by NASA picked a very good morning to return from the moon. 50 years ago today, the Apollo 17 crews landed in the Taurus Littrow Valley on the lunar surface, where they planted the last of the six flags the Apollo crews would leave behind to celebrate their moment in history. Today, the space agency symbolically planted a new flag when the Orion crew capsule of the Artemis 1 mission crashed into the Pacific Ocean at 9:40 a.m. Pacific Time, 320 km (200 miles) off the coast of Baja California, Mexico. . The safe return marked the end of a 25-day lunar orbital mission, proving airworthy for the Orion spacecraft, which is expected to carry a crew of astronauts on a journey around the Moon during Artemis 2 in 2024.
“Leap”, NASA tweeted, seconds after the spacecraft hit the water. “After traveling 1.4 million miles in space, orbiting the Moon, and collecting data that will prepare us to send astronauts into the future. #Artemis missions, @NASA_Orion spacecraft at home.
The rescue of Orion was expected to be smooth and uneventful – “nominal” as NASA refers to these things. Navy’s USS portland it was at the splash zone, only 8 km (5 miles) away; After the capsule hit the water, a five-hour period began when a rescue team left the ship in small boats for Orion. There, the plan requires them to attach cables to the spacecraft and pull them back into the spacecraft. portlandA winch rope and four support lines were waiting to get Orion to the ship’s deck.
“We completed our final rehearsal with the USS last week. portlandMelissa Jones, NASA’s director of landing and recovery, said in a statement on Dec. “We had a great three days with them improving our procedures and integrating our teams.”
The mission the spacecraft flew was an ambitious one, beginning with the November 16 launch of NASA’s much-delayed Space Launch System (SLS) moon rocket. The most powerful rocket ever launched. It took the Orion spacecraft five days to reach near the moon, then started its engine, braking its speed slightly, and entered lunar orbit. It spent the next two weeks making two large, circular circuits around the moon, passing twice as close as 129 km (80 mi) from the surface. At its furthest point, the ship was more than 431,000 km (268,000 miles) from Earth and 69,000 km (43,000 miles) above the far side of the Moon. This broke the distance record of 400,000 km (250,000 miles) set for a crew-rated spacecraft during Apollo 13’s one-time pass on the far side of the moon in 1970.
On December 5, when its two orbits of the Moon were complete, Orion fired its main engine for 3 minutes and 27 seconds, increasing its speed to 1,054 km/h (655 mph), giving it enough propulsion to move away from the moon’s gravity. impress and go home. The coast of return to Earth was also purely nominal. But things got more complicated as the spacecraft approached the planet.
Orion was flying at about 40,000 km/h (25,000 mph) when it struck the atmosphere, and eventually began a decline that caused the heat shield to withstand temperatures of 2,760º C (5,000º F). During his descent, he successfully performed a never-before-tried maneuver known as the “entrance jump.”
The spacecraft initially plunged to an altitude of 61,000 m (200,000 ft.), or about 61 km (38 mi.). Then it turned 180 degrees – so that future astronauts sitting upright inside would now be upside down – shifting the center of gravity. This caused the ship to jump through the atmosphere and essentially bounce back into space up to 99,000 m (325,000 ft) or 99 km (61 mi). After this parabolic maneuver, Orion continued to descend, with the guidance system directing it directly into the waters off Baja California.
The jump entry served two primary purposes. First of all, the Apollo astronauts had to withstand forces of 6.8 g (or 6.8 times Earth’s gravity) during their re-entry before their speed slowed, their parachutes opened, and they crashed into the water. The slightly parabolic flight of the jump entry will reduce g-forces to just 4 for future astronauts.
Equally important, receiving a bead to the ground from that 99 km altitude during the jump portion of the maneuver allows the spacecraft’s guidance system to direct the capsule to a near pinpoint landing anywhere within a range of 8,890 km (5,524 mi). This means landing in daylight closer to home, as Orion did, compared to the splashdown of Apollo crews, who were much more limited in their choice of landing site and time. Apollo 8, for example, landed in the Pacific Ocean in the predawn darkness, an area where sharks are known to feed before sunrise. The crew had to wait in suffocatingly hot spaceships in choppy Pacific waters until they were light enough for the navy frogmen to arrive on the scene for rescue.
With Artemis 1 successfully in the books, NASA can begin selecting a crew and begin training for Artemis 2 in just two years. After that, probably not before 2026, Artemis 3 will send astronauts back to the lunar surface, adding a seventh flag to the half-dozen still standing there.
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