RD-701: A Rocket Engine Too Beautiful For This World

There is a mythical engine, built in the dying days of the Soviet Union that would have revolutionized spaceflight, had it been fitted to a working orbiter. It is said it broke records that stood for almost 30 years.

Problem is, the RD-701 never actually broke any records, because it never existed.

You may have found this video through my previous video about a tripropellant engine. The RD-701 would have been similar in name only: it was an entirely different concept for an entirely different use case.

3D Modelling by Artem Tatarchenko:

The most important source for this video, ie the paper from NPo Energomash can be found on page 154 here. Please cite this instead of this video is you’re updating wikipedia:

Sources here:

Source and story for the newly discovered AN225/Buran photos:

Video sources available here:

Intro music:

00:00 FIRE SALE!!!
01:49 Intro
04:48 Specific impulse: a recap
14:24 Launch System Architecture
18:47 'The Big Plane'
21:43 RD-701: Engine Architecture
32:37 Why I know it Never Existed
41:47 Air Launch Feasibility
58:38 Legacy

[Alexander-the-ok]

7:45 Oops looks like I accidentally mixed up methane and kerosene on my Isp graph.

The word ‘solid’ on that plot also has 2 closing brackets.

17:58 - the RD-58 used kerosene, not Hydrogen. The orbiter would have a small kerosene tank onboard (just like Buran)

[liljohnth]

The beginning of this video is UNHINGED in the best way possible.

[elwoodcope]

10:00. Rocketdyne would never do anything to harm the environment. Those aren’t barrels of contaminated sodium coolant rolling down the hill into a pond for earl to shoot, I swear.

[liljohnth]

The unrelated low res graphic of the Mars Climate Orbiter was savage.

[thatjamontoast]

22:00 I giggled so hard at that little nugget floating out of the cargo bay lol. Artem seriously has outdone himself with this video. These visuals are gorgeous

[jef_]

Ok, I have to defend the RS-25's honor.

In the late 2010s Aerojet Rocketdyne built the AR-22 from spare (and thus, old and out of date) RS-25 parts for the DARPA XS-1 program. This engine was, functionally an RS-25B (an upgrade which first flew on STS-70 in the mid 90s), and it was fired 10 times in 10 days without refurbishment back in 2018. There are articles on it, and NASA press releases, and test reports you can read. DARPA and AJR were confident that it could complete the XS-1's mission of 10 flights in 10 days.

Now mind you, these were 100 second hot-fires, not the ~480s burns of a Shuttle launch. But you also probably wouldn't launch the Shuttle twice in two days, would you? The engine was being stressed in a different way. This also was for a cargo vehicle not a crew vehicle. And companies were the ones handling these operations, not a government agency. I have no idea why the RS-25 was so expensive to refurbish during the Shuttle program; it could be any of the things I've mentioned so far, or something else entirely.

What I do know, what was proven by the AR-22 and it's team, is that it was not an inherent feature of the engine. The RS-25 can be used and reused rapidly and cheaply. Whatever was driving up it's refurbishment cost during the Shuttle program was part of the Shuttle or the program, not the engine.

[kelp]

Thanks for re-fueling my tism again, cheers

[flurfdawg]

0:59 I threw up at the Wisconsin Dells MIR because there's a gyroscope ride out front of the exhibit and nobody thought it'd be a bad idea to let a 10 year old full of pretzels and pool water have a go.
Sorry I damaged history.

[ryanrising]

The RD-701 always had this kind of “what could have been” allure but ever since I looked into it a little more and found it was meant to have *seven* turbopumps I’ve been convinced it was probably for the best it got left at the component test level. I’m really happy to see you doing an exposé on it, and bringing stuff I and many others didn’t know into greater light.

[gragaloth]

Can we all thank Artem for being such a talented artist, even those pics they drew as a teen were very impressive. This channel wouldn't be the same without Artem

[SaiGhillieSniper]

I’m an aerospace engineer working in space mission design and have worked with NASA quite a lot - no one I’ve ever worked with has used non-SI units, and every launch provider I’ve worked with internationally uses seconds as the unit of specific impulse. Great video!

[scythos]

When I first read Ignition by John D Clark, I was shook to the core when he mentioned how he used dimethyl mercury. Also, that poor man from Kodak getting a call asking for him to synthesise a hundred pounds of dimethyl mercury made me crack up.

[waffledraggin]

The use of Holst's Mars is great here. I love both the piece and the AN-225 so combining them was quite the treat.

[guard]

I really love the "whoops I was wrong here's more info" breaks in the video.

[itzvrtx]

Man. This video hurt when it ended. Wow. Alexander truly outdid himself with this one.

[terrancopeland]

I really like the relationship you and Artem seem to be building. The animations are great, adds a lot to the video.

[MKdross]

The tripropellant video is still my favorite of all time. It's the video that introduced me to your channel so I'm maybe a little biased but you don't have a single bad or even mediocre video, honestly!

[TheNekitt]

It’s bittersweet watching your videos as a russian. I do not consider myself a very emotional person, but your videos about late Soviet projects make me tear up. Oh, the things that could have been if it weren’t for russian leadership

[IainShepherd]

I laughed, I cried, I imagined I was brainy. more! please.

[fabian]

Using mars by gustav holst at the introduction of the antonov an-225 basicly trancended me into low earth orbit. As a orchestral trombonist its one of my favourite pieces of that time and genre. Thank you