BHEX Mini

08/03: ISM Scattering + Templeton Grant

Ref Bari, Brown University

BHEX Mini

BHEX Meeting: 08/15 at 2 PM (Friday)

Templeton Grant: 08/15 at 11:59 PM (Friday)

Michael Johnson: 09/22 at 4 PM (Monday)

Princeton IAS: 09/04 at 12 PM (Thursday)

BHEX Mini

BHEX Meeting: 08/15 at 2 PM (Friday)

Templeton Grant: 08/15 at 11:59 PM (Friday)

Michael Johnson: 09/22 at 4 PM (Monday)

Princeton IAS: 09/04 at 12 PM (Thursday)

Laura Kennedy

Laura A. Kennedy is the deputy lead of the Civil Space Systems and Technology Office at MIT Lincoln Laboratory. She helps coordinate a Laboratory-wide portfolio of efforts that develop and deliver dual-use technologies and complex prototypes to enable civilian space missions.

Jade Wang

Laser Communications Lead, BHEX Team

BHEX Mini

BHEX Meeting: 08/15 at 2 PM (Friday)

Templeton Grant: 08/15 at 11:59 PM (Friday)

Michael Johnson: 09/22 at 4 PM (Monday)

Princeton IAS: 09/04 at 12 PM (Thursday)

BHEX Mini

BHEX Meeting: 08/15 at 2 PM (Friday)

Templeton Grant: 08/15 at 11:59 PM (Friday)

Michael Johnson: 09/22 at 4 PM (Monday)

Princeton IAS: 09/04 at 12 PM (Thursday)

BHEX Mini

BHEX Meeting: 08/15 at 2 PM (Friday)

Templeton Grant: 08/15 at 11:59 PM (Friday)

Michael Johnson: 09/22 at 4 PM (Monday)

Princeton IAS: 09/04 at 12 PM (Thursday)

BHEX Mini

Tentative Faculty Co-PIs: 08/15

BHEX Mini

Tentative Faculty Co-PIs

BHEX Mini

Michael Johnson: 09/22 at 4 PM (Monday)

Princeton IAS: 09/04 at 12 PM (Thursday)

BHEX Meeting: 08/15 at 2 PM (Friday)

Laura Kennedy

Jade Wang

...

BHEX Mini

BHEX Mini

BHEX Meeting: 08/15 at 2 PM (Friday)

Templeton Grant: 08/15 at 11:59 PM (Friday)

Michael Johnson: 09/22 at 4 PM (Monday)

Princeton IAS: 09/04 at 12 PM (Thursday)

BHEX Mini

Michael Johnson: 09/22 at 4 PM (Monday)

Princeton IAS: 09/04 at 12 PM (Thursday)

BHEX Mini

BHEX Meeting: 08/15 at 2 PM (Friday)

Templeton Grant: 08/15 at 11:59 PM (Friday)

Michael Johnson: 09/22 at 4 PM (Monday)

Princeton IAS: 09/04 at 12 PM (Thursday)

BHEX Mini

BHEX Mini

BHEX Meeting: 08/15 at 2 PM (Friday)

Templeton Grant: 08/15 at 11:59 PM (Friday)

Michael Johnson: 09/22 at 4 PM (Monday)

Princeton IAS: 09/04 at 12 PM (Thursday)

Michael Johnson

PI, BHEX

• Does the Foundation have particular funding areas?
• Does the Foundation have formal funding deadlines?
• Does the Foundation fund non-U.S. organizations?
• Does the Foundation provide challenge grants?

• Does the Foundation have particular funding areas?
  • Yes, guided by the vision of the founder of the John Templeton Foundation, we have identified several major funding areas. Learn more about them on our website.
• Does the Foundation have formal funding deadlines?
  • Yes. We have several funding cycles with different deadlines. You can submit an application (an Online Funding Inquiry or OFI) at any point during the year. However, we review all funding requests according to specific dates and deadlines outlined in our grantmaking calendar.
• Does the Foundation fund non-U.S. organizations?
  • Yes, the Foundation has made grants to organizations from around the world.
• Does the Foundation provide challenge grants?
  • Typically no. The Foundation generally funds specific projects and favors proposals where the applicant has sought or secured partial funding from other sources.

• What is the typical duration of the Foundation’s grants?
  • The grant duration is often up to three years. In rare instances the Foundation may support a project for up to five years. The Foundation will not fund any project for more than five years. Projects can be renewed under specific guidelines.
   What funding area should I select for my project?
  • Please select the funding area that you think best fits your project. You can refer to the pages listed under Funding Areas on our website to see examples of projects we’ve previously funded within each area. As part of the review process, Foundation staff may reassign the funding area as needed.
   Should citations or references be included in our OFI?
  • Please use your judgment in deciding how many citations are necessary to include when describing your project idea. While in-line citations for key references can be helpful, especially where the proposed project is building on or challenging a particular line of work, we do not expect a full reference list at the project proposal stage.
   Does the Foundation require co-funding in grant applications?
  • Co-funding is not required for first-time applicants; however, the Foundation prioritizes projects that include substantial funding from other sources. If you are seeking renewal or follow-up funding, your proposal should include plans for securing more than 50% of the project funds from other sources.

