursuing BHEX Mini by Prof. Rick Fleeter
- Submit to Rhode Island Space Grant
BHEX Mini
- Email BHEX Team
Jan 2025
Feb 2025
Mar 2025
- Literature Review
- Advised against pursuing BHEX Mini by Prof. Rick Fleeter
- Submit to Rhode Island Space Grant
BHEX Mini
- Email BHEX Team
Jan 2025
Feb 2025
Mar 2025
- Literature Review
- Advised against pursuing BHEX Mini by Prof. Rick Fleeter
- Submit to Rhode Island Space Grant
BHEX Mini
- Email BHEX Team
Jan 2025
Feb 2025
Mar 2025
- Literature Review
- Advised against pursuing BHEX Mini by Prof. Rick Fleeter
- Submit to Rhode Island Space Grant
BHEX Mini
- Email BHEX Team
Jan 2025
Feb 2025
Mar 2025
- Literature Review
- Advised against pursuing BHEX Mini by Prof. Rick Fleeter
- Submit to Rhode Island Space Grant
BHEX Mini
- Email BHEX Team
Jan 2025
Feb 2025
Mar 2025
- Literature Review
- Advised against pursuing BHEX Mini by Prof. Rick Fleeter
- Submit to Rhode Island Space Grant
BHEX Mini
- Email BHEX Team
Jan 2025
Feb 2025
Mar 2025
- Literature Review
- Advised against pursuing BHEX Mini by Prof. Rick Fleeter
- Submit to Rhode Island Space Grant
BHEX Mini
- Email BHEX Team
Jan 2025
Feb 2025
Mar 2025
- Literature Review
- Advised against pursuing BHEX Mini by Prof. Rick Fleeter
- Submit to Rhode Island Space Grant
BHEX Mini
- Email BHEX Team
Jan 2025
Feb 2025
Mar 2025
- Literature Review
- Advised against pursuing BHEX Mini by Prof. Rick Fleeter
- Submit to Rhode Island Space Grant
BHEX Mini
- Email BHEX Team
Jan 2025
Feb 2025
Mar 2025
- Literature Review
- Advised against pursuing BHEX Mini by Prof. Rick Fleeter
- Submit to Rhode Island Space Grant
BHEX Mini
- Email BHEX Team
Jan 2025
Feb 2025
Mar 2025
- Literature Review
- Advised against pursuing BHEX Mini by Prof. Rick Fleeter
- Submit to Rhode Island Space Grant
BHEX Mini
- Email BHEX Team
Jan 2025
Feb 2025
Mar 2025
- Literature Review
- Advised against pursuing BHEX Mini by Prof. Rick Fleeter
- Submit to Rhode Island Space Grant
BHEX Mini
- Email BHEX Team
Jan 2025
Feb 2025
Mar 2025
- Literature Review
- Advised against pursuing BHEX Mini by Prof. Rick Fleeter
- Submit to Rhode Island Space Grant
BHEX Mini
- Email BHEX Team
Jan 2025
Feb 2025
Mar 2025
- Literature Review
- Advised against pursuing BHEX Mini by Prof. Rick Fleeter
- Submit to Rhode Island Space Grant
BHEX Mini
- Email BHEX Team
Jan 2025
Feb 2025
Mar 2025
- Literature Review
- Advised against pursuing BHEX Mini by Prof. Rick Fleeter
- Submit to Rhode Island Space Grant
BHEX Mini
- Email BHEX Team
Jan 2025
Feb 2025
Mar 2025
- Literature Review
- Advised against pursuing BHEX Mini by Prof. Rick Fleeter
- Submit to Rhode Island Space Grant
BHEX Mini
- Email BHEX Team
Jan 2025
Feb 2025
Mar 2025
- Literature Review
- Advised against pursuing BHEX Mini by Prof. Rick Fleeter
- Submit to Rhode Island Space Grant
- Email BHEX Team
Jan 2025
Feb 2025
Mar 2025
- Literature Review
- Advised against pursuing BHEX Mini by Prof. Rick Fleeter
- Submit to Rhode Island Space Grant
Apr 2025
- Ivy Space Conference
- Ben Hudson (BHEX, KISPE)
- Luke Anderson (Orion Space Systems)
BHEX Mini
- Email BHEX Team
Jan 2025
Feb 2025
Mar 2025
- Literature Review
- Advised against pursuing BHEX Mini by Prof. Rick Fleeter
