Heat Shields, VASIMIR and Hydrogen Peroxide - Supporter Questions Episode 11

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[danieljensen]

I like how your recording setup is basically something most people could throw together (with the purchase of the large ring light and a single square of audio foam) even though you have more than a million subscribers. But your videos are great so obviously there's no need to get any fancier!

[zenklok]

When he talked about his DJ equipment, it sounded like rocket science

[RCAvhstape]

RE. launching through the eye of a hurricane: that was a key plot point in the awesome film Marooned, where an Apollo spacecraft was stranded in LEO, unable to deorbit itself, and NASA had to figure out how to mount a rescue mission. The film was scary enough that it influenced NASA's decision to have a spare Apollo-Saturn IB stacked up for rescue during Skylab missions.

[richardwild]

I am the Harbour Master for Scapa Flow, most of the WW1 fleet were raised after the war. Some do remain here and are the few wrecks from the war that can be freely dived as they are not war graves. The running joke here is that the German Admiral was supposed to have said "I said subtle retreat, not scuttle the fleet!"

[shehulsuratwala]

No fancy video cameras equipments but pure rich knowledge delivered.
Thank you for your hard work Scott.

[DrDeuteron]

Re: Low Background Steel. When you say "work with low radiation hardware", it gives the impression you're talking about radiation sensitivity (damage), which is ofc not the case: hardware is much tougher than people, and modern steel is completely safe. We're literally talking about "background". If you have steel plates in your neutrino / double-beta decay / axion detector, where your signal may be 4 events per month: you simply cannot have Cobalt-60 gamma rays appearing at 2 events per month. Even though Trinity was 14.5 half-lives ago, and 99.996% of Co-60 has decayed, the problem is that Avogadro's number is HUGE. A single microgram of Co-60 in 1944 will yield 4 event per second in 2021. That is huge background.

[rougenaxela]

10:55 It's worth noting that reflectivity and emissivity are inversely related material properties, and emissivity in the wavelengths associated with black body radiation affects how efficiently something can cool itself radiatively. To keep a surface as cool as possible, you actually want it to be dark in the wavelengths predominantly corresponding to black body radiation at the temperatures you need to cool it down from. In regimes & wavelengths where a surface's own thermal glow is brighter than it's surroundings, you actually want it to be dark/absorbant, but in other wavelengths/regimes where the surroundings (which could include reentry plasma) are brighter than your surface, want it to be light/reflective. No one material is ideal for staying cool in all regimes and environments, but this can be worth considering. In any given regime there are ranges of wavelengths where you're best off being dark and other wavelengths where you're best off being light, when it comes to staying cool.

[AsbestosMuffins]

Low background steel isn't needed because they switched from atmospheric oxygen to liquified oxygen for most steel production, so no radioactive contaminates

[OlleErikssonL]

An idea for a future video I would love to watch: how inertial guidance was used to guide early rockets like the V2 to their target.

[glenn_r_frank_author]

I think the "black heat shield" question may have been been better phrased "black Thermal Protection Tiles"... thinking the kid's question was referring to the black tiles used on the shuttle and starship not the shields on capsules.

[DocHuard]

As to painting, paint and coatings add weight. While this doesn't seem like much, it adds up. They quit painting the external tank on the shuttle and saved 800 pounds. Interestingly, some have a questioned whether or not that paint helped reduce the foam shedding that plagued later shuttles.

[willjackson]

Hi Scott, My Grandpa actually worked at NASA since the Apollo missions and ran the lunar receiving lab. I got to go to his lab and it was deep underground and he got to be one of the first people to test the moon rock for what the elements where in the rocks. The lab walls and equipment was made from steel forged before any nukes and was sources from old WWII ships. Funny to hear about this again.

[brianarbenz]

14:51 Drew may have been prompted to ask this by the movie "Marooned, " which came out in 1970, showing the crew of a fictionalized Skylab mission being rescued (well 2 of 3 were saved) by a Soviet-U.S. effort that featured the American launch through the eye of a hurricane. It was dramatic and true to NASA technology, but had enough cliches to get it sent up to Joel and the robots on the Satellite of Love in MST3K. (It was shown there, and heckled, under its re-release title "Space Travelers.")

[PAZags]

Thanks Helium Road. I saw the movie "Marooned" on TV, circa 1972, when I was a wee lad, and thought it was fantastic! I thought of it instantly when Scott read the question. Perhaps Scott should watch it and critique it for technical accuracy. It had an experimental Von Braun style boost glider atop a booster that was to be pressed into service as the rescue vehicle.

[Libertylute]

Vegas! Yesss! Used it for every one of the several hundred music videos I have posted to YouTube (none under this username, though). Very flexible and versatile software.

[Tim]

The H2O2 question reminded me of the old rocket tests on the Isle of Wight that are available on YouTube. You pour a small amount on anything organic and it bursts into flames. The guys handling it were well covered up. Also, the Government cancelled the Black Arrow program before the last rocket was launched but they lit it up anyway and now we still have Prospero!

[robertrjm]

Scott, I very much enjoy your presentations and the scientific accuracy and details (especially your program on Lagrange points and Chernobyl) .
Now on to a personal question, following on from Katharina N's question:
" What is your favourite dram? I only see a While Label on your shelf. As a proper Scot there must be a single malt hidden somewhere! "

On to a more scientific / technological topic:
Seeing heat tiles fling off during or sitting askew after a static fire on Starship, I feel there is still a very long way to go for this rapid, reusable space craft. Or is it that the underlying stainless steel structure of the body and its "simplified" cylindrical shape is much more forgiving compared to a similar loss of tile or leaking protection in the space shuttle. The catastrophic failure on challenger was due to the plasma penetration into the wing space leading to a breakup from inside.

Would love to hear your thoughts.
PS: greetings from near "home" i.e Edinburgh on a stormy/rainy autumn day. And "Stay Safe"

[tundramanq]

Lead is like the steel. We grabbed up as much of the sheet lead from the walls of the old VA hospital demolition at Kirtland AFB for SNL's detector shielding. Very low background.

[WayneTheSeine]

Love your videos Scott. Always a pleasure to watch and I always learn something...usually a lot.

[AnonymousFreakYT]

8:40 - And because I expect people will ask - when he talks about the "bladder tank", that's generally how the ullage thrusters fuel tanks work. The ullage thrusters had separate propellant tanks, that were either bladder-lined (so the bladder would shrink and squeeze) or pressurized. So you had these "pressure-fed" small thrusters that would be used to add some small acceleration enough to push the propellant in the main tanks back to be able to light the main engine. (Or the ullage thrusters could just be a pressurized cold gas directly.)