A NANOSATELLITE MISSION TO ASSESS SOLAR SAIL PERFORMANCE IN LEO Kieran A. Carroll, Gedex Inc. Henry Spencer, SP Systems Robert E. Zee, Space Flight Laboratory George Vukovich, Canadian Space Agency

20-22 July 2010A Nanosatellite Mission to Asses Solar Sailing Performance in LEO International Solar Sail Symposium 2010, New York 2 Goals of This Presentation To introduce publicly the CanX-9 solar sail technology mission To convey a sense of the design approach that has been followed. To provide a starting point for coordinating this missions objectives with those of others who are working to mature solar sailing technology, e.g.: –IKAROS –Nanosail-D2 –Lightsail-1 –Cubesail

20-22 July 2010A Nanosatellite Mission to Asses Solar Sailing Performance in LEO International Solar Sail Symposium 2010, New York 3 Background: History of Solar Sailing in Canada 1978: Modi & Van Der Ha orbital dynamics papers (UBC)

20-22 July 2010A Nanosatellite Mission to Asses Solar Sailing Performance in LEO International Solar Sail Symposium 2010, New York 4 Background: History of Solar Sailing in Canada 1978: Modi & Van Der Ha papers : Canadian Solar Sail Project (CSSP) –CCQJC Race to Mars –Canadian Space Society –University of Toronto Institute for Aerospace Studies (UTIAS) –(Team members included Carroll and Spencer)

20-22 July 2010A Nanosatellite Mission to Asses Solar Sailing Performance in LEO International Solar Sail Symposium 2010, New York 5 CSSP Initial Design Concept Novel non-spinner Hexagonal planform Venetian blind sail vanes: –Stowed rolled-up –Deployed and actuated by cables Compressive booms, each 60 m long 500 kg, 10,000 m 2 Smallsat-class Ariane 4 launch to escape

20-22 July 2010A Nanosatellite Mission to Asses Solar Sailing Performance in LEO International Solar Sail Symposium 2010, New York 6 CSSP Eventual Preliminary Design Novel spinner Pinwheel configuration 30 vanes, each 30 x 0.5 m, stowed and deployed roller- blind fashion 3 of the vanes with adjustable angle of attack for spin-rate control Precess spin vector (and hence sail pointing) direction via shifting mass center 25 kg, 500 m 2 Microsat-class Scout or Pegasus launch to escape

20-22 July 2010A Nanosatellite Mission to Asses Solar Sailing Performance in LEO International Solar Sail Symposium 2010, New York 7 Background: History of Solar Sailing in Canada 1978: Modi & Van Der Ha papers : Canadian Solar Sail Project (CSSP) –CCQJC Race to Mars –Canadian Space Society –University of Toronto Institute for Aerospace Studies (UTIAS) –Team members included Carroll and Spencer

20-22 July 2010A Nanosatellite Mission to Asses Solar Sailing Performance in LEO International Solar Sail Symposium 2010, New York 8 Background: History of Solar Sailing in Canada 1978: Modi & Van Der Ha papers : CSSP 1990s: Dynacon –Polar Relay Satellite (POLARES) concept study: ~100 kg polesitter for north pole region data backhaul With SPAR, for Canadian DND Heliogyro-like, with ~25 kg despun comms payload (Independently conceived pole-sitter concept) –Several solar sailing conference papers –Solar sail applications study for CSA –Supervised M.A.Sc. magnetosphere mission study

20-22 July 2010A Nanosatellite Mission to Asses Solar Sailing Performance in LEO International Solar Sail Symposium 2010, New York 9 Background: History of Solar Sailing in Canada 1978: Modi & Van Der Ha papers : CSSP 1990s: KAC Dynacon solar sail activities : MOST microsat mission for CSA –Learned how to design and build microsats –UTIAS Space Flight Laboratory founded, major subcontractor to Dynacon

20-22 July 2010A Nanosatellite Mission to Asses Solar Sailing Performance in LEO International Solar Sail Symposium 2010, New York 10 Background: History of Solar Sailing in Canada 1978: Modi & Van Der Ha papers : CSSP 1990s: KAC Dynacon solar sail activities : MOST microsat mission : –SFL nanosats –CanX program

