What do the words you will hear during the launch of Artemis I to the Moon mean?

Few things are more exciting than watching a spacecraft blast off from the launch pad, as NASA’s Artemis I mission prepares to do on Monday.

But if you’re a casual observer, few things may be more confusing than hearing some of the jargon used by mission control.

Celebrities and spectators from around the world will gather at NASA’s Kennedy Space Center in Florida to watch the new Space Launch System rocket and the uncrewed Orion spacecraft make their journey to the Moon.

And for those who cannot attend in person, there will be live broadcasts on various platforms and have been organized watch parties across the country. Many people are trying to distinguish LH2 from LO2 and find out what L minus is.

For those of you who aren’t NASA scientists or amateur astrophysicists, here are some of the terms you’ll hear during the historic launch, and what they mean.

takeoff jargon

NASA aims to launch Artemis I between 8:33 and 10:33 am ET on Monday, with backup windows on September 2 and 5 in case of bad weather or delays. If the launch is a “yes”, it means that things are on the right track. If it is a “no”, the launch can be postponed.

As the mission teams count down, they will use phrases and abbreviations that may be unfamiliar. Expect to hear “SLS” to indicate the rocket, rather than Space Launch System, and “rated” to mean things are normal or going according to plan.

When the rocket is loaded with cryogenic (supercold) liquid oxygen and liquid hydrogen to fuel liftoff, the abbreviation is “LO2” for oxygen and “LH2” for hydrogen.

The Artemis launch team will most likely mention “ICPS”, which refers to the intermediate cryogenic propulsion stage. This upper rocket segment will provide Orion with the propulsion it needs in space after the two solid-fuel booster rockets and the core stage, or backbone, of the rocket separate from the spacecraft.