SATELLITE TYPES


Beacon Satellite
Tech Level: 9
Surface Monitoring Satellite
Tech Level: 9
Surface Sensing Satellite
ech Level: 9
Communication Satellite
Tech Level: 9
Deep Space Relay Satellite
Tech Level: 9
Automated Laboratory Satellite
Tech Level: 9
Observatory Satellite
Tech Level: 9
Hunter/Killer Satellite
Tech Level: 9
Cache Satellite
Tech Level: 10
Micro Satellite
Tech Level: 10
Mirror Satellite
Tech Level: 10
Space Tethers
Tech Level: 11
Atmospheric Skimmer
Tech Level: 11
Orbital Weapons Platform, Anti-Satellite
Tech Level: 12
Orbital Weapons Platform, Surface Targeting
Tech Level: 12
Solar Power Satellite
Tech Level: 12
De-Orbiter
Tech Level: 12
Automated Orbital Factory
Tech Level: 13
Orbital Weapons Platform, Deep Space Targeting
Tech Level: 13
Gravity Wave Detector
Tech Level: 13
Electromagnetic Cargo Launcher
Tech Level: 13
Redirected Asteroid
Tech Level: 14
Junk Eater
Tech Level: 14

Satellites come in many varieties and functions. This is a brief overview of the general types of satellites that either currently exist or are envisioned for the future, taken from a large variety of sources. Manned stations and major structures will be addressed in their own sections. Some of these concepts may be further expanded on in other articles.


BEACON
Tech Level: 9

A beacon satelliteís main function is to transmit a continuous signal for various purposes. The first satellites at the dawn of the Space Age such as Sputnik and Pioneer were primarily beacon satellites, emitting radio signals that could be tracked on the ground.

A more modern form of the beacon satellite are the Global Positioning System component satellites, which continually transmit their locational data. Signals from three or more GPS sats allows units on the ground to precisely triangulate their positions on the surface of earth.


SURFACE MONITORING
Tech Level: 9

Also ubiquitously known as "spy" satellites, these are sats equipped with high-power cameras, designed to photograph and visually monitor the surface of a planet. Some of the most powerful optical cameras ever developed were deployed on spy satellites; the best of them could read the fine print on a newspaper from 200 miles up.


SURFACE SENSING
Tech Level: 9

Primarily scientific in purpose but can also be used for military and commercial applications, these satellites employ a host of non-visual sensors, such as thermal imagers, low-light imagers, ultraviolet sensors, radar, and so on, to monitor and explore the composition and features of a planetís surface in great detail. Weather Satellites are a form of surface-sensing satellite.


COMMUNICATION
Tech Level: 9

By far the most commercially valuable satellite, these allow signals to be beamed with precision to anywhere on a planetís hemisphere they are currently passing over. The earliest communications satellites were little more than radio-reflective mirrors; modern satellites receive and retransmit millions of channels of telecommunications data every second.


DEEP SPACE RELAY
Tech Level: 9

Similar to a Communications Satellite, this sat receives signals from the ground, boosts them, then transmits them to a target in deep space. This way, interference to the transmission due to atmospheric interference can be minimized, and the transmission can be boosted by potentially greater power reources available in space, such as solar energy or electrodynamic tethers.


AUTOMATED LABORATORY
Tech Level: 9

These are basically self-contained experiment modules designed to test the microgravity environment of space for some application or another.


OBSERVATORY
Tech level: 9

These are typically large automated facilities designed to observe either a distant celestial object (such as the sun) or deep space, outside the distorting effect of Earthís atmosphere. The Hubble Space Telescope and the CHANDRA observatories are both examples of Observatory Satellites.


HUNTER/KILLER
Tech Level: 9

These are "stealth" satellites, either remaining inert and undetected or disguised (or even function primarily) as a more innocuous type of satellite. However, in a time of war, they will alter their orbit, slide up alongside an enemy satellite, and explode, destroying the sat with shrapnel. The Soviet Union perfected early types of of hunter/killer satellites during the Cold War.



CACHE
Tech Level: 10

Usually used in conjunction with manned stations and often deployed a little ahead or slightly trailing the station in the same orbit. A cache satellite stores supplies, spare parts, and other useful equipment for use in construction, maintenance, and/or emergencies. Basically, an orbiting tool shed.


MICRO SATELLITE
Tech Level: 10

Any satellite that masses 100 kilograms or less. Usually associated with orbital travel schemes designed to launch such smaller masses inexpensively and/or in rapid succession, such as Lightcraft and Electromagnetic Launchers. Usually envisioned as first being used to cheaply resupply manned orbital facilities, more sophisticated versions would be able to perform the function of other satellite types mentioned here.


