TSTI Admin No Comments April 1, 2026

conic sections

The trace of a line formed by slicing a right-circular cone in one of four ways: perpendicular to the longitudinal axis (circle), oblique to the longitudinal axis (ellipseOne half the distance across the long axisOne half the distance across the long axis of an ellipse (or orbit). More of an ellipse (or orbitThe oval-shaped path that a spacecraft follows. Orbits come in various shapes and sizes, but each one has a purpose: to let the spacecraft do its job. Higher orbits require more propellant to get a spacecraft there. More). More), parallel to the opposite edge (parabola), and parallel to the longitudinal axis (hyperbola). These correspond to types […]

TSTI Admin No Comments April 1, 2026

constellation

A collection of cooperating spacecraft. When mission coverage or timing requires nearly continual signal collection and transmission, we use more than one spacecraft and have them help each other. The Global Positioning System and Iridium communicationAn assembly of spacecraft components that collect, process, store, and transmit payload-mission and bus-housekeeping data. The communication and data-handling subsystemAn assembly of spacecraft components that collect, process, store, and transmit payload-mission and bus-housekeeping data. The communication and data-handling subsystem (CDHS) acts as the ears, brain, and mouth of the spacecraft • It has two primary portions — communication and data handling • It translates raw data from the payloads and subsystems into useful information and sends it to the ground system • Commands from ground controllers generally request information from and give specific instructions to individual subsystems More […]

TSTI Admin No Comments April 1, 2026

contact forces

Any forceAn object’s increasing speed toward Earth’s center, caused by the forceAn object's increasing speed toward Earth's center, caused by the force of gravity (the force of attraction between two objects). More of gravityA projectile with a prescribed path that cannot be altered after it has burned its propellant and the laws of ballistics govern its course. When gravity is the only force on it, its path is elliptical. More (the forceAn object's increasing speed toward Earth's center, caused by the force of gravity (the force of attraction between two objects). More of attractionAn object's increasing speed toward Earth's center, caused by the force of gravity (the force of attraction between two objects). More between two objects). More on a spacecraft other than gravityA projectileA projectile with a prescribed path that cannot be altered after it has burned its propellant and the laws of ballistics govern its course. When gravity is the only force on it, its path is elliptical. More with a prescribed pathThe elliptical-shaped path a satellite takes in going from one circular orbit to another as part of a Hohmann Transfer. More that cannot be altered after it has burned its propellantA type of rocket system that heats a propellant by passing it through a sustained electric arc, then ejects the energized gas through a nozzle. Its specific impulse is high compared to chemical rockets, but its thrust is very low. More and the laws of ballistics govern its course. When gravityA projectile with a prescribed path that cannot be altered after it has burned its propellant and the laws of ballistics govern its course. When gravity is the only force on it, its path is elliptical. More is the […]

TSTI Admin No Comments April 1, 2026

control center

The command authority that directs the spacecraft and all other elements of the network. It can have subordinate centers to assist with launch, communicationAn assembly of spacecraft components that collect, process, store, and transmit payload-mission and bus-housekeeping data. The communication and data-handling subsystemAn assembly of spacecraft components that collect, process, store, and transmit payload-mission and bus-housekeeping data. The communication and data-handling subsystem (CDHS) acts as the ears, brain, and mouth of the spacecraft • It has two primary portions — communication and data handling • It translates raw data from the payloads and subsystems into useful information and sends it to the ground system • Commands from ground controllers generally request information from and give specific instructions to individual subsystems More (CDHS) acts as the earsAn assembly of spacecraft components that collect, process, store, and transmit payload-mission and bus-housekeeping data. The communication and data-handling subsystem (CDHS) acts as the ears, brain, and mouth of the spacecraft • It has two primary portions — communication and data handling • It translates raw data from the payloads and subsystems into useful information and sends it to the ground system • Commands from ground controllers generally request information from and give specific instructions to individual subsystems More, brainAn assembly of spacecraft components that collect, process, store, and transmit payload-mission and bus-housekeeping data. The communication and data-handling subsystem (CDHS) acts as the ears, brain, and mouth of the spacecraft • It has two primary portions — communication and data handling • It translates raw data from the payloads and subsystems into useful information and sends it to the ground system • Commands from ground controllers generally request information from and give specific instructions to individual subsystems More, and mouthAn assembly of spacecraft components that collect, process, store, and transmit payload-mission and bus-housekeeping data. The communication and data-handling subsystem (CDHS) acts as the ears, brain, and mouth of the spacecraft • It has two primary portions — communication and data handling • It translates raw data from the payloads and subsystems into useful information and sends it to the ground system • Commands from ground controllers generally request information from and give specific instructions to individual subsystems More of the spacecraft • […]

