【Watch Where Sleeping Dogs Lie Online】

Two tiny NASA satellites nicknamed Wall-E and Watch Where Sleeping Dogs Lie OnlineEva are about to hitch a ride to Mars.

The twin, suitcase-sized spacecraft, called cubesats, will launch to space Saturday aboard the same rocket carrying NASA's InSight lander to Mars, but they'll have very different missions once they reach the red planet in November.

While InSight is expected to unlock the secrets of the planet's interior from the ground, the cubesats -- collectively named MarCO, short for Mars Cube One -- will stay above Mars to test out if these little spacecraft can relay information from the lander as it touches down on Mars back to Earth.

Cubesats, profoundly lighter and cheaper than traditional spacecraft, have never traveled millions of miles though heavily-irradiated deep space, but NASA wants to know how they'll hold up on the journey.

"Spacecraft of MarCO’s size have been developed for Earth's orbit over the last 10 or 15 years," Joel Krajewski, a NASA engineer and project manager for the MarCO mission, said in an interview. "We’re going to attempt to apply those technologies to deep space."

If the Mars-bound cubesats do happen to fail -- perhaps because their electronics get fried or their antennas don't work -- valuable geologic information from the InSight lander won't be lost. NASA won't solely depend on the mini satellites to communicate. Other Mars orbiters are responsible for the longer-term relay of this seismic data back to Earth, said Krajewski.

But if the tiny satellites do successfully work, similar low-cost satellites could be sent to other distant planets and moons, making communication with Earth from these deep reaches of space easier, and in some cases, possible at all.

When NASA lands a spacecraft on another planet, scientists generally need to have a "relay satellite" to beam images and measurements back to Earth.

Space exploration is hugely expensive, and cubesats could provide a much cheaper way to relay this information back home, rather than building and launching heavy spacecraft.

"It makes missions that require relays more practical," said Krajewski.

Such deep-space cubesats might be sent to the intriguing outer moons in our solar system, like Europa and Enceladus, said Krajewski. Or, they could be deployed closer to home.

NASA wants to send a lander into a deep crater in the south pole of the moon, for example, a place that is physically out of sight of Earth. If we want to know what's down there, we'll need a relay satellite, he said.

The two main technologies NASA hopes to prove out on the mission are miniaturized forms of propulsion and communication.

Unlike cubesats that orbit Earth, deep space cubesats will often need to maneuver as they hurtle toward other planets. NASA is testing a technology that shoots out propellant,identical to the material you find in some fire extinguishers, to steer around space, said Krajewski. (The scientists who built the cubesats nicknamed the satellites after two fictional robots from the 2008 Pixar movie Wall-E, because Wall-E also used compressed gas to propel itself around.)

The cubesats come equipped with a radio and antenna, which will beam information back to Earth.

This, said Krajewski, will allow the satellites to relay information about the InSight lander's descent through the Martian atmosphere, including its speed, distance to the ground, and whether or not the parachute opens.

If NASA scientists receive this information from the little cubesats, it will be "the cherry on top of the mission," said Krajewski.

But first, Wall-E and Eva must survive the long journey, persisting through intensely frigid temperatures, exposure to different types of space radiation, and absorbing enough solar energy to stay powered.

"The longer you’re out there, the more likely something might happen," said Krajewski.

UPDATE: May 5, 2018, 8:45 a.m. EDT This story was updated to reflect the fact that the cubesats will not orbit Mars.