I think you're being a pedant, if your point is a grazing entry causing rebound skip ultimately returns to some orbital path downward.
They certainly could've gotten the return wrong but with a perigee of 119 miles they arent even in a stable orbit and likely could deorbit themselves using only rcs thrusters at apogee, or by just waiting a few orbits.
In fact, the trajectory they chose for this mission exploited the opposite effect to yield a free return without propellant expense.
In the modern day, the chance of a math error being the root cause behind this failure mode are vanishingly small, but minor burn execution mistakes that do not require hundreds of extra pounds of propellant are definitely plausible. They were extremely common in the early days of spaceflight and plagued most of the very first moon exploration attempts. Again, with modern RCS this is unlikely. But reentry is still incredibly tight and dangerous. Apollo famously had a +-1° safe entry corridor, and Orion is way heavier and coming in even faster. If their perigee was off they could’ve easily burned up or doubled their mission time, which they may not have been able to survive.
I feel like the original claim paints the whole thing as on a knife edge and barely achieved by virtue of not making a single mistake. In today's age with so many moon landing deniers and worse I feel like we should be specific about where the actual dangers challenges and unknowns there were here. In reality, the orbital mechanics are one of the simplest parts of the entire problem, at least when we're talking about a moon flyby
Artemis II never escaped Earth’s pull.
That video that NASA put out where the craft did a sling shop around the moon is extremely deceptive. The pull of the moon had very little effect.
If they had missed, they would have eventually crashed back to earth in the worst case, and best case just re-adjusted and returned a little bummed.
No, it had a very significant effect: it's what made possible the free return trajectory while observing the far side of the moon.
Like I said, the gif you saw makes it look that way.
Here is a link that explains it very well. https://youtu.be/MF8IbYbVIA0?t=269
I’ll agree, it seems crazy that it left earth, made it to the moon, and never really left earth orbit at all. That the furthest we’ve been away is still destined to return on its own.
Makes it look what way?
Watch the NASA video carefully. It's clear that, even before the "loop" begins, Artemis is slowed down and is soon going to reverse direction relative to Earth. Which of course it would anyway, as you say--because, as the video you linked to points out, it doesn't have Earth escape velocity. The TLI burn gave it just enough velocity to reach the Moon's orbit with a little extra speed left over to get it about 4000 miles further.
But what would not happen without the Moon there is the "backwards" part of the loop--the part that took Artemis around the far side of the Moon. The Moon's gravity is what did that. In the Moon-centered frame in the video, yes, it looks like just a slight deflection--because that frame is moving with the Moon, whereas Artemis was moving backwards--in the opposite direction from the Moon in the Earth-centered frame.
Without the Moon there, Artemis would never have moved backwards, relative to the Moon's orbit, at all. Its trajectory in the Earth centered frame would have been a simple ellipse, with a maximum altitude from Earth a little higher than what it actually achieved (since the Moon's gravity did pull it back a little bit).
No, it's not. You aren't responding to what I actually said. See below.
> the “free return” would have happened if they launched entirely in the wrong direction.
But it would not have been a free return that let them see the far side of the moon, which is what I said. The Moon's gravity is what made that possible. And that was very significant.