The translunar injection burn is underway. The Orion spacecraft is now committed to its journey to the moon.

Mission Control in Houston has given the final “go” for the translunar injection burn. The Artemis II crew said they are a “go” for the burn.

Mission Control told the astronauts, “When the engine ignites, you embark on humanity’s lunar homecoming arc and set the course to return Integrity and her crew safely home. Houston is go for TLS.”

Astronaut Christina Koch replied, “Crew is go for TLI. With this burn to the moon, we do not leave Earth, we choose it."

-ABC News' Matthew Glasser

Following the path of Artemis II may be confusing as the astronauts, mission control and others use specific jargon and phrases.

Here are explanations of some of the terminology people may hear over the course of the mission:

Translunar injection burn

The translunar injection burn is the final step that sends the crew on the path to the moon, committing the Orion spacecraft to the remainder of its 10-day mission.

Lasting just minutes, it's a single-engine firing that propels the spacecraft out of Earth's orbit and on a "free-return trajectory."

Universal waste management system

The universal waste management system, otherwise known as a space toilet, is located inside a stall just like in a public restroom on Earth, according to NASA.

Space toilets use air flow to pull urine and feces away and into receptacles, which are stored for disposal. The astronauts have a handlebar to hold themselves down while using the toilet in the absence of gravity.

Read more here about the terms and jargon you may come across during the Artemis II mission.

NASA astronaut Christina Koch is making history as the first woman to travel around the moon.

Koch, 47, is among the four-person crew aboard the Orion spacecraft for NASA's Artemis II mission, which lifted off Wednesday evening from the Kennedy Space Center in Florida for a 10-day journey.

Koch, who was born in Grand Rapids, Michigan, and grew up in Jacksonville, North Carolina, is no stranger to record-setting NASA missions.

Koch was first selected as a NASA astronaut in 2013. In December 2019, she set the record for the longest single spaceflight by a woman, spending 328 consecutive days in space, according to NASA, and was part of the first all-female spacewalk in October 2019 with Jessica Meir.

Read more about Koch here.

-ABC News' Kelly McCarthy

The Artemis II crew was awakened Thursday by the song “Lonesome Drifter,” by country singer Charley Crockett, as day nine of their 10-day flight officially began.

Reentry and splashdown preparations for a scheduled Friday splashdown off the California coast are now in full swing. The crew is scheduled to execute their second return trajectory burn of the Orion crew module at 10:53 p.m. ET today.

NASA will hold another mission status briefing at 3:30 p.m. ET.

-ABC News' Briana Alvarado