Five Apollo expeditions landed spacecraft on the Moon without incident. One would think that a feat accomplished with 1969-era technology would be a cakewalk today. But landing people on the Moon remains an ambitious feat, writes Mashable.
“Just because we went there 50 years ago does not make it a trivial endeavor,” Csaba Palotai, the program chair of space sciences in the Department of Aerospace, Physics and Space Sciences at the Florida Institute of Technology, told the publication.
The article identifies three main challenges:
- No atmosphere. Spacecraft landing on Earth use the atmosphere as a braking mechanism. No atmosphere on the Moon means no brakes. Spacecraft landing on the Moon must use more propellant to slow the descent. “We cannot float down,” said Palotai. “There’s nothing slowing you down except your engine.”
- No GPS. On Earth, aircraft rely upon a satellite-based navigation system to provide precise landing coordinates. At present, there are no GPS satellites orbiting the Moon. Until there are astronauts will have to rely upon “terrain relative navigation,” which uses a camera to map the ground during the descent.
- Deep shadows. Early expeditions will focus on exploring craters at the lunar south pole where scientists expect to find large deposits of ice. The ice never evaporated because the craters have been cloaked in deep shadow for hundreds of millions of years. “The long shadows make it difficult to discern what the surface looks like,” noted Tom Percy, a lead Human Landing System engineer at NASA’s Marshall Space Flight Center. “That’s especially challenging when you’re trying to land.”