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Apollo 8 orbited the moon, and obviously Apollo 11 landed. I'm wondering if there were any test missions to get unmanned ships to the moon and safely back to Earth? It seems like a big jump to suddenly send manned ships there.

Joe Bob
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I'm wondering if there were any test missions to get unmanned ships to the moon and safely back to Earth?

There were no uncrewed round-trip missions to the moon prior to Apollo 11.

Several one-way missions landed safely on the moon without crew before 1969, but did not return, including the American Surveyor series. The first of these, Surveyor 1, landed on the moon on June 2, 1966.

In 1970, the first robotic round-trip mission, the USSR's Luna 16, returned samples from the moon.

There weren't any huge technical obstacles to robotic lunar round-trip missions. The Luna round-trips used a clever return trajectory that required only a single burn from the moon's surface with no course corrections afterwards, but that technique constrained when and where they could land on the moon; a multiple-burn return would have required a little more sophistication in the probe's guidance and navigation system (and thus more mass and cost), but it wouldn't have been impossible to do pre-Apollo-11.

Returning from the moon takes a vehicle several times larger than one that just needs to get there; if you don't do a lunar orbit rendezvous like Apollo did, then you need to carry all the fuel for your return journey all the way to the moon's surface. Luna 16 was more than 5 times as massive as Surveyor 1, for example, requiring a 700-ton Proton booster to go to the moon instead of a 140-ton Atlas-Centaur.

Lunar orbit rendezvous offers a path to a lunar landing mission with a smaller vehicle at the cost of additional mission complexity, and automatic docking had been demonstrated by the USSR in 1967.

The USSR's lunar landing plan would possibly have landed one LK uncrewed as a backup, followed by a second LK with a single crew member, but they never got the necessary N1 booster to work. The LK itself had a backup ascent engine, so this plan provides 8 times as many ascent engines per crew member as Apollo. They clearly didn't want to strand a cosmonaut on the moon.

It seems like a big jump to suddenly send manned ships there.

It would have been technically feasible to land an Apollo LM (with some modifications) uncrewed. However, one of the major lessons of the X-15 program was that the combination of automation and human capabilities in a complex system was far more reliable than either human or automation alone. If, for example, Apollo 10 had flown its LM to the surface without a crew, it would have had substantial risk of crashing (having no way to know if it was coming down in a field of boulders) and the program would have missed out on the first-hand observations of the crew.

As with other apparently-risky steps taken in the Apollo program (particularly Apollo 8, discussed here and here), skipping an unmanned landing attempt was a calculated risk to save time and money.

Russell Borogove
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    This is a superb answer! – Organic Marble Aug 01 '19 at 02:47
  • orbital rendezvous had been performed several times in LEO, so remotely performing one during the mid 60s was within reach. Automating it, probably not, but no one mentioned automation here. – Innovine Aug 01 '19 at 11:51
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    I think your answer should mention the tortoises on Zond 5. It's an intermediate step between unmanned craft and the manned missions, showing that life support systems could remain operational, and keeping the passengers alive long enough to survive the journey. – Innovine Aug 01 '19 at 11:53
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    @Innovine And in fact the USSR did a remote control docking in ‘67. – Russell Borogove Aug 01 '19 at 13:23
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    (Congrats on the 100k rep!) – BruceWayne Aug 01 '19 at 16:59
  • @Innovine, NASA did its life-support endurance demonstration with Gemini 5 and later with Gemini 7. You don't need to go to the Moon to show that a life-support system can keep running for a week. – Mark Aug 01 '19 at 20:04
  • @Mark Yep, but none of those went through the radiation belts, went outside the magnetosphere, nor endured constant sunshine. I think the Zond 5 mission contributed some. – Innovine Aug 02 '19 at 07:00
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    Congrats on 100k rep! – Shishir Maharana Aug 02 '19 at 09:53
  • I see to recall that the USSR's plan for a manned moon landing was to first land a spare LM in the same area, flown autonomously. – user Aug 02 '19 at 13:16
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    @user That was considered by the US, but the USSR’s final plan was a one-lander LOR plan not too unlike Apollo. A return lander still has to descend and ascend safely (albeit without crew mass on the descent) then you need a whole second ship for descent only, so it’s less efficient. – Russell Borogove Aug 02 '19 at 13:57
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    @RussellBorogove I think their plan was to do the entire landing automatically. Soviet spacecraft tended to be more automated than US ones. So the first lander would be a test of the landing system, and also offer a spare craft if the ascent engine on the later manned one failed. – user Aug 02 '19 at 14:01
  • Ah, you're right, I misremembered. – Russell Borogove Aug 02 '19 at 14:02
  • Small typo: Apollo 11, not Apollo 10. – Martin Schröder Aug 03 '19 at 11:57
  • I meant 10 in that bit. – Russell Borogove Aug 03 '19 at 14:28
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No. NASA was focused on manned missions. The unmanned Surveyor series proved that a Moon landing was possible, and launching from the lunar surface wasn't considered risky enough that an unmanned trial run was considered worth doing. The closest any of the Surveyors came to "Earth return" was Surveyor 6, which performed a "hop" reaching an altitude of four meters, landing three meters to the side of the original touchdown point.

The Soviet Union took two shots at it: an unnamed mission that failed on launch in June 1969 and Luna 15 (crashed into the Moon 13 hours after the start of Armstrong's moonwalk), but the first successful unmanned sample-return mission was Luna 16, in September of 1970.

Mark
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    Zond 5 performed a successful circumlunar flight in '68, and its passengers, a pair of tortoises, returned safely to earth. – Innovine Aug 01 '19 at 16:14