Delta Rocket History - Part II - Legacy Of Thor - America's Most Successful Rocket 

I had quite a few very busy years at McDonnell Douglas and then Boeing. I worked on the development team for the 10 ft Composite fairing for Delta II then went right into Delta III developing composite structures for it, fairing, payload adapter and interstage, then right into Delta IV developing fairings and payload adapters. I worked 7 years where Saturday was a regular work day. I was at the 1st launch of Delta III and was heart broken over the failure. I was at the 1st launch of Delta IV and it was a much better day. Then we became ULA. When Vulcan development was announced I assumed I'd be part of that development, but all composite structure design was subcontracted out to RUAG. So I grabbed a nice severance package and retired at the young age of 61. I had an enjoyable career.

Here's my thought process on Delta Nomenclature: Once a major piece of hardware flies on a Delta, it becomes "Delta hardware," thus making any future vehicles including it eligible for the Delta name. So once the Delta Cryogenic Upper Stage flew on Delta III (which was unquestionably a Delta rocket), it became part of the Delta family and can transfer the Delta name onto any rocket that flies it, thus making SLS Block I Delta V. Once the ICPS is retired for Block II, it's still a Delta family rocket, since by the same logic the SLS core stage has become Delta hardware, meaning that it can carry the Delta name to Block II. By this logic, then, SLS Block I is Delta V, and Block II is now Delta VI. This is flawless logic and I'll be taking no further questions at this time.

Glad you mentioned that Delta II launch failure. That’s probably my favorite rocket explosion of all time for two reasons. First, it was seriously spectacular with the massive fireball and thousands of burning chunks of SRB falling all over the launch site. Second, the commentary on the launch had what was probably the best example of understatement in history “We have had an anomaly…”

16:40 minor correction: At the time Boeing was developing Delta IV, the RS-68 was being developed by Rocketdyne. Which itself was also owned by Boeing. When Boeing bought McDAC they also around the same time bought Rocketdyne from NAA. It wasn't until many years later that UTC, who owned P&W, bought Rocketdyne from Boeing and created Pratt&Whitney-Rocketdyne (they went by PWR). I remember all of this fairly well as I worked for Rocketdyne at Stennis from June 1997 until Sep 2001. When I hired in we were being called Boeing North American as they were working out the logistics of combining the companies. It was some time after I left Rocketdyne for NASA in Sep 2001 that P&W bought them. So to the point, you could say the RS-68 was a Boeing engine at the time they developed D-IV. As a side note, I supported the D-IV Common Booster Core testing at Stennis. My main job at the time was running SSME tests on A-2 test stand but I got to work LH2 fill of CBC during test. Those were fun days.

Love it! "Delta" lives on a little longer. Can't argue with 700 missions for the "family". Guess that's as close as the U.S. will come to all the "Vostok/Soyuz" variants of the R7. I love the Falcon 9, but for many of us, when we think "rocket", that blue-green Delta II will always come to mind. Just FYI: It took about 10 gallons of AkzoNobel's aerospace coating "Blue Fluid Resistant Primer" to cover a single Delta II. Between 1989 and 2018, 155 of the rockets flew. Outside the space program, "Delta Blue" is formally known as Federal Standard 25193. Considered a shade of cyan, it is comprised of 36.47 percent red, 55.69 percent green and 58.82 percent blue. Delta Blue has an approximate wavelength of 488.02 nanometers. Pantone, known for its color matching system, identifies "Delta Blue" as simply "5483-C." If you wanted to paint your rocket - or your room - Delta Blue then you could look for Dutch Boy's "Midnight Run," Sherwin-Williams' "Mountain Stream" (no. 7162) or Valspar Paint's "Ocean Voyage." If you wanted to order your next car in Delta Blue, Chrysler's closest match is "Neptune Green," General Motors' offers "Adriatic Turquoise" and at Ford it is just "Medium Turquoise." To the McDonnell Douglas, Boeing and United Launch Alliance teams that worked on Delta II for three decades though, it was and continues to be "Delta Blue."

Considering SLS to be part of the Delta family because of the second stage makes sense when you remember from the first video that Delta was originally the name for the upgraded Thor second stage. So really, the common factor of a Delta rocket is the second stage lineage, not the first stage.

