According to Space News, NASA is working on a 45-day report to create a new roadmap for space exploration in response to the Trump administration’s mandate to return American astronauts to the moon. The new plan is not going to affect the planned first uncrewed launch of the Orion by a space launch system around the moon. However, NASA is faced with a new choice. Should it build a facility called the Deep Space Gateway in lunar orbit or at one of the Earth-Moon Lagrange points? Or should the space agency go directly to a lunar landing without that intermediate step?
What is the Deep Space Gateway?
The Deep Space Gateway, or as it has sometimes been called the Deep Space Station, has been an idea that NASA has been pushing ever since President Barack Obama canceled the return to the moon Constellation program. The idea was to build a human-tended space station in cislunar space so that systems could be tested for the eventual months-long Journey to Mars at a location just days away from Earth. At the same time, astronauts on the Deep Space Station could operate rovers on the lunar surface in real time. Ultimately, the Mars ship would be assembled at the facility and launched across interplanetary space from there.
Now, with the pivot back to the moon, the purpose of the now named Deep Space Gateway has changed.
Not only would the DSG be used as a base for uncrewed forays to the lunar surface, but also for the first missions by astronauts. Reusable lunar landers would be attached to the facility. Astronauts would voyage to the Deep Space Gateway on board an Orion launched by a Space Launch System. Then, they would transfer to the lunar lander and ride the rest of the way to the moon.
With the mission completed, they would blast off from the lunar surface, dock with the DSG, then ride the Orion back to Earth.
The case against a base in lunar orbit
The alternative to building the Deep Space Gateway would be to go directly to the moon and back, in the same way as was done with Apollo and was planned for Constellation.
The advantage of the direct approach is that the first footsteps would happen years sooner than otherwise would be the case. In any case, if Elon Musk’s BFR spacecraft were to become a reality, the cis-lunar station would become decidedly unnecessary. The facility could still be built later for its original purpose of a jumping off point and refueling stop for missions to Mars.