Transportation rings

"I hate when that happens."

- Jack O'Neill on the hideable nature of ring transporters

Transportation rings, also called ring transporters, transport rings or simply rings, are a form of transport used by a number of species, but they were originally designed and built by the Ancients before their invention of beam transporters.

Overview
Ring transporters are used to transport people or objects over short distances, as from a starship to a planet below, by surrounding the transportees with a number of rings which demolecularize the objects, then transferring them via a matter stream to the intended target. They are also used onboard some Goa'uld spacecrafts in manner similar to elevators. In one instance, they killed Ra's Anubis-headed guard when Colonel Jack O'Neill activated the rings while he was on the edge of the markings.

Some species have the ability to hide their ring transporters for secrecy or surprise, such as the case of the Tok'ra and the Ori.

Ring transporters were built by the Alterans and always seek out the nearest ring transporter, unless programmed otherwise, this was used by Vala to find Gerak's cloaked cargo ship. The Ori also use the rings, but they have Ori writing on them. They are, however, compatible with the ring transporters the Ancients and Goa'uld use. This was proven when Dr. Daniel Jackson managed to escape to an Ori ship using the Korelev's rings and was later rescued by the Odyssey. The Ancients themselves appear to have abandoned the use of ring transporters after Atlantis reached the Pegasus galaxy, although they may be installed on some ships. However, they may have been the basis for the transporters found in Atlantis. After the Ancients returned to Earth from Atlantis, they began to use beam transporters.

Design and usage
A Ring Transporter (or ring teleporter) is a transportation device originally developed and used by the Ancients but now manufactured and used almost exclusively by the Goa'uld and their enemy, the Tok'ra. It consists of several rings that levitate slightly off the ground and stack on top of each other during operation. Almost all Goa'uld transporters have five rings, except for the one installed in the gate room in the Abydos pyramid, which had nine.

Most transport rings are identical (apart from the Ori Rings) and are thought to be mass-produced by the Goa'uld in staggering numbers. Each ring transporter platform weighs 12.9 tons, but it is not clear what components are included in the term "platform." Earth's naquadah generators are capable of powering transport rings. The rings are roughly half the diameter of a Stargate and function under similar principles. The rings move to surround an object or person being transported from a holding platform, which is a cylindrical chamber, contained in either a ceiling compartment or rising up from the floor. They only transport matter from within their perimeter to the perimeter of other rings.

If a pair of rings is transporting and the rings have not yet returned to storage, energy buildup in one ring set will transfer into the paired set, resulting in the destruction of any still-active rings, as proven when the bottom ring of a ceiling-mounted set in an escape tunnel exploded when a bomb destroyed Seth's base.

Function
All matter the rings contain when they are activated is dematerialized and teleported via matter stream to another set of rings in a different location where it is then rematerialized. A unique feature of the ring transporter is that it "swaps" matter between the two locations. If there is a person or object within the receiving set of rings, the rings simply exchange the two simultaneously. This is a safety measure to prevent transmitted matter from "fusing" with ambient matter – an occurrence that would damage inanimate objects and kill organic life even if the ambient was merely atmospheric gasses. It also makes possible a method of covert escape from an area – if one is under the rings as they come down, one will be transported out while an enemy happens to be transporting in.

A set of rings can descend a short distance from a ship hovering above a planet's surface to the ground, a technique commonly used for entering and exiting Tel'taks. When SG-1 used a Tel'tak's rings to enter an Ancient facility on Proclarush Taonas the rings physically smashed through a thin layer of solidified lava to reach their destination. An additional feature of the Ring Transporter is that they can automatically seek out the nearest receiving Ring Transporter even when their location is not known.

Ra's Chief Anubis Guard had been killed when the ring transports were activated while he was under it; his head lay within their transportation area, his body outside of it, and he was decapitated. They can be activated by a transport ring remote worn on the arm or hand by Goa'uld and their Jaffa, or controlled by a remote panel located somewhere near a ring platform. Ring platforms are sometimes extremely well camouflaged, with the rings appearing to emerge from ordinary floors.

