1 Interstellar Heliopause Probe M. Leipold, Kayser-Threde GmbHISSS 2010, New York, July 19 – 22, 2010 Interstellar Heliopause Probe (IHP) System Design of a Challenging Mission to 200 AU

2 Interstellar Heliopause Probe Overview Study Team Propulsion Trade-Off Mission/Trajectory Analysis Spacecraft Architectural Design Mass and Power Budgets M. Leipold, Kayser-Threde GmbHISSS 2010, New York, July 19 – 22, 2010

3 Interstellar Heliopause Probe Study Team - Optical Communication Option M. Leipold, Kayser-Threde GmbHISSS 2010, New York, July 19 – 22, 2010

4 Interstellar Heliopause Probe Propulsion Options Assessed for IHP A) High Thrust Chemical Propulsion (CP) (I sp = 320s s; Cryogenic first stage I sp = 470s), incl. Nuclear Thermal Propulsion (NTP) B) Mixed High/Low Thrust Propulsion C) Nuclear Electric Propulsion (NEP) with I sp = 5,000s... 10,000s D) Solar Sail Propulsion (SSP) with a c = mm/s 2 Assumed Launch Mass to GTO for Options A), B) and C): < 3,020 kg Assumed Launch Mass to Earth Escape for Option D):< 2,030 kg (Kourou) M. Leipold, Kayser-Threde GmbHISSS 2010, New York, July 19 – 22, 2010

5 Interstellar Heliopause Probe Preliminary Spacecraft Architectural Design for NEP-Concept Power Subsystem + Radiation Shield Payload „Core“ Payload PWRE Booms 2 x 35m Magnetometer Boom 7-8m S/C Bus with Payload Deployable Truss M. Leipold, Kayser-Threde GmbHISSS 2010, New York, July 19 – 22, 2010

6 Interstellar Heliopause Probe Propulsion Trade-Off Result High thrust (conventional) propulsion incl. gravity assists proved to be infeasible for 25 year flight time and transported mass of ca. 200 kg Mixed high thrust / low thrust also not feasible NEP scenarios infeasible given the launch vehicle constraint of SOYUZ-FREGAT Solar Sail option was selected as baseline Solar Sail scenarios show performance requirement of 1 mm/s 2 to realize flight times of appr. 25 years to reach 200 AU, i.e. depending on minimum solar approach distance M. Leipold, Kayser-Threde GmbHISSS 2010, New York, July 19 – 22, 2010

7 Interstellar Heliopause Probe Scenarios: Low Thrust Solar Sail Propulsion M. Leipold, Kayser-Threde GmbHISSS 2010, New York, July 19 – 22, 2010

8 Interstellar Heliopause Probe Optimized Transfer Result & Navigation Strategy Strategy: „Dual Solar Photonic Assist“  1 st aphelion: 1.05 AU  1 st perihelion: 0.51 AU  2 nd aphelion: 5.76 AU  2 nd perihelion: 0.25 AU Note: Trajectory not optimized for escape asymptote direction to nose of Heliopause ODYSSEE Low-Thrust Optimization, 2004 M. Leipold, Kayser-Threde GmbHISSS 2010, New York, July 19 – 22, 2010

9 Interstellar Heliopause Probe Evolution of Solar Distance Total time of Flight:25.5 years Cruise Phase until 5 AU:6.7 years (Sail jettisoned) Max. Sail Turn Rates: 28.6°/ day, or 1.2°/hour Conclusions: it pays off to spend more time in the inner solar system by increasing the orbit eccentricity Sail jettisoned M. Leipold, Kayser-Threde GmbHISSS 2010, New York, July 19 – 22, 2010

10 Interstellar Heliopause Probe IHP Launch Configuration HGA RTG LV Adapter Deployable Booms Sail Container LGA HIPS Fairing M. Leipold, Kayser-Threde GmbHISSS 2010, New York, July 19 – 22, 2010

11 Interstellar Heliopause Probe Sail Deployed 20m Central Control Mast 2DOF Gimbal Boom Deployed Sail Container (open) IHP Platform M. Leipold, Kayser-Threde GmbHISSS 2010, New York, July 19 – 22, 2010

12 Interstellar Heliopause Probe Spacecraft Architectural Design: Science Mode 35m Plasma- Wave Experiment Boom 8m Magnetometer Boom Highly Integrated Payload Suite M. Leipold, Kayser-Threde GmbHISSS 2010, New York, July 19 – 22, 2010

