What Is This Debris Falling Off The Sides Of Rockets?

Many videos of Chinese Long March rockets show huge amounts of debris being shed immediately upon liftoff, and I often get asked whether that's normal. These are of course foam insulation panels needed for temperature control and depending on the rocket and the location they might be to keep them cool or to keep them warm.

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[temper]

Mon through Saturday, SpaceX keeps space looking so easy. Anyone can do this.

Sunday, Scott Manley reminds us that space is really, really hard.

[wdavidwoods]

Excellent video as always. I want to add a small detail about the Saturn V. The commentary describes the insulation method used on the vehicle's hydrogen tank (panels in the early examples and spray-on foam on the later vehicles). However, the version of the Saturn V used for Apollo had two hydrogen propellant tanks. You describe the arrangement for the S-II second stage. There was also the S-IVB third stage. The interesting aspect of this is that McDonnell Douglas used a very different insulation arrangement on the third stage. They put it *inside* the hydrogen tank. The advantage for them was that the adhesive used to attach the insulating panels didn't have to work at 20K. The tank walls were milled to have inbuilt strengthening ribs and the insulating tiles were carefully sized to fit around these ribs. In some of the Skylab pictures, you can see the patterning on the walls of the station that show the layout of these tiles.
Another small additional point was that when the S-II had insulating panels (before spray-on foam was used from Apollo 13 onwards), they would pump helium down channels cut between the panels and the tank. This was to flush out air pockets, otherwise the air would liquify, run to where it wasn't wanted then expand again after the wet rehearsal and pop the panels off.

[merlyworm]

You are prolly the best science/space channel to explain in plain terms things like this. Plus I love listening to you speak with your accent. :P

[abilashsivasith]

Holy crap Scott went to all the effort to make a video answering one question that’s been bugging me ever since I saw his deep space video.

[thekenneth]

Massive kudos, Scott, for referencing "Koyaanisqatzi", an amazing movie that I doubt most people have ever heard of. (It's a personal favorite of mine.) And yes, that particular scene was the height of the crescendo! [To anyone inspired to watch it: give it a few minutes, let the music and imagery wrap your mind up. It is truly awesome.]

[Trassik]

Thanks Scott Manley, I enjoy how your video narration is so comfortable, like you telling a story about an old friend you met in a pub, or how your dog leapt off the dock and suddenly found itself in a hostile aquatic environment.

[mikedrop]

For those who were wondering like I was before I Googled it, yes the polyurethane foam Scott is talking about is the NASA specific recipe of the foam we get in a can at the hardware store to fill cracks, gaps and holes in construction and marine uses. The "Great Stuff" brand is the most common brand. It comes in a red can with yellow lid. Also Gorilla glue is the same polyurethane adhesive without the foaming agent.

[RossM]

Always far more interesting information than expected and so clearly explained Not a surprise really as all of Scott’s videos are just great

[alstud]

I LOVE the old archival footage. Hard to find, barely recollected as I'm only 50.

Thank you for your mini documentaries sir

[jeffcox]

I really loved this video Scotty. The rockets I launched were D-5's; Below the surface of the ocean. Nitrogen and dehumidification kept ice away. Short umbilical too btw. Nasty payload.

[DanielSuguwa]

Early viewer here! This is a good video that really answered the question, since lots of people watching rocket launches ask this question commonly. Thanks Scott, and for always flying safe for all of us!

[ttystikkrocks]

Yet another highly educational and fascinating video that taught me things I did not know about space flight. This channel is a treasure; keep doing what you do so well, Scott!

[xyzzyfrobozz]

Scott, great video and channel as always. Thank you for the mention of "Koyaanisqatsi." I watched this when I was 15 on late night TV and was completely mesmerized, but I never knew what it was called. I've tried for literal decades to find it, and no one ever knew what I was talking about. I recognized the explosion a mere moment before you named the movie. I am always learning something new from your channel. Thank you.

[paulhaynes]

Thank you Scott, a question I've long wanted a proper answer to. I love the way you turned a relatively simple answer (it's insulation - end of video) into a fascinating detour into an aspect of rocketry I'd never given any thought to.

[dgk]

I knew about ice buildup, but I didn't know about foam. As always, learning something new every day.

[gateclamp]

I’m glad you made this video because I’ve always been wondering why stuff falls off the Chinese rocket

[brussels]

I’d love to see the details of the connectors that atttach the boosters to the main rockets. Must be very strong, but how do they attached to what must be a rather thin/fragile sides of the rocket. Love the your videos.

[MichaelBennett]

You have the best closing music ever and thanks for the falling foam explanation, I’d always assumed it was always just ice.

[ashemgold]

Mind Blown... In 50 years of watching launches I just thought this was ice. ONLY ICE. Thanks Mr. Manley for the education!

[kranzonguam]

This always puzzled me, especially in the early MTV spots. Took a few years to figure it out. Thanks for confirming my suspicions!