112/2016

Solar System Exploration Program

Goddard Space Flight Center

Johnson Space Center

Langley Research Center

Glenn Research Center

Marshall Space Flight Center

Planetary Defense Coordination Office

Asteroid Impact & Deflection Assessment (AIDA)

DART Mission Overview15 August 2017

Cheryl Reed, APL Project Manager

& DART Team

Approved for Public Release, August 2017

2

DART: A Planetary Defense Mission

2010 National Research Council Committee

“Defending Planet Earth:

Near-Earth Object Surveys and Hazard Mitigation Strategies”

– NRC Recommendation: If Congress chooses to fund mitigation research at an

appropriately high level, the first priority for a space mission in the

mitigation area is an experimental test of a kinetic impactor along with a

characterization, monitoring, and verification system, such as the Don Quixote*

mission that was previously considered, but not funded, by the European Space

Agency. This mission would produce the most significant advances in

understanding and provide an ideal chance for international collaboration

in a realistic mitigation scenario.

*Earlier ESA mission proposal not selected, but has now evolved to AIDA

DART is the first test in a Planetary Defense

Technology Demonstration Plan

3

Regimes of Primary Applicability of the Four types of Planetary Defense Mitigation

Image courtesy of Tim Warchocki

4

DART Objectives & GoalsDART is the first test in a Planetary Defense Tech Demo Plan▪ Primary Test Objectives

• Demonstrate kinetic deflection of realistic scale asteroid and reduce key risks in

autonomous navigation and targeting

• Improve impact models by constraining the momentum enhancement due to ejecta

through comparison to pre-impact predictions

• Refine CONOPS for deflection missions and inform planning for planetary defense

decision process and policy definition

• Concept Programmatic Goals/Constraints

• Provide an affordable, design-to-cost implementation (w/o Launch & HQs. UFE, ~$205M,

Phase A-E) (relative to 2022 impact opportunity)

• Implement under Class D mission risk classification

• Leverage NEO Program initiatives and APL DOD capabilities

• Design for a commercial rideshare opportunity

• Demonstrate NASA’s NEXT Solar Electric Propulsion Technology

• Fly other enabling technologies as appropriate

• ROSAs, CoreSat avionics, SMARTNav, RLSA

• Provide for international collaboration opportunities; measurement independent

6

DART is targeting the Didymos system in October, 2022

▪Didymos is a well-characterized asteroid that

approaches close to Earth, enabling ground-

based observations of impact demonstration

▪The secondary (“Didymoon”) is realistic scale– Small enough to deflect kinetically and measure result

– Smaller NEOs represent a more frequent threat to Earth

Primary Diameter 780 m ± 10%

Secondary Diameter 163 m ± 18 m

Total System Mass (5.278 ± 0.54) × 1011 kg

Component Bulk Density 2,100 kg m−3 ± 30%

Primary Rotation Period 2.2600 ± 0.0001 h

Component Separation 1180 +40/-20 m

Secondary Orbital Period 11.920 +0.004/−0.006 h

Spectral Class S

Preliminary shape model of the Didymos primary from

combined radar and light curve data, diameter ~780 m.

The secondary (not imaged) may be more elongated.

Cheng AF et al. (2015) Acta

Astron., 115: 262

Cheng AF et al. (2016) Planet.

Space Sci., 121:27

Michel P et al. (2016) Adv.

Space Res., 57:2529

7

First Kinetic Impact Test at Realistic Scale for Planetary Defense

DART target much

smaller than the

Deep Impact target

Comet 9P/Tempel 1

Deep Impact target

DART target

Didymos moon

8

DART Baseline Trajectory (Deep Space)

Sun-Centered Inertial Frame

Earth-Centered Frame

2001 CB21

Flyby

Impact

Didymos

Impact2001 CB21

Flyby

▪ Launch Jan 26 2021, 640 kg (1 case within launch period)

▪ Clear GEO Altitude, May 26 2021, 600 kg (120 day)

▪ Clear Upper Van Allen Belts, June 18 2021, 592 kg (143 day)

▪ Escape Aug 28 2021, 568 kg (214 day)

▪ Continuous tangential thrusting, except for eclipses, tracking and phasing

arcs.

