Common Space Vehicle Mechanisms

Actuators at a Glance

Northrop Grumman has been delivering space mechanisms for stowing and articulating spacecraft payloads and solar arrays for 40+ years with 100% mission success and our modular actuators are represented on over 50 missions.

Our designs specialize in:

Long-life or high-use missions
Low disturbance (induced vibrations reduced for simultaneous operation of payloads)
Precision pointing (higher altitude missions)

Data Sheet: Common Space Vehicle Mechanisms

Heritage Products

Deployment Actuators (TRL 9)

Mechanisms to deploy structure or to spool cables. High torque output with current limit drive, or stepper motor (or micro-stepping for low disturbance).

Continuous rotation
Cable winder mechanisms have two assemblies:
- Cable Drive Module (CDM)
- Current Limiter Assembly (CLA)

Solar Array Drive Assembly (TRL 9)

Provides transmission of solar power and electronic signals between solar array and spacecraft; custom or modular slip ring designs for full 360-degree rotation or cable wrap design for limited angle rotations; EMI shielding; Electrically redundant

SADA with limited travel (cable management system)
- Provides bi-directional rotation to maintain limited angle positioning of the solar array
- Provides absolute angular position knowledge
SADA with continuous rotation (slip ring)
- Provides continual 360-degree rotation of the solar array to maintain solar orientation
- Provides null position information (via switch ring 1X/Rev)
Configurable items:
- Modular Slip ring - scalable power with 20 or 30 ring modules; Up to four modules (max 120 circuits)
- Position Feedback: Switch Ring/Poten

Precision Pointing Mechanisms:

Single and multiple axes rotary mechanisms with cable management systems (RF and DC data/power transmission), zero cogging motors (optional jitter compensation algorithms), zero backlash gearing, highly accurate position feedback, and micro-stepping capability yielding arc-second magnitude pointing

Stop Assembly Options:

Deployable/Stowage stops
Large travel range (up to 510 degrees)

Large Rotary Actuators (TRL 9)

High Torque & Large Range of Travel

Large payload (antenna or boom assembly) articulation

Medium Rotary Actuators (TRL 9)

High Torque & Medium Size Payload

Higher speed capability with dual actuator configuration
Higher torque options with larger motor

Biaxial Actuators (TRL 9)

Orthogonal Axes of Rotation/”Cone” Coverage

Commonly used to host medium sized antennas in different orbits (e.g. 1-2 meter diameter)
RF/DC/waveguide for payload signal/power transmission
Used for JWST, AEHF and STSS antennas

Extra Large Rotary Actuators (TRL 9)

High Stiffness/Torque Applications

Extended boom steering mechanisms with beryllium structural parts
10.5" diameter Zero-Cogging Motor
Dual chamber, counter rotating cable wrap with RF and DC data and power transmission
High strength external stop assembly to handle large inertial loads

Custom Mechanisms

Optical pointing, high-speed scanning (terrestrial or space applications), flip mechanisms, tracking and launching mechanisms

Examples:

4 axis deployable boom assembly
High torque latch actuator with bevel gears
Linear actuator utilizing ball screw with photo-resistor position feedback

Modular Actuator Product Line

The Customizable Actuator for Space Precision Rotation (CASPR) product line offers accurateand smooth rotation of spacecraft payloads. It can be used for antenna pointing mechanisms (single axis or biaxial) on communications satellites, or coupled with a slip ring for solar array driving applications. Its long-life design can be adapted for shorter-life missions.

Design Highlights
The actuator comes in two sizes for small (CASPR 10) and medium (CASPR 20) payloads.