Preliminary Mission Design of PROCYON: a Micro-Spacecraft To

Mission to Earth―Moon Lagrange Point by a 6U CubeSat: EQUULEUS (EQUilibriUm Lunar-Earth point 6U Spacecraft)

Ryu Funase Associate Professor, EQUULEUS project manager, Univ. of Tokyo EQUULEUS Project Team (U of Tokyo, JAXA) Intelligent Space Systems Laboratory ISSL The University of Tokyo Growing trend of nano/micro-satellites

©SpaceWorks Now 2 www.space.t.u-tokyo.ac.jp Intelligent Space Systems Laboratory ISSL The University of Tokyo University of Tokyo’s experience

XI-V (2005): 1kg Hodoyoshi-3 and 4 (2014) for tech. demo. remote sensing (~6m GSD) Still operational (>12yrs) Nano-JASMINE: 33kg for Astrometry (space science mission) Awaiting launch… XI-IV (2003): 1kg The first CubeSat PRISM (2009): 8kg Still operational (>14yrs) for remote sensing (20m GSD) 3 Still operational (>8yrs) www.space.t.u-tokyo.ac.jp Intelligent Space Systems Laboratory ISSL The University of Tokyo 6m GSD image taken by Hodoyoshi-4 satellite

www.space.t.u-tokyo.ac.jp Intelligent Space Systems Laboratory ISSL The University of Tokyo

Next frontier for small satellites is...

deep space!

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The First Interplanetary Micro-Spacecraft PROCYON

www.space.t.u-tokyo.ac.jp Intelligent Space Systems Laboratory Piggyback launch with Hayabusa2 on Dec. 3, 2014 ISSL The University of Tokyo

H-IIA rocket Hayabusa-2 (~600kg)

PROCYON (~65kg)

7 © JAXA © JAXA www.space.t.u-tokyo.ac.jp Intelligent Space Systems Laboratory ISSL The University of Tokyo Achievements of PROCYON SSC16-III-05 (2016) • [Primary mission] Demonstration of the deep space micro- satellite bus  Power generation/management (>240W)

 Thermal design to accommodate wide range of Solar distance (0.9~1.5AU) and power consumption mode (electric prop. on/off, 137W/105W)

 Attitude control (3-axis, <0.01deg stability)

www.space.t.u-tokyo.ac.jp Intelligent Space Systems Laboratory ISSL The University of Tokyo Achievements of PROCYON SSC16-III-05 (2016) • [Primary mission] Demonstration of the deep space micro- satellite bus (cont’d)  communication & navigation in deep space • Communication from ~60,000,000 km Earth distance • X-band GaN-based SSPA (Solid-State Power Amplifier) with the world’s highest RF efficiency (>30%)

 Propulsion system for micro spacecraft • RCS (8 thrusters) for attitude control/momentum management • Ion propulsion system for trajectory control (1 axis, Isp=1000s, thrust>300uN), ~220hr operation • Trajectory guidance, control, and navigation σ experiment in deep space (<100km, 3 ) 9

www.space.t.u-tokyo.ac.jp Intelligent Space Systems Laboratory ISSL The University of Tokyo Achievements of PROCYON • [Secondary mission] Scientific observation – Wide-view imaging observation of geocorona with Lya imager from a vantage point outside of the Earth’s geocorona distribution – Imaging observation of the hydrogen emission around the “67P/Churyumov–Gerasimenko” comet (the target of ESA’s ROSETTA mission) to evaluate water release rate from the comet

Hydrogen emission around 67P/Churyumov– Gerasimenko comet was observed on Sep. 13, 2015. This comet is the destination of the European Space Agency's Rosetta mission.

[Shinnaka et al., 2017] 10

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What PROCYON demonstrated:

Possibility of deep space exploration by small satellite

Out next challenge is…

www.space.t.u-tokyo.ac.jp Intelligent Space Systems Laboratory ISSL The University of Tokyo EQUULEUS The first CubeSat to go to Lunar Lagrange point and explore the cis-lunar region

www.space.t.u-tokyo.ac.jp Intelligent Space Systems Laboratory ISSL The University of Tokyo Why we started EQUULEUS? (The goal behind the EQUULEUS mission) 1. Going back to CubeSat “again” by downsizing our deep space bus – Adapt to as much as deep space launch opportunities in the future

2. Enhance the mission capability in deep space – Not only obtaining the ”tricky” deep space trajectory guidance, navigation, and control techniques itself, – but also enhancing our overall capability to conduct deep space missions such as: • astrodynamics, mission planning and analysis, s/c system design, and s/c operation 13

www.space.t.u-tokyo.ac.jp Intelligent Space Systems Laboratory ISSL The University of Tokyo Intelligent Space Systems Laboratory ISSL The University of Tokyo Missions of EQUULEUS

1. [Engineering] (primary mission) demonstration of the trajectory control techniques within the Sun-Earth-Moon region by a nano- spacecraft through the flight to the Earth-Moon Lagrange point L2 (EML2)

2. [Science] Imaging observation of the Earth’s plasmasphere

3. [Science] Lunar impact flash observation

4. [Science] Measurement of dust environment in cis-lunar region

15 Intelligent Space Systems Laboratory ISSL The University of Tokyo Trajectory all the way to EML2...

EQUULEUS will perform ~6 months flight to EML2 with ∆V of as low as ~10m/s (deterministic), by using multiple lunar gravity assists.

