Communications Systems

Light Speed

Radio

The habitat uses radio waves to communicate with Mission Control. The habitat radio system, known as CAPCOM, uses amplitude modulation; as it is not affected by the Doppler effect. This method of communication is suitable mainly for audio-video communications, with limited capacity for computer file transfers. This is because the signal loses strength over great distances because of the diffuse nature of radio waves. Radio is also easily affected by interference, reducing the information transfer rate.

Laser

For the transfer of large files such as astronaut biomeds, digital pictures and maps, the astronauts use a laser-based communications system to communicate with earth. Known as AUXCOM, this system uses a light emitter and receiver to communicate. The laser beam, usually in the infrared of ultraviolet, carries digital information, which is received by a laser receiver on the other end. One set of light receivers and emitters are on board the habitat, whereas the other set is onboard a satellite orbiting earth. The receiving satellite is used so that the light waves are not affected by the scattering effects of earth's atmosphere. Upon receiving the light signal, the satellite beams down the information to Mission Control via traditional radio waves.

The disadvantage is that the satellite used to relay messages to and from Mission Control orbits the earth. Therefore, AUXCOM may only be used when the satellite's orbit takes it between the habitat and earth. Because of this, AUXCOM is used for biomeds and other such data while CAPCOM is used for continuous communications with Mission Control.

Faster than Light

IEST

For longer missions (ie, beyond the asteroid belt), the Habitat is equipped with an experimental Instantaneous Electron Spin Transmitter (IEST). This system operates on the principle that when an atom is split apart, one is able to alter the spin of an electron on one fragment by altering the spin on an electron on the other fragment without ever touching the first fragment. This works no matter how far apart the atom fragments are, and the change is always instantaneous.

The IEST consists of two metal disks coated in ionized atom fragments. One disk is placed on the Habitat and the other in Mission Control. A ferromagnetic needle is passed over the disks to change the spin of certain electrons. The corresponding electrons are altered on the other disk. This system can be easily installed on a normal computer; taking the place of a hard drive. The disks are the same size as hard drive disks; and the needle of a hard drive reader is already ferromagnetic to begin with. Thus, by using this setup, we are able to transmit digital information such as audio and video channels, as well as computer files such as biomeds and experiment results.