Black holes are the most mysterious objects in the cosmos. Due to their extreme nature -- a singularity cloaked by an event horizon -- they are foundational in many fields. Mathematicians use them to study the very stability of space and time; for astronomers, they are powerful actors on the Cosmic stage, not only determining the evolution of galaxies but also forming during the cataclysmic death of stars; for physicists, the unification of general relativity and quantum mechanics at the singularity has occupied center stage for decades; and for philosophers, the event horizon boundary raises unique epistemological questions. Even the curious public wonders at these objects, imbuing them with imagined and fantastic properties that have found their way into literature, art and film.

The Black Hole Initiative formed in 2016 to create a meeting point for all these groups, conceived with the notion that cross disciplinary study would open bold new lines of attack on the big questions: what are black holes and how do they affect the Universe? The BHI has succeeded beyond all expectations. Our interdisciplinary community of scholars captured the first image of a black hole, we devised new approaches to the flow of information through the event horizon, and we harnessed modern computing to simulate the unknown black hole interior as well as the turbulent exterior; all this was recounted in a philosophically-minded feature length film that made these discoveries accessible to humanity.

In this next phase of the BHI, we propose to answer fresh questions posed by these accomplishments and enabled by our unique community. We will move from still images to making movies of black holes, we will simulate the evolution of black holes across cosmic time, the infinities encoded in photon orbits at the event horizon will be mined for new observational tests of gravity, and the cosmic censorship that shields singularities from view will be challenged.

Mathematical & Physical Sciences

For millennia, humanity has found awe and wonder in contemplating the cosmos. Today, scientists use ever-evolving tools to push the boundaries of our knowledge of the universe and our place and purpose within it.

• In our Mathematical and Physical Sciences funding area, we support research seeking to shed light on the fundamental concepts of physical reality. We also explore the interplay between these sciences and broader human experience.

• In our Mathematical and Physical Sciences funding area, we support research seeking to shed light on the fundamental concepts of physical reality. We also explore the interplay between these sciences and broader human experience.
• What is the nature of the universe that we inhabit? What are the most fundamental, microscopic constituents of physical reality? How are physical systems more than “the sum of their parts?” How do these various ideas come together? The John Templeton Foundation is interested in fundamental questions in the mathematical and physical sciences and how they might converge to form a coherent picture of physical reality.

• In our Mathematical and Physical Sciences funding area, we support research seeking to shed light on the fundamental concepts of physical reality. We also explore the interplay between these sciences and broader human experience.
• What is the nature of the universe that we inhabit? What are the most fundamental, microscopic constituents of physical reality? How are physical systems more than “the sum of their parts?” How do these various ideas come together? The John Templeton Foundation is interested in fundamental questions in the mathematical and physical sciences and how they might converge to form a coherent picture of physical reality.
• We also want to understand the roles and implications of the sciences within a wider context of human purposes. How do discoveries in the mathematical and physical sciences challenge our ways of thinking and reasoning? How do cultures, institutions, or societies impact how such research is conducted and vice versa? How can we further inspire awe and wonder at the unveiling of nature’s mysteries?

1. 🎯 Introduction
2. 🔭 Event Horizon Telescope
3. 📻 BHEX (Black Hole Explorer Satellite)
4. 🕰️ BHEX Mini
5. 🕒 BHEX Mini Timeline
6. 💰Funding Deadlines

BHEX Mini

1. 🎯 Introduction
2. 🔭 Event Horizon Telescope
3. 📻 BHEX (Black Hole Explorer Satellite)
4. 🕰️ BHEX Mini
5. 🕒 BHEX Mini Timeline
6. 💰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)

  • Funded under NSF Neural DynAMO Grant

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

1. 🎯 Introduction
2. 🔭 Event Horizon Telescope
3. 📻 BHEX (Black Hole Explorer Satellite)
4. 🕰️ BHEX Mini
5. 🕒 BHEX Mini Timeline
6. 💰Funding Deadlines

BHEX Mini

Black Hole (M87)

Event Horizon Telescope

Event Horizon Telescope (EHT)

Event Horizon Telescope

Event Horizon Telescope (EHT)

1. 🎯 Introduction
2. 🔭 Event Horizon Telescope
3. 📻 BHEX (Black Hole Explorer Satellite)
4. 🕰️ BHEX Mini
5. 🕒 BHEX Mini Timeline
6. 💰Funding Deadlines

BHEX Mini

Event Horizon Telescope

Event Horizon Telescope (EHT)

Black Holes: An Intro

Black Hole Explorer Satellite (BHEX) Mission

Imaging a Black Hole

(The black hole explorer: Motivation and vision, Johnson et. al., 2024)

1. 🎯 Introduction
2. 🔭 Event Horizon Telescope
3. 📻 BHEX (Black Hole Explorer Satellite)
4. 🕰️ BHEX Mini
5. 🕒 BHEX Mini Timeline
6. 💰Funding Deadlines