My first job out of college (Parks College of Saint Louis University) was testing Delta II Second Stage bi-propellant valves with water at Aerojet. Once I mastered that task they let me hot-fire test the whole engine. It was very reliable and I never had a failure.

The Delta II holds a very special place in my heart since I'm lucky enough that my cubesats flew on that final launch with Icesat2 in 2018! Thanks for such an awesome and informative video Scott!

"Down from 10 to 6 PER YEAR!" I first thought I misunderstood, but then I remembered: There were times before SpaceX, Rocketlab etc ... Great video as always, thanks Scott!

Scott, you are the man of the subtle irony. "SLS is a Delta" Fantastic. Thanks for this detailed history of a major launch vehicle.

I love the Delta IV Heavy. It looks so awesome, plus it runs on hydrogen! Also, it just kicks butt that it lights itself on fire T-0. What a vehicle.

Very bold move adding SLS to the Delta family. But it's a bold move I can approve.

It was an immensely stupid decision by NASA to not build a 5th version of the Delta rocket, named Delta V.

Would love to see a series like this on the history of all the different Atlas variants leading into its retirement.

Great video as always, Scott. And I thought it was a classy decision not to show the actual explosion of Challenger.

Super excited about the Delta V launch coming up this year Scott! 😉 Fly Safe

Scott can you please do one of these on the Titan family at some point? Don’t really hear a lot about them often

Was at the last night launch of The Beast!!! Wont make it to port Canaveral this time but I'll be watching from 60 miles north.

Scott, what a detailed, highly researched, informative Part II of the Thor/Delta story. Thumbs up! Nobody could have done such a thorough job on this subject. You nailed it!

Thank you Scott!! Just adds another layer of love for the Delta 2/4 rocket.

Make one of these for the Titan rockets next please? Either that or the Japanese rockets?

Thanks for the nice overview and history of this rocket.

One of the best videos of the year so far. Keep it up.

What a great series. Thank you Scott!

Hey, Scott. It's just another Delta... Riiiight. Very nice program. Thanks for sharing! Stay healthy!

A masterful Delta history! Thanks Scott

This is such a great series - I've always been curious about what came before the Delta II, since you'd figure it was Delta I but it was really this long development of different models you've covered here. Thanks!

I was a huge fan of Delta before you made this series.... after watching, I'm an even bigger fan! Great series... thanks loads.

I LOVE THE EXTRA-EXTENDED LONG TANK THOR!!

Great series Scott

Really like this historical review! Thanks Scott

Worked General Dynamics, Lockheed Martin, and ULA as a Quality Inspector. Total - 42 years. The Atlas missile outlived them all and is still going. The GOAT in aerospace!

So well presented! Pretty much a book's worth of knowledge in less than 22 minutes.

I always like your presentations. Thank you for all the study and hard work.

astonishing Thor / Delta history, thank you very much

I had no idea that the Delta had a miniskirt! Thank you for showing us what was under it!

Really, really interesting history, Scott! Thanks! 😃 Stay safe there with your family! 🖖😊

Well done Scott

Great content Scott

"Ballast", showing image of astronauts... I chuckled 🙂

Good to see an informational video

Love the pun in the still at 0:09... Marvelous. 😁

Thanks so much Scott I've enjoyed this series

Hey Scott, what an information rich series about this historic rocket. I can remember the Thor from my childhood, so it’s been great to see the full panoply of this rocket’s career. You probably have a book in this! Thanks for the hard work and deep digging.

While reading press releases and stuff for upgraded boosters recently I saw a strange graphic from NASA of an SLS in Delta II teal, and wow that would've looked great, I don't think it was ever seriously considered but for whatever reason someone decided to make a little blue SLS for a info page and it's a great "could've been".

LOL - "SLS is just another version of Delta". Great punch line, and a nice way to end the series.

I enjoy this kind of video, always fun

I'm playing KSP with the RP-1 modset once again and I always find myself building a Delta and Titan clone, both are very adaptable.

Oooh you should do the Titan Family of rockets (1959 -2005)

Great video very insightful thanks please do more history videos on different rockets

I know I have a deep seated love of ugly rockets, because something about the Delta III makes me happy and always has.

I want to say that I love these rocket history videos! I hope you’ll do a titan history too

That was a wonderful series particularly for the corps of aging geeks. Thank you .

