Sounding rocket payloads are designed to accommodate extremely diverse scientific objectives. As a result, payloads vary greatly in design characteristics and requirements. Mechanical and electrical engineers work closely to ensure that design elements are fully integrated and that proper interfaces between payload subsystems are in place. Both work hand in hand with the Customer to ensure that high quality and safety standards are maintained and all scientific objectives met. Specific mechanical engineering responsibilities include:

	Design sounding rocket internal and external structural components as well as the design of structural components for special, non-sounding rocket related projects such as design of mobile radar vans, field command and control units, safety hardware on several scales, heavy lift equipment, and weather-resistant antenna pedestal mounts. SolidWorks ® 3-D CAD software is the primary design tool. Click here to see a video demonstration of SolidWorks in action. The Fiberglass Boom Mount in this video housed the booms which were deployed as part of the Labell Mission 36.200, launched from PFRR in January, 2003.
	Conduct structural analysis of sounding rocket hardware and special projects hardware to validate the design. Finite Element Analysis capability is available with MSC/NASTRAN.
	Prepare design documentation for presentation to a panel of peers and customers for review.
	Coordinate fabrication efforts with the NSROC Drafting Department and the Machine Shop; providing oversight and direction to shop personnel as needed during fabrication.
	Coordinate environmental testing of sounding rocket components, subassemblies and full payloads. This includes defining test plans and test loads, coordinating testing, and interpreting and presenting test results.
	Provide field support when needed during launch operations.
	Act in supervisory role on special, non-sounding rocket related projects.

Nose Cones
Several types of nose cones are available for a variety of applications. These include 11 ° and 19 ° straight taper cones as well as 3:1 ogive shapes for 14 and 17.26 inch based diameters. These nosecones are typically available in Aluminum or Stainless Steel, and clamshell (straight taper only) or one-piece. Nose cones of other materials or special shapes can be provided when necessary.

Structures and Skins
Skins for the 14, 17.26, and 22 inch diameter payloads are usually custom made although some standard items may be used. Internal structures are also designed to fit the application, whether it be a telemetry section or for packaging several scientific instruments, but standard design features such as decks and longerons are commonly employed.

Vacuum Doors
Electrically operated vacuum doors (also known as shutter doors) are available for 17.26 and 22 inch diameter payloads. These doors open an aperture of approximately 15 and 20 inches diameter, respectively, at the end of a payload structure. Vacuum doors are also available which open a rectangular aperture in the side of a 17.26 inch diameter payload. Vacuum doors are operated to open above the atmosphere and close again before re-entry to maintain a vacuum tight seal during re-entry.

Deployment Mechanisms
Deployment mechanisms actuated by pyrotechnic or other means are available for doors, booms, shutters, etc. Common pyrotechnic actuators include guillotine cutters, used to shear bolts and retaining cords, pin pullers for releasing a mechanism with stored energy, and gas generators for actuating a piston.

Vacuum/Water Sealing
Payloads may be designed with o-ring sealed sections and hermetically sealed feed-through devices to prevent entry or exit of gasses and liquids as required.

Despin Systems
In many cases, payloads must operate without the residual spinning motion imparted by the launch vehicle. Also, in special cases, payloads must have very specific spin rates in order to accomplish scientific goals. Payload despin (to zero cps or to a desired residual rate) can be accomplished by the use of mechanical yo-yo despin systems which release weights on fly-away cables that are wrapped around the payloads circumference and unwind when released. This technique is relatively simple and very reliable. The despin system is utilized to despin both the launch vehicle final stage and payload prior to payload separation. Roll control (roll-up or roll-down) can be provided by cold gas pneumatic systems. These systems are generally part of attitude control systems which are discussed in Chapter 5 of the Sounding Rocket Program Handbook.