20-22 July 2010A Nanosatellite Mission to Asses Solar Sailing Performance in LEO International Solar Sail Symposium 2010, New York 11 SFLs CanX Program Canadian Advanced Nanospace eXperiment program Developing/flying significantly capable nanosats (1-10+ kg) Providing nanosat launch services via XPOD launcher i/f Current missions use the Generic Nanosat Bus (GNB) platform (20x20x20 cm)

20-22 July 2010A Nanosatellite Mission to Asses Solar Sailing Performance in LEO International Solar Sail Symposium 2010, New York 12 CanX-9 Mission Concept Fly a solar sail technology demonstrator using SFL nanosat technology Seek a partner to provide the solar sail subsystem Demonstrate directed solar sail thrusting Fly as a secondary payload in LEO Expected total cost: <<$10M

20-22 July 2010A Nanosatellite Mission to Asses Solar Sailing Performance in LEO International Solar Sail Symposium 2010, New York 13 CanX-9 Programmatics Initial preliminary design carried out at SFL Partners include: –Technology P.I. and Team Source of mission requirements Processes technology payload data to accomplish tech demo Membership drawn from participating organizations –SFL Mission prime contractor Bus and XPOD supplier Arrange launch –LGarde Provision of solar sail subsystem –CSA Supported initial design study Considering funding the mission

20-22 July 2010A Nanosatellite Mission to Asses Solar Sailing Performance in LEO International Solar Sail Symposium 2010, New York 14 Mission Objectives Address issues impeding the use of solar sailing in operational missions Qualitative: –Demonstrate significant orbit changes via active solar sailing –Flight-test inflatable-boom square-sail technology Quantitative: –Determine sail reflectivity to within 1% by measuring orbit changes –Determine changes in SRP force and torque with time

20-22 July 2010A Nanosatellite Mission to Asses Solar Sailing Performance in LEO International Solar Sail Symposium 2010, New York 15 Some Design Drivers/Issues Cost drives use of nanosat development approach: –Thus COTS EEE parts used –Radiation TID constraint drives altitude limit to below 1000 km or above GEO Cost drives use of secondary-payload launch: –Secondary launch availability constrains orbit availability and launch timing –Sun-synchronous orbit preferred due to availability of launches, and resulting slowly- varying Sun-phase angle which simplifies some aspects of mission and system design Lack of available SRP torque actuators drives preference for low Earth orbit, thus 1000 km upper altitude constraint: –Strong Earth magnetic field in LEO advantageous –Also reduces power for comms Atmospheric force/torque effects provide a 700 km (TBC) lower altitude constraint: –Issue: magnitude of these forces and torques difficult to analyze in advance (area of active research) –Will depend somewhat unpredictably on launch timing and Solar cycle phasing

20-22 July 2010A Nanosatellite Mission to Asses Solar Sailing Performance in LEO International Solar Sail Symposium 2010, New York 16 Mission and System Design Secondary payload launch using XPOD Sun-synchronous orbit, km altitude Sail area 25 m 2, mass <14 kg, mass/area ratio: <560 grams/m 2 Payloads for measuring orbit changes to determine reflectivity to within 1% in 1 month Use SFL UHF-up/S-band-down ground station Quick-look payload data evaluation capability to support day-to-day mission planning Non-real-time analysis of payload data to accurately estimate model parameters for solar radiation pressure and atmospheric forces

20-22 July 2010A Nanosatellite Mission to Asses Solar Sailing Performance in LEO International Solar Sail Symposium 2010, New York 17 XPOD Duo Launcher I/F Developed for CanX-4/5 mission Capacity: –Designed to carry a dual-GNB bus –20x20x40 cm –14 kg Size (w/o spacecraft): –47 x 47 x 52 cm –10 kg Customizable Relatively softer ride Can accommodate fixed appendages