Thanks for the update Scott seems that years of experience cannot overcome changes in technology and more complicated mission requirements.

After this do you plan on doing a detailed history of the Titan rocket Family?

Scott Manley: Explains a bunch of *incremental changes* made to a launch system. Me: So that's why they call it *delta.*

These ballast jokes never get old.

Excellent review. I spent 27 years on Delta launch pads.

I have always, and will always love Thor and the Delta I through III rockets. I miss the Delta II sooo much.

I rewatched the previous two videos before this, and i think if you put them together like a documentary it would be amazing!

SLS is another version of Delta? Sir, the lawyers for the Delta family have just filed a suit for libel.

A few years ago my neighbour found in his farm a delta ii solid Upper stage that reentered earth's atmosphere, the uss governent came and gave him medalls and invited him to the united states but he didn't accept the offer. He showed me the medalls and told me the story when i was younger, it inspired me to learn about rockets.

Watching this show for me is like playing golf. If I understand 20% of what Scott is saying, I’m happy. It’s a good day.

can’t wait for the delta V launch in a couple of hours! 😁

When Scott Manley says he was "unlucky enough to have his car break down while parked at the launch site." what he's really saying is he was trying to convince the base staff to let him stay for the next launch.

I love to listen to you while im stoned.

That was a great dig about calling the SLS a Delta. You should totally call it Delta-SLS from now on!

Delta II Heavy, I just really like the thing; definitely somewhere on my top favorite orbital launch vehicles. I dunno, I think it just LOOKS right. A simple long tube, single engine at the bottom, and "added more boosters".

0:50 yes people! That's a white fuel tank on the Space Shuttle (only on the first two launches). The orange one came afterward and is thanks to the findings that the white paint wasn't necessary for its purpose (ultra-violet protection) and leaving it off saved 272 kilograms.

SLS definitely belongs with the Delta IV when you look at the cost.

Great video series - thank you Scott. Any chance of a similar one for the Titan?

Oh wow! You were at Vandenberg for the last launch?! It was a great launch I crawled out of bed and drove out there to go watch it.

Most of your math is beyond me; however please keep adding it. Great video, thank you very much. Excellent video, thank you.

I'm definitely gonna start calling sls delta 5

Love see life and work rocket engine Robert Truax

i wasn't prepared for that plot twist ending! delta V go!

great video always loved the delta rockets 🚀

Gotta say, those Graphite Epoxy Motors were truly outrageous.

Got me with the benefits of rockets flying without unnecessary ballast" *shot of astronauts* 😬 And then Delta has a little disaster of its own...ugh.well played sir.

I came for the Scott Class, i hit the like button once i saw the shirt. I don't care what your ex says, you Rock! 🙌🏾

Wouldn't it have been quite the memory to have the last Delta II launch melt your car to slag?

The kindest thing one can say about Delta IV is that it was significantly less expensive than Titan IV, which was significantly less expensive than Shuttle. It's all relative...

So….history of Titan next??

Nice!

"You expected you were completely new, but it was I, Delta!" -Delta to SLS, probably

Every time Scott says "Explorer", I hear "Exploder"

In school we did a thing where we had to make cool concepts in class and I drew something called: the delta 5” it was supposed to be a mix of the delta 2 and delta 3. the main rocket is like a esa Vega c rocket with boosters and a green second stage.

for more videos like this 👏👏👏👏👏

There's something about the Delta IV Heavy that is just so kickass, what an absolute unit of a rocket. I know Falcon and Falcon Heavy absolutely outperform it, but I'll still have some nostalgia for the Delta IV-H

Has something bad happened between you and Bill Nelson in the past? You never miss the chance to slightly roast him 😀

An interesting history of the Thor/Delta/......SLS, family

@Scott Manley I would love to see you do a video like this but on the titan rockets.

Ballast Nelson... I see what you did there!

Nice

Thinking sls is the next/last delta variant is definitely a plus for sls in my book!

The Delta GOES explosion from 1986 has a guest appearance on The Martian as the exploding supply rocket.

So Delta V uses a Delta IV CSS, Space shuttle Main Engines and SRBs. Seems about right...

wow the description of the shuttle sounds like SpaceX and starship

...benefits of rockets flying without unnecessary ballast _showing shuttle crew_

Scott please do the titan family next