Custom Ball Screw Assemblies for the Juno Spacecraft

The project highlighted here is set of custom ball screw assemblies for the Juno space craft traveling to Jupiter. Lockheed Martin contracted Emcor Incorporated to manufacture the ball screw assemblies which were utilized in the solar panel actuator assembly used to position the 3 panels. The ball screws were manufactured of a unique alloy to take advantage of mechanical proprieties which would allow the reduction of required mass and to minimize the magnetic effects on the sensitive instrument package the craft is transporting. The screws required precision grinding and an Emcor engineered block style return system to meet design parameters and testing to prove the return system would still function after a critical loading event. The space craft launched in August of 2011 and is currently operating and in excellent health.

For additional details about this project or projects like this, contact us directly.

Custom Ball Screw Assemblies for the Juno Spacecraft Highlights

Product Description: Ball screw for spacecraft used in solar panel positioning

Processes: Each ball screw was manufactured from exotic alloys and required precision grinding, including thread grinding

Tolerances: Ball thread grind tolerance of +/-.0001

Materials: MP35N for ball screw, nut, and return system
Silicon nitride ball bearings
Materials heat treated to meet design and customer performance targets.

Testing: Stall load torque test included axial loads in excess of 6500 lbf to verify return system would endure an overload event and continue to maintain an operational state. Design was accepted.

Assembly: Assembly required precision weighing of each component for final spacecraft weight calculations and included a total assembly weight to confirm proper assembly procedures were followed. Assembly was completed to Lockheed Martin specifications.

Engineering Assistance: Ball screw load and life calculations
Return system design
Testing

Additional Information

Industry: Space

Diameter and length: .620" O.D. x 12" O.A.L.

Pitch: .200"