BHEX Mini

Spaceflight Heritage

EQUiSat

SBUDNIC

PVDX

Spaceflight Heritage

SBUDNIC

PVDX

EQUiSat

BHEX Mini

BHEX Mini

Imaging a Black Hole

"Metrics and Motivations for Earth–Space VLBI: Time-resolving Sgr A* with the Event Horizon Telescope​" Palumbo et. al. ApJ 2019

BHEX Mini

BHEX Mini

BHEX Mini

BHEX Mini

Jan 2025

BHEX Mini

Jan 2025

BHEX Mini

Jan 2025

BHEX Mini

Jan 2025

Feb 2025

BHEX Mini

Jan 2025

Feb 2025

Mar 2025

Rick Fleeter

Jan 2025

Feb 2025

Mar 2025

Apr 2025

BHEX Mini

Ben Hudson

Luke Anderson

• Advised on BHEX Mini by Prof. Rick Fleeter
• Submit to Rhode Island Space Grant

Jan 2025

Feb 2025

Mar 2025

Apr 2025

May 2025

BHEX Mini

Jeffrey Olson

• Advised on BHEX Mini by Prof. Rick Fleeter
• Submit to Rhode Island Space Grant

Jun 2025

Jul 2025

Todd Ely

Joseph Lazio

Eric Burt

Jan 2025

Feb 2025

Mar 2025

Apr 2025

May 2025

Jun 2025

Jul 2025

• Advised on BHEX Mini by Prof. Rick Fleeter
• Submit to Rhode Island Space Grant

Feb 2025

Mar 2025

Apr 2025

May 2025

Jun 2025

Jul 2025

• Advised on BHEX Mini by Prof. Rick Fleeter
• Submit to Rhode Island Space Grant

Aug 2025

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

Supplement (u,v) coverage at 86 GHz

Enable parameter estimation of Sgr A*/M87

Achieve Space-Space VLBI

BHEX Mini

Partner Satellite to BHEX

Supplement (u,v) coverage at 86 GHz

Enable parameter estimation of Sgr A*/M87

Achieve Space-Space VLBI

BHEX Mini

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:

• What kind of targets can we observe with this angular resolution?

BHEX Mini

Sub-milli arcsecond angular resolution:

Dual short and long baseline lengths

• What kind of targets can we observe with this angular resolution?

BHEX Mini

Sub-milli arcsecond angular resolution:

Dual short and long baseline lengths

• What kind of targets can we observe with this angular resolution?

BHEX Mini

Sub-milli arcsecond angular resolution:

Dual short and long baseline lengths

• What kind of targets can we observe with this angular resolution?

BHEX Mini

Sub-milli arcsecond angular resolution:

Dual short and long baseline lengths

• What kind of targets can we observe with this angular resolution?

Multifrequency Black Hole Imaging for the Next-generation Event Horizon Telescope (Chael et. al., 2023, ApJ)

BHEX Mini

Rapid coverage of (u,v) plane

• 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

BHEX Mini

BHEX Mini

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

BHEX Mini

Decreased signal loss from LEO

Maximum data transmission rate (in bits per second); How fast can you send data from BHEX Mini to the earth?

BHEX Mini

Decreased signal loss from LEO

Power of Transmitted Signal: Strength of downlink signal in Watts (i.e., shouting louder to be heard further away!)

BHEX Mini

Decreased signal loss from LEO

Transmitter Gain: How well-focused your signal is when it leaves the satellite

(i.e., shouting into a megaphone instead of into the wind)

BHEX Mini

Decreased signal loss from LEO

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)

BHEX Mini

Decreased signal loss from LEO

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!)

BHEX Mini

Decreased signal loss from LEO

Receiver Gain: How effectively the ground station collects and concentrates the incoming signal (i.e., ALMA's big dish listening to our incoming signal)

• 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 signal loss from LEO

Decreased radiation environment in LEO vs. MEO

Decreased ISM scattering at LEO than MEO

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

Intrinsic Gaussian Source

BHEX Mini

Decreased ISM scattering at LEO than MEO

ISM Scattering

• 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

BHEX Mini Visibility Amplitude Advantage

Regardless of Source Flux Density!

BHEX Mini

BHEX Mini

Size

Weight

Power

Power

Cost

BHEX Mini SWaPC

Size

Weight

Power

Power

Cost

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

Phase Error

BHEX Mini

Ultra-Stable Oscillator

BHEX Mini

Ultra-Stable Oscillator

Allan Deviation

ABRACON SMD OCXO

BHEX Mini

Digital Backend

BHEX Mini

Original Analog Radio Signal

BHEX Mini

Sample the Signal every Unit Interval

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

BHEX Mini

Quantization Efficiency: how much of the analog SNR is retained after digitization

BHEX Mini

SNR: Signal to Noise Ratio

BHEX Mini

Data Generation Rate: In Bits per Second

BHEX Mini

Cross-Correlation

🕒 Prospective Timeline

June

July

August

September

🕒 Prospective Timeline

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