Space friends

The "space friends" are a race of scientifically and technologically advanced extraterrestrials who operate from a satellite of the planet Mars and communicate with the Swifts.

Description
The space friends, or "space beings", as they are often referred to, communicate with the Swifts via mathematical symbols. The beings are located on a satellite orbiting the planet Mars, but it is not clear whether or not they are actually Martians. The beings first communicated with the Swifts in 1954 via a missile engraved with the symbols which crash-lands at Swift Enterprises. The beings later communicate via radio, their signals being viewed through an oscilloscope.

The beings are much more technologically advanced than humans, possessing the abilities of interplanetary and interstellar travel. The beings express interest to the Swifts in visiting earth, but repeatedly refuse to answer questions about their physical description, which renders the Swifts unable to help them. The space beings, however, indirectly guide the Swifts on many of their expeditions, and send multiple specimens to the Swifts, such as a sample of plant and small animals life in a rocket which crash lands in the ocean, a spacecraft containing sickened plants and animals in a remote-controlled spacecraft which orbits the moon, and an animal picked up from another planet during an interstellar expedition. They also launch the satellite Nestria into orbit around the earth, placing an artificial device which increases the force of the satellite's gravity. During the Nestria Expedition, Swift discovers that the beings hoped Tom would create an earth-like atmosphere on the surface, which would allow for the space friends to test it out. It is also implied that the space friends were probably run off by the Brungarian expedition as they approached the satellite, as the Brungarians detected a fast-moving spacecraft on their radar leaving the satellite. This also indicates that the space beings could have been on the planet when the Swifts arrived, although they scanned the entire surface before landing and found no evidence of any spacecrafts.

During multiple of the Swifts' expeditions, they discover evidence that the space beings visited earth in the distant past, such as space symbols on Mayan ruins in the Yucatan peninsula in Mexico and hieroglyphs which resemble space symbols and a wrecked spacecraft in the undersea city of Atlantis.