▪ Flyby: Mar 03 2022, 640 kg, 11.37 km/s (67 day coast arc)

▪ Impact: Oct 07 2022, 529 kg, 5.92 km/s (82 day coast arc)

Flyby-30d

TCM 1a

Flyby-10d

TCM 1b

IPS Cruise

Period 1

IPS Cruise

Period 2

E-30d

TCM 2b

E-60d

TCM 2aE-10d

TCM 2c

E-2d

TCM 2d

E-12hr

Handoff to

SMARTNav

*All planned, deterministic maneuvers are accomplished with IPS

*Zero planned, deterministic, impulsive DV by mission design in

baseline reference trajectory

Rideshare to

Initial GTO,

Jan. 2021

9

DART Mission Design - Path To Terminal Guidance

Autonomous Navigation and Targeting (SMARTNav)

@2022 Intercept (~10.9M km; 6.8M miles from Earth)

1. Ascent / Boost 2. Cruise / Calibration 3. Target Detection

/ Coarse Acquisition

4. Scene Classification

5. Target Selection 6. Homing Until Intercept 7. Impact Assessment

Flyby of PHA allows sensor calibration and control-gain tuning

Seeker counts and classifies closely spaced objects

With sufficient confidence, seeker selects target and locks on.

Direct Launch or Low-Thrust Spiral*

Earth tracking and AIM quantify intercept success.

Pro-Nav executes precision engagement and is robust to target uncertainties

Weeks prior to impact, seeker detects primary

<6-9 months for EP>

<108 km from target>

<7 months until impact>

<108 km from target><2 months until impact>

<107 km from target>

<3 hours until impact>

<65,000 km from target>

<1.5 hours until impact>

<32,000 km from target> <Executed until final 2 minutes>

<6.0 km/s Impact><3 months>

* 15-18 months total flight time

10

Didymos Reconnaissance and Asteroid Camera for OpNav (DRACO) Imager

▪ Instrument UsesProvides images used for distant, 30-day out, ground-based optical navigation to

Didymos

Provides images and centroids for close, autonomous guidance to Didymos (SMARTNav)

Provides final images of the surface used for determining impact location and impact site

morphology. These are used for impact modelling and understand effectiveness of

impact.

DRACO Overview

Aperture 200 mm

F Number f/12.63

Wavelength 350 nm – 850 nm

FOV 0.29 degree full angle

IFOV 2.5 urad

PSD* (300 km) 1.0 meter

PSD* (150 km) 0.5 meter

PSD* (30 km) 0.1 meter

SNR (30 days) >7

SNR (final) >100

*Pixel Sample Distance

▪ Design Summary▪ Heritage design based on LORRI from New Horizons mission

▪ Uses of a CMOS ~2k x 2k (BAE sCMOS) detector instead of LORRI CCD

▪ Data Processing functions implemented in Avionics IEM instead of LORRI DPU

▪ Visible narrow angle camera with a large aperture and good optical performance

▪ LORRI optics, with in-progress trade of switching from Al optics to less thermally

sensitive material

11

Spacecraft Layout

Stowed Configuration

NEXT Engine

(with “Top Hat”)

8X Thruster

2X ROSAStar Tracker

Sun Sensor

2X Battery DRACO

RLSA

2X LGA

Z

YX Z

YX

ROSA ARRAYS

12

NEXT-C Project: DART Collaboration

▪ NASA’s Evolutionary Xenon Thruster (NEXT) began as a technology development project

▪ NEXT-C project’s objective is to transition the NEXT technology to flight and create a

commercially available product (Managed by NASA GRC)

▪ The NEXT-C project is producing two flight qualified thrusters and two Power Processing

Units (PPUs). A single thruster and PPU (with simulators, testbeds, test data &

documentation) are GFE to the DART project.

▪ Flight project preparing to support a mission(s) with GFE flight hardware delivery in early

2019

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Performance Characteristics

Thruster Power, kW 0.5 – 6.9

Specific Impulse, sec 2500 - 4200

Thrust, mN 25 - 235

Thrust –to-Power, mN/kW 32 - 48

Thruster Efficiency 0.32 – 0.7

Lifetime - Xenon Throughput, kg

> 600

DART is the first flight of NEXT and will complete the

system qualification for future deep space missions.

