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The four astronauts on the Artemis II mission have now left the Earth's orbit . . . .

BBC News 03 April 2026

My understanding of the word 'orbit' is that the earth orbits around the sun. The moon is held to the earth by gravity and thus the moon also orbits around the sun, in tangent with the earth. Meanwhile, of course, the moon orbits around the earth.

2.a.Astronomy. The regularly repeated, typically elliptical course of a celestial object, satellite, spacecraft, etc., around a more massive body

Nor could it be said that Artemis has left the earth's gravity as the moon is held in a balance of gravity with the earth, thus even objects on the moon, such as a vehicle, are still within that influence. Indeed, one has to escape the entire solar system to be free of the influence of the sun, gravitationally.

Nor do I believe that relativity will be, in this particular instance, relevant.

I cannot think of another way of putting what the reporter is trying to say. Conceptually, and physically, all that can be said is that Artemis has left the earth's atmosphere.

I am focussing on the word 'orbit' in English. I cannot see that there would be any need to migrate this question to SE-Astronomy.

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    I would have used "Earth orbit" rather than "Earth's orbit" here. The craft entered into Earth orbit after launch and left it for the trans-lunar phase. But it remains within Earth's orbit (Earth's path around the sun) in that it is still in the region dominated by Earth. Commented yesterday
  • Note that it can be argued the module is still in Earth orbit, albeit an elongated one, since it will return to Earth in a free return. Commented yesterday
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    @bradimus Yes. I agree. I look forward to an answer based on your observation 'earth orbit' that is to say 'the orbit of Artemis around the earth'. Commented 20 hours ago
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    Furthermore, if a spacecraft is orbiting the moon, is it orbiting the Earth? Commented 8 hours ago

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If Artemis II was merely taking off from Earth and going straight to the moon, then the word orbit would be a weird way of describing its trajectory. However, here is an illustration of its actual flight path from ABC News:

enter image description here

As you can see, Artemis II will indeed orbit round Earth before slingshotting off to the Moon. It is the circumnavigation of the Earth using the Earth's own gravity which warrants the use of the word orbit here.

References:

Kakatos, Mary. (2026). 'Artemis II mission timeline: What the 10-day journey to and from the moon will look like'. ABC News, 1 April. Available at: https://abcnews.com/Technology/artemis-ii-mission-timeline-10-day-journey-moon/story?id=131572035

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    That would be leaving an Earth orbit, not leaving Earth’s orbit. Commented 10 hours ago
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    @TinfoilHat The gentitive does not work like that. It can have twenty odd meanings, but essentially just means something like "associated with". So "Tinfoil Hat's robbery", for example can mean the robbery where someone robbed Tinfoil, or the robbery that Tinfoil carried out. Same kind of thing with "orbit" here. Commented 5 hours ago
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The analysis of the informal word 'orbit', rather than the formal meaning in physics, is that one thing 'goes around' another.

'Orbiting' and 'an orbit refer to a particular context of two things, one small and one large. First Artemis is going around the Earth, and so is the Moon, independently of Artemis. Then Artemis 'leaves' the Earth orbit and goes to the Moon.

Forgetting the Earth for the moment, once Artemis reaches the Moon, it will orbit the Moon (go around it multiple times). Or maybe Artemis just loops around the Moon once and then returns to the Earth (I haven't looked at the flight plan). In that case, you probably wouldn't say "Artemis orbited the Moon." because there's some informal implication of a connection, and by association, repetition (of course more formally once is enough to be called 'orbit', but less formally 'looped' would be the more likely term).

In some sense, yes Artemis is still orbiting the earth but that is being pedantic (or to NASA scientists exactly how the locations of these objects should be calculated), and all three are orbiting the Sun. You're thinking about too many things at once here. Just think about only two things at once for orbit.

