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.
Orion performs Lunar Flyby, closest outbound approach
by Leah Cheshier for NASA Blogs
Houston TX (SPX) Nov 24 - On its sixth day into the Artemis I mission, Orion successfully completed its fourth orbital trajectory correction burn using the auxiliary engines at 1:44 a.m. CST ahead the first of two maneuvers required to enter a distant retrograde orbit around the Moon.
The first three trajectory correction burns provided an opportunity to fire all three thruster types on Orion with the first using the large orbital maneuvering system engine, the second using the small reaction control system thrusters, and the third using the medium-sized auxiliary engines.
Orion completed the outbound powered flyby at 6:44 a.m., passing about 81 miles above the surface at 6:57 a.m. The spacecraft speed increased from 2,128 mph before the burn to 5,102 mph after the burn.
Shortly after the outbound flyby burn, the space craft passed about 1,400 miles above the Apollo 11 landing site at Tranquility Base at 7:37 a.m. Orion later flew over the Apollo 14 site at about 6,000 miles in altitude and then over the Apollo 12 site at an altitude of about 7,700 miles.
"The mission continues to proceed as we had planned, and the ground systems, our operations teams, and the Orion spacecraft continue to exceed expectations, and we continue to learn along the way about this new, deep-space spacecraft," said Mike Sarafin, Artemis I mission manager, in a Nov. 21 briefing at Johnson Space Center.
Orion will enter distant retrograde orbit beyond the Moon on Friday, Nov. 25 with the second maneuver, called the distant retrograde orbit insertion burn. 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. This orbit provides a highly stable orbit where little fuel is required to stay for an extended trip in deep space to put Orion's systems to the test in an extreme environment far from Earth.
Orion will travel about 57,287 miles beyond the Moon at its farthest point from the Moon on Nov. 25, pass the record set by Apollo 13 for the farthest distance traveled by a spacecraft designed for humans at 248,655 miles from Earth on Saturday, Nov. 26, and reach its maximum distance from Earth of 268,552 miles Monday, Nov. 28.
As of Monday, Nov. 21, a total of about 3,700 pounds of propellant has been used, about 75 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 200 pounds from prelaunch expected values.
Just after 2:45 p.m. CST on Nov. 21, Orion had traveled 216,842 miles from Earth and was 13,444 miles from the Moon, cruising at 3,489 miles per hour.
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Orion performs first Lunar flyby with closest outbound approach
Houston TX (SPX) Nov 22, 2022
On its sixth day into the Artemis I mission, Orion successfully completed its fourth orbital trajectory correction burn using the auxiliary engines at 1:44 a.m. CST ahead the first of two maneuvers required to enter a distant retrograde orbit around the Moon. The first three trajectory correction burns provided an opportunity to fire all three thruster types on Orion with the first using the large orbital maneuvering system engine, the second using the small reaction control system thrusters, and the th ... read more