Mechanical/​Mechatronics

A report discusses algorithms for realtime planning of translation paths of multiple spacecraft flying in formation. The algorithm takes account of requirements to avoid collisions while operating within resource constraints (e.g., not calling for an acceleration greater than maximum possible) and...

A report proposes the development of a microfabricated, integrated colloid thruster as a prototype of devices for propulsion and control of the attitudes of microspacecraft. (In a colloid thruster, a beam of positively charged, microscopic droplets is extracted electrohydrodynamically from a column...

A report discusses the continuing development of a normally closed, piezoelectrically actuated valve fabricated mostly by micromachining of silicon. The design and operation of the microvalve as described in the instant report are basically the same as those of the version described in...

A report presents a theoretical approach to designing a low-energy transfer of a spacecraft from an orbit around the Earth to ballistic capture into an orbit around the Moon. The approach is based partly on the one presented in “Low-Energy Interplanetary Transfers Using Lagrangian Points”...

TLC is a computer program that determines corrections for radiotelescopepointing errors associated with tilts and elastic deformations. These errors occur because for rotation in azimuth, a radiotelescope is mounted on wheels that move on a circular track that deviates from perfect...

A report proposes the development of a ground-based launch-assist apparatus that would accelerate a spacecraft to a speed of about 270 m/s. The apparatus would include a track along which the spacecraft would ride on a sled coupled to a large piston driven by compressed air along a tube (more...

A unique lightweight wrist with three degrees of rotational freedom has been developed as a prototype of wrists for future anthropomorphic robots that would perform a variety of tasks on Earth and in outer space. The three degrees of freedom (two rolling, one bending) intersect at the...

An improved probe has been proposed for burrowing vertically into ice for scientific exploration of polar icecaps, glaciers, and the like. The predecessor of the improved probe is a Philbert probe, which contains an electric heater to melt the ice in contact with it and thereby make it descend...

Improved designs have been conceived for lightweight tubes that can withstand the large (as much as 8 or 9 volume percent) freeze/thaw expansions and contractions of typical heat-transfer fluids like water and ammonia. Intended originally for radiators for rejecting waste heat from spacecraft, these...

Two reports summarize progress thus far in the continuing development of a spacecraft nuclear reactor, some or all of the fuel rods of which would not be loaded until the spacecraft was in orbit. (Keeping the fuel rods out of the reactor core before and during launch is intended to...

A report proposes the development of two different mechanisms that would prevent inadvertent startup of reactors in nuclear-fission-based propulsion and power systems in future spacecraft. The purpose of this development is to contribute to safety by ensuring that radioactivity is kept to...

Structural dynamics are often an important consideration when evaluating system characteristics. A concern related to structural dynamics is the analysis of flutter for a flight vehicle. The instability associated with flutter can be quite sensitive to the structural dynamics; therefore, analysis of...

A thermoelectric contact cooler/ freezer is designed to utilize thermal conduction to rapidly freeze blood and urine samples in test tubes and syringes. This apparatus is dependable, wastes little energy, contains no moving parts other than a fan, can operate in a wide temperature range and in any orientation...

A report presents the mathematical basis of a method of controlling multiple spacecraft flying in formation, subject to control constraints. The spacecraft are assumed to be equipped with relative-position-sensing, relative-velocity-sensing, and communication infrastructure, and with...