Solid Rocket Boosters Were A Bold Choice

[mitchellminer]

For those who don't know: The solid fuel inside the rocket boosters was not one solid cylinder of fuel burning from the bottom up. It had a hollow center running from bottom to top, which ignited so the fuel was burning all along the length, from the center out. That increased the burning surface area, which increased thrust.
However, if the fuel burnt outward from the center, the area of fuel-burn surface would increase, increasing thrust too much.
So, the rocket scientists made the hollow core into a star shape instead of a simple cylinder. That gave a larger surface at first ignition, and as the points of the star burnt away into a larger, rounded shape, the overall burning surface remained constant.
The star can be seen in the sketches in the video.
There were other factors, of course, that were addressed by varying the overall size of the hollow core, as discussed.

[WilliamRWarrenJr]

Storey Musgrave used to say, "The main engines would start, and the stack would flex, but before it came straight upright again it could still be aborted. When it got straight up and the solids went off ... well, you _knew_ you were going *_SOMEWHERE!"_*

[ferrumignis]

If only the warnings of the engineers about O ring performance in cold temperatures was met with extreme concern.

[jehoiakimelidoronila]

The crew really took the "one-way" trip ticket to the heart as they can't abort the launch. Once lit up, *those big fellas WILL stay lit* 'til they're empty and get separated

Mad respect to those guys

[BritishBeachcomber]

SRBs were a bold choice. But Morton Thiokol warned NASA that the O-rings were brittle at freezing temperatures. They were ignored and the astronauts died.

[benktubes]

Each one 40% as powerful as a Saturn V, burn for two minutes with no abort option. absolutely wild

[anticarrrot]

"The very notion of using SRBs for a crude space shuttle..."
Ah, youtube autocaptions. Never change.

[christianeaster]

I didn't know they had engineered the solid fuel rockets to have a varying thrust like this. A simple but effective way to do this. Brilliant!

[princecharon]

The designers AFAICT wanted to use liquid-fueled boosters, but a powerful senator or representative demanded that his state get jobs relating to the shuttle program or he'd stop them from getting enough money. The only significant thing his state produced that might be useful were solid rocket boosters (or the fuel thereof?), so the shuttle design had to be modified to use them. (Note that I'm going from memory, here, so bits may be a little off.)

[mikes]

Smart design meant better performance. Much higher T:W and much less complex during flight and safe storage is incredibly easy. These took another rather large rocket motor at the top in order to ignite them and that motor starter was lit by a special blend of fancy igniter. You can't just walk up to rubber with a lit match or an arc igniter and expect the propellant to care. (The propellant is a rubber based binder.)

[jimjankswankson]

Just getting in that shuttle to pretty much be strapped to a bomb to LEAVE your planet is absolutely INSANE! And has to take balls made of titanium. Shout out to the men and women that have had the privilege to take that journey. 👍🏾

[ghost]

Someone in the early days suggested using solid fuel rockets.
Werner Von Braun and his team stated they would never work on such dangerous rockets for manned flights.

[Steve-ounw]

The SRBs also had steerable exhaust nozzles, could adjust thrust about 4-5 degrees. The avionics were in the nosecones

[jjxtwo]

Once the Solid Rocket Boosters were lit you were going somewhere. It may not be in the correct direction but you were going and fast.

[TransCanadaPhil]

The Soviet Buran shuttle used liquid boosters instead with the main engine as part of the core stage of the Energia booster. I always wish it has flown more, would have loved to compare its flight profile and staging.

[west]

The amount of thought and then Engineering involved in the boosters alone is amazing, Nevermind the rest of the system. Over 1 million moving parts and it worked reliably.

[mariano]

A unique clear footage of the buster's ring in flame 👍

R.I.P. brave crew

[WilkinsonX]

It’s like they were building a bomb but got bored, so they glued a spaceship on it.

[JarheadCrayonEater]

I used to work for Lockheed and Rolls-Royce at Stennis Space Center, from 2004-2012.

The Rolls-Royce facility I worked at was the former ASRM test faculty. Advanced Solid Rocket Motor, that was intended to replace the original SRM that we see in this video.

Ultimately, the ASRM project was cancelled so the site was left dorment into RR showed up and took it over in 2007, where I worked.

[SynthiaVan]

Very interesting, never really knew how SRBs worked. Some commenters give even more detail.