20-22 July 2010A Nanosatellite Mission to Asses Solar Sailing Performance in LEO International Solar Sail Symposium 2010, New York 18 Payloads Solar sail subsystem –Inflatable-boom square sail –To be provided by LGarde Cameras –To provide deployment video –Boom-mounted to get far enough above sail plane for a good view GPS receiver –To provide low-frequency data on orbit changes –Flight heritage from CanX-2 3-axis accelerometer –To provide high-frequency data on orbit changes –Performance requirement: m/s 2 RMS accuracy at 0.01 Hz Total mass ~ 3 kg

20-22 July 2010A Nanosatellite Mission to Asses Solar Sailing Performance in LEO International Solar Sail Symposium 2010, New York 19 Satellite Design Bus –Thermal –OBC –Radios –Power –Structure –ACS Payloads –Solar Sail subsystem –Cameras + boom –GPS receiver –Accelerometer Per existing GNB designs Significantly modified GNB designs New designs

20-22 July 2010A Nanosatellite Mission to Asses Solar Sailing Performance in LEO International Solar Sail Symposium 2010, New York 20 CanX-9 Bus To be developed by SFL Mass ~ 12.5 kg –Including sail support structure –Including 25% margin 20x20x40 cm main structure: –20x20x20 cm lower bus –20x20x15 cm upper bus –Sail stowed in 20x20x5 cm sail- box layer between lower and upper bus sections

20-22 July 2010A Nanosatellite Mission to Asses Solar Sailing Performance in LEO International Solar Sail Symposium 2010, New York 21 CanX-9 With Sail Deployed

20-22 July 2010A Nanosatellite Mission to Asses Solar Sailing Performance in LEO International Solar Sail Symposium 2010, New York 22 Solar Sail Subsystem To be supplied by LGarde Miniaturized version of LGarde 20m ground system demonstrator: –Square sail, 5.5m across flats, 25 m 2 area –Four 4.1m inflatable booms, thermally rigidized –Stripe-net support Mass ~ 1.5 kg (including 20% margin): –Sail: 0.2 kg –Booms: 0.3 kg –Deployment gear: 1.0 kg

20-22 July 2010A Nanosatellite Mission to Asses Solar Sailing Performance in LEO International Solar Sail Symposium 2010, New York 23 Attitude Control Subsystem Zero-momentum, 3-axis stabilized to 1 degree accuracy Sensors: –9 Sun sensors on bus faces –3-axis magnetometer on fixed boom –3 angular rate sensors Actuators: –3 magnetic torque rods –3 reaction wheels All hardware and ACS software has CanX flight heritage Mass ~ 1.75 kg, power ~ 4W

20-22 July 2010A Nanosatellite Mission to Asses Solar Sailing Performance in LEO International Solar Sail Symposium 2010, New York 24 Power Subsystem Power Loads by Mode: –Safe-Hold: 2 W –Detumble:2.5 W –Pre-deployment: 6 W –Deployment: 29 W –Post-deployment: 9 W Sail boom heaters and valves: –14 W, for 1-2 orbits around deployment time Payload power: –2-3 W orbit-average Transmitter power: –5 W, 100% duty cycle when sending down deployment video Power Supply –45 pairs of ~ 27% efficiency (BOL) triple-junction solar cells –27 pairs body-mounted –18 pairs wing-mounted –Each with 920 mW max power generating capacity at worst- case-hot temperature –2x 20 W-hr Li-ion batteries Mass: –~ 2.25 kg

20-22 July 2010A Nanosatellite Mission to Asses Solar Sailing Performance in LEO International Solar Sail Symposium 2010, New York 25 Thermal Subsystem Mostly passive (careful choice of coatings) Spot-heaters on some parts (battery, accelerometer) Large heaters in sail booms, to raise their temperature prior to deployment Boom-to-bus insulation to keep booms from cooling too quickly during deployment Choice of boom epoxy, to have a glass transition temperature to match bus worst-case-hot temperature Analysis of Solar radiation incident on the bus versus sail orientation with respect to the Sun: –Maximum reflected-Sunlight bus heating level of ~ 12W (versus direct- incidence Sunlight ~ 35W) Analysis of sail heating radiatively coupling into bus heating: –Face-on to the Sun, the sail temperature can reach 150 C –This effect is largest when the reflected Sunlight effect is least