Orion has left its distant lunar orbit and is on its return journey home. The spacecraft successfully completed the distant retrograde departure burn at 3:53 p.m. CST, firing its main engine for 1 minute 45 seconds to set the spacecraft on course for a close lunar flyby before its return home.
The burn changed Orion’s velocity by about 454 feet per second and was performed using the Orion main engine on the European Service Module. The engine is an orbital maneuvering system engine modified for use on Orion and built by Aerojet Rocketdyne. The engine has the ability to provide 6,000 pounds of thrust. The proven engine flying on Artemis I flew on 19 space shuttle flights, beginning with STS-41G in October 1984 and ending with STS-112 in October 2002.
The burn is one of two maneuvers required ahead of Orion’s splashdown in the Pacific Ocean on Dec. 11. The second will occur on Monday, Dec. 5, when the spacecraft will fly 79.2 miles above the lunar surface and perform the return powered flyby burn, which will commit Orion on its course toward Earth.
Teams also continued thermal tests of the star trackers during their eighth and final planned test. Star trackers are a navigation tool that measure the positions of stars to help the spacecraft determine its orientation. In the first three flight days of the mission, engineers evaluated initial data to understand star tracker readings correlated to thruster firings.
A trajectory correction burn is planned for approximately 9:53 p.m. CST today, when Orion’s auxiliary thrusters will fine-tune the spacecraft’s path.
Just after 4:30 p.m. CST on Dec. 1, Orion was traveling 237,600 miles from Earth and 52,900 miles from the Moon, cruising at 2,300 mph.
The Artemis I mission management team met today 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.
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.
On Wednesday, Nov. 30 at 5 p.m. EST, NASA will host a briefing to preview distant retrograde departure on Thurs., Dec. 1 and how the recovery teams are preparing for entry and splashdown. The briefing will be live on NASA TV, the agency’s website, and the NASA app.
NASA’s uncrewed Orion spacecraft reached the farthest distance from Earth it will travel during the Artemis I mission — 268,563 miles from our home planet — just after 3 p.m. CST. The spacecraft also captured imagery of Earth and the Moon together throughout the day, including of the Moon appearing to eclipse Earth.
Reaching the halfway point of the mission on Flight Day 13 of a 25.5 day mission, the spacecraft remains in healthy condition as it continues its journey in distant retrograde orbit, an approximately six-day leg of its larger mission thousands of miles beyond the Moon.
“Because of the unbelievable can-do spirit, Artemis I has had extraordinary success and has completed a series of history making events,” said NASA Administrator Bill Nelson. “It’s incredible just how smoothly this mission has gone, but this is a test. That’s what we do – we test it and we stress it.”
Engineers had originally planned an orbital maintenance burn today but determined it was not necessary because of Orion’s already precise trajectory in distant retrograde orbit. Based on Orion’s performance, managers are examining adding seven additional test objectives to further characterize the spacecraft’s thermal environment and propulsion system to reduce risk before flying future missions with crew. To date, flight controllers have accomplished or are in the process of completing 37.5% of the test objectives associated with the mission, with many remaining objectives set to be evaluated during entry, descent, splashdown, and recovery.
NASA’s Exploration Ground Systems team and the U.S. Navy are beginning initial operations for recovery of Orion when it splashes down in the Pacific Ocean. The team will deploy Tuesday for training at sea before return to shore to make final preparations ahead of splashdown.
Managers also closed out today a team formed earlier in the mission to investigate readings associated with the spacecraft’s star trackers after determining the hardware is performing as expected and initially suspect readings are a byproduct of the flight environment.
Flight controllers also have completed 9 of 19 translational burns and exercised the three types of engines on Orion – the main engine, auxiliary thrusters, and reaction control system thrusters. Approximately 5,640 pounds of propellants have been used, which is about 150 pounds fewer than prelaunch expected values. More than 2,000 pounds of margin remain available beyond what teams plan to use for the mission, an increase of more than 120 pounds from prelaunch expected values. So far, teams have already sent more than 2,000 files from the spacecraft to Earth.
