The document discusses a concept for using repeated external acceleration from stations positioned throughout the solar system to propel probes to distances of 200 AU within 15 years. It summarizes the current study analyzing trajectories for probes accelerated by single and dual stations in Earth and Jupiter orbits. The document also reviews potential station and probe configurations that could enable such an ambitious interstellar exploration architecture.

1. Interstellar Exploration
Through Repeated External
Acceleration
Andrew Bingham
NIAC Student Fellows Prize
Department of Mechanical and Aeronautical Engineering, Clarkson University
NIAC Fellows Meeting, March 7thNIAC 7th--8th, 20068th, 2006

2. Agenda
„„ Introduction/Background
„„ Repeated External Acceleration Concept
„„ Current Study
„„ Future Work
„„ Acknowledgements/References

3. The Heliosphere

4. Current Missions
•Voyager 1 & 2
•Launched in 1977
•Extended Interstellar mission
•Passing Termination Shock
•Communications until 2020 and approximately 120 AU
•Pluto New Horizons
•Launched December 2005
•Extended mission to visit KuiperBelt Objects
•Communications until 2020 and approximately 50 AU

5. Future Scientific Objectives
„„ Investigate physical properties and
composition of local interstellar medium
for comparison to solar system and
galactic abundance.
„„ Measure cosmic ray nuclei and electrons
without the interference of the
heliosphere.
„„ Gather data on astrophysical processes
such as acceleration by supernova
shockwaves, interstellar radio and x x-ray
emissions, nucleosynthesis nucleosynthesis, and the
, dynamics of interstellar medium.
„„ Perform direct measurements of the
size and structure of the heliosphere.

6. Agenda
„„ Introduction/Background
„„ Repeated External Acceleration Concept
„„ Current Study
„„ Future Work
„„ Acknowledgements/References

7. Repeated External Acceleration
„„ Acceleration stations
external to the
spacecraft provide
primary propulsion.
„„ Stations are positioned
throughout the solar
system.
„„ Form a ‘solar system
sized slingshot’

8. Repeated External Acceleration
„„ Architecture is reusable and expandable.
„„ Stations can carry out other functions in in-situ.
„„ Major issues include trajectory planning, station
and probe hardware configurations

9. Agenda
„„ Introduction/Background
„„ Repeated External Acceleration Concept
„„ Current Study
„„ Trajectory Analysis
„„ Station Configuration
„„ Probe Configuration
„„ Future Work
„„ Acknowledgements/References

10. Trajectory Analysis
„„ Critical Trajectory Features
„„ Reach 200AU in 10 10-15 years
„„ Exit heliosphere in direction of
bow shock
„„ Problem Space Simplification
„„ No station at Mars due to small
gravity assist available
„„ Stations at multiple outer
planets avoided due to long
orbital periods
„„ Two main cases
„„ Single station in Earth orbit
„„ Dual stations in Earth and
Jupiter orbits

11. Basic Calculations
Based on travel to 200AU in 15 years:
„„ Single station at Earth requires Vinf = 63.2 km/s
„„ Dual 40 km/s stations at Earth & Jupiter10203040506070050100150200250300350400Delta Vinf Earth Delta Vinf Jupiter Delta Vinf at Jupiter vs Delta Vinf at Earth, 200AU in 15 years
Jupiter

12. Requested Software
„„ SNAP –– NASA Glenn
„„ Spacecraft N N-Body Analysis Program
„„ Propagates using 8 8th th order Runge Runge-Kutta Fehlberg routine
„„ MIDAS –– Jet Propulsion Laboratory
„„ Patched conic trajectory optimization program
„„ Capable of automatically varying, adding, deleting mission
phases
„„ Satellite Toolkit
„„ Industry standard trajectory planning tool

13. SNAP
„„SNAP runs in Linux and other UNIX/BSD environments.„„Input and output are in the form of formatted text.„„Fortran source code is available for custom applications.„„Does not perform optimization.

14. SNAP
„„ Input files for the two
cases of station
configuration are being
created.
„„ Case 1 –– Single station in
LEO
„„ Case 2 –– Dual stations in
LEO and Jupiter orbits
„„ Station accelerations
currently modeled as
impulsive.