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DART Baseline Launch Readiness Date (LRD) (Commercial Rideshare)

▪ Nominal LRD includes

– 5-month launch period

– 7-month spiral to Earth escape

– Asteroid 2001 CB21 flyby

– Impact in Oct 2022

▪ Backup trajectory eliminates the flyby

– Launch period extended to 7 months

– Spiral duration and impact date unchanged

▪ Opportunities above can be somewhat replicated two years later for a 2024 impact

opportunity, however, you loose the global 1-2 meter ground-based optical telescope and

radar capabilities.

▪ There may be other NASA-mission co-manifest opportunities but these need to be studied.

5-month

launch period

7-month Spiral

20 Dec

2020

03 Mar

2022

07 Oct

2022

Cruise

Flyby Nominal Trajectory

7-month

launch period

7-month Spiral

07 Oct

2022

Cruise

Backup Trajectory

JHU/APL Proprietary

JHU/APL Proprietary14

DART Investigation Team & Working GroupsDART Core Team

Andrew Cheng (APL) AIDA Coordination lead

Andrew Rivkin (APL) DART Investigation Team Lead

Angela Stickle (APL) DART Investigation 1 lead

Cristina Thomas (PSI) DART Investigation 2 lead

Derek Richardson (UMD) DART Investigation 3 lead

Olivier Barnouin (APL) DART Investigation 4 lead; shape model development

Eugene Fahnestock (JPL) DART Investigation 5 lead

Steven Chesley (JPL) Dynamics lead

Brent Barbee (GSFC) V&V lead

Investigation 1: Modeling and Simulations of Impact OutcomesMegan Bruck Syal (LLNL) impact modeling using spheral and SPH

Paul Miller (LLNL) planetary defense interpretation and applications

Emma Rainey (APL) impact modeling using CTH

Collaborators: Dan Durda (SWRI), Galen Gisler (LANL); Keith Holsapple (UW); Kevin Housen (Boeing); Daniel Jontof-Hutter (Penn St); Naor Movshovitz(UCSC); J. Michael Owen (LLNL); Cathy Plesko (LANL); KT Ramesh (JHU); James Richardson (Arecibo); Pete Schultz (Brown)

Investigation 2: Remote Sensing ObservationsPaul Abell (JSC) Strategic Knowledge Gap (SKG) and human exploration applications

Lance Benner (JPL) radar observations

Shantanu Naidu (JPL) Analysis of radar data

Collaborators: Michael Busch (SETI); Ellen Howell (UofA); Matthew Knight (Lowell/UMD); Emily Kramer (JPL); Jian-Yang Li (PSI); Tim Lister (LCOGT); Amy Mainzer (JPL); Nicholas Moskovitz (Lowell); Michael Nolan (UofA); Dagmara Oszkiewicz (Lowell); David Osip (LCO); William Ryan (NMT); Eileen Ryan (NMT); Amanda Sickafoose (MIT/SAAO); Jessica Sunshine (UMD); Audrey Thirouin (Lowell); Cristina Thomas (PSI); Padma Yanamandra-Fisher (JPL)

Investigation 3: Dynamical and Physical PropertiesJulie Bellerose (JPL) gravity and dynamics

Daniel Scheeres (U Colorado) geotechnical properties

Douglas Hamilton (UMD) orbital dynamics

Collaborators: Eric Asphaug (ASU); Bill Bottke (SWRI); Toshi Hirabayashi (Purdue); Jay McMahon (U Colorado); Paul Sánchez (U Colorado); Gal Sarid(UCF); Simon Tardivel (JPL); Kevin Walsh (SWRI)

Investigation 4: Science Proximity ObservationsNancy Chabot (APL) DRACO Instrument Scientist

Carolyn Ernst (APL) impact site morphology characterization

Investigation 5: Ejecta Dynamics and Evolution

Stephen Schwartz (ASU) WG co-lead, ejecta simulation, low speed ejecta

Collaborators: Douglas Hamilton (UMD); Christine Hartzell (UMD); Toshi Hirabayashi (Purdue); Daniel Jontof-Hutter (Penn St); Ludmilla Kolokolova(UMD); Jim Richardson (PSI); Gal Sarid (UCF); Gonzalo Tancredi (Ciencias)

We expand community participation through annual open international

workshops (Held 3 to date)

15

DART Has a Parallel Ground-Based Observation Program -2017 Didymos Observations

▪ Have data in hand for four observing sessions:

▪ 25 February UT from GTC (Spain)

▪ 25 February UT from MMT (Arizona)

▪ 27 February UT from SALT (South Africa)