Just before 8 p.m. EST, Orion was 268,457 miles from Earth and 43,138 miles from the Moon, cruising at 1,679 miles per hour.
On the 12th day of the Artemis I mission, team members conducted another planned test of the star trackers aboard Orion as it continued along a distant retrograde orbit of the Moon, and began another reaction control thruster flight test.
Engineers hope to characterize the alignment between the star trackers and the Orion inertial measurements units, both of which are part of the guidance, navigation and control system, by exposing different areas of the spacecraft to the Sun and activating the star trackers in different thermal states. Star trackers are navigation tools that measure the positions of stars to help the spacecraft determine its orientation. The inertial measurement units contain three devices, called gyros, used to measure spacecraft body rotation rates, and three accelerometers used to measure spacecraft accelerations.
Together, the star tracker and inertial measurement unit data are used by Orion’s vehicle management computers to compute spacecraft position, velocity, and attitude. The measurements will help engineers understand how thermal states affect the accuracy of the navigation state, which ultimately affects the amount of propellant needed for spacecraft maneuvers. Read more about Orion’s guidance, navigation, and control system in the Artemis I reference guide.
Engineers began a development flight test objective today that changed the minimum jet firing time for the reaction control thrusters over a period of 24 hours. This test objective is designed to exercise the reaction control system jets in a different configuration to model how thruster jets will be used for the crewed Artemis II mission.
Teams also activated and interacted with the Callisto payload, a technology demonstration from Lockheed Martin in collaboration with Amazon and Cisco. Callisto is located in the Orion cabin and will test voice activated and video technology in the deep space environment.
Monday, Nov. 28, Orion will reach its farthest distance from Earth when it is nearly 270,000 miles from our home planet.
As of 4:30 p.m. CST, Orion was over 264,000 miles from Earth and 45,600 miles from the Moon, cruising at 1,750 miles per hour.
On day 11 of the Artemis I mission, Orion continues its journey beyond the Moon after entering a distant retrograde orbit Friday, Nov. 25, at 3:52 p.m. CST. Orion will remain in this orbit for six days before exiting lunar orbit to put the spacecraft on a trajectory back to Earth and f a Sunday, Dec. 11, splashdown in the Pacific Ocean.
Orion surpassed the distance record for a mission with a spacecraft designed to carry humans to deep space and back to Earth, at 7:42 a.m. Saturday, Nov. 26. The record was set during the Apollo 13 mission at 248,655 miles from our home planet. At its maximum distance from the Moon, Orion will be more than 270,000 miles from Earth Monday, Nov. 28.
Engineers also completed the first orbital maintenance burn by firing auxiliary thrusters on Orion’s service module at 3:52 p.m. for less than a second to propel the spacecraft at .47 feet per second. The planned orbital maintenance burns will fine-tune Orion’s trajectory as it continues its orbit around the Moon.
Flying aboard Orion on the Artemis I mission is a suited manikin named after a key player in bringing Apollo 13 safely back to Earth. Arturo Campos was an electrical engineer who developed a plan to provide the command module with enough electrical power to navigate home safely after an oxygen tank aboard the service module of the Apollo spacecraft ruptured. Commander Moonikin Campos is outfitted with sensors to provide data on what crew members may experience in flight, continuing Campos’ legacy of enabling human exploration in deep space.
Artemis builds on the experience of Apollo. With Artemis, humans will return to the lunar surface, and this time to stay. NASA will use innovate technologies to explore the Moon’s South Pole and more of the lunar surface than ever before using the Gateway space station in lunar orbit along with advanced spacesuits and rovers. NASA will lead the way in collaboration with international and commercial partners to establish the first long-term presence on the Moon. Then, we will use what we learn on and around the Moon to take the next giant leap: sending the first astronauts to Mars.
As of 1:16 p.m., Orion was 252,133 miles from Earth and 52,707 miles from the Moon, cruising at 2,013 miles per hour. You can track Orion via the Artemis Real-Time Orbit Website, or AROW.
