1 misuratore dipolvere Interceptor per Cometla DISC (Dust ImpactSensor and Counter) il nuova nuova missione aduna ESA cometa. Vincenzo Della Della Vincenzo Corte INAF - IAPS

Comet Interceptor An ESA mission to an ancient world an ancient to mission ESA An Comet Interceptor UCL UCL Mullard and the Comet Interceptor Team InterceptorComet the and Space Science Laboratory, UK Laboratory, Science Space University of Edinburgh, UK of Edinburgh, University Colin Snodgrass @ Geraint Jones colinsnodgrass @ einionyn

Comet Interceptor • • • • OVERVIEW 3 point, in 2028 Shared launch with Ariel exoplanet telescope, to Sun fundinstruments and the science teams. ESA member states and other collaborating agencies generally €150M. Maximum cost to ESA at completion, excluding launch: its firstF On June 20 2019, Comet Interceptor was selected by ESA as • • during launch Must fitunderneath Ariel, and be designed to support it onLimits mass (originally1000 kg, now 800 kg) - class mission. - Earth L2

Comet Interceptor 4 • • • • Why? comet, or an interstellar object. targeting a dynamically Comet Interceptor is a mission surface ices laid down as first at the Solar System’s formation A missionto a DNC would encounter a the Sun forthe firsttime A dynamically their surfaces Targets were relatively evolved, with thick coatings ofdust on passed the Sun many times All previous comet missionshave been to objects that have - new new comet ( DNC - ) oneis that probably is nearing new pristine comet, comet, with

Comet Interceptor • • • • • • Multiple Multiple Spacecraft Architecture B2:nucleus + coma B1:inner coma A: main spacecraft approaches close gain / high high risk and measurements /distant safe Separating distances studies atdifferent & fields + particlesnucleus + coma Simultaneous in coma variationsspace and timeTo separate • • • • • • • • • • Spin nostabilised, AOCS In Targeted at nucleus (butunlikely to actually hit it) 3 axisstabilised In Targeted to throughpass inner coma Minimum payload to ensure results even ifother spacecraft fail Propulsion + communication Data relay for other spacecraft Passes sunward ofcomet at ~1000 km ('safe'distance) - - situ sampling, nucleus + coma imaging situ sampling, coma imaging 5

Comet Interceptor • • repeat repeat of previous missions. A missionto short period comet carrywill out new science: not • • • • SOLUTIONS CHALLENGES < 5 years Cost means that entire mission should be > 70 km/s in worst case Retrograde orbits could mean speeds flyby range ofpossible trajectories and encounter speeds Mission has to be designed to encounter comets on a wide comets comets identified, including 73P. Ifno suitable target found, backup short period Wait at L2 limited to ~3 years Dust shielding equivalent to that used on Giotto encounter geometries Spacecraft design can cope with range ofdifferent – no HGA to Earth at encounter. 6

Comet Interceptor • • • Comet Interceptor Profile Mission 7 take take place close to the ecliptic Short cruise and fastof flybytarget comet near Earth’s distance from the Sun; e Waits for up to 2 Mission ‘parked’ at stable Lagrange point L2after launch with Ariel - 3 years fornew target discovery – the plane ofEarth’s orbit ncounter has to

Comet Interceptor • Comet Interceptor Profile Mission 8 Orbit computed Orbit computed and crossingecliptic point predicted

Comet Interceptor • Comet Interceptor Profile Mission 9 Comet Comet Interceptor leaves L2to intercept comet’s path

Comet Interceptor • Comet Interceptor Profile Mission 10 Encounter with comet close to the plane ecliptic

Comet Interceptor Proposed payload Spacecraft JAXA ESA ESA B1 B2 A Instrument MANIaC MIRMIS EnVisS CoCa OPIC WAC DFP PS HI Dust, Fields & PlasmaFields Dust, (similar on A andB2) All NIR/ThermalIR spectral imager Lyman - sky imagermultispectralvisible Wide Angle CameraWide Mass spectrometer Visible/NIRimager imager Visible/NIR - alpha Hydrogen imager Plasma Suite Description

Comet Interceptor 12

Comet Interceptor Nucleus Science Goals 13

Comet Interceptor Neutral Coma Neutral Science Goals 14

Comet Interceptor Dust Science Goals 15

Comet Interceptor Plasma Science Goals 16

Comet Interceptor A B1 B2 17

Comet Interceptor 18

Comet Interceptor 19

Comet Interceptor 20

Comet Interceptor coma coma from a flybysingle structure ofnucleus and spacecraft reveal 3D nucleus Multiple views of cometary : views from three 21