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  • Artemis II crew clears Earth orbit, heads for the moon. The first three paragraphs describe a break from Earth somewhat, its gravitational pull. If you're not being pulled in, you're out of the orbit? It's probably more complicated than that. Commented 22 hours ago
  • It is more complicated than that. The moon is said to orbit Earth, but it is slowly escaping. Commented 20 hours ago
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    @bradimus Of course the physics is much more complicated than that. And the meaning of the word 'orbit' in multiple different contexts. But the accepted informal meaning is as I described: one thinks of the Earth and Moon as fixed and Artemis as going around one then traveling to the other and going around it. Even the NASA spokespeople use it like this (but understand the physical nuances to adjust when it matters. Commented 19 hours ago
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    Artemis II isn't going around the moon multiple times or even one full time. It's on a free-return trajectory where it will travel around the far side of the moon and the moon's gravity will pull it around the moon and essentially throw it back towards Earth. Its current trajectory isn't a normal orbit of either the Earth or the moon, but kind of a combination of both. It would not follow anything near its planned trajectory if not for the gravity of both Earth and the moon. Commented 6 hours ago
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The headline is not technically correct. A more accurate phrasing would be:

"The four astronauts on the Artemis II mission are now on an elliptical transfer orbit that will intersect the Moon's sphere of influence"

You can see why they went for a more colloquial phrasing.

Artemis II's flight path includes several distinct orbits:

  1. Low Earth Orbit: This was their first real 'stop' after the launch.
  2. Elliptical Earth Orbit number 1: They burned their engines, blooming out their previously circular orbit into an elliptical (oval-shaped) orbit.
  3. Elliptical Earth Orbit number 2: They burned again, blooming their orbit even higher such that one end of the orbit reaches ~to the moon. This is called a 'transfer orbit' and occurs after a 'trans-lunar injection' engine burn.
  4. Hyperbolic Lunar Orbit: Once the spacecraft gets close to the Moon, it will enter its 'sphere of influence': where the Moon's gravity begins to out-weigh the Earth's. The spacecraft is traveling too fast with respect to the Moon to be in a closed orbit; it will simply fly-by. The shape of the trajectory as seen from a Moon-centered frame is a hyperbola (vaguely 'v' shaped).
  5. Elliptical Earth Orbit number 3: After the spacecraft leaves the Moon's sphere of influence, it will once again be in an elliptical orbit around the earth. The shape of this orbit will be very similar to that of 'elliptical earth orbit number 2' except small adjustments are made to assure the other end of the orbit dips into the Earth's atmosphere so that the spacecraft can be slowed and landed.

So you can see that at only one phase of the mission can Artemis II be considered to have 'left Earth Orbit'. And that is still a few days away as of the date of this answer.

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Personally, I would say that the assertion is actually accurate. At least in the normal sense of the word, Artemis II is no longer in Earth orbit.

NASA, for example, provides this (admittedly somewhat simplified) definition of an orbit:

An orbit is a regular, repeating path that one object in space takes around another one.

https://spaceplace.nasa.gov/orbits/en/

Artemis II's current trajectory takes it towards the moon where it will experience much more gravitational influence from the moon than from Earth, which is what will pull it around the moon and back towards Earth.

Here's an artist's conception illustration from NASA of approximately what the Artemis II mission's planned trajectory would look like (obviously, it's not to scale):

NASA illustration of Artemis II trajectory
Source: NASA

An object is normally said to be 'orbiting' another one if the other (generally more massive) object's gravity combined with the object's own momentum is holding the orbiting object in a closed (or at least very nearly closed) elliptical path around the more massive object. That's not what what Artemis II is doing right now, since they have already completed the trans-lunar injection burn, placing them on a trajectory that will take them in a figure-8-style pattern around the moon rather than in a closed ellipse around Earth.

As such, I would not personally call their current trajectory an orbit of either the Earth or the moon, as it is not in a closed elliptical path around either of them, nor anything particularly closely resembling such a path.

That being said, it does depend on exactly which definition you're using. The Encyclopedia Britannica, for example, seems to have a broader definition of 'orbit,' which could include Artemis II's current trajectory. It provides this example:

Some bodies may follow parabolic or hyperbolic paths (open-ended curves). The orbit of a body approaching the solar system from a very great distance, curving once around the Sun, and receding again is such an open curve.

Personally, I would not consider that to be an orbit, since it is not a closed path (and, at least in my experience, such objects are not typically said to be in solar orbit in astronomical circles.) Such a definition seems problematic to me, since such an object would be on an escape trajectory which is normally a classic example of a trajectory that is not an orbit. However, if you go by their definition, then it could be said that Artemis II is still in Earth orbit (and also lunar orbit.)

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