Flight Controllers in the White Flight Control Room at NASA’s Johnson Space Center in Houston successfully performed a burn to insert Orion into a distant retrograde orbit by firing the orbital maneuvering system engine for 1 minutes and 28 seconds at 4:52 p.m. CST, propelling the spacecraft at 363 feet per second. Shortly before conducting the burn, Orion was traveling more than 57,00 miles above the lunar surface, marking the farthest distance it will reach from the Moon during the mission. While in lunar orbit, flight controllers will monitor key systems and perform checkouts while in the environment of deep space.
The orbit is distant in that Orion will fly about 40,000 miles above the Moon. Due to the distance of the orbit, it will take Orion nearly a week to complete half an orbit around the Moon, where it will exit the orbit for the return journey home. About four days later, the spacecraft will harness the Moon’s gravitational force once again, combined with a precisely timed lunar flyby burn to slingshot Orion onto its return course to Earth ahead of splashdown in the Pacific Ocean on Sunday, Dec. 11.
On Saturday, Nov. 26, Orion spacecraft will break the record for farthest distance traveled by a spacecraft designed to carry humans to space and safely return them to Earth. This distance is currently held by the Apollo 13 spacecraft at 248,655 miles (400,171 km) from Earth. Orion was specifically designed for missions to carry humans farther into space than ever before.
On Artemis I, engineers are testing several aspects of the Orion spacecraft needed for deep space missions with crew, including its highly capable propulsion system to maintain its course with precision and ensure its crew can get home, communication and navigation systems to maintain contact with the ground and orient the spacecraft, systems and features to handle radiation events, as well as a heat shield that can handle a high-speed reentry from the Moon. Both distance and duration demand that spacecraft must have systems that can reliably operate far from home, be capable of keeping astronauts alive in case of emergencies and still be light enough that a rocket can launch it.
Artemis II will test the systems required for astronauts to live and breathe in deep space. Long duration missions far from Earth drive engineers to design compact systems not only to maximize available space for crew comfort, but also to accommodate the volume needed to carry consumables like enough food and water for the entirety of a mission lasting days or weeks.
Learn more about Orion’s capabilities for deep space missions with crew.
Live coverage is underway on NASA Television, the agency’s website, and the NASA app for Orion’s distant retrograde orbit insertion burn as a part of the Artemis I mission. The burn is planned for 4:52 p.m. EST. Orion will fire the orbital maneuvering system engine on its European service module to propel the spacecraft into an orbit over 40,000 miles above the surface of the Moon. The distant retrograde orbit provides a highly stable destination where little fuel is required to stay while engineers put Orion’s systems to the test in a deep space environment far from Earth.
The orbital maneuvering system engine on the European Service Module is the main engine that provides the primary propulsion for Orion’s major in-space maneuvers. The engine provides 6,000 pounds of thrust and is equipped to steer the spacecraft.Orion’s European Service Module is provided by ESA (European Space Agency) with contributions from 10 European countries and the United States, including Germany, Italy, Switzerland, France, Belgium, Sweden, Denmark, Norway, Spain, and the Netherlands.
Earlier in the day on flight day 10 of the 25.5-day mission, engineers continued planned testing with the star tracker in a variety of orientations in deep space as part of one of several flight test objectives.
Orion is currently traveling over 237,000 miles from Earth and over 57,000 miles from the Moon, cruising at about 2,300 miles per hour.
Orion is now about one day away from entering into a distant retrograde orbit around the Moon. The orbit is “distant” in the sense that it’s at a high altitude approximately 50,000 miles from the surface of the Moon. Due to the distance, the orbit is so large that it will take the spacecraft six days to complete half of a revolution around the Moon before exiting the orbit for the return journey back to Earth.
During the last day in the transit to distant retrograde orbit, flight controllers performed a third in a series of planned star tracker development flight tests relative to the Sun, with a fourth planned for tomorrow. Star trackers are a navigation tool that measure the positions of stars to help the spacecraft determine its orientation. In the first three flight days, engineers evaluated initial data to understand star tracker readings correlated to thruster firings.
