पृथ्वी पर वापस लौटा Orion spacecraft  | Artemis 1
Channel: सर्वत्र विज्ञान
Date: 2022-12-11

पृथ्वी पर वापस लौटा Orion spacecraft  | Artemis 1 
#artemis1 #artemis #orionspacecraft #spacelaunchsystem #nasa #moon #sls 


NASA's Artemis 1 moonship returned to Earth Sunday, slamming into the upper atmosphere at more than 24,000 mph and enduring a 5,000-degree re-entry inferno before settling to a picture perfect splashdown in the Pacific Ocean to close out a 25-day 1.4-million-mile test flight to the moon and back.

Descending under three huge parachutes, the unpiloted 9-ton Orion capsule gently hit the water 200 miles west of Baja California at 12:40 p.m. EST, 19 minutes after encountering the first traces of the discernible atmosphere 76 miles up.

In an appropriate if unplanned coincidence, the splashdown came 50 years to the day after the final Apollo 17 moon landing in 1972 and just 10 hours after SpaceX launched a Japanese moon lander, the first sent up in a purely a commercial venture, from Cape Canaveral.

From Tranquility Base to Taurus-Littrow to the tranquil waters of the Pacific, the latest chapter of NASA's journey to the moon comes to a close," said NASA commentator Rob Navias at the moment of Orion's splashdown, referring to the Apollo 11 and 17 landing sites. "Orion, back on Earth."
A joint Navy-NASA recovery team was standing by within sight of the Orion splashdown to inspect the scorched capsule and, after a final round of tests, tow it into the flooded well deck of the USS Portland, an amphibious dock ship.

After the sea water is pumped out, Orion will settle onto a protective cradle for the voyage back to Naval Station San Diego and, eventually, a trip home to the Kennedy Space Center.

Re-entry and splashdown were the final major objectives of the Artemis 1 test flight, giving engineers confidence the spacecraft's 16.5-foot-wide Apollo-derived Avcoat heat shield and parachutes will work as designed when four astronauts return from the moon after the next Artemis flight in 2024.
There is no arc jet or aerothermal facility here on Earth capable of replicating hypersonic reentry with a heat shield of this size," he said. "And it is a brand new heat shield design, and it is a safety-critical piece of equipment. It is designed to protect the spacecraft and (future astronauts) ... so the heat shield needs to work."

And it apparently did just that, with no obvious signs of any major damage. Likewise, all three main parachutes deployed normally as did airbags needed to stabilize the capsule in light ocean swells.

The Orion flew through half of a "distant retrograde orbit" around the moon that carried it farther from Earth — 268,563 miles — than any previous human-rated spacecraft. Two critical firings of its main engine set up a low-altitude lunar flyby last Monday that, in turn, put the craft on course for splashdown Sunday.

NASA originally planned to bring the ship down west of San Diego, but a predicted cold front bringing higher winds and rougher seas prompted mission managers to move the landing site south by about 350 miles, to a point just south of Guadalupe Island some 200 miles west of Baja California.

After a final trajectory correction maneuver early Sunday, the Orion spacecraft plunged back into the discernible atmosphere at an altitude of 400,000 feet at 12:20 p.m.

The re-entry profile was designed to ensure that Orion skipped once across the top of the atmosphere like a flat stone skipping across calm water before making its final descent. As expected, Orion plunged from 400,000 feet to an altitude of about 200,000 feet in just two minutes, then climbed back up to about 295,000 feet before resuming its computer-guided fall to Earth.

Within a minute and a half of entry, atmospheric friction began generating temperatures across the heat shield reaching nearly 5,000 degrees Fahrenheit — half the temperature of the sun's visible surface — enveloping the spacecraft in an electrically charged plasma that blocked communications with flight controllers for about five minutes.