- Submit to Rhode Island Space Grant
Apr 2025
- Ivy Space Conference
- Ben Hudson (BHEX, KISPE)
- Luke Anderson (Orion Space Systems)
BHEX Mini
Ben Hudson
Luke Anderson
- Email BHEX Team
Jan 2025
Feb 2025
Mar 2025
- Literature Review
- Advised against pursuing BHEX Mini by Prof. Rick Fleeter
- Submit to Rhode Island Space Grant
Apr 2025
May 2025
- Ivy Space Conference
- Ben Hudson (BHEX, KISPE)
- Luke Anderson (Orion Space Systems)
- Trained ~6 undergraduates to run simulations on BHEX Mini
- Jeffrey Olson (Cryocooler Engineer, Lockheed Martin)
- Rejected from RISG
BHEX Mini
Jeffrey Olson
- Email BHEX Team
Jan 2025
Feb 2025
Mar 2025
- Literature Review
- Advised against pursuing BHEX Mini by Prof. Rick Fleeter
- Submit to Rhode Island Space Grant
Apr 2025
May 2025
Jun 2025
Jul 2025
- Ivy Space Conference
- Ben Hudson (BHEX, KISPE)
- Luke Anderson (Orion Space Systems)
- Trained ~6 undergraduates to run simulations on BHEX Mini
- Jeffrey Olson (Cryocooler Engineer, Lockheed Martin)
- Rejected from RISG
- Completed Antenna SWaPC Requirements
- Obtained Preliminary Grant Funding from Nelson Center
- Began correspondence with NASA JPL on Space-Space VLBI
- Rejected from International Astronautical Congress
- Constrained BHEX Mini SWaPC Requirements
- Approved by Brown Division of Research as PI for BHEX Mini
- Submitted to NASA NIAC Phase I Solicitation
- Accepted to SmallSat Europe 2026
Todd Ely
Joseph Lazio
Eric Burt
Ben Hudson
Luke Anderson
Rick Fleeter
BHEX Mini
Partner Satellite to BHEX
Stand-alone Satellite
Pathfinder Mission
BHEX Mini
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
20,200\text{ km}
400\text{ km}
BHEX Mini
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
20,200\text{ km}
400\text{ km}
BHEX Mini
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
BHEX Mini
BHEX Mini
OJ 287
OJ 287
OJ 287
BHEX Mini
BHEX Mini
BHEX Mini
BHEX Mini
BHEX Mini
BHEX Mini
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
BHEX Mini
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
BHEX Mini
BHEX Mini
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)
BHEX Mini
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
22\mu as<\theta_{\text{BHEX-Mini}} < 1800 \mu as
- What kind of targets can we observe with this angular resolution?
BHEX Mini
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
22\mu as<\theta_{\text{BHEX-Mini}} < 1800 \mu as
- What kind of targets can we observe with this angular resolution?
5.6 G \lambda < b_{s s}<9.3 G \lambda
0.11 G \lambda < b_{s g}<3.5 G \lambda
20,000\text{ km}
12000\text{ km}
400\text{ km}
BHEX Mini
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
22\mu as<\theta_{\text{BHEX-Mini}} < 1800 \mu as
- What kind of targets can we observe with this angular resolution?
5.6 G \lambda < b_{s s}<9.3 G \lambda
0.11 G \lambda < b_{s g}<3.5 G \lambda
20,000\text{ km}
12000\text{ km}
400\text{ km}
Metrics and Motivations for Earth–Space VLBI: Time-resolving Sgr A* with the Event Horizon Telescope (Palumbo et. al., ApJ 2019)
BHEX Mini
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
22\mu as<\theta_{\text{BHEX-Mini}} < 1800 \mu as
- What kind of targets can we observe with this angular resolution?
