The flow diagram provided for fracture control is incredible. Quite a work of art. [1][1] <a href="https:&#x2F;&#x2F;substackcdn.com&#x2F;image&#x2F;fetch&#x2F;$s_!AOMG!,f_auto,q_auto:good,fl_progressive:steep&#x2F;https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fd54b9b30-ccb2-4b40-8d3d-3a3149c52fa8_1864x1306.jpeg" rel="nofollow">https:&#x2F;&#x2F;substackcdn.com&#x2F;image&#x2F;fetch&#x2F;$s_!AOMG!,f_auto,q_auto:...</a>Update: After staring at this flow diagram for quite some time, I realize it&#x27;s actually the most robust, &quot;complete-seeming&quot; finite state machine I have seen used in the real world.

That was an excellent read for explaining why space isn’t just hard, but expensive.

In 2010 I was coming back to the UK from Japan. Walked through security carrying a 500ml bottle of water. Realised after clearing everything that it was in my bag. Turned round, went back to the security and handed them the bottle, saying it&#x27;s just water but I knew I could not take it on board. The guy there took the bottle, placed it into a recess in the desk&#x2F;table, pressed a button and lights happened in the recess. Then he gave me the bottle back &quot;Yes, water&quot; and indicated I could board.The tech has been around for over 15 years.

Do you know that for months we were able to bring water again in Europe airports? Thanks to an European regulation change that said that most scanners are now good enough and there is no need for this stupid rule.But then It was reverted because of US, for them it was unacceptable that we had that in Europe...

Same in Berlin, can now saunter through with liquids. Then there is Ben Gurion Airport TLV where you could always take liquids with.

At London Heathrow too, the 100ml limit was scrapped early this year.<a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=46736815">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=46736815</a>

I enjoyed reading this! But on one thing&gt; You and I will probably die before we’re allowed to take a bottle of water through airport security againWe could again bring water through airport security for some time in e.g. Rome&#x27;s FCO (2 years maybe? It&#x27;s been a while)

That doesn&#x27;t make sense to me. On a cheap RV inverter maybe, but on solar for a house? The inverters should be rated to continuously output whatever the panel is generating. It shouldn&#x27;t care whether the 2kW is going back on the grid or into your water kettle, it should be doing that all day every day.

From a quick Google that kinda makes sense, it’s just the strong, _sustained_ power draw that gives them issues. So I’d say fundamental AND inverter design — imagine pushing 2kW continuously through an inverter.It’s funny, power use can be really unintuitive. Try convincing someone that using the big air conditioner for heating is more efficient than using that little plug-in bar heater. Or yeah, a power board with 8 tiny wattage wall-warts isn’t using a lot of power.I could probably run my big fridge overnight off my portable battery generator, but it wouldn’t run my small electric kettle without putting it into a special mode and for nowhere near as long.

&gt; and that this is common folk knowledge among solar installers.I think it&#x27;s partially that people want to spend less money and undersize their inverter setup. The average end user non technical consumer (maybe a person buying an off grid PV system from an installer) may not fully understand what 1500W really is, and that something as boring as a $35 tiny space heater that sits on the floor can be a 1500W load.People will be really surprised if you tell them that their tiny floor space heater uses the same amount of energy as charging twenty high performance laptops simultaneously.It takes just a few high wattage single item electrical things to totally screw up the electrical load budget of a site, if somebody has something like a single 8000W rated inverter.If you want to use electric space heaters and kettles and hairy dryers and hair curlers and such, along with the other regular daily load items of a house, you&#x27;re looking at a setup with multiple 6000-8000W inverters in parallel with each other and synchronizing their output waveforms. Not many people want to spend the sort of money that&#x27;ll get them 3 x 8000W inverters in parallel with each other all properly installed in an electrical room next to the PV stuff, breaker panels, etc.

Surely in British solar installations the inverters must be big enough to handle kettles ?

Assuming the heating element has a positive temperature coefficient (which seems likely), there will be inrush current greater than the operating current.As an extreme example, a tungsten filament in a lightbulb would rise to 1500C (2700F) which with even a small temperature coefficient can mean inrush current 10x higher than the operating current.

Good read.&quot;Since that time, I’ve learned that small heaters (like coffee makers or kettles) can be kryptonite to an inverter, and that this is common folk knowledge among solar installers.&quot;Is there any more on this? It can understand inductive loads maybe challenging inverters but resistive loads should be easy? Is it an issue of cheap inverter design, or something more fundamental?

Are you sure Lavazza didn&#x27;t eat the cost? It&#x27;s great marketing material for them.This could be similar to the fisher space pen. There&#x27;s a common urban legend that NASA spent millions developing the space pen, while the soviets simply used pencils. Fisher actually paid for the development of the space pen.<a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Writing_in_space" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Writing_in_space</a>

Also it&#x27;s really hard to get up in the morning when the days are so short

Astronauts can spend many months on the ISS, and it’s very important they don’t become irritable and kill one another before the research is complete.

The article assumes single digit million as cost. That is a drop in the water when it comes to cost of running ISS.Additionally the technical paper claims psychological benefits for humans to have something familiar in a harsh and unfamiliar environment. Which will also come in handy for when humans travel beyond LEO.

To quote the official paper:&gt; The food system for long-duration space missions not only provides nutrition to the crew, but it also provides a form of psychological support by providing a familiar element in an unfamiliar and hostile environment

Because, Espresso is a life elixer?But seriously. As the article says, there are other needs for having high pressure hot water. The learnings from this can be used elsewhere.As the siblings said, it can also have been paid for by Lavazza. Aside of the marketing value now, imagine securing the right&#x2F;first mover advantage to make all coffee makers into the foreseeable future? Speaking of barrier to entry. ;-)

Why this ISSpresso machine was developed and sent into orbit at all? What scientific outcome does it have? Why was it necessary spending taxpayer&#x27;s money developing it?

The Pressurized Payloads Interface Requirements doc is kind of interesting. Lots of diagrams &amp; such that would be great for art projects.

Bitter Lessons from the ISSpresso