MIRROR
Tech Level: 10

These are large orbiting sheets of highly reflective material that can be from several meters to many kilometers across. Their main purpose is to deflect raw sunlight from orbit to the ground. The Russian space agency recently tested a small-scale mirror satellite as part of a plan to bring more sunlight to urban centers near the arctic circle.


TETHERS
Tech Level: 11

Aka skyhooks. Used for momentum transfers and power generation. See the seperate article on Space Tethers.


SKIMMERS
Tech Level: 11

These satellites periodically "dip" into the outer layers of an atmosphere during the aphelion of their orbit in order to scoop up supplies of gas. Around terrestial planets, these can be used to harvest oxygen and other gasses for use on manned stations, thus avoiding the energy-expensive task of going all the way down to the ground and back up for such supplies. On scientific missions to other worlds, skimmers can be used to inexpensiely retrieve atmospheric samples. Around gas giants, fleets of skimmers can be used to gather deuterium, helium-3, and hydrogen for use as spacecraft fuels.


WEAPONS PLATFORM, ANTI-SATELLITE
Tech Level: 11

This is an orbiting tactical or strategic weapon designed to shoot down other object in orbit or vehicles at the apex of a sub-orbital hyperbolic trajectory, such as an ICBM. These types of platforms typically use beam weapons such as lasers or particle beams, or high-velocity projectiles such as electromagnetic coil guns. Almost all orbiting weapons envisioned by President Reaganís SDI program were this type of satellite.


WEAPONS PLATFORM, SURFACE TARGETING
Tech Level: 12

These are orbiting weapons platforms sporting weapons designed to take out targets on the ground. Since the atmosphere tends to disperse most types of beam weapons, these sats invariable employ missiles or deadfall weapons, both specially designed to handle re-entry.


SOLAR POWER SATELLITE
Tech Level: 12

These are orbiting Solar Cells that measure anywhere from several dozen meters to many kilometers across. Their main purpose is to gather energy via sunlight and transmit it to receiver stations on the ground via microwave beams.


DE-ORBITERS
Tech level: 12

Designed to help relieve the orbital debris problem by hunting down dead or disabled satellites as well as significantly-sized bits of debris and deorbiting them. Would use very fuel-efficient engines such as solar-electric or ion drives to maneuver from dead sat to dead sat, attach themselves via tether, then use gradual momentum transfer to de-orbit the target as well as boost itself into a higher orbit to track down the next victim.


AUTOMATED ORBITAL FACTORY
Tech Level: 13

Orbital manufacturing facilities are usually envisioned as being manned, but for either economic or safety reasons some of them may be fully automated, tended to by remote-operated vehicles or automated drones.


WEAPONS PLATFORM, DEEP SPACE TARGETING
Tech Level: 13

These are orbiting weapons designed to target and destroy objects approaching the planet from deep space. Though usually envisioned by science fiction writers as defending a planet from invading space fleets, these were also seriously proposed at different times over the past decade as a defense against future asteroid and comet collisions. Missiles are the weapons most often associated with these sats, but any weapon that can function effectively in space can be used.


GRAVITY WAVE DETECTOR
Tech Level: 13

Gravity waves are theoretically very difficult to detect, as one has to cancel out the gravity effects of every nearby object such as the sun, planets, and moons. While detectors on the ground may eventualy be able to detect gravity waves, getting any useful data out of them may necessitate moving the detectors to deep in space. One of the lagrange points between earth and the moon or Earth and the Sun have been suggested as a possible point to place a gravity wave detector; others have suggested placing one beyond the orbit of Saturn.


ELECTROMAGNETIC CARGO LAUNCHER
Tech Level: 13

A large, heavy duty coil gun placed in orbit in order to transfer large amounts of cargo either between low and high orbital stations or between orbital facilities and those further out in the solar system. The trajectory of each shot is carefully calibrated via computer so that gravitational forces of the target body (or the gravitational force of the primary if used between two orbits) is used to slow the projectile enough to eventually inject it into a stable orbit for pick-up. The cargo launcher can also use its shots for thrust to help it maintain a stable orbit, depending on its orientation and position in its orbit.


REDIRECTED ASTEROID
Tech Level: 14

Simple in concept but very difficult in execution, given the irrgular shapes and densities of asteroids and the very real danger of a catastrophic disaster if something goes wrong. Basically, a small asteroid up to several kilometers across is maneuvered into Earth orbit, to be used as raw materials for space manufacturing as well as a ready-made base for manned settlement. Unlike the Moon and Earth, the asteroid would have negligible surface gravity, making its use as a source for construction materials far less potentially expensive than the alternatives, provided that a moderate orbital infrastructure or better is already in place.


JUNK EATER
Tech Level: 14

This is a type of microsatellite, usually employed in large numbers. These small orbital craft, usually not more than a few kilograms in mass, would hunt down and either collect or de-orbit small bits of debris. They would be programmed to avoid significantly-sized satellites altogether.



Article added 2005

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