But in the past two decades, mini-satellites called CubeSats have made space accessible to a new generation. These briefcase-sized boxes are more focused in their abilities and have a fraction of the mass -- and cost -- of some past titans of space.
In May, engineers will be watching closely as NASA launches its first pair of CubeSats designed for deep space. The twin spacecraft are called Mars Cube One, or MarCO, and were built at NASA's Jet Propulsion Laboratory in Pasadena, California.
The MarCOs won't produce any science of their own, and aren't required for InSight to send its data back home (the lander will rely on NASA's Mars orbiters for that, in addition to communicating directly with antennas on Earth). But the twins will be a crucial first test of CubeSat technology beyond Earth orbit, demonstrating how they could be used to further explore the solar system.
The official names of these two scouts are "MarCO-A" and "MarCO-B." But to the team that built them, they're "Wall-E" and "Eva" -- nicknames based on Pixar characters. Both MarCOs use a compressed gas commonly found in fire extinguishers to push themselves through space, the same way Wall-E did in his 2008 film.
Survival is far from guaranteed. As the saying goes: space is hard. The first challenge will be switching on. The MarCO batteries were last checked in March by Tyvak Nano-Satellite Systems of Irvine, California, which inserted each CubeSat into a special dispenser that will propel it into space. Those batteries will be used to deploy each CubeSat's solar arrays, with the hope that enough power will be left over to turn on their radios. If power is too low, the MarCO team may hear silence until each spacecraft is more fully charged.
The MarCOs could also prove that CubeSats are ready to go beyond Earth. CubeSats were first developed to teach university students about satellites. Today, they're a major commercial technology, providing data on everything from shipping routes to environmental changes.
NASA scientists are eager to explore the solar system using CubeSats. JPL even has its own CubeSat clean room, where several flight projects have been built, including the MarCOs. For young engineers, the thrill is building something that could potentially reach Mars in just a matter of years rather than a decade.
"We're a small team, so everyone gets experience working on multiple parts of the spacecraft," Klesh said. "You learn everything about building, testing and flying along the way. We're inventing every day at this point."
The MarCOs were built by JPL, which manages InSight and MarCO for NASA. They were funded by both JPL and NASA's Science Mission Directorate. A number of commercial suppliers provided unique technologies for the MarCOs. A full list, along with more information about the spacecraft, can be found here.
Jet Propulsion Laboratory, Pasadena, Calif.