Lunar flyby sequences

DV2 Earth-Moon L2 libration orbit LGA3 Capture to EML2 libration orbit

Sun DV1

Insertion to EML2 LGA1 LGA2 Moon libration orbit using DV3 Sun-Earth week Earth stability regions

*LGA: Lunar Gravity Assist, EML2: Earth-Moon L2 point 16 Intelligent Space Systems Laboratory ISSL The University of Tokyo Missions of EQUULEUS (2/4) 1. [Engineering] (primary mission) demonstration of the trajectory control techniques within the Sun-Earth-Moon region by a nano-spacecraft through the flight to the Earth-Moon Lagrange point L2 (EML2) 2. [Science] Imaging observation of the Earth’s plasmasphere

0.5U Detector (MCP) Metal thin film filter

Mechanical shutter Primary mirror (multilayer film 10cm optimized for He+(30.4nm) 17 Intelligent Space Systems Laboratory ISSL The University of Tokyo Missions of EQUULEUS (3/4) 1. [Engineering] (primary mission) demonstration of the trajectory control techniques within the Sun-Earth-Moon region by a nano-spacecraft through the flight to the Earth-Moon Lagrange point L2 (EML2) 2. [Science] Imaging observation of the Earth’s plasmasphere 3. [Science] Lunar impact flashes observation

0.5U

10cm

5cm 10cm 18 Intelligent Space Systems Laboratory ISSL The University of Tokyo Missions of EQUULEUS (4/4) 1. [Engineering] (primary mission) demonstration of the trajectory control techniques within the Sun-Earth-Moon region by a nano-spacecraft through the flight to the Earth-Moon Lagrange point L2 (EML2) 2. [Science] Imaging observation of the Earth’s plasmasphere 3. [Science] Lunar impact flash observation 4. [Science] Measurement of dust environment in cis-lunar region

Dust impact sensors installed within spacecraft thermal blanket (MLI)

19 Intelligent Space Systems Laboratory ISSL The University of Tokyo

Solar Array Paddles with gimbal Ultra-stable Oscillator Propellant (water) Tank Transponder X-Band MGA

X-Band LGA X-Band LGA 20cm Battery Water resistojet thrusters CDH & EPS 30cm Attitude control unit

PHOENIX (plasmasphere observation)

DELPHINUS (lunar impact flashes observation)

20 Intelligent Space Systems Laboratory ISSL The University of Tokyo Technological challenge/advancement • Miniaturization of the deep space bus (e.g. deep space communication transponder) into the CubeSat form factor XTRP demonstrated in PROCYON (2014) XTRP being developed for CubeSat （EQUULEUS）

* Miniaturization * Modularization * Reduction of RF output * Reduction of power consumption Digital Processing Module &Rx Module

*XTRP: X-band Transponder

Power Amplifier & XTx Module

www.space.t.u-tokyo.ac.jp Intelligent Space Systems Laboratory ISSL The University of Tokyo Technological challenge/advancement • Miniaturization of the deep space bus (e.g. deep space communication transponder) into the CubeSat form factor XTRP demonstrated in PROCYON (2014) XTRP being developed for CubeSat （EQUULEUS） Spec. of our CubeSat X-band deep space transponder Bit Rate: 15.625/125/1k* Miniaturization [bps] (CMD) * Modularization 8 ～262.144k [bps] (TLM) * Reduction of RF output Dimension: 80*× Reduction80×(<50) of power[mm], consumption ~0.5U Digital Processing Module &Rx Module Mass: < 500 [g] Power: <13 [W] (@Tx ON) *XTRP:RF output: X-band Transponder1 [W] (+30 dBm) Navigation: RARR, DDOR

Power Amplifier & XTx Module

www.space.t.u-tokyo.ac.jp Intelligent Space Systems Laboratory ISSL The University of Tokyo Technological challenge/advancement • Development of the new resistojet (warm gas) propulsion system using water as the propellant. – Water is perfectly safe, non-toxic propellant, which is advantageous when we consider piggyback launch. – (In-situ space resource utilization age in the future is also in my mind...) ~2.5U 4 x RCS thrusters

Water tank 2 x Delta-V thrusters Vaporization chamber 23

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24 Intelligent Space Systems Laboratory ISSL The University of Tokyo

25 Intelligent Space Systems Laboratory ISSL The University of Tokyo

26 Intelligent Space Systems Laboratory ISSL The University of Tokyo Summary • University of Tokyo has started to challenge deep space exploration by nano/micro satellite, based on the successful nano/micro satellites development and operation in Low Earth Orbit.

• The first deep space micro satellite “PROCYON” successfully demonstrated the deep space micro-satellite bus system in 2015.

• After that, we have proposed and started the development of a 6U CubeSat mission to Earth - Moon Lagrange point "EQUULEUS" in the summer of 2016.

• The primary mission of EQUULEUS is the trajectory control demonstration in cis-lunar region, and some scientific observation missions are also carried. These missions are enabled by downsizing the deep space bus system to fit the CubeSat standard and also by developing the new propulsion system.

• The development of the spacecraft started in the summer of 2016 and the engineering model integration and testing was completed. The flight model development will be completed by the spring of 2018, to be ready for the launch by SLS’ first flight in 2019. 27