Humans have not returned to the lunar surface in half a century. NASA is working with multiple American aerospace companies to return astronauts as part of the Artemis program which aims to build a base on the Moon's South Pole. To return to our celestial neighbor, NASA developed the Space Launch System (SLS) rocket and Orion capsule alongside U.S. companies: Boeing, Aerojet Rocketdyne Northrop Grumman, and United Launch Alliance; and selected SpaceX to develop a lunar-optimized Starship Human Landing System (HLS).

The two launch systems will work in coordination to achieve landing the first woman and next man on the Moon by the year 2025. The SLS rocket is designed to propel the Orion capsule carrying four astronauts to Earth's orbit. Orion will ferry the crew to lunar orbit where SpaceX's Starship HLS will be waiting. Orion will dock to HLS and a pair of astronauts will get inside Starship’s cabin to land on the Moon, while the other crewmates monitor operations in lunar orbit aboard Orion. After astronauts complete their lunar exploration activities, they will liftoff aboard Starship HLS from the moon's surface to lunar orbit where Orion will dock with HLS and the crew will head back to Earth aboard Orion. The capsule will reenter Earth’s atmosphere with a parachute-assisted splashdown in the ocean. The concept of operations is shown in the graphic below.

NASA is preparing to conduct the uncrewed SLS rocket's debut flight test this year, known as the Artemis I mission. NASA will conduct a wet dress rehearsal of launch day activities to ensure the vehicle and systems are working properly and that all staff is ready for liftoff. The agency rolled-out the SLS rocket to Launch Complex 39B at NASA’s Kennedy Space Center in Florida on Thursday, March 17.

Your ride has arrived.

Today, @NASAGroundSys teams will begin to roll the @NASAArtemis I rocket four miles to the launch pad for its final prelaunch test.

Coverage begins at 5pm ET (21:00 UTC): https://t.co/z1RgZwQkWS pic.twitter.com/3D9Jvxfyu1

— NASA (@NASA) March 17, 2022

Engineers will initiate SLS pre-flight testing at the launch pad on April 3 at 7:00 a.m. EDT. "The rehearsal will run the Artemis I launch team through operations to load propellant into the rocket’s tanks, conduct a full launch countdown, demonstrate the ability to recycle the countdown clock, and also drain the tanks to give them an opportunity to practice the timelines and procedures they will use for launch," said agency representatives in a press release. The testing will last two days; "Teams will start by activating the facilities needed for launch and formally beginning the countdown sequence. Team will staff the Launch Control Center at Kennedy and connect with staff in the Mission Control Center at NASA’s Johnson Space Center in Houston, the Space Force Eastern Range, and the SLS Engineering Support Center at the agency’s Marshall Space Flight Center in Huntsville, Alabama. Launch controllers will power on different rocket and spacecraft systems, along with ground support equipment."  

LIVE NOW: @NASAKennedy teams debut the @NASA_SLS rocket & @NASA_Orion spacecraft — the vehicle that will lead the way for astronauts to explore the Moon.
Tune in as @NASAGroundSys begin to roll @NASAArtemis I to the launchpad for its final prelaunch test: https://t.co/gsLssGSXpS

— NASA (@NASA) March 17, 2022

During the wet dress rehearsal, NASA teams will load more than 700,000 gallons of cryogenic propellants including liquid hydrogen and liquid oxygen into the SLS rocket. The rocket's core has four RS-25 engines and two solid boosters capable of generating max 8 million pounds of thrust at full throttle. See the Space Launch System's configuration in the image below. "During the wet dress rehearsal, once launch controllers reach the point just before the rocket’s RS-25 engines will ignite on launch day, they will recycle back to the T-10 minute point, and then resume the countdown once more after a hold. The team will then deliberately halt the countdown at about 10 seconds before the simulated liftoff to demonstrate stopping a launch and draining the propellants from the rocket. [...] Demonstrating the ability to remove propellants will ensure teams are prepared for various launch day scenarios," the agency shared. After the wet dress rehearsal, the SLS/Orbion will be rolled back to the Vehicle Assembly Building (VAB) where technicians will remove sensors  used for monitoring the wet dress rehearsal and perform other tasks to prepare the rocket for liftoff. When the wet dress rehearsal is complete NASA will to announce a launch date for the uncrewed Artemis I mission. The agency also plans to conduct an Artemis II demonstration mission to lunar orbit before launching the crewed Artemis III spaceflight in 2025. SpaceX is also actively testing its launch system to perform a debut orbital flight test this year. Read more: SpaceX Performs First Cryogenic Proof Test With A Fully Stacked Starship

Featured Images Source: NASA