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Comment by nanna | Hacker News Reader

> Statistically, it has proven very hard to land on the Moon. Only about half of all attempts have succeeded.

Why is this still the case given that NASA were able to land humans on the moon 55 years ago, not to mention do so in a way that could also bring them home?

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I'm guessing having humans on board makes it easier, since they can tend to the landing instead of having to do it semi-autonomously all the way from Earth

That does make the most sense. Given the technological gap over more than 50 years, that's the one advantage those missions had, and with 6 successful landings (and none of the failures being in the moon landing phase) it couldn't just be luck.

To an extent, given how crewed spaceflight safety standards have improved since then, it was a combination of luck and only doing it 6 times that no crew was lost on the Moon.

Famously there were two versions of the president's speech prepared, one for the case that the astronauts would be unable to return.

Yes, agreed that there was some luck involved, certainly. I'm just saying that there were enough successes that it's statistically significant that their results were better than more recent ones. And agreeing with the parent that the manned component is the best explanation for that.

As I recall, Armstrong chose the landing site personally, using the awesome power of looking out of the window and judging a good descent speed for touchdown. He avoided big rocks and craters.

He had no choice since he had only 20 seconds before the fuel ran out.

Are you saying there was only one spot for him to land? 20 seconds gave him time to make many adjustments.

Because most of the time it's something small and "dumb" that cause the issue, but with no human there it's not possible to fix it instantly.

The difficulty is in planning for every contingency possible in advance, which you can't, and then hope that whichever one your mission encounters is in the list you planned for, essentially.

SLIM is a technology demonstrator for landing on slopes, with "pinpoint landing" accuracy (say, 10 meters).

Previous landings had to be made on limited large flat areas, deemed relatively safe for several kilometers around, and often the landing happened just in the rough vicinity of the target area, kilometers off the mark.

This is really interesting. They had a team of incredibly smart people and it seems that humans on board can handle difficult situations better than a computer. Apollo 11 would probably have crashed without a highly trained human on board.

That never happened. 54 years. I should know, I watched it happen and I'm 58.

What?

He's pedantically correcting the poster who said "NASA were able to land humans on the moon 55 years ago". The first moon landing was July 20, 1969, so 54 years and 193 days ago.

To be fair to jaquesm, it looks like nanna's comment used to say '80 years ago' and was edited, so the correction was more significant. See comment by kitd.

That depends on how you're rounding. Human age is always rounded downwards, but with general timeranges, it differs. 193 days is 52.8% of a year (52.7% of a leap year), so you can round that to 55.

It said '80'.

>80 years ago

Either this is wrong or I'm doing great for 84

I think you're doing better than me ;)

Corrected.

Budget is likely a large contributing factor.

Commonly thought - as well as intuitive, but 100% untrue. The entire Apollo program, from start to finish, cost $178 billion (in 2022 dollars), over 11 years. [1] That's a bit more than $16 billion a year. NASA's budget has been greater than $16 billion/year (in 2022 dollars) every year since 1963. [2]

And that was going from absolutely nothing - having never even put a man in orbit, to putting a man on the Moon, all in 8 years.

[1] - https://en.wikipedia.org/wiki/Apollo_program

[2] - https://en.wikipedia.org/wiki/Budget_of_NASA

Never underestimate a good dick measuring contest.

That's comparing budget of a program to NASA's overall budget, ignoring that NASA hasn't been pouring its overall budget into a single lunar program since then (lack of political will), and ignoring that many of the recent landers are explicitly cheaper missions intended to have some risk of failure, either because the country attempting the landing has never done it before, or because they're trying to stimulate private competition in the industry.

Absolutely. But you're also not really considering that that was starting from literally nothing, and going at a hyper-accelerated rate. Now that we have that knowledge, to say nothing of a million other technological improvements, costs ought be dramatically lower. And indeed the Falcon Heavy's entire development cost about $500 million, over about 3 years of active development. [1]

The SLS, which is NASA's latest ship - being developed by Boeing/Lockheed, started 13 years ago and has, so far, cost more than $30 billion (the costs listed on Wiki are 5 years outdated). [2] If/when it is ever completed, its ideal goal will be to carry ~2x as much as a Falcon Heavy, at a launch cost about of well over 20x as much.

[1] - https://en.wikipedia.org/wiki/Falcon_Heavy#Conception_and_fu...

[2] - https://en.wikipedia.org/wiki/Space_Launch_System

I agree that costs should be lower, and they are indeed coming down. That's the intent of stimulating private competition, to replicate what Falcon did for rocketry.

We'd have gotten on this path sooner and the waste that is SLS wouldn't have existed, if Congress+MIC hadn't intentionally misaligned incentives to suppress progress in favor of profit for decades.

SLIM is a $100m project, including half of the launch(rideshare with XRISM x-ray telescope on H-IIA), not a billion dollar JPL project on a dedicated Atlas V, so budget likely is a factor.

Any source on the mission cost? I'm quite curious. The best Wiki has is a page from 8 years ago that gave an estimated 'cost of development' (which is unclear if it includes e.g. launch costs) of $121.5 million. [1]

[1] - https://en.wikipedia.org/wiki/Smart_Lander_for_Investigating...

