National Aeronautics and Space AdministrationJet Propulsion LaboratoryCalifornia Institute of Technology
6/25/2019 COMPETITION SENSITIVE: PRE-DECISION DRAFT: For Planning and Discussion Purposes Only
1PRE-DECISION DRAFT: For Planning and Discussion Purposes Only
NEOCam Update
Joe Masiero(NASA Jet Propulsion Laboratory/California Institute of Technology)
June 2019
March 2019 Pre-Decisional Information – For Planning and Discussion Purposes only
National Aeronautics and Space AdministrationJet Propulsion LaboratoryCalifornia Institute of Technology Top Goal
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National Aeronautics and Space AdministrationJet Propulsion LaboratoryCalifornia Institute of Technology Top Goal
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National Aeronautics and Space AdministrationJet Propulsion LaboratoryCalifornia Institute of Technology
NEOs: The Critical Questions• Need to know when impacts could occur and how bad they will be
• When: Comes from finding objects & determining good orbits for them
• How bad: Comes from measuring the impact energy (KE)• Impact energy scales as KE = ½ mass x velocity2• Velocity comes from orbit• Mass = density x volume = density x diameter3• Impact energy depends strongly on diameter
• NEOCam is narrowly focused on answering these questions
NEOCam is a dual-channel imager operating in a single step-and-stare survey mode.
• PI: Amy Mainzer• 50 cm telescope• Two 16 megapixel HgCdTe focal
planes at 4-5.2 & 6-10 μmsimultaneously imaged
• Detectors passively cooled to 40K• Sun-Earth L1 orbit• First proposed 2005• Awarded technology development
funding in 2011 Discovery• Awarded Extended Phase A in 2016• System Requirements Review/Mission
Definition Review passed Feb 2018• Pre-KDP-B review for instrument
passed 11/18 – KDP-B to be scheduled soon
NEOCam
Pre-Decisional Information – For Planning and Discussion Purposes only
PresenterPresentation NotesNEOCam is designed to leverage the NEOWISE experience at finding and characterizing asteroids using a space-based IR telescope.
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Asteroid Spectral Energy Distributions Peak in the Infrared
Albedo = 3%
Albedo = 17%
Wavelength (µm)
Flux
(Jy)
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National Aeronautics and Space AdministrationJet Propulsion LaboratoryCalifornia Institute of Technology
NEOs Are Bright in IR; Stars Less So
Cyan = 3.4 micronsYellow = 12 micronsRed = 22 microns
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NEOCam Is Capable of Approaching 90% for PHAs >140m
From NASA NEO SDT Report (Stokes et al. 2017)• GBO = Ground-based observatory
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Cadence & Follow Up
• The NEOCam survey cadence is designed to produce orbits good enough to distinguish an NEO from an MBA
• Cadence optimized for this purpose
• Most objects are detected on many epochs spanning months or years
• In the event there is an object of particular interest, we have the ability to interrupt survey with a Target of Opportunity mode
• Survey cadence consists of a repeating pattern collected on either side of the Sun on ~2 week cycle
National Aeronautics and Space AdministrationJet Propulsion LaboratoryCalifornia Institute of Technology Mission Objectives
• Find 2/3 of PHAs >140 m in 5 years (goal: 90%) [driving requirement]
• Produce diameters for all detected objects
• Compute albedos where visible data are available
• Compute cumulative chance of impact over next century from PHAs >50 m and comets
• Deliver tracklet data daily; images & extracted source lists every 6 months
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Extended Phase A Technical Progress• Manufacturing flight pathfinder sensor chip assemblies (SCAs)
• Monolithic 2048 x 2048 devices shown to exceed NEOCamrequirements
• Multiple lots grown and processed of both 5 um and 10+ um devices• Extensive radiation & environmental testing performed
• Engineering Unit Camera Enclosure Assembly fabricated and undergoing thermal testing to validate predicted heat loads and temperatures
• Prototyping of NEOCam science data processing pipeline components underway, including
• construction of simulated images • development image differencing proof-of-concept• machine learning-assisted quality assurance• tracklet linking simulations
National Aeronautics and Space AdministrationJet Propulsion LaboratoryCalifornia Institute of Technology
Detectors• Partnership between Teledyne Imaging Sensors, Univ. of Rochester, JPL• 4 x 1 mosaic of detectors in each channel imaging simultaneously• Long-wavelength HgCdTe material bonded to 20482 HAWAII-2RG readout
• Cutoffs >10 um demonstrated to exceed NEOCam dark current requirements• Mode of dark current driven down to
National Aeronautics and Space AdministrationJet Propulsion LaboratoryCalifornia Institute of Technology
NEOCam Investigation Team Functions• Investigation Team members ensure mission achieves its Level 1 requirements.
• NEOCam Investigation Team consist of experts in systems engineering, asteroid & comet properties, focal planes, IR instrumentation, & data system architecture.
