this post was submitted on 09 Mar 2025
35 points (84.3% liked)
Showerthoughts
31755 readers
1073 users here now
A "Showerthought" is a simple term used to describe the thoughts that pop into your head while you're doing everyday things like taking a shower, driving, or just daydreaming. The most popular seem to be lighthearted, clever little truths, hidden in daily life.
Here are some examples to inspire your own showerthoughts: 1
Rules
- All posts must be showerthoughts
- The entire showerthought must be in the title
- No politics
- If your topic is in a grey area, please phrase it to emphasize the fascinating aspects, not the dramatic aspects. You can do this by avoiding overly politicized terms such as "capitalism" and "communism". If you must make comparisons, you can say something is different without saying something is better/worse.
- A good place for politics is c/politicaldiscussion
- If you feel strongly that you want politics back, please volunteer as a mod.
- Posts must be original/unique
- Adhere to Lemmy's Code of Conduct and the TOS
If you made it this far, showerthoughts is accepting new mods. This community is generally tame so its not a lot of work, but having a few more mods would help reports get addressed a little sooner.
Whats it like to be a mod? Reports just show up as messages in your Lemmy inbox, and if a different mod has already addressed the report the message goes away and you never worry about it.
founded 2 years ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
Meanwhile, they now have nuclear diamond batteries. Hell, the Voyagers have been running on aging plutonium for nearly 50 years.
You'd figure a modern expensive system like that might have a modern secondary power source, at least enough juice to run for two weeks FFS...
Who has nuclear diamond batteries? Those are a total myth drummed up to get investor money. They don't actually exist.
Sure the concept exists, in the form of betavoltaic batteries, those have been around for decades. They are tough and last dozens of years if not longer. The only problem is, they put out microwatts. You can use them in very niche applications, but those are few and far between. It's hard to convey how little power a microwatt is, it's basically nothing.
What you care about when going to space is energy density, and the proposed energy density of nuclear diamond batteries is very poor.
Rtgs are very useful for longterm missions, but are crazy expensive. They also aren't being made anymore, so getting a hold of one is hard. The weight is an issue as well, they are super heavy.
These commercial moon missions are primarily demonstrator missions. They aren't meant to last, they don't really have a goal and often don't do something useful. The idea is to show you can do it, so you can sell a product. Other people that do want to do useful stuff can then pay to get their stuff to the moon. So if the mission is over when the sun sets in two weeks time, that's perfectly fine.
'They aren't being made anymore'
Yep, I think we've identified at least part of the problem. Once humans figure out a technology that can last decades, we test it, verify it works, and then stop using it in favor of cheaper shit meant to fail as fast as a dozen eggs rot..
Meh that may be true in some ways, but not really in this case. RTGs were made using a surplus from production for nuclear bombs. As that production ramped down combined with better solar and batteries, the demand went down and it became more expensive to produce them. So not making them made sense.
An RTG is really only useful for missions that go far away from the Sun, making solar non-viable. RTGs are a pain in the neck all throughout the process, are heavy and expensive (even back in the day). The amount of electrical power an RTG delivers is also very low. This is because an RTG only gets warm, nothing more. So we put TEG (Seebeck) devices on the sides to generate electrical energy from the thermal gradient. But TEGs suck ass, they are super inefficient. For example the RTG the big Mars rovers use put out 2000W of thermal energy, but they manage to get only 110W of electrical energy out of that. So if you are near enough to the Sun, solar is the much better option.
Good explanation. People that design space missions have a lot of restrictions, and things that seem obvious on the surface can cause a lot of problems in practice.
Because for the amount of power needed they would have to halve its payload capacity if they used RTGs