"A fast-tracked schedule to meet this ambitious date - along with some technical risks - mean that it's less likely a lunar landing will happen in 2024," a GAO press release explaining the report said. "For example, most of the lunar projects are still early in development and some are relying on immature technology."

NASA's pace to develop a lander needed to shuttle astronauts between a spacecraft orbiting to Moon and the lunar surface relies on a schedule that is most likely overly ambitious, the release said.

The pace is "months faster" than other spaceflight programs and a lander is inherently more complex because it supports human spaceflight, the release added.

The report also questioned NASA's plans for the Gateway, an orbiting space station intended to provide a base for multiple landings, because plans call for power and propulsion technology that has never been used. In addition, contractor efforts to develop the technology are behind schedule.

NASA has said it plans to bypass the Gateway for the initial landing of two astronauts on the Moon's South Pole in 2024 and instead rely on a direct flight from Earth to lunar orbit followed by a descent to the surface in a lander - not unlike the earlier Apollo program.

Source: RIA Novosti