5.6 G \lambda < b_{s s}<9.3 G \lambda
0.11 G \lambda < b_{s g}<3.5 G \lambda
400\text{ km}
Metrics and Motivations for Earth–Space VLBI: Time-resolving Sgr A* with the Event Horizon Telescope (Palumbo et. al., ApJ 2019)
BHEX Mini
Sub-milli arcsecond angular resolution:
Dual short and long baseline lengths
Rapid coverage of (u,v) plane
22\mu as<\theta_{\text{BHEX-Mini}} < 1800 \mu as
- What kind of targets can we observe with this angular resolution?
5.6 G \lambda < b_{s s}<9.3 G \lambda
0.11 G \lambda < b_{s g}<3.5 G \lambda
Multifrequency Black Hole Imaging for the Next-generation Event Horizon Telescope (Chael et. al., 2023, ApJ)
400\text{ km}
BHEX Mini
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
22\mu as<\theta_{\text{BHEX-Mini}} < 1800 \mu as
5.6 G \lambda < b_{s s}<9.3 G \lambda
0.11 G \lambda < b_{s g}<3.5 G \lambda
T_{orb}=90 \text{ min}
- What is the integration time for BHEX Mini on the (u,v) plane?
- Could BHEX Mini possibly enable direct imaging of dynamic accretion disk around Sgr A*? (i.e., creating a movie of a black hole!)
BHEX Mini
\text{To time resolve Sgr A*, we must have} \\f_{coverage}>50\% \text{ in } t < T_{ISCO} \sim 30 \text{ min}
BHEX Mini
\text{To time resolve Sgr A*, we must have} \\f_{coverage}>50\% \text{ in } t < T_{ISCO} \sim 30 \text{ min}
BHEX Mini
BHEX Mini
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
22\mu as<\theta_{\text{BHEX-Mini}} < 1800 \mu as
5.6 G \lambda < b_{s s}<9.3 G \lambda
0.11 G \lambda < b_{s g}<3.5 G \lambda
T_{orb}=90 \text{ min}
BHEX Mini
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
22\mu as<\theta_{\text{BHEX-Mini}} < 1800 \mu as
5.6 G \lambda < b_{s s}<9.3 G \lambda
0.11 G \lambda < b_{s g}<3.5 G \lambda
T_{orb}=90 \text{ min}
R_{\max } \approx \frac{P_t G_t G_r \eta}{k T_b B}\left(N_{\bmod }\right)
Maximum data transmission rate (in bits per second); How fast can you send data from BHEX Mini to the earth?
R_{\max } \approx \frac{P_t G_t G_r \eta}{k T_b B}\left(N_{\bmod }\right)
BHEX Mini
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
22\mu as<\theta_{\text{BHEX-Mini}} < 1800 \mu as
5.6 G \lambda < b_{s s}<9.3 G \lambda
0.11 G \lambda < b_{s g}<3.5 G \lambda
T_{orb}=90 \text{ min}
R_{\max } \approx \frac{P_t G_t G_r \eta}{k T_b B}\left(N_{\bmod }\right)
Power of Transmitted Signal: Strength of downlink signal in Watts (i.e., shouting louder to be heard further away!)
