The Artemis I mission management team met to review the overall status of the flight test and polled "go" for Orion to depart from its distant retrograde orbit, where it has been since Nov. 25. Orion will conduct a burn to depart the orbit at 3:53 p.m. CST Thurs., Dec. 1 and begin its trek back toward Earth.

"We are continuing to collect flight test data and buy down risk for crewed flight," said Mike Sarafin, Artemis mission manager. "We continue to learn how the system is performing, where our margins are, and how to operate and work with the vehicle as an integrated team."

On Flight Day 15, Orion also performed a planned orbit maintenance burn to maintain the spacecraft's trajectory and decrease its velocity ahead of its Thursday departure from a distant lunar orbit. During the burn, Orion used six of its auxiliary thrusters on the European Service module to fire for 95 seconds. The burn was initially planned for a shorter duration but was lengthened as part of the team's effort to add test objectives to the mission. The 95-second burn provided additional data to characterize the thrusters and the radiative heating on the spacecraft's solar array wings to help inform Orion's operational constraints. All previous thruster burns were 17 seconds or less.

Orion's European-built service module has provided the propulsive capabilities to adjust the spacecraft's course in space via its 33 engines of various types, and serves as Orion's powerhouse, supplying it will electricity, thermal control, and air and water for future crews, in addition to propulsion. Artemis I is the first time NASA is using a European-built system as a critical element to power an American spacecraft. Provided by ESA (European Space Agency) and its partner Airbus Defence and Space, the service module extends NASA's international cooperation from the International Space Station into deep space exploration.

NASA is continuing to extend its relationships with its international partners to explore the Moon under Artemis. The agency's Gateway, a multi-purpose outpost in development to orbit the Moon that will provide essential support for long-term lunar exploration, includes contributions from ESA as well as the Canadian Space Agency and the Japan Aerospace Exploration Agency. Agencywide, NASA has more than 600 active international agreements with organizations and space agencies around the world.

Teams also elected to add four additional test objectives to Orion's return trip to Earth to gather additional data on the spacecraft's capabilities. Two will evaluate whether opening and closing a valve the pressure control assembly affects a slow leak rate in that system; a third will demonstrate Orion's ability to perform attitude maneuvers at the rate that will be necessary for a test on Artemis II; and the fourth will test its capability to fly in a three degree of freedom attitude control mode, as opposed to the six degree of freedom mode it typically flies in.

Prior to today's orbital maintenance burn, a total of 5,681 pounds of propellant had been used, 203 pounds less than values expected before launch. Some 2,004 pounds of margin is available beyond what is planned for use during the mission, a 94-pound increase above prelaunch expected values.

Just after 4 p.m. CST on Nov. 30, Orion was traveling 253,079 miles from Earth and 50,901 miles from the Moon, cruising at 2,052 mph.

Coverage of the distant retrograde orbit departure burn will begin Thursday at 3:30 p.m. CST, with the burn scheduled to occur at 3:53 p.m. Watch live on NASA TV, the agency's website, and the NASA app.

View the latest imagery of the Moon, Earth, and Orion on NASA's Johnson Space Center?Flickr?account and?Image and Video Library. When bandwidth allows, views of the mission are available in real-time.

Artemis I - I Flight Day 14: Deep Space Testing Continues
Engineers continued with the jet firing development flight test objective that began on flight day 12. Today, teams demonstrated the "low" portion of the reaction control thruster firing time range. This test objective is designed to exercise the reaction control system jets in a different configuration to model how thruster jets will be used during the Artemis II mission, furthering our understanding of spacecraft operations before we have crew onboard.

As part of?planned testing throughout the mission, the guidance, navigation, and control officer, also known as GNC, performed the sixth of eight planned tests of the star trackers that support Orion's navigation system. Star trackers are a?navigation tool?that measure the positions of stars to help the spacecraft determine its orientation. The star trackers continue to provide excellent data to develop our required navigation solutions.

Engineers will characterize the alignment between the star trackers that are part of the guidance, navigation and control system and the Orion inertial measurements units, by exposing different areas of the spacecraft to the Sun and activating the star trackers in different thermal states to determine if the temperature differences induce any changes.?The inertial measurement units contain three devices, called gyros, used to measure spacecraft body rotation rates, and three accelerometers used to measure spacecraft accelerations.

A new flight test objective was added to flight day 14 to collect additional information on the thermal characterization of Orion. During a majority of the mission Orion is typically in a tail-to-sun attitude, meaning that the solar arrays face toward the sun to generate power. This flight test objective purposefully orients Orion outside of a perfect tail-to-sun attitude by up to 20 degrees in order to evaluate the spacecraft and gather additional data. Currently, when Orion is out of the tail-to-sun attitude for more than three hours, a ten-hour tail-to-sun recovery period is required. This additional flight test objective will help engineers understand the range of Orion's thermal performance to incorporate into Artemis II and beyond.

Time in distant retrograde orbit allows engineers to test the spacecraft and its systems in a deep-space environment ahead of future missions with crew. Distant retrograde orbit is a highly stable orbit where little fuel is required to stay for an extended period. While visiting a distant retrograde orbit allows engineers to capitalize on an orbit that was comprehensively studied as part of mission planned for earlier agency efforts, future Artemis mission will visit different orbits.

On Artemis II, four astronauts in Orion will travel around the Moon and fly several thousand miles above the lunar far side before trekking back to Earth. On Artemis III, the first Artemis mission to the lunar surface, Orion will venture to near-rectilinear halo orbit, an orbit balanced between the Earth's and Moon's gravity that hangs almost like a necklace from the Moon. The orbit provides access to the Moon's South Pole, where 13 candidate landing regions have been identified for future Artemis missions. ?

Just after 4 p.m. CST, Orion was over 264,000 miles from Earth and nearly 46,000 miles from the Moon, cruising at 1,790 mph.

Watch the latest episode of Artemis All Access to learn more about Orion's journey so far.

Related Links
Artemis at NASA
Mars News and Information at MarsDaily.com
Lunar Dreams and more

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Beijing (XNA) Nov 23, 2022
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