Mission and Spacecraft Design MarcoPolo-R Mission and Spacecraft Design Lisa Peacocke – 19th June 2013 IPPW 2013, San Jose, USA

MarcoPolo-R Mission ESA Cosmic Vison M-class candidate Aim: To return a sample from a primitive near-Earth asteroid Currently Phase A, down-selection in Feb 2014 Target is primitive asteroid 2008 EV5 MarcoPolo-R Assessment Study and CCN Demonstrate technical and programmatic feasibility of the mission Achieve a cost-effective and consolidated mission design Astrium team kicked off in February 2012 Team of 18 engineers currently working on the study 2

1996 FG3 Primary and Secondary Mission Design Launch on Soyuz-Fregat to 2008 EV5 Launch years 2022, 2023, 2024 All outward trajectories require an Earth GAM Mission durations 4.5-6.5 years 2008 EV5 DeltaV’s relatively low Plasma propulsion architecture becomes feasible Reduced return velocities for Earth re-entry Other benefits of 2008 EV5 Smaller asteroid => less surface area to map Less extreme orbit with more consistent Sun distance Lower mass asteroid => lower gravity environment 1996 FG3 Primary and Secondary 2008 EV5 3

Science Operations Operations phases give ~140 GB data 8 hours data downlink per day is feasible ESA’s 35 m ground stations 4

Spacecraft Design 5

Spacecraft Design Mechanical Propulsion Thermal AOCS Electrical Solar Orbiter derived structure, modifications to support plasma thrusters Propulsion Three Snecma PPS1350 plasma thrusters (1.5 kW) with pointing mechanisms and PPUs – SMART 1 Two Xenon tanks and a high pressure regulator – BepiColombo MTM Aeolus derived monopropellant system with 20N thrusters and hydrazine tanks Thermal ‘Standard’ design with heaters and MLI, detailed analysis ongoing One panel with embedded heat pipes to aid PPU heat dissipation AOCS Off-the-shelf European IMU, star tracker, reaction wheels and sun sensors Electrical Two rotating solar array wings (7.5 m2 each) with drive mechanism – Sentinel 1 & 2 Lithium-ion battery and TerraSAR-X2-based 50V PCDU Mars Express 1.6 m high gain antenna; MGA and LGAs with 80 W RF TWTA and deep space transponder – BepiColombo/Solar Orbiter/LISA Pathfinder Gaia-based on-board computer with mass memory, and Solar Orbiter RIU 6

Spacecraft Design 7

Payload Accommodation All instruments mounted on same structure panel Facilitates integration and mutual alignment Accommodated inside spacecraft with views through cutouts 8

Key Technologies Proximity GNC Visual navigation uses Wide Angle Camera based on NPAL development and a Radar Altimeter Simulations performed for descent/touchdown Sample Acquisition, Transfer and Containment Rotary brush sampling mechanism developed and tested Touchdown damping from boom back-driven motor Minimal forces at 10 cm/s Earth Re-entry Capsule Hard landing, no parachute or beacons/battery Hayabusa-shape aeroshell 9

Proximity GNC/AOCS 10

Touchdown Dynamics 11

Sampling and Transfer 12

Sampling Mechanism Early Testing 13

Sampling Mechanism 14

Earth Re-entry Capsule Main requirements Maximum entry velocity = 12 km/s Maximum heat flux = 15 MW/m2 Maximum total pressure at stagnation point = 80 kPa Fully passive, no parachute – cost and MSR demonstration Ensure impact loads to sample are less than 800 g No beacon or battery on board Land at Woomera, Australia Entry flight path angle of -10.8 degrees selected Based on entry dispersion and appropriate landing ellipse Hayabusa aeroshape selected Stable and meets g-load, aerothermo requirements θc = 45 deg, RN/D = 0.5 4‑3 Dispersion at impact as a function of the FPA dispersion Huygens aeroshape can be considered if g-load limit is relaxed to 2000 g 3 June 2013 - 15

Earth Re-entry Capsule Design Properties Diameter = 0.880 m, Mass = 45.6 kg, Centring = 28.75% D (Max ~33% D) TPS: 56 mm ASTERM on frontshield (low density carbon phenolic, 280 kg/m3) 11 mm Norcoat Liége on backcover (low density cork phenolic, 470 kg/m3) 170 mm Aluminium foam crushable material, PU foam surrounds container Aluminum panels with lateral stiffeners ensure a free path for sample container, even with an impact at 20 degrees Using a stroke efficiency factor (70%) and a safety margin (15%) the absorbing material thickness is 170 mm. An interface material is necessary to link the TPS onto the structure and to stuff the empty joints between the Norcoat liege tiles. The silicone glue ESP495 is proposed (ExoMars material). 3 June 2013 - 16

Earth Re-entry Capsule 2 rpm min spin-up 3 June 2013 - 17

Earth Re-entry Capsule Landing ellipse is 68 km along longitudinal axis 3 June 2013 - 18

Conclusions Phase A study finishing at the end of July Preliminary Requirements Review in Oct/Nov Selection will occur in February 2014 Astrium’s mission & spacecraft design is feasible Key technologies are well into development Extensive unit re-use or modification Keeps development costs to a minimum, reduces cost risk MarcoPolo-R is a very promising M-class mission candidate New target has simplified engineering & design significantly Serendipitous short mission trajectories – right time for asteroid sample return 19

Questions? MarcoPolo-R Team: Steve Kemble, Héloise Scheer, Jean-Marc Bouilly, Antoine Freycon, Steve Eckersley, Brian O’Sullivan, Jaime Reed, Martin Garland, Mark Watt, Marc Chapuy, Kev Tomkins, Howard Gray, Bill Bentall, Andrew Davies, Chris Chetwood, Andy Quinn, Alex Elliott, Mark Bonnar, David Agnolon, Remy Chalex, Jens Romstedt 3 June 2013 - 20