R_{\max } \approx \frac{P_t G_t G_r \eta}{k T_b B}\left(N_{\bmod }\right)
BHEX Mini
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
22\mu as<\theta_{\text{BHEX-Mini}} < 1800 \mu as
5.6 G \lambda < b_{s s}<9.3 G \lambda
0.11 G \lambda < b_{s g}<3.5 G \lambda
T_{orb}=90 \text{ min}
R_{\max } \approx \frac{P_t G_t G_r \eta}{k T_b B}\left(N_{\bmod }\right)
Transmitter Gain: How well-focused your signal is when it leaves the satellite
(i.e., shouting into a megaphone instead of into the wind)
R_{\max } \approx \frac{P_t G_t G_r \eta}{k T_b B}\left(N_{\bmod }\right)
BHEX Mini
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
22\mu as<\theta_{\text{BHEX-Mini}} < 1800 \mu as
5.6 G \lambda < b_{s s}<9.3 G \lambda
0.11 G \lambda < b_{s g}<3.5 G \lambda
T_{orb}=90 \text{ min}
R_{\max } \approx \frac{P_t G_t G_r \eta}{k T_b B}\left(N_{\bmod }\right)
Receiver Gain: How effectively the ground station collects and concentrates the incoming signal (i.e., ALMA's big dish listening to our incoming signal)
R_{\max } \approx \frac{P_t G_t G_r \eta}{k T_b B}\left(N_{\bmod }\right)
Received Power: How strong is the signal once it hits the ground receiver? (after traveling through empty space)
P_r = P_tG_tG_r \left( \frac{\lambda}{4\pi R}\right)^2 \cdot \eta
BHEX Mini
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
22\mu as<\theta_{\text{BHEX-Mini}} < 1800 \mu as
5.6 G \lambda < b_{s s}<9.3 G \lambda
0.11 G \lambda < b_{s g}<3.5 G \lambda
T_{orb}=90 \text{ min}
R_{\max } \approx \frac{P_t G_t G_r \eta}{k T_b B}\left(N_{\bmod }\right)
Receiver Gain: How effectively the ground station collects and concentrates the incoming signal (i.e., ALMA's big dish listening to our incoming signal)
R_{\max } \approx \frac{P_t G_t G_r \eta}{k T_b B}\left(N_{\bmod }\right)
Distance: How much distance did the signal travel through free space? (LEO vs. MEO!)
P_r = P_tG_tG_r \left( \frac{\lambda}{4\pi R}\right)^2 \cdot \eta
BHEX Mini
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
22\mu as<\theta_{\text{BHEX-Mini}} < 1800 \mu as
5.6 G \lambda < b_{s s}<9.3 G \lambda
0.11 G \lambda < b_{s g}<3.5 G \lambda
T_{orb}=90 \text{ min}
R_{\max } \approx \frac{P_t G_t G_r \eta}{k T_b B}\left(N_{\bmod }\right)
Receiver Gain: How effectively the ground station collects and concentrates the incoming signal (i.e., ALMA's big dish listening to our incoming signal)
R_{\max } \approx \frac{P_t G_t G_r \eta}{k T_b B}\left(N_{\bmod }\right)
- Since BHEX Mini's laser downlink would suffer less signal loss from LEO than BHEX at MEO, can we transmit more data?
- Can this be leveraged to use 2-bit quantization instead of 1-bit quantization?
BHEX Mini
Sub-milli arcsecond angular resolution
Dual short and long baseline lengths
Rapid coverage of (u,v) plane
