Direct Imaging Black Holes from LEO
Ref Bari | 06/21 Update
Physics
Engineering
Funding
Phy
Eng
Fund
Phy
Eng
Fund
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
Phy
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
Phy
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
Phy
Sub-milli arcsecond angular resolution:
Dual short and long baseline lengths:
Rapid coverage of (u,v) plane:
Fund
Decreased signal loss from LEO:
Decreased radiation environment in LEO vs. MEO
Decreased radiation environment in LEO vs. MEO
Phy
Rapid coverage of (u,v) plane:
Fund
Decreased signal loss from LEO:
Decreased radiation environment in LEO vs. MEO
Decreased radiation environment in LEO vs. MEO
Phy
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
Phy
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
Phy
Challenges of Low-Earth Orbit at 86 GHz
Phy
BHEX Mini Science Objectives (Safety)
BHEX Mini Science Objectives (Match)
BHEX Mini Science Objectives (Reach)
Eng
Fund
Phy
Eng
Fund
Phy
Eng
Fund
Phy
Eng
Fund
Phy
Eng
Fund
Phy
Eng
Fund
Phy
Eng
Fund
Phy
Eng
Fund
Phy
Eng
Fund
Phy
Eng
Fund
Phy
Eng
Fund
Phy
Eng
Fund
Phy
Eng
Fund
LT-RSP2 Cryocooler
Raytheon long life cryocoolers for future space missions (T. Conrad et. al., Cryogenics 2017)
Phy
Eng
Fund
Stirling Cryocooler
Development of Advanced Two-Stage Stirling Cryocooler for Next Space Missions (Y. Sato et. al., Cryocoolers 15, 2009)
Phy
Eng
Fund
Stirling Cryocooler
Development of Advanced Two-Stage Stirling Cryocooler for Next Space Missions (Y. Sato et. al., Cryocoolers 15, 2009)
Phy
Eng
Fund
Phy
Eng
Fund
Phy
Eng
Fund
Phase Error
Observing Frequency
Timing Jitter
Allan Deviation
Integration Time
Integration Time
Phy
Eng
Fund
Phy
Eng
Fund
Phy
Eng
Fund
Coherence Loss
Observing Frequency
Integration Time
Allan Deviation
Allan Deviation
ABRACON SMD OCXO
Allan Deviation
ABRACON SMD OCXO
Allan Deviation
ABRACON SMD OCXO
Phy
Eng
Fund
Phy
Eng
Fund
Phy
Eng
Fund
Phy
BHEX Mini Science Objectives (Safety)
BHEX Mini Science Objectives (Match)
BHEX Mini Science Objectives (Reach)
Todd Ely
Joseph Lazio
Eric Burt
Ben Hudson
Luke Anderson
Rick Fleeter
Todd Ely
Todd Ely
TLDR: It will be tough to fit an highly accurate clock on a small satellite
TLDR: It will be tough to fit an highly accurate clock on a small satellite
Eric Burt
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:
Sub-milli arcsecond angular resolution:
Dual short and long baseline lengths:
Sub-milli arcsecond angular resolution:
Dual short and long baseline lengths:
Sub-milli arcsecond angular resolution:
Dual short and long baseline lengths:
Sub-milli arcsecond angular resolution:
Dual short and long baseline lengths:
Rapid coverage of (u,v) plane:
Michael Johnson et. al., BHEX Team, 2024
Sub-milli arcsecond angular resolution:
Dual short and long baseline lengths:
Rapid coverage of (u,v) plane:
Mid-Range Science Objectives for the Event Horizon Telescope (EHT Collaboration, 2024)
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:
Less power required for data downlink from LEO than MEO:
Sub-milli arcsecond angular resolution:
Dual short and long baseline lengths:
Rapid coverage of (u,v) plane:
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:
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:
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:
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:
Antenna Efficiency: How efficient are
both the space and ground antennas?
Sub-milli arcsecond angular resolution:
Dual short and long baseline lengths:
Rapid coverage of (u,v) plane:
Noise Temperature: Background noise
of (similar to thermal noise) of receiver; Lower T means higher SNR.
Sub-milli arcsecond angular resolution:
Dual short and long baseline lengths:
Rapid coverage of (u,v) plane:
Bandwidth: How "wide" the signal is in frequency space. A high frequency bandwidth is good (except possibly for thermal noise*!)
