In its heyday Earth was a great interplanetary trading post on account of its low gravity moon which was used as a warehouse for all kinds of goods.

The Moon was covered almost entirely in large warehouses and each had a staff of thousands. These people were manual workers, management and administrators plus technicians to maintain living conditions. All the people you would expect for a large business. None of them were research scientists although there were a few engineers.

Sadly Earth was hit by an asteroid causing extinction of all non-aquatic animal life. Many edible plants and sea-creatures survived.

Even more sadly, this coincided with a slump in the galactic economy. Trade died and no-one came their way any more - not even pirates who have no access to FTL travel.

Can they ever escape from the Moon back to Earth?

Resources

1. They have whatever minerals etc. already exist on the Moon (as known in 2018).




2. They have their buildings and equipment which are made of 2018-level technology and materials.




3. They have a vast quantity of goods in the warehouses.




4. These goods consist of (and only of) anything that could be bought on Amazon in 2018. But they don't have to buy it - it's already in their warehouses.




5. They have all home comforts for family life including fresh fruit and vegetables grown locally.

Unavailable resources

1. There are no petroleum deposits on the Moon as life had never existed there before the advent of humans.




2. They don't have any kind of space ship. They relied entirely on a now defunct shuttle service to get from Earth and back assuming they wanted to.




3. There was limited farming of animals because of the difficulty in growing sufficient quantities of foodstuffs. Meat is a luxury and most pets were banned as a consequence.

Question

So - can they ever escape from the Moon to Earth and land safely? If not can they survive indefinitely on the Moon as a community?

Forgetting for a moment all about the resources they do and don't have if the population are primarily moon-born return isn't an option. Anyone born on the Moon almost certainly can't go to Earth and definitely doesn't want to. Its a matter of gravity, humans who spend time in low gravity lose bone density, fast, people born in 17% Earth gravity are going to be exceedingly delicate, they wouldn't survive re-entry and their skeletons would collapse under full Earth Gravity if they did. If you wanted to recolonise Earth you'd need something like an O'Neill Cylinder first in which to breed a gravity adjusted population.

Nope

Mainly because:

These goods consist of (and only of) anything that could be bought on Amazon in 2018. But they don't have to buy it - it's already in their warehouses.

I just did a few searches in amazon.com, amazon.ca and amazon.co.uk. unfortunately they don't seem to sell hydrogen in any form and amount that you could use for rockets. They don't even sell RCS systems like the Appolo program lunar modules ascent stage used, nor RCS propellants like Aerozine 50 and nitrogen tetroxide.

Without scientists, and with a limited amount of supplies and people for throughout testing, I don't think you could emulate a space program, nor do a desperate attempt to jury rig a few toys into a proper ship to Earth.

As for living indefinitwly on the Moon - I think a regular shuttle service from Earth means that you'd get your food from there.

The moon might have had the odd hippie growing their own food in their quarters, but large scale farming on the Moon is not something you would do. Not when it lacks a natural atmosphere and rich soil for the plants, while having those things in abundance on Earth, which is just a few hours away.

Even if those guys are on full survival mode... Andy Weir's The Martian had a lot of handwaving, and that was just one person involved. You can't feed a whole population on improvised farming. That would be a nutrition nightmare.

You can buy packs of sugar, cardboard tubing and baking soda on amazon, you can make a solid booster rocket from those ingredients. Nothing fancy but enough to get into orbit from the moon… with a ton of luck.

This would be more a 'lets get help' solution, since i doubt the hundreds of thousands of people all have half a ton of sugar available.

Although… they have farms, maybe they can grow it? Id scale down the amount of people needed to staff the facilities tbh.