Decreased radiation environment in LEO vs. MEO
22\mu as<\theta_{\text{BHEX-Mini}} < 1800 \mu as
5.6 G \lambda < b_{s s}<9.3 G \lambda
0.11 G \lambda < b_{s g}<3.5 G \lambda
T_{orb}=90 \text{ min}
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
22\mu as<\theta_{\text{BHEX-Mini}} < 1800 \mu as
5.6 G \lambda < b_{s s}<9.3 G \lambda
0.11 G \lambda < b_{s g}<3.5 G \lambda
T_{orb}=90 \text{ min}
Decreased ISM scattering at LEO than MEO
R_{\max } \approx \frac{P_t G_t G_r \eta}{k T_b B}\left(N_{\bmod }\right)
P_r = P_tG_tG_r \left( \frac{\lambda}{4\pi R}\right)^2 \cdot \eta
BHEX Mini
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)
BHEX Mini
Decreased ISM scattering at LEO than MEO
V_{obs}(b) = S\cdot \exp\left(-\frac{\pi^2 b^2\theta^2}{4\ln 2}\right)\exp \left(-\frac{1}{2} C_\phi^2 b^\alpha r_F^{2-\alpha}\right)
Intrinsic Gaussian Source
b=\frac{\lambda}{D}\to \text{BHEX Mini: } 0.1G\lambda b_{sg}<3.5G\lambda
b=\frac{\lambda}{D}\to \text{BHEX:}\geq 20G\lambda
BHEX Mini
Decreased ISM scattering at LEO than MEO
V_{obs}(b) = S\cdot \exp\left(-\frac{\pi^2 b^2\theta^2}{4\ln 2}\right)\exp \left(-\frac{1}{2} C_\phi^2 b^\alpha r_F^{2-\alpha}\right)
ISM Scattering
C_{\phi}\propto \lambda^2 (\lambda_{\text{BHEX Mini}}=3.5 mm)
- At MEO, BHEX is 20x the orbital altitude of BHEX Mini
- BHEX observes at a f=320 GHz, 4x higher than BHEX Mini
BHEX Mini
Decreased ISM scattering at LEO than MEO
V_{ratio}(b) = \frac{e^{-b_{\text{BHEX-Mini}}^2} e^{-\lambda_{\text{BHEX-Mini}}^2 b^\alpha}}{e^{-b_{\text{BHEX}}^2} e^{-\lambda_{\text{BHEX}}^2 b^\alpha}}
\lambda_{\text{BHEX Mini}}=3.7\lambda_{\text{BHEX}}, b_{\text{BHEX Mini}} = \frac{1}{5}b_{\text{BHEX}}
\lambda_{\text{BHEX}}=1.33mm, b_{\text{BHEX Mini}} \sim 20G\lambda
V_{\text{BHEX-Mini}}\sim 10V_{\text{BHEX}}
BHEX Mini Visibility Amplitude Advantage
Regardless of Source Flux Density!
V_{obs}(b) = S\cdot \exp\left(-\frac{\pi^2 b^2\theta^2}{4\ln 2}\right)\exp \left(-\frac{1}{2} C_\phi^2 b^\alpha r_F^{2-\alpha}\right)
BHEX Mini
BHEX Mini
Size
Weight
Power
Power
Cost
\sim 2.5m
\sim 25-50kg
22 kg
300W
400mW @15^{\circ}K
\$10 \text{mln}
754 mm \times \\ 146 mm \times \\ 300 mm
\$2-5 \text{Mln}
\$4-11 \text{Mln}
10-20W
\text{(deployment)}
5-7 kg
\sim 10W
\sim \$ 1 \text{mln}
\sim0.02m^3
\sim 1 kg
\sim 3W
\sim \$1\text{mln}^*
60 mm\times \\60mm \times \\32 mm
1U (100 mm\times \\100 mm \times \\100 mm)
1.2 kg
1.2 kg
100W
\sim \$100\text{k}
3U (300 mm\times \\300 mm \times \\300 mm)
100W
3 kg
\sim \$1\text{mln}^*
\sim 4W
\sim 4W
12 mm \times \\12 mm
\sim \$1\text{mln}^*
BHEX Mini SWaPC
Size
Weight
Power
Power
Cost
\sim 2.5m
\sim 25-50kg
22 kg
300W
400mW @15^{\circ}K
\$10 \text{mln}
754 mm \times \\ 146 mm \times \\ 300 mm
\$2-5 \text{Mln}
\$4-11 \text{Mln}
10-20W
\text{(deployment)}
5-7 kg
\sim 10W
\sim \$ 1 \text{mln}
\sim0.02m^3
