<div><span style="font-size: 1rem;">NASA called off the test flight on Monday of its largest-ever Moon rocket because of a temperature issue with one of the four giant engines.</span><br></div><div><br></div><div>"The launch director has called a scrub for the day," the US space agency said.</div><div><br></div><div>Alternative dates for launch of the Artemis 1 mission, an uncrewed flight around the Moon as part of an ambitious program to eventually go to Mars, are Friday and next Monday.</div><div><br></div><div>Blastoff had been planned for 8:33 am (1233 GMT) but was put on hold because of a temperature problem with one of the four engines on the 322-foot (98-meter) Space Launch System (SLS) rocket.</div><div><br></div><div>Tens of thousands of people -- including US Vice President Kamala Harris -- had gathered near the Kennedy Space Center in Florida to watch the launch, which comes 50 years after Apollo 17 astronauts last set foot on the Moon.</div><div><br></div><div>The goal of the flight is to test the SLS and Orion crew capsule that sits atop the rocket. Mannequins equipped with sensors are standing in for a crew for the mission.</div><div><br></div><div>Overnight operations to fill the orange-and-white rocket with more than three million liters of ultra-cold liquid hydrogen and oxygen were briefly delayed by a high risk of lightning.</div><div><br></div><div>Around 3:00 am, another hiccup emerged: a potential leak was detected during the filling of the main stage with hydrogen, causing a pause. After tests, the flow resumed.</div><div><br></div><div>But NASA engineers later detected a problem with the temperature in one of the four RS-25 engines and put a hold on the countdown before eventually scrubbing the launch.</div><div><br></div><div>The rocket's Orion capsule is to orbit the Moon to see if the vessel is safe for people in the near future. At some point, Artemis aims to put a woman and a person of color on the Moon for the first time.</div><div><br></div><div>"This mission goes with a lot of hopes and dreams of a lot of people," NASA Administrator Bill Nelson said.</div><div><br></div><div>- Extreme temperatures -</div><div><br></div><div>During the 42-day trip, the Orion capsule will orbit the Moon, coming within 60 miles (100 kilometers) at its closest approach, and then fire its engines to shoot out 40,000 miles -- a record for a spacecraft rated to carry humans.</div><div><br></div><div>One of the mission's primary objectives is to test the capsule's heat shield, which at 16 feet in diameter is the largest ever built.</div><div><br></div><div>On its return to Earth's atmosphere, the heat shield will have to withstand a speed of 25,000 miles per hour and a temperature of 5,000 degrees Fahrenheit (2,760 degrees Celsius) -- roughly half as hot as the Sun.</div><div><br></div><div>The dummies aboard the spacecraft will record acceleration, vibration and radiation levels.</div><div><br></div><div>The craft will deploy small satellites to study the lunar surface.</div><div><br></div><div>A complete failure would be devastating for a program costing $4.1 billion per launch that is already years behind schedule.</div><div><br></div><div>- Life on the Moon -</div><div><br></div><div>The next mission, Artemis 2, will take astronauts into orbit around the Moon without landing on its surface. The crew of Artemis 3 is to land on the Moon in 2025 at the earliest.</div><div><br></div><div>And since humans have already visited the Moon, Artemis has its sights set on another lofty goal: a crewed mission to Mars.</div><div><br></div><div>The Artemis program is to establish a lasting human presence on the Moon with an orbiting space station known as Gateway and a base on the surface.</div><div><br></div><div>Gateway would serve as a staging and refueling station for a voyage to Mars that would take a minimum of several months. - AFP</div><div><br></div><div>bnbd24/fas</div>