UCLA Extension

Spacecraft Mechanisms

The course is an introduction and overview to a wide variety of mechanisms and mechanical devices used on spacecraft and space instruments. Spacecraft for a wide variety of missions are using more deployments and moving elements to increase functionality and performance compared to earlier missions. Design guidelines and tips for the successful development of moving mechanical assemblies are explored and discussed. Space mechanisms have unique and competing needs for lightweight design and functional reliability. These are presented, along with requirements for an adequate verification test program. The course includes examples from previously flown missions that demonstrate the design options presented to a mechanisms design engineer. Rather than a detailed lesson in machine design, this course tackles the subject as one of mechanical systems, designing a functional system that includes elements that are procured and designed, and whose engineering tasks include structural design, force/torque margin analysis, mechanical assembly instruction, testing, and documentation.

This course is designed for engineers responsible for the development of typical spacecraft mechanisms. All of the design drivers and considerations are covered, from initial requirements to implementation choices, testing, and operational needs. Managers and systems engineers who need to obtain a greater understanding of the complexities and trades considered by a mechanisms engineer can also benefit from this course.

Course Materials

Lecture notes are distributed on the first day of the course. These notes are for participants only and are not for sale.

Coordinators and Lecturers

Mark E. Johnson, MS, Section Manager, Spacecraft Mechanical Engineering, Jet Propulsion Laboratory, Pasadena, California. Mr. Johnson began his career in the aerospace industry at the Space Systems Division of Rockwell International in 1986, where he worked on the Space Shuttle program. He served as a stress analyst for the Orbiter during the post-Challenger, Return to Flight engineering. In 1990, he joined Lockheed-Martin Missiles & Space to work on the International Space Station deployable solar arrays. He designed the structural hinges for the packaged solar arrays which are deployed by astronauts (EVA), as well as the structural interface and fasteners operated by astronauts in the event of on-orbit replacement of a re-stowed solar array. These designs included validation by underwater testing in a neutral buoyancy facility by NASA astronauts. Mr. Johnson also designed and tested multiple mechanisms required for the deployment and control of the large, flexible solar arrays on ISS. These include a motorized latch mechanism, manual (EVA) override mechanism, array tensioning mechanism, and cable reel mechanism. He also worked at the Lawrence Livermore National Laboratory designing adjustable kinematic mounts for high-power laser components within the National Ignition Facility.

For the past dozen years Mr. Johnson has worked at NASA/Caltech’s Jet Propulsion Laboratory, where he has served as the supervisor of the Mechanisms Engineering group, and manager of the Spacecraft Mechanical Engineering section. In this capacity he has overseen the design, build, and test of mechanisms and other mechanical hardware for a wide range of robotic space vehicles. These include filter wheels and precision positioning stages for optical instruments, deployment and mobility mechanisms for Mars rovers, and pyrotechnic devices and launch locks.

Mr. Johnson has published at the Aerospace Mechanisms Symposium. He received his BSAE from the University of Southern California and an MSAE from the University of Texas at Austin

Kobie Boykins, BS, Group Supervisor, Mechanisms & Mobility Group, Jet Propulsion Laboratory, Pasadena, California. Mr. Boykins began his career in the aerospace industry in the Advanced Mechanical Systems group at NASA/Caltech’s Jet Propulsion Laboratory as a student in 1995 and full time in 1997. His first program, Mars Pathfinder, teamed him with the Entry, Descent, and Landing team where Mr. Boykins worked on the multibody system drop test and with the rover mobility team working on the Sojourner rover.

Mr. Boykins has been able to create mechanical systems in the technology world as well. First working on the Muses-C Nanorover as the mobility engineer, he designed a mobile platform for exploration of a small body within a micro-G environment. He was also tasked with creating multiple sub-surface explorers for the underwater exploration of fumaroles and precursor mission technology demonstrators for Europa explorers.

In late 2000, Mr. Boykins was asked to work on the Mars Exploration Rover as the Rover Solar Array Cognizant Engineer. In this role he designed, built, tested, and delivered the deployable solar array structure and mechanisms for both the Spirit and Opportunity vehicles that have re-written the history books on the past existence of water on Mars. On the Mars Science Laboratory, he is the lead mechanical engineer on the rover actuators. Currently, Mr. Boykins is responsible for all the motors and actuators on the rover subsystem.

For the past several years Mr. Boykins has served JPL as the supervisor of the Mobility and Mechanisms Engineering group, within the Spacecraft Mechanical Engineering section. In this capacity he has overseen the designing, building, and testing of mechanisms and other mechanical hardware for a wide range of robotic space vehicles. These include deployment and mobility mechanisms for Mars rovers, pyrotechnic devices, launch locks and latches, multi-axis gimbals as well as technology development for the next missions including Actuators.

Mr. Boykins has given presentations to the award winners of the Presidential Awards for Excellence in Mathematics and Science Teaching, as well as doing public outreach across the U.S. for NASA/JPL in terms of creating the next generation of Space explorers. He also serves as National Geographic Society Speakers Bureau presenter. Mr. Boykins received his BSME from Rensselaer Polytechnic Institute, Troy, New York.

Course Program


  • Force/torque/speed
  • Range of motion
  • Volume/packaging
  • Precision
  • Life

Motors and Actuators

  • Brushless DC
  • Stepper
  • Brushmotors
  • Drive electronics

Bearings and Bushings

  • Ball bearings
  • Angular contact/radial/deep groove
  • Cages
  • Mounting and preloading
  • Analysis
  • Rollers and non-rolling bushings


  • Spur
  • Planetary
  • Geometry and stress


  • Grease
  • Oil
  • Solid films


  • Compression
  • Torsion
  • Flexures
  • Constant force


  • Fluid
  • Eddy current
  • Friction brake

Pyromechanisms and Non-Pyro Separation Devices

  • Initiators and boosters
  • Pinpullers
  • Separation nuts and bolts
  • Cable cutters
  • Other devices

Other Mechanisms

  • 4-bar linkages
  • Pivots and hinges
  • Power and lead screws

Materials and Structure

  • Common mechanism materials
  • Housings
  • Structural interface and alignments

Fault Trees and Failure Analysis

  • Use in design
  • Use in failure recovery

Environmental and Functional Loads

  • Launch loads
  • Resistive loads
  • Hard stops
  • Landing loads

Thermal Requirements

  • Predicted, allowable, and test temperatures
  • Gradients
  • Thermal control hardware

Launch Locks

  • Separation device interface
  • Pushoff springs
  • Preloaded snubbers
  • Balanced designs (no locks)


  • Functional
  • Environmental
  • Life


  • Schedules
  • Cost estimation
  • Subcontracts


  • Telemetry
  • Control logic, software, and scripting

For more information contact the Short Course Program Office:
shortcourses@uclaextension.edu | (310) 825-3344 | fax (310) 206-2815