13 Interstellar Heliopause Probe IHP Science Payload Total of 8 instruments accommodated Total mass: 20.9 kg incl. subsystem margin M. Leipold, Kayser-Threde GmbHISSS 2010, New York, July 19 – 22, 2010

14 Interstellar Heliopause Probe M. Leipold, Kayser-Threde GmbHISSS 2010, New York, July 19 – 22, 2010 Platform Concept (incl. Science Platform)

15 Interstellar Heliopause Probe M. Leipold, Kayser-Threde GmbHISSS 2010, New York, July 19 – 22, 2010 AOCS Maximum turn rate sailing mode:29°/day (heliocentric, near sun) Pointing stability science mode:0.5° Life time: sailing mode:ca. 6.5 years science mode:ca. 19 years Minimum mechanical complexity Sailcraft controllability for first natural frequency of Hz Coherent AOCS design for sailing mode and science mode (sensors etc.) Need to design two different ADCS for IHP

16 Interstellar Heliopause Probe M. Leipold, Kayser-Threde GmbHISSS 2010, New York, July 19 – 22, 2010 Sail Control Schemes Trade-Off

17 Interstellar Heliopause Probe M. Leipold, Kayser-Threde GmbH IHP AOCS Architecture ISSS 2010, New York, July 19 – 22, 2010

18 Interstellar Heliopause Probe M. Leipold, Kayser-Threde GmbHISSS 2010, New York, July 19 – 22, 2010 IHP Sail ADCS Analysis IHP Sail Configuration Moments of inertia = (433000, , ) kg-m 2 cm-cp offset = m (0.25% of 210 meter sail edge) SRP Thrust = F max =  PA = N where,  is the sail efficiency (1.8 assumption), P is the SRP constant P = x N/m 2 at 1 AU, A is the projection area (210 x 210 m 2 ) N SRP, SRP Disturbance torque = F (cm-cp) =0.189 N-m Angular momentum storage/dumping > (N SRP )(3600 s)= 680 N-m-s per hour Use a 0.65 deg/s spin rate for 0.5 deg pointing accuracy, 1-2 rpm

19 Interstellar Heliopause Probe M. Leipold, Kayser-Threde GmbHISSS 2010, New York, July 19 – 22, 2010 Intermediate ACS-Results: - MATLAB Simulations - 35 deg in 6 hrs - 20m Mast x 210 m kg science s/c kg total mass - Gimbal angle < 5 deg

20 Interstellar Heliopause Probe Launch Vehicle Accommodation on SOYUZ-FREGAT (Fairing Type ST) SOYUZ-FREGAT M. Leipold, Kayser-Threde GmbHISSS 2010, New York, July 19 – 22, 2010

21 Interstellar Heliopause Probe IHP Mass Budget: Platform + Sail M. Leipold, Kayser-Threde GmbHISSS 2010, New York, July 19 – 22, 2010

22 Interstellar Heliopause Probe Summary IHP showed that advanced Solar Sails can outperform Nuclear Electric Propulsion for High-  v Missions in Deep Space IHP provided important results for sailcraft ACS simulations and sail controllability IHP helped to define the technology requirements and the definition of a solar sail technology roadmap for ESA

23 Interstellar Heliopause Probe Thermal Control Concept High temperature MLI with reflective outer layer effective emittance: total area: ca. 4 m² Bus Radiators: black coated Size: 0.1m² each RTG: black coated decoupled from bus RTG shield: reflective Couplings: Bus – Radiator: 2 Heat pipes per radiator; C = 2.5 W/K each Bus – RTG: 0.1 W/K each Bus – Antenna: 0.25 W/K Instruments – Radiator: 0.07 W/K total Instruments – Boom: 0.09 W/K total Instrument Radiator: black coated Size: 0.08m² M. Leipold, Kayser-Threde GmbHISSS 2010, New York, July 19 – 22, 2010

24 Interstellar Heliopause Probe Operations Candidate Ground Stations New Norcia Villafranca del Castillo, Spain Weilheim, Germany Only small modifications are required for ground stations Downlink Data Rate at Ka Band: 1 kbps downlink during cruise phase up to 6 AU 200 bps downlink up to 200 AU 4h per week contact time planned (average) M. Leipold, Kayser-Threde GmbHISSS 2010, New York, July 19 – 22, 2010