TSTI Admin No Comments April 1, 2026

control systems

An assembly of devices that receive inputs, act on the plant, and produce an output. The two fundamental types are open- and closed-loop control systemsAn assembly of devices that receive inputs, act on the plant, and produce an output. The two fundamental types are open- and closed-loop control systems. More.

TSTI Admin No Comments April 1, 2026

controller

The part of a closed-loop control systemAn assembly of devices that receive inputs, decide to change the plant conditions, act to change the plant, measure the plant outputs, and adjust the inputs to improve the outputs. More that decides what to do by comparing sensor measurements with the desired output. The brainAn assembly of spacecraft […]

TSTI Admin No Comments October 7, 2024

convection

Heat transfer from hot to cold through a fluidA method to maintain a spacecraft’s internal temperatureA method to maintain a spacecraft's internal temperature using a closed-loop control system to measure current temperature and adjust inputs, outputs and internal heat flow. It requires a working fluid, heaters, pumps, or other mechanical devices. More using a closed-loop control systemAn assembly of devices that receive inputs, decide to change the plant conditions, act to change the plant, measure the plant outputs, and adjust the inputs to improve the outputs. More to measure currentWe define current,i, as the rate at which charges flow through a given area, such as the cross section of a wire. The unit for current is amperes (amps), which equals the charges flowing per second. More temperatureA method to maintain a spacecraft's internal temperature using a closed-loop control system to measure current temperature and adjust inputs, outputs and internal heat flow. It requires a working fluid, heaters, pumps, or other mechanical devices. More and adjust inputs, outputs and internal heat flowA method to maintain a spacecraft's internal temperature using a closed-loop control system to measure current temperature and adjust inputs, outputs and internal heat flow. It requires a working fluid, heaters, pumps, or other mechanical devices. More. It requires a working fluidA method to maintain a spacecraft's internal temperature using a closed-loop control system to measure current temperature and adjust inputs, outputs and internal heat flow. It requires a working fluid, heaters, pumps, or other mechanical devices. More, heaters, pumps, or other mechanicalA method to maintain a spacecraft's internal temperature using a closed-loop control system to measure current temperature and adjust inputs, outputs and internal heat flow. It requires a working fluid, heaters, pumps, or other mechanical devices. More devices. More medium. Example: boiling water in a pot on a fire.

TSTI Admin No Comments April 1, 2026

coordinate system

A frame of reference that engineers use as a foundation for describing an object’s motionA rotating object’s spinA rotating object’s spin rate. We use the right-hand rule to determine its direction. More rate. We use the right-hand rule to determine its direction. More. Coordinate systems have a center point (originDefines a physically identifiable starting point for the coordinate system. More), two or three axis lines that start at the originDefines a physically identifiable starting pointThe job of the attitude determination and control subsystem (ADCS) is to keep its spacecraft pointed in the right direction. More for the coordinate systemA frame of reference that engineers use as a foundation for describing an object’s motion. Coordinate systems have a center point (origin), two or three axis lines that start at the origin, and one of the axis lines designated as the principal direction. More. […]

TSTI Admin No Comments April 1, 2026

coplanar orbits

OrbitsThe study of the moving objects under the influence of gravityA projectile with a prescribed path that cannot be altered after it has burned its propellant and the laws of ballistics govern its course. When gravity is the only force on it, its path is elliptical. More from another body. Astrodynamicists designDesign is an intricate process involving reviewing constraints, identifying and characterizing the mission subject, deriving the payload and orbital requirements, determining spacecraft mass, power and other detailed design requirements, identifying potential launch vehicles, deriving operations systems requirements and iterating. More orbitsThe study of the moving objects under the influence of gravity from another body. Astrodynamicists design orbits and study how gravity affects them. More and study how gravity affects them. More in the same plane.

TSTI Admin No Comments April 1, 2026

cosmic year

The time for our solar system to revolve once around the center of the Milky Way Galaxy (240 million years, or so).