NASA's Artemis I Orion spacecraft made its final flyby of the Moon at an altitude of 80.6 miles as it headed back to Earth for an impending splashdown in the Pacific Ocean on its 19th day in orbit. But before everything else, though, it called home! However, the communications system went weird again after the call.
On Monday, mission control in Houston prepared for Orion's return, propelled by a lunar flyby burn in which it flew near enough to the Moon to utilize its gravity to "slingshot" back to Earth. Almost everything went according to plan. The event Splashdown is planned for Sunday, Dec. 11.
The powered flyby burn, Orion's final significant engine maneuver for this mission, took 3 minutes and 27 seconds to complete and changed the spacecraft's velocity by around 655 mph (961 feet per second).
ZDNet said Orion was cruising at 668 mph and was 244,629 miles from Earth and 16,581 miles from the Moon as of Dec. 5 (5:29 pm CST / 6:29 pm EST).
A mockup of NASA's Orion spacecraft is seen inside the Space Vehicle Mockup Facility during a media preview for an upcoming public open house at NASA's Johnson Space Center on October 24, 2018, in Houston, Texas.
NASA Artemis 1 Orion Calls Home Through Deep Space Network
Orion was using NASA's Deep Space Network to send its data signal back to ground stations on Earth when it left its far-off retrograde orbit around the Moon. During this time, Scott Tilley, an amateur visual and radio astronomer, captured and recorded Orion's data signal, which, when sonified (converted into audible sound), genuinely sounds out of this world.
One of the signal's harmonics-sections of the frequency wave that are whole number multiples of the signal's fundamental, or primary frequency-was captured in the recording of the Artemis 1 data signal that Tilley posted on Twitter.
Let me introduce you to 'Lower45' it's the 24th idle harmonic of #Artemis1's data signal and one of the strongest harmonics. The harmonics repeat at 1/528us rate w/ the 12th and 24th being amoung the loudest.
Lower45 = -45.4545454545454545...KHz below nominal carrier. pic.twitter.com/02GtZjXHDK— Scott Tilley 🇺🇦 (@coastal8049) December 4, 2022
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Tilley refers to this specific harmonic as the "Lower 45" since it occurs 45.45454545 kilohertz below the signal's normal frequency. Tilley told Space.com that these harmonics could be useful for helping to track Orion using the Doppler effect, a change in a wave's frequency caused by changes in an observer's position relative to the signal source. In this instance, the Doppler effect results from the Earth's rotation around the sun and Orion's path through space.
DSN Malfunctioned After Orion Called Home
The unmanned Artemis 1 spacecraft continued to reach a significant milestone in its mission when it completed a 207-second engine burn approximately 79 miles (128 kilometers) above the lunar surface as of Dec. 5. The move put Orion on course to return to Earth, where, if all goes according to plan, it will splash down in the Pacific Ocean on Dec. 11.
Mike Sarafin, the Artemis mission manager at NASA Headquarters in Washington, waxed poetic during the teleconference (per another Space.com report) about the amazing exploits Orion had already accomplished, including shattering the previous human-rated spacecraft distance record held by Apollo 13.
Mission management explained how a site-wide failure at the Deep Space Network station in Goldstone, California, resulted in a four-and-a-half-hour snag in contact between ground controllers and Orion after it phoned home. Fortunately, teams had the chance to swiftly reestablish connectivity because the outage was brought on by hardware problems at the ground station rather than any Orion gear.
The four devices in charge of the vehicle's propulsion and heating subsystems lost power on Sunday (Dec. 4) due to a problem with a power conditioning distribution unit onboard Orion. However, power was quickly recovered, and NASA stated in a statement (opens in new tab) that Orion's vital systems, including its navigation and communication systems, never lost power.
Orion's shakedown flight is still ongoing, but for the time being, things are going so well that mission managers are eagerly anticipating the next "pre-planned decision gate" on Thursday (Dec. 8), when a landing location off the coast of California will be chosen for Orion's Dec. 11 landing.
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