STP Data Exchange

1
STP Data Exchange

• Professor David W. Miller
• March 24, 2008

2
Overview

• Laboratory environment aboard the ISS
• 3 6-DOF free-flyer, self-contained
  nano-satellites 3 support satellites in ground
  operations
• Satellite-to-ground (laptop) and inter-satellite
  communications
• Custom pseudo-GPS metrology system
• Guest Scientist Program supports multiple
  investigators includes in-house simulator

Control Panel
Pressure Regulator
Ultrasound Sensors
2D Lab Tests
Simulation
Pressure Gauge
Incremental Algorithm Update
Battery (2x)
Thrusters
Data Analysis
ISS
SPHERES nano-satellite
SPHERES Operations Cycle
3
Flight Data

• Launches
• Mission duration
• 16 Test Sessions (11 Completed) by 16/Jan/2010
• Volume
• Stored in up to three MLE (Mid-deckLocker
  Equivalent) containers
• Power
• 13W per Satellite
• PI Cost
• 1.5M Build, 1.0M Research Operations

4
Science Objectives

• MOA 5.2.a DARPA agrees to provide a PI that
  willdefine experiment requirements
• Develop a platform to demonstrate and validate
  metrology, control, autonomy, and artificial
  intelligence algorithms for distributed satellite
  systems (DSS)
• Demonstrate different configurations of DSS
• Rendezvous and docking algorithms
• Servicing missions
• Space assembly
• Autonomous formation flight
• Optical telescopes
• Space based radar
• Provide a representative environment for the
  demonstrations
• 6 DOF
• Long duration m-g

• Full satellite simulation
• Allow science payloads

DARPA
JPL
DARPA
F6
TPF
Orbital Express
5
Evaluation of Results

• 1) Develop a platform to demonstrate DSS
  algorithms
• SPHERES has operated 11 times with over 150
  tests, demonstrating the ability to mature
  control, estimation, and autonomy algorithms.
• 2) Demonstrate configurations
• 2.1) Rendezvous and docking (to continue)
• During the first 11 sessions SPHERES has been the
  first team to demonstrate 1) docking to a
  tumbling target 2) the effects of plume
  imingement on similar sized spacecraft, 3)
  on-line path planning to determine a docking
  path. During these sessions SPHERES has also
  began research on control of the satellites after
  docking, relevant to in-space autonomous assembly
  of large spacecraft.
• 2.2) Autonomous formation flight (to continue)
• SPHERES tests have been the first to demonstrate
  three satellite formation flight relevant to
  missions such as space based radar. Tests have
  demonstrated multiple algorithms to reconfigure a
  formation taking into account the use of multiple
  spacecraft.
• 3) Provide a representative environment
• SPHERES provides 6 DOF, long-duration
  micro-gravity, and are representative of a
  complete satellite bus
• The satellites allow for "science payloads"
  through the SPHERES Expansion port (use requires
  new manifests)

Partial
Partial
6
ResultsDemonstrate Mature Algorithms

• 11 Test Sessions have successfully been used to
  mature, incrementally, a substantial number of
  algorithms for DSS.

Key Success, Partial, - Failure, o
Out of time
7
ResultsDocking Plume Impingement

• Results Success
• Satellites made contact
• Plume impingement effects were clear
• State estimates smooth throughout
• Illustrates potential problems with a straight
  line approach

• Future
• Develop algorithms that account for plume
  impingement

8
ResultsDocking Online Path Planning

• Results Success
• Planned path avoided stay-out area
• Path demonstrate 3D operation
• Satellites made contact

• Future
• Re-planning during intermediate steps
• Complex target motion

9
ResultsDocking to a Tumbling Target

• Results Success
• Chaser satellite maintained close-proximity
  stability during docking
• Estimator FDI successfully rejected external
  disturbances
• Test Sequence Complete (traditional control
  algorithms)

10
ResultsThree Satellite Formation Flight

• Results Success
• Demonstrated ability of 3 satellites to describe
  a synchronized circular formation within 2cm
  error
• Tested communications synchronization algorithms
• Used basic PID control