Sub-milli arcsecond angular resolution:
Dual short and long baseline lengths:
Rapid coverage of (u,v) plane:
Bits per photon: How many bits each photon is encoded by (i.e., 1 bit or 2 bit)
Sub-milli arcsecond angular resolution:
Dual short and long baseline lengths:
Rapid coverage of (u,v) plane:
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:
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:
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
Original Mission
Descoped Mission
Descope Mission #2
OG
Descoped Mission
Descope Mission #2
OG
DS1
Descope Mission #2
OG
DS1
DS2
Antenna
Cryocooler
Frequency Reference System
Antenna
Cryocooler
Frequency Reference System
Antenna
RSP2
Frequency Reference System
Antenna
RSP2
USO
Antenna
RSP2
USO
3C 84
NRAO 530
NGC 1052
BL Lac
3C 273
3C 84
NRAO 530
NGC 1052
BL Lac
3C 273
3C 84: Nucleus of galaxy NGC 1275 (22 GHz)
NRAO 530
NGC 1052
BL Lac
3C 273
3C 84
NRAO 530: Quasar 230 GHz, 20 μas (EHT)
NGC 1052
BL Lac
3C 273
3C 84
NRAO 530
NGC 1052: Bright Elliptical Galaxy (65 mln lys)
BL Lac
3C 273
3C 84
NRAO 530
NGC 1052
BL Lac
3C 279: An 'optically violent' variable quasar
Gamma Ray Image
3C 84
NRAO 530
NGC 1052
BL Lac
3C 273
LT-RSP2 Cryocooler
Raytheon long life cryocoolers for future space missions (T. Conrad et. al., Cryogenics 2017)
Stirling Cryocooler
Development of Advanced Two-Stage Stirling Cryocooler for Next Space Missions (Y. Sato et. al., Cryocoolers 15, 2009)
Stirling Cryocooler
Development of Advanced Two-Stage Stirling Cryocooler for Next Space Missions (Y. Sato et. al., Cryocoolers 15, 2009)
Stirling Cryocooler
Development of Advanced Two-Stage Stirling Cryocooler for Next Space Missions (Y. Sato et. al., Cryocoolers 15, 2009)
Phase Error
Observing Frequency
Timing Jitter
Allan Deviation
Integration Time
Integration Time
Coherence Loss
Observing Frequency
Integration Time
Allan Deviation
Allan Deviation
ABRACON SMD OCXO
Allan Deviation
ABRACON SMD OCXO
Allan Deviation
ABRACON SMD OCXO
🕒 Prospective Timeline
June
July
August
September
🕒 Prospective Timeline
June
July
August
September
🕒 Prospective Timeline
June
July
August
September
🕒 Prospective Timeline
June
July
Aug
September
🕒 Prospective Timeline
June
July
Aug
Sep
🕒 Prospective Timeline
Antenna
🕒 Prospective Timeline
Cryocooler
🕒 Prospective Timeline
Solar Panels
🕒 Prospective Timeline
Orbital Parameters
🕒 Prospective Timeline
Data Downlink
🕒 Prospective Timeline
Systems Integration
💰Funding Oppurtunities
June
$3,000
💰Funding Oppurtunities
July
$175,000
$3,000
$175,000
💰Funding Oppurtunities
Sep
$175,000
$3,000
$250,000
💰Funding Oppurtunities
Oct
$175,000
$3,000
$250,000
💰Funding Oppurtunities
🎯 Mission Statement
🎯 Mission Statement
🎯 Mission Statement
Secondary
Science Targets
Gaussian Source Approximation
Visibility Amplitudes
Thermal Noise Constraints
SEFD Constraint
Constraints
Parameter Space
Antenna Diameter + Temperature!
Delta
Delta
Delta
Delta
Delta
🧠 The (u,v) Plane
🧠 The (u,v) Plane
🧠 The (u,v) Plane
🧠 The (u,v) Plane
🧠 The (u,v) Plane
🧠 The (u,v) Plane
🧠 The (u,v) Plane
🧠 The (u,v) Plane
Goal:
🧠 The (u,v) Plane
Intensity of a certain part of the sky/
sky brightness pattern
Goal: Measure
🧠 The (u,v) Plane
Goal: Measure
Coordinates in the sky
🧠 The (u,v) Plane
Now we add the effects of the radio interferometer ...
Coordinates in the sky
🧠 The (u,v) Plane
Now we add the effects of the radio interferometer ...
Multiplicative envelope:
comes from size of antennas
🧠 The (u,v) Plane
Now we add the effects of the radio interferometer ...
Simulates interference pattern
🧠 The (u,v) Plane
Now we add the effects of the radio interferometer ...
(u,v): Baseline vector
u: East-west baseline distance
v: North-south baseline distance
🧠 The (u,v) Plane
Take all the signals from the sky and add them up ...
🧠 The (u,v) Plane
Take all the signals from the sky and add them up ...
Visibility Function
🧠 The (u,v) Plane
Take all the signals from the sky and add them up ...
Multiplicative Envelope
🧠 The (u,v) Plane
Take all the signals from the sky and add them up ...
Sky Intensity/Brightness
🧠 The (u,v) Plane
Take all the signals from the sky and add them up ...
Interferometric Pattern
🧠 The (u,v) Plane
It's a Fourier Transformation!
One pair of antennas measures one single point on the (u,v) plane: one fourier mode!
🧠 The (u,v) Plane
It's a Fourier Transformation!
What we want
🧠 The (u,v) Plane
It's a Fourier Transformation!
What we get :(
🧠 The (u,v) Plane
It's a Fourier Transformation!
Fill up the (u,v) plane
and then fourier transform back to the real image!
🧠 The (u,v) Plane
It's a Fourier Transformation!
Fill up the (u,v) plane
and then fourier transform back to the real image!
🧠 The (u,v) Plane
But how do you fill up the (u,v) plane?
🧠 The (u,v) Plane
But how do you fill up the (u,v) plane?
🧠 The (u,v) Plane
🧠 The (u,v) Plane
🧠 The (u,v) Plane
But how do you fill up the (u,v) plane?
2. Earth Rotation Aperture Synthesis
🧠 The (u,v) Plane
2. Earth Rotation Aperture Synthesis