\sim 1 kg
\sim 3W
\sim \$1\text{mln}^*
60 mm\times \\60mm \times \\32 mm
1U (100 mm\times \\100 mm \times \\100 mm)
1.2 kg
1.2 kg
100W\\\text{generated}
\sim \$100\text{k}
3U (300 mm\times \\300 mm \times \\300 mm)
100W
3 kg
\sim \$1\text{mln}^*
\sim 4W
\sim 1 kg^*
12 mm \times \\12 mm
\sim \$1\text{mln}^*
\sim85.3 kg
\sim 437 W
\sim \$25\text{ million}
N/A
BHEX Mini
BHEX Mini
Antenna
BHEX Mini
Receiver
BHEX Mini
Cryocooler
BHEX Mini
Cryocooler
HiPTC Heat Intercepted Pulse Tube Cooler
- Cost: $10 Million
- Mass: 22kg
-
Cooling power
- 400 mW at 15K
- 5.2 W at 100K
- Electric power: 300 W
BHEX Mini
Solar Panels
BHEX Mini
Ultra-Stable Oscillator
BHEX Mini
Ultra-Stable Oscillator
\Delta \phi = 2\pi \cdot f \cdot \sigma_t
\sigma_t = \sigma_f \cdot \Delta t
Phase Error
BHEX Mini
Ultra-Stable Oscillator
\sigma_f = 5\cdot 10^{-11}, f_{obs}=86 \text{ GHz}
\Delta t = 1s:
\sigma_t = 5\cdot 10^{-11} \cdot 1s = 5\cdot 10^{-11} s
\Delta \phi = 2\pi \cdot (86\cdot 10^9 \text{ Hz}) \cdot 5\cdot 10^{-11} s=27.01 \text{ rad}
\Delta t = 10s:
\sigma_t = 5\cdot 10^{-11} \cdot 10s = 50\cdot 10^{-11} s
\Delta \phi = 2\pi \cdot (86\cdot 10^9 \text{ Hz}) \cdot 50\cdot 10^{-11} s=270.01 \text{ rad}
\Delta \phi<1 \text{ rad for Phase Coherence}
BHEX Mini
Ultra-Stable Oscillator
Allan Deviation
f=86 \text{ GHz}, t=10s, \sigma_y = 5\cdot 10^{-11}
L = 1-\exp\left[-2\pi^{2}(86\cdot 10^9)^{2}(10)^{2}(5\cdot 10^{-11})^{2}\right]
ABRACON SMD OCXO
L = 1-\exp\left(-2\pi^{2}f^{2}t^{2}\sigma_y^{2}\right)
L\sim 1\%<10\% \text{ required for Phase Coherence}
BHEX Mini
Digital Backend
BHEX Mini
Original Analog Radio Signal
BHEX Mini
Sample the Signal every Unit Interval
f_s\geq 2f
Nyquist-Shannon Sampling Theorem
BHEX Mini
Retain only the samples and record the sign of the voltage for each sample
BHEX Mini
Reconstruct the original signal
BHEX Mini
\eta_{Q}(N_{bit})\sim 1-\frac{\pi}{2}\cdot 2^{-2N_{bit}}
SNR = \eta_{corr}\times \frac{T_{source}}{T_{system}}\times \sqrt{\Delta \nu \cdot \tau}
\operatorname{Rate}(\mathrm{bps})=N_{\text {bits }} \times \Delta \nu \times 2_{\text {pol }} \times 2_{\text {Nyquist }}
\eta = \sqrt{\eta_1\eta_2}
BHEX Mini
\eta_{Q}(N_{bit})\sim 1-\frac{\pi}{2}\cdot 2^{-2N_{bit}}
SNR = \eta_{corr}\times \frac{T_{source}}{T_{system}}\times \sqrt{\Delta \nu \cdot \tau}
\operatorname{Rate}(\mathrm{bps})=N_{\text {bits }} \times \Delta \nu \times 2_{\text {pol }} \times 2_{\text {Nyquist }}
\eta = \sqrt{\eta_1\eta_2}
Quantization Efficiency: how much of the analog SNR is retained after digitization
\eta_{Q}(1)\sim 63\%
\eta_{Q}(2)\sim 88\%
BHEX Mini
\eta_{Q}(N_{bit})\sim 1-\frac{\pi}{2}\cdot 2^{-2N_{bit}}
SNR = \eta_{corr}\times \frac{T_{source}}{T_{system}}\times \sqrt{\Delta \nu \cdot \tau}
\operatorname{Rate}(\mathrm{bps})=N_{\text {bits }} \times \Delta \nu \times 2_{\text {pol }} \times 2_{\text {Nyquist }}