Comet Interceptor New Science New • • comet at a processes exchange wind solarof first observations Energetic Neutral Atoms plasma including environment,cometary Multi - - neutral charge neutral point measurements : of of Multispectral and polarimetric mapper polarimetric and Multispectral polarimetry, neutral gas, gas, neutraland ion polarimetry, All • - Entire Visible Sky sky view of dust, dust, including of sky view ( features EnVisS ): 22

Comet Interceptor DFP DFP - Dust Impact SensorCounter and - DISC

Comet Interceptor • • 24 The Dust Field and Plasma (DFP) package is a combined experiment dedicated to the dedicated experiment combined isa Plasmapackage and (DFP)Field Dust The neutrals, spacecraft potential and the cometary dust impacts,dust the cometary and potential spacecraft neutrals, energetic ions and of electrons,functions distributionthe speed), temperature, magneticwillfield,The DFPmeasure field,electricplasma parameters (density, the Sun. and environment space surrounding the withits interaction of and comet target dynamicallynew of the coma situ,multiin - point study of the multi study of point - phased ionized and dusty environment in the in environment and dusty ionized phased

Comet Interceptor DFP - Dust Field Dust Field and Plasma Package

Comet Interceptor 26 count;impactparticle duration; particledustdustdensity/structure; DISC, if mountedon both S/C B2 S/C and A, bewill to determine abledust mass distribution; particles the S/C, speedthe particleisretrieved. eachdustdetectedits momentum particle is measured. From the momentum, knowingspeed theof The aim is to characterizethe dustenvironment in the coma of targetdynamically newthe comet. For maps,around the nucleus.s .

Comet Interceptor DFP ╺ Measurement ofindividual dust particle physical properties: - DISC Science ╶ ╶ ╶ ╶ Particle tensile Particle tensile Mass distribution m/s kg Momentum Size strenght 10 1 – - 4 200 micron 200 – 10 - 10

Comet Interceptor • • principle Description DFP • particle produces The waves A sensors squared DISC particle maximum - sensing on DISC momentum/kinetic underneath plate the impact a potential Al element plate equipped displacement & on . Working the that that : sensing a are energy with is thin detected directly of plate ( piezoelectric . 0 . 5 the mm) induces proportional by PZT the aluminium PZTs crystals flexural (PZTs) . to

Comet Interceptor • • wrt Sensitiveelementcantechnique& reading beimproved DISC: adirect heritageof the Rosetta/GIADAImpact Sensor(GIADA • • constraints. Improvementstailoredtakingintomission accountdevelopmenttime Noon impactdetectorand design qualification. GIADA Heritage anddevelopment DFP GIADA Flight GIADASpare Flight - IS: - DISC GIADA - IS Development Model IS Development - IS).

Comet Interceptor 120 mm GIADA IS 120 mm configuration

85 mm DISC 85 mm configuration

Comet Interceptor ACCOMODATION DFP design/accommodation Optimal DFP SC SC B2 DISC DISC sensing thick

S/C - DISC B2 dust shield plate - DISC S/C RAM direction S/C A DFPDISC A

Comet Interceptor Hyper Hyper VelocityImpacts (HVI) DFP • waves drops Liu et dramatically al, convert 2016 - DISC to (Journal the as bulk a consequence of waves Applied and Mechanics) are of the guided wave : by as attenuation the the plate shock wavegenerated also by HVI impact to retrieve all information from the plate The IS GIADA and DISC is design capable plate wavetheory. of the wavescan be described theusing spot, propagation Therefore, in the areas distant from the HVI by and waves taking diffraction the propagate formality distance the of “lamb HVI ; subsequently, - induced waves” . pressure shock

Comet Interceptor • • • • damage The the GIADA The A HVI Signal minimal analysis sensing spot sensing and - analysis IS . distance and on of plate PZTs impacting the DISC shows . full on it is are the signal that necessary particle fully DISC the registered capable plate shock characteristics to obtain will wave of by be detecting the this placed converts . PZT modification only and allows to During Signal at “lamb register the to in registerd retrieve corners HVI HVI impact the wave” the shockwave “lamb quickly information by experiments Liu waves” as et al 2016 (few propagation on mm) propagating sensing from plate in

Comet Interceptor