Wasn't the moon landing + reentry much harder to do than SpaceX's reusable rockets/boosters?

Question

Over 45 years ago, we know that USA/Russia were able to send satellites/humans and return them to the Earth. Isn't that supposed to be much more difficult to do than what SpaceX is doing now by returning (landing) the rockets/boosters on the Earth (not the Moon)?

It is more difficult to land on the Moon or the Earth? I would say that it is easier to land stuff on the Earth because it is closer to us, it's easier to exchange signals.

Or is it the mass of the lander/rockets we are landing that makes things harder? The rocket such as Falcon 9 is much heavier than the rovers/landers that were landed on the moon and then returned back to the earth.

Answer 1

Comparing the whole Saturn V mission vs an orbital delivery is totally apples to oranges. There's no doubt that developing Saturn V was vastly harder but they are so different that the comparison is pointless.

There is one point where comparing them makes sense: Vertical landing of a rocket-powered vehicle.

It's still an unfair comparison for one fundamental reason: one was man-controlled, while the other was automatic. There's a human at the heart of the lunar lander controls, where Falcon 9 uses a computer.

In one hand, the tasks before the computer are harder. There's a precise point of landing vs any random semi-flat piece of Lunar surface. There's a vehicle with a much higher point of mass and poorer landing legs configuration. There's a much higher gravity to brake against. In case of barge landing the landing point moves. A computer to land a lunar lander would be much, much easier to build.

But on the other hand you have a human in a terribly unwieldy spacesuit, with only rudimentary instrumentation (heavily depending on observing shadows on the ground!), subjected to all kinds of accelerations, doing something he had never done it outside of simulation, under immense amount of stress, and having only one go at it.

So while theoretically the computer's task is harder than the human's, the number of handicaps the human suffered while performing the landing well balances it out.

Answer 2

Over 45 years ago, we know that USA/Russia were able to send satellites/humans and return them to the Earth. Isn't that supposed to be much more difficult to do than what SpaceX is doing now by returning (landing) the rockets/boosters on the Earth (not the Moon)?

Landing a rocket containing people on the Moon in the 1960s was orders of magnitude harder than what SpaceX is trying to do now. The Apollo program would have been shut down shortly after Apollo 13 had that mission been preceded by Apollo 11 and 12 punching the barge. The Moon landings had to work, the first time, and every time. Failure was not an option.

There were people on those rockets, and national prestige was at stake. None of the Apollo missions punched the barge. That failure is an option for SpaceX (until they get it right), that people's lives aren't at stake, and that corporate success is at stake compared to national prestige makes SpaceX's task much, much easier.

Over two percent of the entire United States federal budget went to NASA from 1963 to 1969 (peaking at over 4% in 1965 and 1966), and over half of NASA's budget from 1964 to 1970 went to the Apollo program. A sizable fraction of those monies went to the problem of landing a rocket on the Moon, first time and every time.

In comparison, NASA currently receives less than half a percent of the federal budget, and it only sends a tiny fraction of that tiny fraction to SpaceX. SpaceX in turn only dedicates a small fraction of its incomes to the problem of landing a rocket on a barge.

Answer 3

Landing on the Moon is simultaneously easier and more difficult than SpaceX's landing of a first stage:

• Easier: there's no atmosphere, so you don't have to worry about aerodynamic heating and pressure.
• Easier: because the Moon has a much lower gravity, you need far less energy to ascend from the Moon to an orbit around the Moon than you need for a launch from Earth. This also makes the landing on the Moon easier.
• More difficult: The hard part about the Moon landing is getting off the surface of the Earth and into Moon orbit. We needed a gigantic 2000-ton Saturn V to get that far, but we could land and ascend again in a 10-ton LM.
• More difficult: In the 1960, computers were barely up to the task of helping a pilot land safely. These days, we have enough computer power that we can allow a rocket to land autonomously without human intervention.

Answer 4

It depends on how you want to define "difficulty". Using cost as a proxy for difficulty, the Apollo program cost more than the equivalent of US\$100 billion. SpaceX has probably spent under ten billion to date, maybe closer to 5.