The Magnum was a large super-heavy-lift rocket designed by NASA's Marshall Space Flight Center during the mid-1990s. The Magnum, which never made it past the preliminary design phase, would have been a booster some 96 meters (315 feet) tall, on the scale of the Saturn V and was originally designed to carry a human expedition to Mars. It was to have used two strap-on side boosters, similar to the Space Shuttle Solid Rocket Boosters (SRBs), but using liquid fuel instead. Some designs had the strap-on boosters using wings and jet engines, which would enable them to fly back to the launch area after they were jettisoned in flight. The Magnum was designed to carry around 80 tons of payload into low Earth orbit (LEO).