The spacecraft completed its sixth outbound trajectory correction burn at 3:52 p.m. CST, firing the European Service Module’s auxiliary engines for 17 seconds to propel the spacecraft at 8.9 feet per second. This is the final trajectory correction before entering distant retrograde orbit. When in lunar orbit, Orion will perform three orbital maintenance burns to keep the spacecraft on course.
Overnight, engineers will begin a 24-hour test of the reaction control system engines to evaluate engine performance for standard and non-standard thruster configurations. This test will provide data to inform procedures and ensure that the reaction control thrusters can control Orion’s orientation in an alternate configuration if there is an issue with the primary configuration.
Just after 1:42 p.m. CST on Nov. 24, Orion was traveling 222,993 miles from Earth and 55,819 miles from the Moon, cruising at 2,610 miles per hour.
NASA Television coverage of the distant retrograde orbit insertion burn, scheduled for 4:30 p.m. EST on Friday, Nov. 25. The burn is scheduled to take place at 4:52 p.m.
Images are sent down to Earth, and uploaded to NASA’s Johnson Space Center Flickr account and Image and Video Library. When bandwidth allows, views of the mission will be available in real-time via video stream.
On the eighth day of its mission, Orion continues to travel farther away from the Moon as it prepares to enter a distant retrograde orbit. The orbit is “distant” in the sense that it’s at a high altitude from the surface of the Moon, and it’s “retrograde” because Orion will travel around the Moon opposite the direction the Moon travels around Earth.
Orion exited the gravitational sphere of influence of the Moon Tuesday, Nov. 22, at 9:49 p.m. CST at a lunar altitude of 39,993 miles. The spacecraft will reach its farthest distance from the Moon Friday, Nov 25, just before performing the next major burn to enter the orbit. The distant retrograde orbit insertion burn is the second in a pair of maneuvers required to propel Orion into the highly stable orbit that requires minimal fuel consumption while traveling around the Moon.
NASA’s Mission Control Center at the agency’s Johnson Space Center in Houston unexpectedly lost data to and from the spacecraft at 12:09 a.m. for 47 minutes while reconfiguring the communication link between Orion and Deep Space Network. Teams have resolved the issue, and the spacecraft remains in a healthy configuration while engineers analyze data to determine the cause.
While in transit to the distant retrograde orbit, engineers conducted the first part of the propellant tank slosh development flight test, called prop slosh, which is scheduled during quiescent, or less active, parts of the mission. The test calls for flight controllers to fire the reaction control system thrusters when propellant tanks are filled to different levels. Engineers measure the effect the propellant sloshing has on spacecraft trajectory and orientation as Orion moves through space. The test is performed after the outbound flyby burn and again after the return flyby burn to compare data at points in the mission with different levels of propellant onboard.
Propellant motion, or slosh, in space is difficult to model on Earth because liquid propellant moves differently in tanks in space than on Earth due to the lack of gravity. The reaction control thrusters are located on the sides of the service module in six sets of four. These engines are in fixed positions and can be fired individually as needed to move the spacecraft in different directions or rotate it into any position. Each engine provides about 50 pounds of thrust.
As of Wednesday, Nov. 23, a total of about 3,971 pounds of propellant has been used, about 147 pounds less than prelaunch expected values. There is more than 2,000 pounds of margin available over what is planned for use during the mission, an increase of about 74 pounds from prelaunch expected values.
Just after 1 p.m. CST on Nov. 23, Orion was traveling about 212,437 miles from Earth and was more than 48,064 miles from the Moon, cruising at 2,837 miles per hour.
To follow the mission real-time, you can track Orion during its mission around the Moon and back, view a live stream from Orion’s cameras, and find the latest imagery and videos on Flickr. The second episode of Artemis All Access is now available as a recap of the last few days of the mission with a look ahead to what’s coming next.