• Key functions of the Investigation Team:• Develop Level 1 requirements • Calculate & monitor observatory performance against the Level 1
requirements throughout development phases• Develop survey cadence & ensure that it delivers adequate orbits• Develop & deliver survey planning tool used during ops• Contribute expertise on IR focal planes & instrumentation• Ensure data are properly calibrated (fluxes & positions)• Process data & extract moving object candidates• Link candidate moving objects into tracklets & submit to archives• Compute physical properties for objects & deliver to archives
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National Aeronautics and Space AdministrationJet Propulsion LaboratoryCalifornia Institute of Technology
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Mission Objectives• Make significant rapid progress toward finding &
tracking the majority of near-Earth asteroids & comets large enough to cause severe regional damage (diameters >=140m)
• Constrain impact energies to assess risk• Predict the chance of impact from objects capable
of causing severe local damage (diameters 50-140m)
Mission Highlights• 50-cm infrared telescope• Sun-Earth L1 Lagrange point halo
orbit• 2 channels: 4-5.2 um & 6-10 um• FOV: 12.7 sq deg• 3 arcsec pixels• Survey cadence optimized for
detection of potentially hazardous near-Earth asteroids & comets
Approach• JPL will provide the single instrument, including
systems engineering & thermal design• Instrument integration & electronics provided by
Space Dynamics Lab • Telescope (3-mirror anastigmat, beamsplitter, filters,
baffles) provided by L3-SSG• Detectors designed & manufactured by Teledyne
Imaging Systems• Detector characterization performed at U of Rochester• Spacecraft bus & flight system I&T provided by Ball• Survey planning tool & performance prediction by PSI• Image processing & data archiving by IPAC/Caltech
Key Milestones• Discovery Step 1 2006, 2010, 2015• Technology development funding awarded for
detectors in 2011• Discovery Step 2 in 2016• Extended Phase A awarded 2017• SRR/MDR February 2018• Pre-KDP B for instrument November 2018
Near-Earth Object Camera (NEOCam)PI: Amy Mainzer
Telescope entrance aperture
Sunshade & solar panels
Pre-Decisional Information – For Planning and Discussion Purposes only
National Aeronautics and Space AdministrationJet Propulsion LaboratoryCalifornia Institute of Technology
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Data System & Products• Data products scoped to provide minimum needed to meet planetary
defense mission objectives: • Reliable detections & orbits• Diameters for all objects• Albedos where visible archival data are available• Updated estimate of impact probabilities from asteroids & comets
• Data system architecture based on WISE, 2MASS, Spitzer architecture
• Detections delivered daily to Minor Planet Center (MPC)• Required to provide >90% reliable detections to MPC avoid
contaminating catalog & producing false alarms
• Images, static sky atlas, extracted source databases delivered every 6 months to NASA’s Infrared Science Archive
• Lead: Caltech/IPAC
• Minor planet diameters & albedos delivered to NASA’s Planetary Data System every 6 months
• Lead: Investigation Team
National Aeronautics and Space AdministrationJet Propulsion LaboratoryCalifornia Institute of Technology Why 140 m and up?
• Two detailed studies (Stokes et al. 2003 & 2017) showed that the bulk of the integrated risk (probability x severity) comes from the largest objects that have not been found and eliminated from further consideration.
• Basically, the big impactors are extremely bad because of D3• This term dominates the risk calculation
• Below 140 m, the risk switches to become evenly split between smaller asteroids and long-period comets
• Small asteroids are far more numerous, but their impacts are less bad • However, their true numbers are poorly known
• Long-period comets are far less numerous, but their impacts are very bad due to high velocities & large sizes
• However, their true numbers are also poorly known
• NEOCam would address the risk from the largest objects (>140 m) and would tell us about the relative numbers of smaller asteroids and long-period comets
• Thus, it would inform whether or not to do any further planetary defense surveys after this one
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National Aeronautics and Space AdministrationJet Propulsion LaboratoryCalifornia Institute of Technology NEO Albedo Distribution
• There is a population of very dark NEOs (3% albedo), and a population of less dark ones (17% albedo)
• Data from NEOWISE• Recent results from Ryugu and
Bennu confirm very low albedos
Albedo
Num
ber o
f Obj
ects
3% albedo 17% albedo
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National Aeronautics and Space AdministrationJet Propulsion LaboratoryCalifornia Institute of Technology Mission Summary:
NEOCam Is a Planetary Defense Mission
• NEOCam is designed to respond to the objectives of NASA’s Planetary Defense Coordination Office by discovering, tracking, and characterizing NEOs
• NEOCam is optimized for the task of finding and characterizing the risks posed by potentially hazardous objects (PHOs), both as individual objects and as populations
• NEOCam provides critical decision support for stakeholders who must assess the risks of NEO impacts to Earth and must identify potential mitigation strategies
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National Aeronautics and Space AdministrationJet Propulsion LaboratoryCalifornia Institute of Technology
Orbit: Sun-Earth L1 Lagrange Point
• Close, constant distance from Earth allows full-frame images to be downlinked
• Thermal environment allows passive cooling to 40 K
• Key enabling technology
NEOCam Viewing Zones
NEOWISE Viewing Zone
National Aeronautics and Space AdministrationJet Propulsion LaboratoryCalifornia Institute of Technology Cadence
NEOCam Update��Joe Masiero�(NASA Jet Propulsion Laboratory/California Institute of Technology)��June 2019Top GoalTop GoalNEOs: The Critical QuestionsNEOCamAsteroid Spectral Energy Distributions Peak in the InfraredNEOs Are Bright in IR; Stars Less SoNEOCam Is Capable of Approaching 90% for PHAs >140m Cadence & Follow UpMission ObjectivesExtended Phase A Technical ProgressDetectorsNEOCam Investigation Team FunctionsBackupSlide Number 15Data System & ProductsWhy 140 m and up?NEO Albedo DistributionMission Summary: �NEOCam Is a Planetary Defense MissionOrbit: Sun-Earth �L1 Lagrange PointCadence
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