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Nov. 23, 2022
Artemis I – Flight Day Seven: Orion to Test Search Acquire and Track Mode, Exit Lunar Sphere of Influence
The Orion spacecraft is now on its seventh day into the Artemis I mission, a flight test around the Moon, paving the way for astronauts to fly on future missions. At 12:02 a.m. CST, Orion completed the fifth outbound trajectory correction by firing the European service module’s auxiliary engines for 5.9 seconds, which changed Orion’s velocity by 3.2 feet per second.
Flight Day 6: Orion's Optical Navigation Camera Captures Lunar Surface
The R-4D-11 auxiliary engines are a variant of the flight proven R-4D engine, which was originally developed for the Apollo program and was employed on every mission to the Moon. The engines are positioned at the bottom of the service module in four sets of two, and each provide about 100 pounds of thrust. In total, Orion’s highly capable service module has 33 engines of various sizes and serves as the powerhouse for the spacecraft, providing propulsion capabilities that enable Orion to go around the Moon and back on its exploration missions.
The team in the White Flight Control Room at NASA’s Johnson Space Center in Houston continued testing the spacecraft’s star trackers to determine their sensitivity to thermal variations as part of planned testing, and engineers used the optical navigation system to gather additional imagery of the Moon. The star trackers and optical navigation system are part of Orion’s advanced guidance, navigation, and control system, responsible for always knowing where the spacecraft is located in space, which way it’s pointed, and where it’s going. It even controls the propulsion system to keep the spacecraft on the correct path. The optical navigation can serve later in this mission and in future missions as a backup, ensuring a safe trip home should the spacecraft lose communications.
Earth Rise as Seen from Orion Spacecraft
Overnight, flight controllers will conduct the search acquire and track (SAT) mode developmental test objective. SAT mode is an algorithm intended to recover and maintain communications with Earth after loss of Orion’s navigation state, extended loss of communications with Earth, or after a temporary power loss that causes Orion to reboot hardware. To test the algorithm, flight controllers will command the spacecraft to enter SAT mode, and after about 15 minutes, restore normal communications. Testing SAT mode will give engineers confidence it can be relied upon as the final option to fix a loss of communications when crew are aboard.
Orion will exit the lunar sphere of influence, or the gravitational pull of the Moon, at 10:31 p.m. CST and continue traveling toward distant retrograde orbit. The next live event will be NASA Television coverage of the distant retrograde orbit insertion burn, scheduled for 4:30 p.m. EST on Friday, Nov. 25. Shortly before entering the orbit, Orion will travel about 57,287 miles beyond the Moon at its farthest point from the lunar surface during the mission. View the Artemis I mission map to see Orion’s path in space.
On Saturday, Nov. 26, Orion will pass the record set by Apollo 13 for the farthest distance traveled by a spacecraft designed for humans at 248,655 miles from Earth, and the spacecraft will reach its maximum distance from Earth of 268,552 miles Monday, Nov. 28.
Just after 4 p.m. CST on Nov. 22, Orion was traveling over 208,000 miles from Earth and was over 36,000 miles from the Moon, cruising at over 3,000 miles per hour.
Listen to a replay of the Twitter Spaces NASA hosted Tuesday, Nov. 22, with NASA Flight Director Gerry Griffin, Jim Geffre from Orion, Nijoud Merancy with the Artemis program and Jennifer Ross-Nazzal with the NASA history office to discuss the milestone.
Artemis I – Flight Day Eight Update: Unexpected Loss of Communication with Orion is Restored
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. CST for 47 minutes while reconfiguring the communication link between Orion and Deep Space Network overnight. The reconfiguration has been conducted successfully several times in the last few days, and the team is investigating the cause of the loss of signal. The team resolved the issue with a reconfiguration on the ground side. Engineers are examining data from the event to help determine what happened, and the command and data handling officer will be downlinking data recorded onboard Orion during the outage to include in that assessment. There was no impact to Orion, and the spacecraft remains in a healthy configuration.
Artemis I – Flight Day Eight: Orion Exits the Lunar Sphere Of Influence
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.
Image above: (Nov. 22, 2022) Flight Day 7, Orion’s Optical Navigation camera captured the far side of the Moon, as the spacecraft orbited 81.1 miles above the surface, heading for a Distant Retrograde Orbit. Orion uses the optical navigation camera to capture imagery of the Earth and the Moon at different phases and distances, providing an enhanced body of data to certify its effectiveness under different lighting conditions as a way to help orient the spacecraft on future missions with crew.
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.
Related articles:
Artemis I – Flight Day Six: Orion Performs Lunar Flyby, Closest Outbound Approach
https://orbiterchspacenews.blogspot.com/2022/11/artemis-i-flight-day-six-orion-performs.html
Artemis powering past the Moon
https://orbiterchspacenews.blogspot.com/2022/11/artemis-powering-past-moon.html
Orion Successfully Completes Lunar Flyby, Re-acquires Signal with Earth
https://orbiterchspacenews.blogspot.com/2022/11/orion-successfully-completes-lunar.html
Artemis I – Flight Day Four: Testing WiFi Signals, Radiator System, GO for Outbound Powered Flyby
https://orbiterchspacenews.blogspot.com/2022/11/artemis-i-flight-day-four-testing-wifi.html
NASA’s Artemis I Cameras to Offer New Views of Orion, Earth, Moon
https://orbiterchspacenews.blogspot.com/2022/11/nasas-artemis-i-cameras-to-offer-new.html
Artemis I Liftoff! 50 years after Apollo 17, Orion on Its Way to the Moon
https://orbiterchspacenews.blogspot.com/2022/11/artemis-i-liftoff-50-years-after-apollo.html
Artemis I return for launch
https://orbiterchspacenews.blogspot.com/2022/11/artemis-i-return-for-launch.html
Related links:
Track Orion: https://www.nasa.gov/trackartemis
Artemis I: https://www.nasa.gov/artemis-1
Orion spacecraft (ESA): https://www.esa.int/Science_Exploration/Human_and_Robotic_Exploration/Orion
Orion Spacecraft (NASA): https://www.nasa.gov/exploration/systems/orion/index.html
Images, Video, Text, Credits: NASA/Sandra Jones/Shaneequa Vereen/NASA TV/SciNews.
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