The launch of the National Aeronautics and Space Administration (NASA) crewed spacecraft ‘Artemis II’, which will carry four people to the Moon, is moving into full swing. NASA has begun preparing a test that loads cryogenic fuel and oxidizer into the Artemis II vehicle and then removes them. If no issues appear in this test, Artemis II is expected to depart for space near the Moon as early as the 6th of next month.

On the 21st (local time), NASA announced in an official release that it is beginning preparations for the ‘wet dress rehearsal (WDR)’ for ‘Artemis II’, which is scheduled to carry four astronauts toward the Moon.

WDR is a test in which propellants (fuel and oxidizer) are loaded into the launch vehicle body and then drained. In an actual launch, propellants are loaded just before liftoff. WDR is a kind of drill that simulates this situation. NASA stated, “We will load 700,000 gallons (2.64 millionℓ) of propellant into Artemis II and commence the launch countdown.”

The main reason for conducting WDR is to check whether the propellant temperatures do not overstrain the launch vehicle. The fuel used in Artemis II, liquid hydrogen, is at minus 253 degrees, and the oxidizer, liquid oxygen, is at minus 183 degrees. Such cryogenic temperatures can rupture plumbing or freeze valves. WDR is conducted to take preventive measures before such issues occur during an actual launch.

Because WDR requires demanding technical procedures, it is carried out only when important missions must be performed. In the case of Artemis II, unlike Artemis I, which lifted off uncrewed, four astronauts will be aboard, which is the main reason for conducting WDR. Since a malfunction during flight could risk loss of life, launch preparations are carried out with extra caution.

NASA positioned Artemis II on the launch pad at Kennedy Space Center in Florida on the 17th and plans to conduct WDR before the 2nd of next month. NASA explained that it will determine the final launch date after evaluating the WDR results. Earlier, the agency said it planned to attempt launch as early as the 6th of next month.

Artemis II is a massive launch vehicle with a total length of 98ｍ. The mission is to go to space near the Moon and then make a U-turn back. The total flight duration is about 10 days. It is expected to travel as far as 400,000㎞ from Earth, which is farther than the Moon (380,000㎞).

The astronauts will not land on the lunar surface, but they will in effect see the Moon’s far side. If they complete the mission, they will earn the title of the people who traveled farthest from Earth and returned in human history. NASA plans to launch Artemis III in 2027 to land people on the Moon.