M. Leipold, Kayser-Threde GmbH

1

Interstellar Heliopause Probe

M. Leipold, Kayser-Threde GmbH ISSS 2010, New York, July 19 – 22, 2010

Interstellar Heliopause Probe (IHP)

System Design of a Challenging Mission to

200 AU

2


Overview

Study Team

Propulsion Trade-Off

Mission/Trajectory Analysis

Spacecraft Architectural Design

Mass and Power Budgets


3


Study Team ESA / ESTEC SCI-A(Customer)

- Study Management- Mission Architecture, LV Selection- Propulsion Trade-offs- Highly Integrated Payload Suite &

Payload Accommodation- Mission Analysis & System Costing

University of Bochum(Consultant)

D

Surrey Space Center(Sub-Contractor)

UK

Kayser-Threde(Prime Contractor)

D

- Platform Design- Subsystem Thermal and

Structural Analyses- On-Board Nuclear Power

Sources- Micro-/Nano-Technologies- Subsystem Costing

Consultancy on- Science Payload Operations

Planning- Science Operations Ground

Support

German Aerospace Center(Consultant)

D

Consultancy on- Deep Space Operations- Ground Station Infrastructure

and Requirements

- Preliminary Payload Definition- Science Objectives

- Optical Communication Option


4


Propulsion Options Assessed for IHP

A) High Thrust Chemical Propulsion (CP) (Isp = 320s ... 370s; Cryogenic first

stage Isp = 470s), incl. Nuclear Thermal Propulsion (NTP)

B) Mixed High/Low Thrust Propulsion

C) Nuclear Electric Propulsion (NEP) with Isp = 5,000s ... 10,000s

D) Solar Sail Propulsion (SSP) with ac = 0.75 .. 3.0 mm/s2

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)


5


Preliminary Spacecraft Architectural Design for NEP-Concept

Power Subsystem + Radiation Shield

Payload „Core“

Payload PWRE Booms2 x 35m

Magnetometer Boom 7-8m

S/C Bus with PayloadDeployable Truss


6


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/s2 to realize flight

times of appr. 25 years to reach 200 AU, i.e. depending on minimum solar

approach distance


7


Scenarios: Low Thrust Solar Sail Propulsion

ParameterFast Mission

„IHP_3“Slow Mission_1

„IHP_2“

Slow Mission_2„IHP_1“

SlowMission_3

NEW

Characteristic Acceleration, ac(mm/s2)

3.0 1.5 0.85 0.75 1.0

Sail Configuration Disc Disc Square Square Square or Disc

Hyperbolic Excess, C3 (km2 s-2) 0 0 0 0 0

Launch Mass (kg) 1016 605 831 280 400 -550

Useful Mass (kg) 195 199 200 125 180- 200

Solar Photonic Assists (Solar Fly-by)

1 1 2 + JGA 3 2

Minimum Solar Radius, rp (AU) 0.25 0.25 0.16 0.10 0.20 – 0.25

Maximum Sail Film Temperature,Tmax (K)

516 523 501 785 ( =0°)747 (=35°)

525

Reflectivity 0.85 0.85 0.92 0.92 0.85

Emissivity (Back side) 0.64 0.64 0.9 0.9 > 0.64 (TBC)

Velocity @ 5AU (AU/yr) 15.0 9.610.9 (after JGA) 10.69

(50.7km/s)@ 150 AU

10 - 11 AU/year

Time to 200 AU (yrs) 15.7 24.1 25.0 21.1 25.5


8


Optimized Transfer Result & Navigation Strategy

Strategy:

„Dual Solar Photonic Assist“

1st aphelion: 1.05 AU

1st perihelion: 0.51 AU

2nd aphelion: 5.76 AU

2nd perihelion: 0.25 AU

- 3 - 2 - 1 0 1 2 3 4 5D I S T A N C E R x [ A U ]

- 5

- 4

- 3

- 2

- 1

0

1

2

3

DIS

TA

NC

E R

y [A

U]

Note: Trajectory not optimized for escape asymptote direction to nose of Heliopause

ODYSSEE Low-Thrust Optimization, 2004


9


Evolution of Solar Distance

0 1000 2000 3000Tim e of F light [days]

0

4

8

12

16

20

So

lar

Dis

tan

ce [

AU

]

rm in = 0 .25 AU

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


10


IHP Launch ConfigurationHGA

RTG

LV Adapter

Deployable Booms

Sail Container

LGA

HIPS

Fairing


11


Sail Deployed20m Central Control Mast

2DOF GimbalBoom Deployed

Sail Container (open)