▪ 2 March UT from MMT

▪ Mutual events seen in data reduced so far

▪ Allows timing of mutual events for rest of apparition

▪ 14 more observing sessions scheduled through end of April

▪ Next up: 10 March at Magellan (Chile)

▪ Team in process of incorporating new data with 2003-2015 data

0.7

0.8

0.9 1

1.1

1.2

1.3 8.5 9

9.5 10

10.5 11

11.5 12

12.5 13

Instrumental Magnitude (r)

UT (Hours)

65803 Didymos 25-Feb-2017 M

MT photom

etry

Mutual events:

Didymos B

occulting or

being eclipsed

by Didymos A

25 February UT:

Gran Telescopio Canarias

25 February UT:

MMT

16

Observing Strategy for Impact Epoch

▪ Network of telescopes around globe to be used in observing campaign

– Observatories on 5 continents allow potential for near continuous optical coverage with 4-m or larger telescopes

– Telescopes as small as 1 m can obtain useful data, mitigating risk of bad weather or equipment failure at specific sites

▪ Goldstone and Arecibo radar allow measurements to be made throughout impact period

▪ Option to use space-based telescopes

– HST observations during impact period possible

– JWST rate limits allow observation ~6 weeks after impact

– Future space-based NEO survey

17

Outline of 2022 Impact Observing Campaign

▪ DART impact during excellent apparition: Didymos at V ~ 14-15, very well placed for Chile, observable from other observatories

▪ Planetary Radar participation hugely useful

▪ Didymos primary and secondary are separated by up to 0.02 arcsec when 0.08 AU from Earth

– Marginally resolvable with ALMA (sub-mm), Magellan adaptive optics

▪ Post-impact brightening and ejecta stream as extended object (“coma”) may be observable from Earth

▪ Debris cloud analogous to YORP-driven MBCs?

P/2013 P5 ~250 m,

observed at 1.1 AU

distance from Earth

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2022 Observing CampaignSelected telescopes expected to be available

Facility Telescope(s) Location(s) Capability

IRTF 1 3.0m NH: Mauna Kea Low & high res IR spectroscopy

Keck 2 10.0m NH: Mauna Kea Low & high res Optical & IR spectroscopy, AO

Gemini 2 8.0mNH: Mauna Kea,

Optical and IR imaging & spectroscopy, AOSH: Chile

Magellan 2 6.5m SH: Chile Optical and NIR imaging & spectroscopy

Las Campanas 1 2.5m SH: Chile Optical imaging & spectroscopy

DCT 1 4.3m NH: Arizona Optical & NIR imaging & low res spectroscopy

WHT 1 4.2mNH: Canary Islands

Optical & IR imaging & spectroscopy, AO

ESO4 8.2m, 1 3.6m, 1 3.5m

SH: ChileOptical & IR imaging & spectroscopy, AO, IR high res spectroscopy

GTC 1 10.4mNH: Canary Islands

Optical imaging, Optical low res spectroscopy

MRO 1 2.4m NH: New Mexico Optical imaging, Optical low res spectroscopy

LCOGT 11 1m, 2 2m

NH: 1 2m, 3 1m

Optical imaging, Optical low res spectroscopySH: 1 2m, 8 1m

IUCAA 1 2.0m NH: India Optical imaging

AAO 1 3.9m SH: Australia NIR imaging & spectroscopy

SAAO1 11.0m, 1 1.9m

SH: South Africa Optical imaging & low res spectroscopy

19

First mission (with AIM) to study a binary asteroid system, its origins and interior structure

First mission to measure asteroid deflection by constraining the “ejecta momentum amplification factor” of a kinetic impactor, as well as the initial conditions (impact conditions, target’s properties)

DART Firsts

First mission to fly NASA’s NEXT solar electric propulsion technology.

Contributes valuable data to many disciplines, i.e., planetary defense, science, human exploration and resource utilization.

20

Project Status

▪ DART is in Phase B

▪ Launch Readiness Date (LRD) for 2022 impact opportunity is

December 2020

▪ PDR is scheduled for 12-14 February, 2018

– sPDRs are now underway

▪ KDP-C is scheduled for 13 March 2018

▪ International contributions are being explored, studied

▪ A LV RFI for commercial rideshare will soon be released through

FedBizOps. RFI notes APL as the procuring entity.

Visit us at:

www.dart.jhuapl.edu