A sophisticated satellite-based system allows pinpointing a person’s location in a dangerous, isolated situation on land or sea. It thus hopefully speeds their subsequent rescue in many cases. This final part looks at the next generation of system satellites and some ideas for a similar lunar system. The MEOSAR satellites The most recent enhancement to […]
Satellite-based search-and-rescue, Part 3: Space segment and satellites
A sophisticated satellite-based system allows pinpointing a person’s location in a dangerous, isolated situation on land or sea. It thus hopefully speeds their subsequent rescue in many cases. Cospas-Sarsat uses three types of satellites: low-Earth orbit search-and-rescue (LEOSAR), medium-Earth orbit search-and-rescue (MEOSAR), and high-altitude geosynchronous orbit search-and-rescue (GEOSAR satellites). There are five LEOSAR, seven GEOSAR, […]
Satellite-based search-and-rescue, Part 2: Ground segment and transmitter beacons
A sophisticated satellite-based system allows pinpointing a person’s location in a dangerous, isolated situation on land or sea. It thus hopefully speeds their subsequent rescue in many cases. Over one million emergency beacons are in use worldwide, all operating at 406 MHz (with some exceptions, called out below). Cospas-Sarsat does not manufacture or sell beacons. […]
Satellite-based search-and-rescue, Part 1: The overall system
A sophisticated satellite-based system allows pinpointing a person’s location in a dangerous, isolated situation on land or sea. It thus hopefully speeds their subsequent rescue in many cases. You’ve undoubtedly seen or read stories about someone miraculously recused at sea or in some relatively uninhabited, remote part of the Earth, without a way to call […]
Reaction wheels ensure satellites maintain the right attitude: Part 2
Electrically driven reaction wheels use conservation of angular momentum to keep a satellite pointed in the right direction, eliminating the need for fuel-powered and limited thrusters. Part 1 was an introduction to reaction wheel basics. This part continues the investigation into their performance and construction. Physics and analysis Although the basic principle of reaction wheels […]
Reaction wheels ensure satellites maintain the right attitude: Part 1
Electrically driven reaction wheels use conservation of angular momentum to keep a satellite pointed in the right direction, eliminating the need for fuel-powered and limited thrusters. Orbiting satellites usually must maintain a precise and stable orientation for various reasons: to keep their cameras or radar pointed at their Earth targets or to keep their telescopes […]
How too many tradeoffs can kill a project
It’s often about focus: designing a product to meet two overlapping objectives may be nice in principle but often leads to harsh tradeoffs, substandard performance, and eventual failure in practice. Engineering design is more than just ensuring the various hardware and software components fit together and work as intended. During both planning and implementation phases, […]
Basics of induction heating, Part 5: Do-It-Yourself versions
Induction heating is widely used in industry and even consumer appliances as a contact-free heating technique with many distinct advantages. We conclude this article by looking at how advanced amateurs can build their own induction-heating system. Induction heaters are among the many dramatic projects constructed by experimenters and hobbyists. After all, it’s impressive to heat […]
Basics of induction heating, Part 4: Consumer use
Induction heating is widely used in industry and even consumer appliances as a contact-free heating technique with many distinct advantages. Although we have looked only at induction heating for industrial applications, some of its attributes make it attractive in the kitchen as well. Of course, the kitchen-cooking scenario is not as constrained or well-defined as […]
Basics of induction heating, Part 3: Implementation
Induction heating is widely used in industry and even consumer appliances as a contact-free heating technique with many distinct advantages. The induction coil and workpiece are at the system’s core, but there’s much more to an induction-heating arrangement (Figure 1). In addition, there’s a power supply and resonant-tank circuit as a power amplifier which creates […]