Sigma

The Sigma is a small interstellar ship used by the Rescue Bot team Rescue Force Sigma-17. Its max velocity drive provides faster-than-light travel, and it has stasis pods so that the crew can travel while in stasis. The ship's capabilities also include a cloaking shield, which can render it invisible.

Storybooks
The Rescue Bots on Cybertron received a message from Optimus Prime inviting them to join him. With Chase as pilot, they headed to Earth and set down in a forested area, where they were met by Optimus.

Rescue Bots cartoon
The Sigma and its crew were on their way back to Cybertron following a routine patrol when they picked up a distress call, leading them to a derelict vessel. There they were attacked by an Energon eater, and when even the cloaking shield failed to dissuade it, the crew went into stasis and shut the ship down so that the creature would not be able to smell their energon. Drifting, the Sigma came back online when it received a message from Optimus Prime calling all Autobots to go to Earth. It automatically switched course and eventually touched down at a military base somewhere in the United States of America, where the revived crew met with Optimus and received a new assignment on Griffin Rock. It was stored in a hidden hanger under the fire station's basketball court. When their assignment as a rescue force was usurped by Dr. Morocco, Heatwave worked on getting the ship back into service, just in case.

When the Asgard became stuck in orbit, the Rescue Bots launched their ship again, with Boulder navigating, and Chase and Blades as co-pilots. They also had an unintended stowaway in the form of Cody Burns. The Sigma reached the stranded ship, but Heatwave found that the tether cable was jammed, so he had to jump to the Asgard without it. Once he'd rescued Graham and Doc Greene, they used the Sigma to tow the Asgard back to Earth.

Chase and Boulder took the Sigma into space again to make another attempt to rescue the crew of the derelict ship, only to find that it was a trap set by the Energon eater. The creature drained the Sigma's power core, leaving it disabled, however the two Rescue Bots were able to trap the creature and use its stored energon to repower the ship, enabling them to return to Earth.

The ship and its crew were shrunk down to microscopic size so they could enter Kade and retrieve some scrubmites he'd accidentally ingested. When the mites turned out to be slightly too large to fit into the ship, the Rescue Bots instead strapped them to the roof, where the mites were able to chew on the hull and caused damage to the ignition panel. As a result, the ship required a jump start from Kade's nervous system to get going again.

Boulder, Graham and Salvage installed a new interface named ERVIS into the ship, shortly before it was stolen by Blurr.

Though Blurr intended to take the ship to Hydrus Four so he could race, its power was knocked out by a solar flare. By the time he got the ship back online, Griffin Rock was threatened by a rogue satellite, though he had to have help from the ground to get the ship's laser cannon working. The ship's cloaking device activated in the resulting satellite explosion, but he was otherwise able to safely land the ship afterwards.

Graham and Boulder dismantled the Sigma for maintenance purposes, and it was hence unavailable for use when Griffin Rock was teleported to the Arctic. The ship's engine was used for propulsion after they made the island float by filling the forcefield dome with floatium.

The ship was again deployed when Dani's test flight aboard the Echinoderm One hit trouble. Though the ship was not fast enough to catch up with her vessel, the team was able to use the onboard jetpacks to get Blades to her ship so he could steer it onto a slingshot course around the Moon.