It’s my strong opinion that all Apollo landing sites should be left alone and treated as protected areas. That said, there are some items of scientific value that should be retrieved, including the human waste bags left behind by the astronauts. These bags, containing urine and poop, contain biological materials that scientists would very much like to study. Any microbes, such as bacteria, that once lived in these waste products are probably long dead, but biologists would like to prove that for certain, as it speaks to the potential for interplanetary microbial contamination.

NASA’s Surveyor 3 lander is the first and only human-built probe to be visited by humans on the surface of another celestial body. From 1966 to 1968, the space agency sent Surveyor 3, along with a batch of similar landers, to the Moon in advance of the Apollo missions. Five of the seven Surveyors sent to the Moon performed successful soft landings, but only Surveyor 3 was re-visited, a feat accomplished during Apollo 12. I’d very much like to see us reunited with the lander for a second time.

The first wheeled rover to reach the lunar surface did so on November 17, 1970. The eight-wheeled Soviet rover, named Lunokhod 1, sent back valuable information about the composition of the lunar regolith (soil) and the local topography, before finally expiring. The rover is currently collecting dust in Mare Imbrium, but its lander is clearly visible to lunar satellites passing overhead. We know where you are, Lunokhod 1.

The Apollo astronauts left three Lunar Roving Vehicles, or LRVs, behind. These are the first cars to be driven on another celestial body—an accomplishment that still boggles my mind. These Moon buggies, as they were affectionately called, were amazingly reliable, transporting astronauts and cargo across dozens of miles during the course of the Apollo 15, 16, and 17 missions. Maybe we can make an exception to my “leave the Apollo artifacts alone” rule and retrieve one of these buggies for the spaceflight museum.

Launched on March 2, 1972, Pioneer 10 was NASA’s first mission to visit an outer planet, flying past Jupiter on December 4, 1973. The probe then crossed Saturn’s and Neptune’s orbit, as it ventured farther than any spacecraft before it. Pioneer 10's final signal was received in January 2003, and it’s now heading out of the solar system in the direction of the red star Aldebaran. The probe would make for a fine museum installation, but it’s now way out of reach and likely lost to space forever. But that’s all good, as it contains an informative plaque should it eventually be intercepted by aliens.

NASA’s Viking 1 lander reached the surface of Mars on July 20, 1976, where it took exhilarating photos of the dusty and rock-strewn surface. The stationary probe worked for four years on the western slope of Chryse Planitia, gathering important chemical data about the Martian regolith. Viking 1, as the first lander to reach the Red Planet, certainly belongs in our imaginary museum, but the Smithsonian National Air and Space Museum has already claimed ownership of the artifact. Yes, really. Humph.

Two retired space-based telescopes, Spitzer and Kepler, would be a great fit for our museum. NASA’s infrared Spitzer worked from 2003 to 2020, collecting astronomical data about stellar nurseries, hot Jupiters, and distant stars, among other celestial phenomena. NASA’s Kepler, in operation from 2009 to 2018, was an intrepid planet hunter, helping astronomers to identify more than 2,600 exoplanets. Spitzer and Kepler remain in space, with the former trailing Earth along its orbit and the latter in orbit around the Sun.

NASA’s 25-pound Sojourner rover, in addition to being the most adorable robot ever sent to space, is the first wheeled vehicle to rove around the surface of another planet. As a key component of the 1997 Mars Pathfinder Mission, Sojourner spent 83 days exploring the Red Planet, taking photos and gathering chemical and atmospheric data. It’s still out there on the plains of Chryse Planitia, though likely covered in a thick layer of red Martian dust.

The European Space Agency’s pioneering Huygens probe is lying somewhere on the surface of Saturn’s moon Titan. Well, unless it got gobbled into Titan’s thick, oily seas. The probe landed on the murky moon on January 14, 2005 following a 27-minute parachute-assisted descent to the surface. The probe lived for just 72 minutes, but it’s the first and only landing to be successfully performed in the outer solar system, thereby earning a place in our museum.

It still blows my mind to know that a car—specifically Elon Musk’s Tesla Roadster—is currently in a heliocentric orbit beyond the orbit of Mars. The SpaceX CEO made it the dummy payload during the inaugural launch of the company’s Falcon Heavy rocket on February 2, 2018. A manikin named “Starman” went along for the ride, which, together with the Tesla Roadster, should also be considered for our improbable museum.