• Future
• Maneuvers relevant to synthetic imaging

11
ResultsFormation Reconfiguration

• Results Success
• Demonstrated multiple types of formation
  rotations
• Obtained data to compare rigid body baseline

• Future
• Develop fuel-time optimal control algorithms

Planned
Actual
12
ResultsLost-in-Space Formation Scatter

• 2Sat Formation Scatter
• Results Success
• Satellites scattered opposite each other,
  calculating the scatter online
• Future
• 3 satellite tests
• Integrate with threat detection

• 2Sat Lost-in-Space
• Results Success
• Both satellites found each other and pointed
  within a 5 degree error
• Future
• 3 satellite algorithm development

13
ISS Remaining Objectives

• Primary remaining objectives for each science
  task
• Docking increment knowledge on online path
  planning and collision avoidance
• Formation Flight fuel optimal and robust control
  algorithms, formation reconfigurations, use of
  relative metrology, complete mission simulations

14
Dissemination of Results

• Dissemination of results occurs only once a
  substantial advance in an algorithm has been
  demonstrated
• Results are presented to DARPA multiple times a
  year as parts of presentations working towards
  future SPHERES Operations
• The PI participates in multiple invited lectures
  at both DoD and NASA
• When the contracts permit it, results are
  presented at conferences or published in journals
  of reknowed professional engineering associations
  such as AIAA, SPIE, and IEEE
• Examples
• Swati Mohan, Alvar Saenz-Otero, Simon Nolet, et
  al, SPHERES Flight Operations Testing and
  Execution, International Astronautical Congress,
  Hyderabad, India, 24-28 Sept 2007
• Christophe Mandy, Hiraku Sakamoto, Alvar
  Saenz-Otero, David W Miller, Implementation of
  Satellite Formation Flight Algorithms Using
  SPHERES aboard the International Space Station,
  International Symposium on Space Flight Dynamics,
  Annapolis, MD, 24-28 Sept 2007
• Simon Nolet, The SPHERES Navigation System from
  Early Developmen to On-Orbit Testing, AIAA
  Guidance, Navigation Control, Hilton Head, SC,
  20-23 Aug 2007
• Nolet, S, Kong, EMC, Miller, DW, Design of an
  Algorithm for Autonomous Docking with a Freely
  Tumbling Target, Proceedings of the SPIE Defense
  and Security Symposium 2005, Vol. 5799-16,
  Orlando, FL, March 2005

15
Benefits Transition Plan

• DARPA's F6 testing of cluster management
  algorithms to support concept of spacecraft
  fractionation
• SPHERES is an active member of multiple F6
  industry teams working to demonstrate the
  feasibility of fractionated spacecraft
• SPHERES will be used to directly test and
  demonstrate algorithms which will be used in the
  final flight experiment of F6
• ONR/NRL interest in using SPHERES for
  vision-based navigation for satellite inspection
• Naval Post Graduate School testing its proximity
  operations and collision avoidance algorithms in
  support of robotic assembly
• Lockheed-ATC interest in using SPHERES to test
  in-space robotic assembly (approaching DARPA with
  some concepts)
• Orbital Express complement OE results with
  docking with tumbling targets
• NASA while not DoD, applications include robotic
  assembly (GSFC, MSFC), FDIR and on-line inertia
  characterization (ARC), formation control (JPL),
  and throughput-efficient distributed formation
  control (GSFC)
• Education SPHERES has helped educate over a
  dozen graduate students and close to 50
  undergraduates.

16
SPHERES Points of Contact

• Principal Investigator
• Prof. David Miller
• Director, MIT Space Systems Laboratory
• [phone]
• millerd_at_mit.edu

Science Lead Dr. Alvar Saenz-Otero MIT Space
Systems Lab. [phone] alvarso_at_mit.edu
Payload Integration John Merk Aurora Flight
Sciences Corp. [phone] jmerk_at_aurora.aero
Space Test Program (Code WR1) Maj Matthew Budde,
USAF, [phone] Mark Adams, SAIC, (281)
483-3520
spheres_at_mit.edu http//ssl.mit.edu/spheres