IHP Platform


12


Spacecraft Architectural Design: Science Mode

35m Plasma-Wave Experiment Boom

8m Magnetometer Boom

Highly Integrated Payload Suite


13


IHP Science Payload

InstrumentAbbreviation

Description Mass Power

IPA Interstellar Plasma Analyzer 2.0 1.3

IPWE Interstellar Plasma Wave Experiment 4.5 4.0

IMAG Interstellar Magnetometer 3.7 3.4

INCADI Interstellar Neutral and Charged Atom Detector and Imager 0.5 1.8

IEPD Interstellar Energetic Particle Detector 1.8 1.2

IDA Interstellar Dust Analyser 1.0 1.0IUVP Interstellar UV- Photometer 0.3 0.3

Solar Monitor Solar Activity Monitoring 0.6 3.0

Structures Structures for HIPs accommodation 2.0 -CPS Central Payload Power Supply 1.0 -

Margin 20% 3.5 3.2

Total 20.9 19.2

Total of 8 instruments accommodated

Total mass: 20.9 kg incl. subsystem margin


14



Platform Concept (incl. Science Platform)

15



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 0.0065 Hz

Coherent AOCS design for sailing mode and science mode (sensors etc.)

Need to design two different ADCS for IHP

16



Sail Control Schemes Trade-Off

17


M. Leipold, Kayser-Threde GmbH

IHP AOCS Architecture

ISSS 2010, New York, July 19 – 22, 2010

18



IHP Sail ADCS Analysis

IHP Sail Configuration

Moments of inertia = (433000, 433000, 865000) kg-m2

cm-cp offset = 0.525 m (0.25% of 210 meter sail edge)

SRP Thrust = Fmax = PA = 0.3621 N

where, is the sail efficiency (1.8 assumption), P is the SRP constant P = 4.536 x 10-6 N/m2 at 1 AU, A is the projection area (210 x 210 m2)

NSRP , SRP Disturbance torque = F (cm-cp) =0.189 N-m

Angular momentum storage/dumping > (NSRP )(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



Intermediate ACS-Results:

- MATLAB Simulations

- 35 deg in 6 hrs

- 20m Mast

- 210 x 210 m

- 200 kg science s/c

- 400 kg total mass

- Gimbal angle < 5 deg

20


Launch Vehicle Accommodation on SOYUZ-FREGAT (Fairing Type ST)

Launch Vehicle Payload to EarthEscape (C3 = 0)

Payload to EarthEscape (C3 = 10km2/s2)

ROM Launch Costs

SOYUZ-FG 2B 1930 kg (Baikonur)2030 kg (Kourou)

1250 kg (Baikonur) 38 Mio. Euro

ROCKOT +STAR 37 FM

440 kg - 14-15 Mio. € + 2-3 Mio. USDfor STAR 37 FM

SOYUZ-FREGAT


21


IHP Mass Budget: Platform + Sail

Subsystem kg Margin [%] Total [kg]

Payload 17,4 20,0 20,9

Power 40,1 20,0 48,1

AOCS incl. Control Mast 28,9 20,0 34,7

OBDH 7,8 10,0 8,6

TM/TC 16,3 20,0 19,6

Thermal Control 11,0 20,0 13,2

Structures 13,9 10,0 15,3

Harness 6,7 10,0 7,4

Platform Total 167,8

Solar Sail 206,0

System Margin 75,0

Total Flight System 448,8


22


Summary

IHP showed that advanced Solar Sails

can outperform Nuclear Electric

Propulsion for High-Dv 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


Thermal Control Concept

High temperature MLIwith reflective outer layereffective emittance: 0.025total area: ca. 4 m²

Bus Radiators: black coatedSize: 0.1m² each

RTG: black coateddecoupled from bus

RTG shield: reflective

Couplings:Bus – Radiator: 2 Heat pipes per radiator; C = 2.5 W/K eachBus – RTG: 0.1 W/K eachBus – Antenna: 0.25 W/KInstruments – Radiator: 0.07 W/K totalInstruments – Boom: 0.09 W/K total

Instrument Radiator: black coatedSize: 0.08m²


24


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 GmbH

Documents

Transcript of M. Leipold, Kayser-Threde GmbH