Artemis II glossary. Terms to know as astronauts approach moon
The world has been watching as humans have for the first time in more than 50 years set out on a journey toward the moon .
But unless you're a space geek who avidly tracks rocket launches and cosmic ventures, you may find yourself confused by some of the terminology you've heard or read as you follow updates on NASA's Artemis II mission .
Not to worry: We've got you covered.
As of Friday, April 3, the Artemis II astronauts are officially moonbound two days after launching from Florida after the Orion spacecraft they're aboard completed a pivotal maneuver to send them beyond Earth's orbit. In the days ahead, the mission will see the astronauts become the first to ever lay eyes on a view of the far side of the moon that not even the Apollo astronauts witnessed.
Along the way, they'll test out systems and hardware to ensure NASA is ready to put boots on the lunar surface as early as 2028. The space agency's multibillion-dollar Artemis campaign is far from a reprise of its Apollo program, as the series of missions are aimed to set up a moon base toward the lunar south pole ahead of the first crewed expeditions to Mars .
Artemis II and it’s crew of four lift off from Kennedy Space Center April 1, 2026 on a 10-day mission around the Moon and back. Craig Bailey, FLORIDA TODAY via USA TODAY NETWORK
But let's not get too far ahead of ourselves. In the meantime, here are definitions for some of the jargon-y space terms you may come across in the days ahead as you follow along with the Artemis II astronauts amid their journey around the moon .
Artemis II glossary: Terms to know ahead of moon approach
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Translunar injection burn: a maneuver that required the Orion spacecraft's service module to fire its engines to send the vehicle beyond Earth's orbit and toward the moon. Located below the crew module where the astronauts reside, the service module fired its main engine for nearly six minutes to get Orion on the correct moonbound trajectory.
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Outbound transit: a term referring to the next three days of the Artemis II astronauts' journey toward the moon. Along the way, the Orion capsule's service module could perform up to three smaller burns of its main engine to ensure it stays on the right path.
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Sphere of influence: the region where, in this case, either the pull of the Earth's or the moon's gravity is stronger on the Orion spacecraft. During their lunar transit, the astronauts are expected on Sunday, April 5, to enter the lunar sphere of influence. After swinging around the far side of the moon, Orion will on Tuesday, April 7, exit the lunar sphere of influence and head back toward Earth orbit.
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Lunar flyby: the event during which the Artemis II astronauts will pass by the moon, whizzing up to 6,000 mile above the surface. During the flyby, the astronauts are due to reach about a quarter-million miles from Earth, taking them farther than any humans have ever been in space.
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Lunar targeting plan: the astronauts' guide for what they will do during the six-hour window they have for observations on Monday, April 6. That includes plans for documenting features such as craters and ancient lava flows, as well as the late addition of plans to observe a solar eclipse. During the eclipse, the sun will be hidden from the astronauts' view as it moves behind the moon from their perspective, revealing the sun's elusive outermost layer, the corona.
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Deep Space Network: NASA's array of giant radio network antennas on Earth that is now responsible for maintaining communications with the Artemis II astronauts aboard Orion.
Where is Artemis II now? Location tracker
Want to follow the astronauts along the Artemis II lunar journey? NASA has an Artemis II tracker available online and on its mobile app that allows users to see where Orion is, how fast it's traveling and how far the spacecraft is from both the Earth and the moon.
The mobile version for smartphones even includes an augmented reality feature that allows users to move their phones to see where Orion is relative to Earth.
Artemis II astronauts
The crew members of Artemis II includes NASA astronauts Reid Wiseman, Christina Koch and Victor Glover, and the Canadian Space Agency's Jeremy Hansen.
The mission will make Glover the first Black man to venture within the vicinity of the moon, while Koch will become the first woman and Hansen the first Canadian to do so.
All three Americans are experienced astronauts who have been to space before on ventures to the International Space Station , while Hansen, a veteran aviator, is making his first spaceflight.
How long is the Artemis II mission? Here's when they'll land on Earth
With the moon rendezvous complete, the astronauts will then make a four-day journey back to Earth, using our planet's gravity to naturally "slingshot," or pull Orion back home , negating the need for propulsion or much fuel.
Once Orion blazes through Earth's atmosphere, a protective heat shield will be cast off to make way for parachutes to deploy and slow the vehicle down.
The capsule will then make a water landing likely Friday, April 10, in the Pacific Ocean near California off the coast of San Diego, after which five orange airbags will inflate around the top of the spacecraft and flip the capsule into an upright position. After the landing, the crew would exit the vehicle onto a U.S. Navy recovery vessel within about two hours.
Eric Lagatta is the Space Connect reporter for the USA TODAY Network. Reach him at elagatta@usatodayco.com
This article originally appeared on USA TODAY: Translunar injection? Artemis II terms to know ahead of moon flyby
