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Comment Re:The only weight loss plan that works (Score 1) 425

Wait, is there any nutritional content that gets lost through sweat?

I mean, I ate 3000kcal worth of food, shat out 1000kcal worth of shit, that would mean I acquired 2000kcal of energy which I either burned through activity or accumulated in fat or blood sugar.

Or do you imply, if I in the meantime, sweated out 500ml of sweat, if we dehydrate that sweat, what is left can be burned for any reasonable amount of calories?

Comment I wonder about dog's teeth. (Score 3, Interesting) 63

Recently mother, extremely unnerved, called me - claiming her dog brought a dud firework home and it exploded, nearly causing a fire.

Later it was revealed it was not a firework. The dog stole a Li-Ion battery for my phone from my room. Biting into it shorted it, and the battery exploded hard, shooting ribbons of burning lithium all around like a true firework.

So... would this new invention prevent it?

Comment Re:A psycological issue? (Score 1) 373

The atmosphere does great most of the deceleration, including slowing the lateral speed. You only need to slow down enough not to burn up, and that is an engineering issue - especially that it's only 1.6km/s vs Soyuz's 8km/s. Energy proportional to square of velocity, Soyuz kinetic energy despite being so much lighter is still 6 times higher, and concentrated in a much smaller package - lesser radiation/absorption/conduction area. I also believe in that phase a classic parachute would be a mistake; instead it should be a kind of a solid metal airbrake/heatshield discarded once it overheats.

As for cutting the chute, it starts falling in a semi-chaotic fashion (still somewhat weighed down with whatever clamp was holding it to the rocket, but no longer burdened by the many tons of the rocket), at something like 5m/s. Meanwhile the rocket quickly drops to the landing pad and finishes the landing before the chute reaches it (and needs to be extremely unlucky to tangle into it once it falls, I mean, wind direction reversing or something like that...)

Comment Re: Okay... (Score 1) 119

Layer 1: RPi runs Linux. Good luck with the exe.
Layer 2. RPi comes without any internal storage to install this on. They'd need to include it in SD images
Layer 3. RPi is a tinkerer's machine, the malware wouldn't survive a day.
Layer 4: "The exe creates a desktop shortcut to our website" - you need .exe for that?
Layer 5: even if it does - most RPis are run headless. And many of these with screens run without network ...there are more if you think about it.

Comment Re:A psycological issue? (Score 1) 373

The Boostback can be - and will be forfeited for heavier payloads. The rocket will travel in a ballistic trajectory instead of looping back to the launchpad.

The reentry burn - that highly depends on the rocket's speed. Not viable for orbital reentry but quite realistic for this - we're dealing with energy roughly 16 times lower. A drogue chute is often used in a later phase for these purposes - most Russian reentry vehicles used one. Another option is airbrakes - even disposable(ablative) ones.

Then the landing, upon which we mostly agree. Discarding the parachute some 50m above the landing would mitigate the headaches of it dragging the rocket upon landing.

Yes, it's not entirely simple, but it's neither as bad as you present it.

Comment Re:A psycological issue? (Score 1) 373

Q: "How does the mass of the necessary parachute compare to the mass of the fuel needed to do the same job?".

A: Quadratically, vs linearly.

In the range of speeds where the parachute works at all, its efficiency is proportional to square of airspeed. The engine provides deceleration directly proportional to the speed change needed.

That means that even a very modestly sized parachute could adequately replace the middle burn and a major part of the final burn. It can do wonders at high airspeeds, but it's lousy for the last several m/s that make the difference between a crash and a landing.

But it also really sucks for precision of the landing. If the landing pad was a dry salt lake, it would be a no-brainer solution. But for a barge landing it would be rather risky.

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"Hey Ivan, check your six." -- Sidewinder missile jacket patch, showing a Sidewinder driving up the tail of a Russian Su-27

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