Author: Sandra Jones

 

Orion continues its journey back to Earth on day 22 of the 25.5-day Artemis I mission with flight controllers and engineers continuing to test the spacecraft and its systems in preparation for future flights with humans aboard.

Engineers conducted the second part of the propellant tank slosh development flight test, called propellant slosh, which is scheduled during quiescent, or less active, parts of the mission. 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 test calls for flight controllers to fire the reaction control system thrusters when propellant tanks are filled to different levels. The reaction control thrusters used are located on the sides of the service module 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 Engineers measure the effect the propellant sloshing has on spacecraft trajectory and orientation as Orion moves through space.

The test was first performed after the outbound flyby burn, and now again after the return flyby burn, to compare data at points in the mission with different levels of propellant onboard. Approximately 12,060 pounds of propellant has been used, which is 215 pounds less than estimated prelaunch, and leaves a margin of 2,185 pounds over what is planned for use, 275 pounds more than prelaunch expectations. The first prop slosh test objective was completed on day eight of the mission as it prepared to enter the distant retrograde orbit.

A few key milestones for Orion remain, including the entry system check outs and propulsion system leak checks on mission days 24 and 25, respectively.

Orion will travel at around 25,000 mph while reentering Earth’s atmosphere, testing the world’s largest ablative heat shield by reaching temperatures up to 5,000 degrees Fahrenheit – approximately half the heat of the sun. The heat shield is located at the bottom of the Orion capsule, measuring 16.5 feet in diameter, and sheds intense heat away from the crew module as Orion returns to Earth. The outer surface of the heat shield is made of 186 billets, or blocks, of an ablative material called Avcoat, a reformulated version of the material used on the Apollo capsules. During descent, the Avcoat ablates, or burns off in a controlled fashion, transporting heat away from Orion. Learn more about Orion’s heat shield in the Artemis I reference guide.

On Thursday, Dec. 8 at 5 p.m. EST, NASA will host a briefing to preview Orion’s return scheduled for Sunday, Dec. 11 and to discuss 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.

Watch the latest episode of Artemis All Access for a look back at recent mission accomplishments and a preview of splashdown, including parachute information.

Just after 3 p.m. CST on Dec. 7, Orion was traveling 234,100 miles from Earth and 127,700 miles from the Moon, cruising at 820 miles per hour.

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.

 

 

Orion exited the lunar sphere of gravitational influence Tuesday, Dec. 6, at 1:29 a.m. CST for the last time on the Artemis I mission less than a day after completing the return powered flyby burn that put the spacecraft on course for splashdown Sunday, Dec. 11. Earth’s force of gravity is now the primary gravitational force acting on the spacecraft. 

Orion successfully performed the fourth return trajectory correction burn at 4:43 a.m. using the reaction control system thrusters. The burn lasted 5.7 seconds and changed the velocity of the spacecraft by 0.6 feet per second.

Flight controllers used Orion’s cameras to inspect the crew module thermal protection system and European Service Module, the second of three planned external spacecraft inspections. Teams conducted this survey early in the mission to provide detailed images of the spacecraft’s external surfaces after it had flown through the portion of Earth’s orbit containing the majority of space debris, and teams reported no concerns after reviewing the imagery. This second inspection during the return phase is being used to assess the overall condition of the spacecraft several days before re-entry.  

During both inspections, the Integrated Communications Officer, or INCO, commanded cameras on the four solar array wings to take a series of still images. Engineers and flight controllers at NASA’s Johnson Space Center in Houston will review the imagery over the coming days. A final photographic survey will be conducted Friday as Orion continues its journey home. 

Teams responsible for recovering Orion after its splashdown are continuing preparations ahead of the Dec. 11 splashdown off the coast of California. The mission management team will determine the landing site location Thursday, Dec. 8. Listen to NASA’s Artemis I recovery director, Melissa Jones, talk about what it takes to fetch the Orion spacecraft from the Pacific Ocean at the end of the mission on “Houston We Have a Podcast.” 

Just after 5:30 p.m. on Dec. 6 , Orion was traveling 244,000 miles from Earth and about 79,000 miles from the Moon, cruising at 500 miles per hour. 

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. 

 

 

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. 

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. 

To follow the mission real-time, you can track Orion during its mission around the Moon and back, and check the NASA TV schedule for updates on the next televised events. The latest imagery and videos can be found on the Johnson Space Center Flickr. 

 

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.   

Learn more about Orion in the Artemis I reference guide, and track Orion via the Artemis Real-Time Orbit Website, or AROW.