The "Budgets" page in JAXA website([1], will quote below) indeed don't have a detailed breakdown:

| Small Lunar Lander Proving Craft(SLIM) | 180 oku-yen(~$121m) | 149 oku-yen(~$100.7m) | FY Reiwa 5 (FY2023) | Phase D (Production/testing phase) (snip) | March, Heisei 28: Project migration review at JAXA (...snip...) March, Heisei 30: At JAXA, changes of plan due to change in launch vehicle(Epsilon -> H-IIA rideshare), as well as change in launch dates. Incorporating the results, adjusted total development cost. (180 oku-yen -> 149 oku-yen) (...snip...) | (snip) |

There are few more media sources[2][3] that state 149 oku-yen[4] figure covers "part of the launch and initial operation". One of such articles[3] estimates Epsilon launch cost as 50 oku-yen or ~$35m, and theorizes change to H-IIA to be intending to save launch cost. Not sure if there are readily available English source, sorry for that - very few of us think in English and these deep topics rarely have English coverage.

1: https://www.jaxa.jp/about/transition/index_j.html

2: https://newswitch.jp/p/345

3: https://moonstation.jp/blog/lunarexp/slim/slim-launche-to-be...

4: 1 oku means 0.1 billion, 1 USD is ~150 yen, so 1 oku-yen is ~0.75 million dollar

Thanks for the links/translation! That's quite interesting. So is that to say it actually ended being done even substantially below budget?

On budget, but at quite a small one for what it is. Epsilon all-solid launcher had anomalies and changes in these years too, so that could also be a reason for LV change.

Inflation adjustments don’t really work well for projects like this across such different periods. Project Mercury spent $277 million (1965) or 2.6 billion (2022) to get 20 uncrewed developmental flights and 6 crewed orbital launches plus all associated R&D.

Which seems insane by modern standards, Mercury however wasn’t quite that efficient, manpower costs for example have risen faster than inflation. Which makes a huge difference for non automated tasks like building novel spacecraft.

Similarly a barrel of oil in 1969 was $3.09 or 25$ today vs the actual price of 82$ today.

You're conflating rockets. The rockets used during the Mercury program [1] were literally retrofitted ICBMs designed to deliver nukes. It offered a great proof of concept and kept prices extremely low, but is nowhere near what's need for things like a Moon mission. It had a payload capacity of ~3,000 pounds!

As for oil, its price is largely driven by geopolitics, not inflation. In April 2020 prices were all the way down to below $20 a barrel. [2]

[1] - https://en.wikipedia.org/wiki/Atlas_LV-3B

[2] - https://tradingeconomics.com/commodity/crude-oil

That doesn’t make as large a difference as you might think. The Falcon Heavy is dramatically cheaper than the Falcon 9 per kg even though it’s the same company and very similar hardware. Rockets just scale really well.

Also, those missions needed a capsule not just the rocket and more importantly a great deal of R&D.

PS: April 2020 prices were due to drastic decreases in demand due to the pandemic not politics. Many current oil ‘wells’ ie oil sands lose money at even 60$/barrel therefore the market price needs to be higher than that or supply is reduced.

If you haven't seen it, "The Right Stuff" is an absolutely awesome movie about this era. Of course it takes some dramatic liberties, but is overall also quite historically accurate. So one fun anecdote, that really happened, is that these capsules/suits were so barebones that there wasn't even urine collection. The pilot was expected to simply 'hold it.' In one launch, there was a delay of 4 hours and Alan Shepard ended up pissing his suit - resulting in short circuits among the telemetry. The solution on the next flights was for astronauts to wear rubber pants... seriously! [1]

Put another way, these guys were being treated like a glorified version of Laika [2], and they knew it. It was all about achieving the mission goal as quickly and cheaply as possible. Everything else was secondary. This sort of stuff wouldn't pass muster in a million years in modern times, which again gets back to the original topic.

[1] - https://en.wikipedia.org/wiki/Project_Mercury#Pilot_accommod...

[2] - https://en.wikipedia.org/wiki/Laika

The book is even better than the (great) movie. The Mercury astronauts had to fight to get a window in the capsule and some amount of control over the attitude jets. They didn't mind being expendable -- they were test pilots, after all -- but they didn't want NASA to forget that they were pilots, not passengers.

Easily solvable in the design. Is a robot, it does not need a head and a tail, or to carry people that needs to have their heads up.

Just remove the up and down constrains and make any part able to be the upper part, or design it as a tumbler doll.

As a rule of thumb, solutions starting with "just..." get something wrong.

As a rule of thumb, nobody sane would propose to go to the moon. I would be very disappointed if this people would follow general rules instead to point to the excelence.

That's designing specifically for this failure case, when the typical case is that a sensor or engine encounters an overlooked edge case during the descent phase and smashes into the surface.

In such big projects as this, you just can't say "we didn't though about that, we will wait to see if we have luck".

Having B-plans for each specific case that you could reasonable obtain is a must. They were paid big sweet money for thinking about that.

The idea that the machine can be moved only if receives sun by some specific direction, is not logical when you play at this level.

This isn't a $20B project paid for by a corrupt government and poorly educated population like what NASA deals with, where indeed they cannot go without a measure for every contingency and without promising to burn billions of dollars buying votes, because otherwise they won't get funding at all. This had a total cost of $121M.

Like any sane engineering project, it did accept some risk and chance of failure as part of the tradeoffs. Part of that was potentially landing in a bad orientation.

> not a project paid for by a corrupt government and poorly educated population like what NASA deals with,

Was that part really necessary?

If nose landing is ok for the Japanese, is ok for me.

Also, this failure case was loss of engine 50 meters high. That'll ruin the day of just about any landing strategy.

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