low thrust trajectory design n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Low-thrust trajectory design PowerPoint Presentation
Download Presentation
Low-thrust trajectory design

Loading in 2 Seconds...

play fullscreen
1 / 30

Low-thrust trajectory design - PowerPoint PPT Presentation


  • 187 Views
  • Uploaded on

Low-thrust trajectory design. ASEN5050 Astrodynamics Jon Herman. Overview. Low-thrust basics Trajectory design tools Real world examples Outlook. Low-thrust. Electric propulsion Solar electric propulsion (SEP) Nuclear electric propulsion (NEP) SEP is mature technology, NEP not exactly

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Low-thrust trajectory design' - travis


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
low thrust trajectory design

Low-thrust trajectory design

ASEN5050

Astrodynamics

Jon Herman

overview
Overview
  • Low-thrust basics
  • Trajectory design tools
  • Real world examples
  • Outlook
low thrust
Low-thrust
  • Electric propulsion
    • Solar electric propulsion (SEP)
    • Nuclear electric propulsion (NEP)
    • SEP is mature technology, NEP not exactly
  • Solar sails
    • Comparatively immature technology
    • Performance currently low
  • All very similar from trajectory design stand point
electric propulsion
Electric Propulsion
  • Chemical propulsion
    • Up to ~17 000 000 N
    • About 4 000 000 000 sheets of paper
  • Engine runs for minutes
  • Electric Propulsion
    • About 0.2 Newton
    • About 4 sheets of paper
  • Engine runs for months-years
  • 10 times as efficient
hall thrusters
Hall thrusters

Exhaust velocity: 10 – 80 km/s

Conservation of momentum

(University of Tokyo, 2007)

specific impulse
Specific impulse

Specific impulse:

Rocket equation:

rocket equation
Rocket equation

Dawn

SMART-1

LEO/GTO to GEO

implications for optimal trajectories
Implications for optimal trajectories
  • The optimal transfer properly balances
    • Specific impulse
    • Spacecraft power
    • Mission ΔV
  • Unique optimum for every mission
    • ΔV no longer a defining parameter!(arguably: ΔV no longer a limiting parameter)
trajectory example
Trajectory example
  • What is difficult about low-thrust?
    • Trajectory is “continuously” changing
    • No analytical solutions
    • Optimal thrust solution only partially intuitive
    • Specialized, computationally intensive tools required!
example method
Example Method

Fly by, probe release, etc...(discontinuous state)

Backward integration

  • JPL’s MALTO
    • Mission Analysis Low Thrust Optimization
    • Originally: CL-SEP (CATO-Like Solar Electric Propulsion)

Match Points

Forward integration

Small impulsive burns

Source: Sims et al., 2006

malto type tools
MALTO-type tools
  • Optimize...
    • Trajectory
      • Subject to whatever desired trajectory contraints
    • Specific impulse (Isp)
    • Spacecraft power supply
      • Using solar power
      • Using constant power (nuclear)
      • Possible: solar sail size, etc.
strengths
Strengths
  • Fast
  • Robust
  • Flexible
  • Optimizes trajectory & spacecraft!
weaknesses
Weaknesses
  • Ideal for simple (two-body) dynamics
  • Limited to low revolutions (~8 revs)
    • No problem for interplanetary trajectories
    • ~Worthless for Earth departures/planetary arrivals
dawn nasa
Dawn (NASA)
  • Dawn ( 2007 – Present day)
    • Most powerful Electric Propulsion mission to date
    • Visiting the giant asteroids Vesta and Ceres
smart 1 esa
SMART-1 (ESA)
  • Launched in 2003 to GTO
  • Transfer to polar lunar orbit
  • Only Earth ‘escape’ with low-thrust
  • Propellant Mass / Initial Mass:

23% (18% demonstrated later)

smart 1
SMART-1

(ESA, 1999)

hayabusa jaxa
Hayabusa (JAXA)
  • First asteroid sample return (launched 2003)
  • 4 Ion engines at launch
  • 1 & two half ion engines upon return
hayabusa end of life operation
Hayabusa end-of-life operation

Engine 1

Engine 2

(University of Tokyo, 2007)

aehf 1 usaf
AEHF-1 (USAF)
  • GEO communications satellite, launched 2010
  • Stuck in transfer orbit (due to propellant line clog)
  • Mission saved by on-board Hall thrusters

(Garza, 2013)

commercial geo satellites
Commercial GEO satellites

(Bostian et al., 2000)

commercial geo satellites2
Commercial GEO satellites

(Byers&Dankanich, 2008)

electric propulsion developments
Electric propulsion developments
  • Boeing
    • Four GEO satellites, 2 tons each
    • Capable of launching two-at-a-time on vehicles as small as Falcon9
    • Private endeavor
  • ESA/SES/OHB
    • Public-Private partnership
    • One “small-to-medium” GEO satellite
    • Possibly the second generation spacecraft of the Galileo constellation
  • NASA
    • 30kW SEP stage demonstrator (asteroid retrieval?)
conclusion
Conclusion
  • Electric propulsion rapidly maturing into a common primary propulsion system
  • This enables entirely new missions concepts, as well as reducing cost of more typical missions
  • Very capable trajectory design tools exist, but not all desired capability is available or widespread