CAPE CANAVERAL, Fla., Sept. 3 Ground teams at the Kennedy Space Center prepared Saturday for a second attempt to launch NASA’s towering next-generation lunar rocket on its maiden flight, hoping to have fixed technical problems causing the had thwarted the first countdown five days earlier.
The 32-story-tall Space Launch System (SLS) rocket and its Orion capsule were scheduled to launch at 2:17 p.m. EDT (1817 GMT) from Cape Canaveral, Florida, to launch the ambitious moon-to-mars Artemis program NASA launch 50 years after the last Apollo moon mission.
The previous launch bid on Monday ended with technical problems that forced a pause in the countdown and a postponement of the unmanned flight.
Tests showed technicians have since repaired a leaking fuel line that contributed to Monday’s canceled launch, Jeremy Parsons, an assistant program manager at the space center, told reporters on Friday.
Two other key issues on the rocket itself — a faulty motor temperature sensor and some cracks in the insulating foam — have been resolved to NASA’s satisfaction, Artemis mission leader Mike Sarafin told reporters Thursday night.
Weather is always an additional factor beyond NASA’s control. According to the US Space Force at Cape Canaveral, the latest forecast put a 70 percent chance of favorable conditions during Saturday’s two-hour launch window.
If the countdown clock were stopped again, NASA could postpone another launch attempt until Monday or Tuesday.
Dubbed Artemis I, the mission marks the first flight for both the SLS rocket and the Orion capsule, built under NASA contracts with Boeing Co and Lockheed Martin Corp, respectively.
It also signals a major change in direction for NASA’s post-Apollo human spaceflight program after decades of focusing on low Earth orbit with space shuttles and the International Space Station.
Named after the goddess who was Apollo’s twin sister in ancient Greek mythology, Artemis aims to return astronauts to the lunar surface as early as 2025.
Twelve astronauts walked on the moon during six Apollo missions from 1969 to 1972, the only spaceflights to date that have placed humans on the lunar surface. But Apollo, born of the American-Soviet space race during the Cold War, was less science-driven than Artemis.
The new moon program has enlisted commercial partners such as SpaceX and the space agencies of Europe, Canada and Japan to eventually establish a long-term lunar base as a springboard for even more ambitious human voyages to Mars.
Getting the SLS Orion spacecraft into the air is an important first step. Its first voyage is set to put the 5.75 million pound vehicle through its paces in a rigorous test flight to push its design limits and hopefully prove the spacecraft is capable of flying astronauts.
If the mission is successful, a manned Artemis II flight around the moon and back could take place as early as 2024, followed within a few years by the program’s first lunar landing of astronauts, including a woman, with Artemis III.
Dubbed the world’s most powerful and complex rocket, the SLS is the largest new vertical launch system the US space agency has built since the Apollo-era Saturn V.
Barring last-minute difficulties, Saturday’s countdown should end with the rocket’s four R-25 main engines and its two solid-fuel rocket boosters firing to produce 8.8 million pounds of thrust, about 15 percent more thrust than the Saturn V, and rocket the spaceship into the sky.
Approximately 90 minutes after launch, the Orion rocket’s upper stage will lift from Earth orbit on course for a 37-day flight that will take it within 60 miles of the lunar surface before flying 40,000 miles (64,374 km) beyond the moon and back sails earth. The capsule is scheduled to land in the Pacific on October 11.
Although there will be no humans on board, Orion will carry a simulated crew of three — one male and two female mannequins — equipped with sensors to measure radiation levels and other exposures astronauts would be exposed to in real life.
A key objective of the mission is to test the durability of Orion’s reentry heat shield as it impacts Earth’s atmosphere on its return from lunar orbit at 24,500 miles (39,429 km) per hour, or 32 times the speed of sound — much faster than more frequent re-entries of capsules returning from Earth orbit.
The heat shield is designed to withstand reentry friction, which is expected to raise temperatures outside the capsule to nearly 5,000 degrees Fahrenheit (2,760 degrees Celsius).
More than a decade in development with years of delays and budget overruns, the SLS Orion spacecraft has cost NASA at least $37 billion to date, including design, construction, testing and ground facilities. NASA’s Office of the Inspector General has projected that the total cost of Artemis will be $93 billion by 2025.
NASA defends the program as a boon to space exploration, which has created tens of thousands of jobs and billions of dollars in commerce.