Storage and mobile rings
After a completed transport, the rings move back into their storage platform and deactivate. The rings themselves do not transport. Some ring platforms are portable, and can be moved when they are inactive. They contain sensors that detect other active transport rings in an area.

Transport rings are also sometimes used to enter and exit from spacecraft, with one set of rings inside the craft and another set of rings mounted outside the hull. This is commonly seen with the Goa'uld Tel'tak cargo ships and Al'kesh, but the Earth ship Prometheus also uses them in this way. A Tel'tak's ring transporter was used to transport a Kull Warrior outside while it was in flight in a planet's atmosphere and once the Kull Warrior had rematerialized outside the hull, the external rings fell away from the craft along with him.

Transported matter passes between sets of rings in a "matter stream" that can be detected by a ship's sensors. It is possible to intercept a matter stream that is in transport by interposing a set of mobile rings (like those in a Goa'uld shuttlecraft) between the sending rings and the planned receiving rings. However, such an intercept requires that the entire matter stream be captured by the intercepting rings (i.e. the intercepting craft must be still); otherwise, the transported people will not be able to fully reintegrate and will die.

Ori ring transporter
The Priors of the Ori apparently also use ring transporters. The ring platform, like its Ancient counterpart, consists of six rings, however the Ori have also used a version that consists of five transporter rings in the Milky Way galaxy, although the rings themselves are smoother, luminescent on the inside and adorned with unknown symbols.

These rings are carried aboard Ori warships, and are also used to transport Priors to Celestis, the Ori sacred city.

During the Battle of P3Y-229, Daniel Jackson was able to beam over to an Ori warship using an Ancient Ring Transporter, indicating that the differences in the two systems are merely cosmetic. Several months later, a portable transporter was deployed on a planet that did not have one to allow military forces from an orbiting ship to be beamed onto the planet. It consists of a ring-shaped platform which is carried by an Ori fighter and simply "dropped" where desired.

Similar technology
There are also some similarities between ring transporters and the transportation booths in Atlantis, including similar flashes of light upon transportation and swapping of the contents of the pair of devices when operated at the same time. The actual beam sound is also the same. Considering that the Ancients invented both, it is conjectured that the technologies are related. It also makes sense that the two devices are compatible allowing rings or transporters from orbiting ships to connect with Atlantis, although it has never been shown. The Ancients also invented the advanced beam transporters much later which do not require platforms.

The Asgard also have an arguably more advanced transport system than the Rings which does not require the use of the platforms. The Tau'ri call it an Asgard "beam" or "beam transporter", possibly referencing Star Trek; it was installed on both the Prometheus and on Daedalus-class battlecruisers. It requires either the use of Asgard sensors or a radio signal from the object to be transported in order to acquire a target. Thor's Hammer appears to use similar technology to transport Goa'uld and/or Jaffa to an underground trap. Unlike rings, however, Asgard transporters cannot penetrate the user's own shields nor those of friendly vessels, nor can the Asgard sensors detect the positioning signals sent out by ring platforms.

The Sodan tribe transport obelisk (Called the Eye of the Gods by the Sodan) also has a similar visual effect. These were also built by Ancients and were used by the Sodan (along with their wrist personal cloaks) to avoid Goa'uld detection and extermination for a thousand years. The obelisk is activated by typing certain symbols in a precise order. One does not have to be touching the obelisk in order to be transported as evidenced by Teal'c not touching the obelisk.

Another type of transport obelisk was built and used by the Ancient Morgan le Fay to transport a group through an active wormhole to avoid detection while building the Sangraal. Her version had no user input required and had blue/green crystals visible on the exterior. The actual beam was much larger than previously seen, transporting the contents of an entire room and all those inside through the gate to similar locations on other planets.