Part of the far side of the Moon looms just behind the Orion spacecraft. Picture: NASA.
The link between NASA’s Mission Control Center and the Orion Artemis I spacecraft was down for nearly an hour during its trip around the Moon.
Mission Control, based in Houston, Texas, lost data to and from Orion for 47 minutes as engineers reconfigured the communications link between the spacecraft and Deep Space Network.
Engineers are currently performing a root cause analysis to understand why the signals failed unexpectedly after the procedure had been tested several times over the past week.
“That’s what we’re testing for,” said Jim Free, NASA associate administrator for exploration systems development, after the link was restored.
The data was not lost, as it was saved on Orion’s onboard systems. The Command and Data Handling Officer (C&DH) – the office that will handle Orion’s display interfaces for future crewed Artemis II missions – will downgrade the data recorded during the outage as part of his analysis.
“There was no impact to Orion, and the spacecraft remains in a healthy configuration,” NASA said in a blog post.
The distant retrograde orbit optimizes Orion’s fuel reserves and is where the spacecraft will remain stable for the next few weeks. Objects in distant retrograde orbit are in balance between the gravitational force of the Earth and that of the Moon. The “retrograde” part refers to the fact that Orion is traveling in the opposite direction of the Moon’s orbit relative to Earth.
Two weeks left
NASA must conserve Orion’s fuel for correction and propulsion in preparation for its flyby of the Moon and its return to Earth, when it crashes into the Pacific Ocean around December 8.
NASA predicts that Orion will leave the distant retrograde orbit on the 1er december. After which it will perform a motorized flyby of the Moon on December 5.
“The spacecraft will reach its furthest distance from the Moon on Friday, November 25, just before performing the next big burn to enter orbit,” NASA detailed on Wednesday.
“The insertion burn in far retrograde orbit is the second of two maneuvers needed to propel Orion into a very stable orbit that requires minimal fuel consumption during the trip around the Moon,” the space agency adds.
Another interesting test conducted by NASA as Orion nears distant retrograde orbit is the “prop splosh” test, or test of the effect of propellant sloshing on Orion’s trajectory and orientation while it moves through space. The tests take place after each flight to the Moon, both outward and return. This allows engineers to compare data when the spacecraft is carrying different volumes of liquid propellant, which is difficult to model on Earth due to differences in gravity.
To swirl the liquid, NASA will use Orion’s reaction control thrusters, which are located on the sides of the service module and can be turned on or off to move the spacecraft and swirl the propellant.
“These motors are in a fixed position and can be turned on individually as needed to move the spacecraft in different directions, or rotate it to any position. Each motor provides about 50 pounds of thrust,” NASA explains.
By Monday, November 21, after Orion’s flyby of the Moon, the spacecraft had used 3,715.7 pounds of propellant. According to NASA, as of Wednesday, November 23, Orion had used approximately 3,971 pounds of propellant.
“There is more than 2,000 pounds of headroom available over what is planned for the mission, an increase of about 74 pounds over the values planned before launch,” NASA notes. This data suggests that the spacecraft and the maneuvers were more efficient than expected.
Preparations for manned voyages
Separately, last week, the Artemis I Space Launch System (SLS) rocket deployed 10 small CubeSats in Orion. One of them, BioSentinel, made its lunar flight on Tuesday. It is used to study the impact of space radiation on yeast, one of Orion’s “biological passengers”.
The idea is to test biological materials in preparation for human travel on “further and longer and longer missions to destinations like Mars”. NASA is testing two strains of yeast in deep space, because the yeast has similarities to human cells and they want to know how human cells are affected by long-term exposure to radiation in deep space.
“Often, DNA damage can be repaired by cells in a very similar process between yeast and humans,” NASA notes.
A strain of yeast tested in space is natural. The other was selected because she has trouble repairing her DNA. “By comparing how the two strains respond to the deep space radiation environment, researchers will learn more about health risks to humans during long-term exploration and be able to develop informed strategies to reduce potential harm,” says NASA.