\eta = \sqrt{\eta_1\eta_2}
SNR: Signal to Noise Ratio
SNR = 0.88\times \frac{1K}{100K}\times \sqrt{32 \text{GHz} \cdot 10\text{s}}=4.98
BHEX Mini
\eta_{Q}(N_{bit})\sim 1-\frac{\pi}{2}\cdot 2^{-2N_{bit}}
SNR = \eta_{corr}\times \frac{T_{source}}{T_{system}}\times \sqrt{\Delta \nu \cdot \tau}
\operatorname{Rate}(\mathrm{bps})=N_{\text {bits }} \times \Delta \nu \times 2_{\text {pol }} \times 2_{\text {Nyquist }}
\eta = \sqrt{\eta_1\eta_2}
Data Generation Rate: In Bits per Second
\text{Rate} = (2+2)\times 32 \text{ GHz} \times 2 \cdot 2=512 \text{Gb/s}
BHEX Mini
\eta_{Q}(N_{bit})\sim 1-\frac{\pi}{2}\cdot 2^{-2N_{bit}}
SNR = \eta_{corr}\times \frac{T_{source}}{T_{system}}\times \sqrt{\Delta \nu \cdot \tau}
\operatorname{Rate}(\mathrm{bps})=N_{\text {bits }} \times \Delta \nu \times 2_{\text {pol }} \times 2_{\text {Nyquist }}
\eta = \sqrt{\eta_1\eta_2}
Cross-Correlation
🕒 Prospective Timeline
June
July
August
September
🕒 Prospective Timeline
June
July
August
September
- NASA NIAC 2025 Phase I Step I
- SpaceCom Conference 2026
- Brown Nelson + Hazeltine Grants
-
Antenna Focus
- Nacer Chahat
- Emmanuel Decrossas
🕒 Prospective Timeline
June
July
August
September
- NSF Foundational Research in Robotics Grant (FRR)
- Fall Walls Foundation Selections
- NASA NIAC 2025 Phase I Step I
- SpaceCom Conference 2026
- Brown Nelson + Hazeltine Grants
-
Antenna Focus
- Nacer Chahat
- Emmanuel Decrossas
-
Cryocooler Focus
- SunPower
- Blue Marble
🕒 Prospective Timeline
June
July
Aug
September
- NSF Foundational Research in Robotics Grant (FRR)
- Fall Walls Foundation Selections
- Brown University Co-Lab
- NASA NIAC Phase I Round I Step B Selections Announced
-
Solar Panel Focus
- DCubed Inc.
- DHV Tech
- NASA NIAC 2025 Phase I Step I
- SpaceCom Conference 2026
- Brown Nelson + Hazeltine Grants
-
Antenna Focus
- Nacer Chahat
- Emmanuel Decrossas
-
Cryocooler Focus
- SunPower
- Blue Marble
🕒 Prospective Timeline
June
July
Aug
Sep
-
Cryocooler Focus
- SunPower
- Blue Marble
- NSF Foundational Research in Robotics Grant (FRR)
- Fall Walls Foundation Selections
- Brown University Co-Lab
- NASA NIAC Phase I Round I Step B Selections Announced
-
Solar Panel Focus
- DCubed Inc.
- DHV Tech
- NSF Advanced Technologies and Instrumentation for the Astronomical Sciences (ATI)
-
Data Downlink Focus
- MIT Lincoln Labs
- ALICE/CLICK Teams
- NASA NIAC 2025 Phase I Step I
- SpaceCom Conference 2026
- Brown Nelson + Hazeltine Grants
-
Antenna Focus
- Nacer Chahat
- Emmanuel Decrossas
💰Funding Deadlines
June
$3,000
💰Funding Deadlines
July
$175,000
$3,000
$175,000
💰Funding Deadlines
Sep
$175,000
$3,000
$250,000
💰Funding Deadlines
Oct
$175,000
$3,000
$250,000
💰Funding Deadlines
BHEX Mini | Brown CASS Talk
By Ref Bari
