Mechanical Components

Focal Plane Alignment Utilizing Optical CMM

This approach will eliminate all requirements on positional tolerances. In many applications, an optical detector has to be located relative to mechanical reference points. One solution is to specify stringent requirements on (1) mounting the optical detector relative to the chip carrier, (2) soldering the chip carrier onto the printed circuit board (PCB), and (3) installing the PCB to the mechanical structure of the subsystem. Figure 1 shows a sketch of an optical detector mounted relative to mechanical reference with high positional accuracy. The optical detector is typically a fragile wafer that cannot be physically touched by any measurement tool.

Posted in: Mechanics, Mechanical Components, Briefs

Read More >>

Long-Life, Lightweight, Multi-Roller Traction Drives for Planetary Vehicle Surface Exploration

These drives can be used for Earth-based applications where extreme temperatures are involved. NASA’s initiative for Lunar and Martian exploration will require long lived, robust drive systems for manned vehicles that must operate in hostile environments. The operation of these mechanical drives will pose a problem because of the existing extreme operating conditions. Some of these extreme conditions include operating at a very high or very cold temperature, operating over a wide range of temperatures, operating in very dusty environments, operating in a very high radiation environment, and operating in possibly corrosive environments.

Posted in: Mechanics, Mechanical Components, Briefs

Read More >>

Wavefront Compensation Segmented Mirror Sensing and Control

Six degrees of freedom can be sensed at each segment edge. The primary mirror of very large submillimeter-wave telescopes will necessarily be segmented into many separate mirror panels. These panels must be continuously co-phased to keep the telescope wavefront error less than a small fraction of a wavelength, to ten microns RMS (root mean square) or less. This performance must be maintained continuously across the full aperture of the telescope, in all pointing conditions, and in a variable thermal environment.

Posted in: Mechanics, Mechanical Components, Briefs

Read More >>

Free-Mass and Interface Configurations of Hammering Mechanisms

These mechanisms are applicable for construction or other industries requiring drills or actuators. A series of free-mass designs for the ultrasonic/sonic driller/corer (USDC) has been developed to maximize the transfer of energy from the piezoelectric transducer through the horn to the bit, as well as to minimize potential jamming. A systematic development was made producing novel designs of freemass configurations where the impact force is spread across a minimal area maximizing the impact on the bit. The designed free masses were made to operate at high temperatures (500 °C) as on Venus, and they can be made to operate at extremely low temperature, too.

Posted in: Mechanics, Mechanical Components, Briefs

Read More >>

Dual-Compartment Inflatable Suitlock

A paper discusses a dual-compartment inflatable suitlock (DCIS) for Extra-vehicular Activity (EVA) that will allow for dust control, suit maintenance, and efficient EVA egress/ingress. The expandable (inflatable technologies) aspect of the design will allow the unit to stow in a compact package for transport.

Posted in: Mechanics, Mechanical Components, Briefs

Read More >>

Thermodynamic Vent System for an On-Orbit Cryogenic Reaction Control Engine

A report discusses a cryogenic reaction control system (RCS) that integrates a Joule-Thompson (JT) device (expansion valve) and thermodynamic vent system (TVS) with a cryogenic distribution system to allow fine control of the propellant quality (subcooled liquid) during operation of the device. It enables zero-venting when coupled with an RCS engine. The proper attachment locations and sizing of the orifice are required with the propellant distribution line to facilitate line conditioning. During operations, system instrumentation was strategically installed along the distribution/TVS line assembly, and temperature control bands were identified.

Posted in: Mechanics, Mechanical Components, Briefs

Read More >>

Static Gas-Charging Plug

A gas-charging plug can be easily analyzed for random vibration. The design features two steeped O-rings in a radial configuration at two different diameters, with a 0.050-in. (≈1.3-mm) diameter through-hole between the two O-rings. In the charging state, the top O-ring is engaged and sealing. The bottom O-ring outer diameter is not squeezed, and allows air to flow by it into the tank. The inner diameter is stretched to plug the gland diameter, and is restrained by the O-ring groove.

Posted in: Mechanics, Mechanical Components, Briefs

Read More >>