We have the record of animals going farthest from the moon discussed in this question.
What is the furthest an animal has been sent away from Earth?
The animals sent farthest from the Earth were the tortoises (and other creatures, see below) on Zond 7. They were sent roughly 407,000 km from the center of the Earth (possibly more depending on whether the distance of Zond 7 from the moon was calculated from the surface or the center).
Will the record stand or will Artemis II crew beat the record?
Artemis wins by roughly 4300 km.
The "roughly 407,000 km" for Zond 7 would be appropriate if it had passed the far side of the moon early on August 11, 1969. But there is a series of earthset photographs taken by the satelite. They show earth almost fully iluminated, and with Newfoundland, I think, at the center of the globe. That would be an approximate 16:00 UTC on that date, and shortly before the maximum distance was reached.
Acording to this Lunar distance calculator, the distance between earth and moon centers was 405,070 km then. If you add to that the closest approach of the vehicle to the moon of 1,985 km (according to the WP article, and also add the moon mean radius of 1737 km, the resulting distance is 408,792 km.
The published maximum distance of Artemis II to the earth will be 252,757 miles, which would be a rounded 406,773 km. Again according to the calculator, at 23:00 UTC the earth to moon distance will be 252,212 miles. Add to that the minimum distance of the spacecraft to the moon of 4,070 mi gives 256,287 mi. That only fits if the distance is computed from the surface of the earth or moon, respectively, not the center. In contrast, on this other documentation site, NASA quotes the expected distance as 413,146.2 km. That one seems to be the one from center earth.
The numbers for Zond 7 measure from the centers of the celestial objects. Measuring from the surface, you would have to reduce the number by 6,371 km (earth mean radius). That would result in a distance of 402,421 km.
Also, this assumes the time of closest approach coincides with the time of the furthest distance. For Artemis II, they are actually 5 minutes apart.
To sum up the numbers:
| Vehicle | from center Earth | from surface Earth |
|---|---|---|
| Zond 7 | 408,792 km | 402,421 km |
| Artemis II¹ | 413,142 km | 406,771 km |
¹ Numbers corrected by what was quoted in the conversation between Mission Control and the Orion capsule on the evening of April 6th.