15. Further Optimization
„„ By wrapping an optimization code around
SNAP, more efficient trajectories can be found.
„„ Currently, a simple optimizer is being written
using GNU/Octave.
„„ Capable of varying parameters within the
representative input files and comparing resulting
output for mission success based on critical
trajectory limitations.

16. Station Configuration
Linear AcceleratorTetherMagBeam „„MagBeamMagBeamStation SelectedStation Selected „„Scaleable system.„„Does not require large space structure.„„Longer interaction times reduce spacecraft loading.„„Hardware currently being demonstrated.

17. Probe Configuration
„„ Pluto New Horizons spacecraft
shares many characteristics with
interstellar probes.
„„ Long Long-duration deep space mission.
„„ Mass minimized (~500kg) to
achieve high velocity.
„„ Some instruments designed to
measure plasma and solar wind
interactions.
„„ Further reducing the payload
mass through miniaturization
could allow the use of a PNH PNH-
derived spacecraft for an
externally accelerated mission to
bow shock.

18. Probe PayloadProbe PayloadInstruments: •Magnetometer•Plasma and Radio Wave Sensor•Solar Wind/Interstellar Plasma/Electron Spectrometer•Pickup and Interstellar Ion Isotope Spectrometer•Interstellar Neutral Atom Spectrometer•SuprathermalIon/Electron Sensor•Cosmic Ray H, He, Electron, Positron, Gamma-Ray Burst Instrument•Anomalous & Galactic Cosmic Ray Isotope Spectrometer•Dust Composition Instrument•Infrared Instrument•Energetic Neutral Atom (ENA) Imager•UV Photometer Resource Requirements: •Power –20W•Communications –25bps•Mass –25kg

19. Technology Readiness
Architecture Component
TRL
Space Nuclear Power Supply
TRL 6
Autonomous Rendezvous
TRL 9
Advanced Deep Space Vehicle
TRL 9
MagBeam System
TRL 4
Miniaturized Instrument Suite
TRL 3

20. Agenda
„„ Introduction/Background
„„ Repeated External Acceleration Concept
„„ Current Study
„„ Future Work/Outreach
„„ Acknowledgements/References

21. Continuing Work & Outreach
„„ Complete trajectory analysis
„„ Potential Case 3 –– LEO + Mars Stations
„„ Publish Web Site
„„ Present at AIAA Region I I-NE Student
Conference, March 30 30th th-April 1 1st st
„„ Present at Clarkson University Symposium for
Undergraduate Research, April 7 7th th
„„ Final Report

22. Agenda
„„ Introduction/Background
„„ Repeated External Acceleration Concept
„„ Current Study
„„ Future Work/Outreach
„„ Acknowledgements/References

23. Acknowledgements
„„ NIAC, for providing the resources to continue
working on this project.
„„ Dr. Kenneth Visser Visser, for advising me throughout
, the process.
„„ NASA Glenn for providing SNAP.
„„ AGI for providing STK.
„„ Family, friends, and everyone else who
supported me throughout the last year.

24. References
Analytical Graphics, Inc, Satellite Toolkit, v.6.2.
Hoyt, et. al, A Modular Momentum-Exchange/Electrodynamic-ReboostTether System Architecture, AIAA-2003-2514.
Interstellar Boundary Explorer Science Strategy. http://www.ibex.swri.edu/mission/strategy.shtml
Martini, Michael. Spacecraft N-Body Analysis Program 2.3 Users Guide. AnalexCorperation, NASA Glenn Research Center, 2005.
Mewaldt, R. A., and Liewar, P. C., An Interstellar Probe Mission to the Boundaries of the Heliosphere and Nearby Interstellar Space, NASA Jet Propulsion Laboratory, 1999.
Pluto New Horizons Science Payload, http://pluto.jhuapl.edu/spacecraft/sciencePay.html
Riehl, Phil.Tools Used By Analysis & Integration Group –MIDAS. http://trajectory.grc.nasa.gov/tools/midas.shtml
Vallado, David A, Fundamentals of Astrodynamicsand Applications, Microcosm, 2001.
Winglee, et. al, Magnetized Beam Propulsion, NIAC Fellows Meeting 2005.

25. Questions?