What Is Distant Retrograde Orbit, And Why Is Artemis 1 Using It? 

A square orbit. Now I've seen everything! Thanks for explaining.

My jaw dropped at that square orbit. Thats amazing.

Really nice explanation. Reminds us that orbital mechanics involving multiple bodies starts to get really complicated really quickly, esp. when you factor in other key constraints like solar panel illumination and non-LOS-comms. Nicely done.

The words "Three Bodies Problem" filled me with existential dread. The trisolarians are coming.

An amazing episode. The visuals provided a whole new context for the awe inspiring majesty of moon landings, and for just a moment I was a small boy watching those brave astronauts on Dad’s b/w TV. Today’s world exceeds my wildest boyhood dreams and every episode of your show expands my universe. Thank you.

Scott, your videos are amazing. I have a family member who is an engineer. He previously worked COTS, then on developing Gateway, and now he is leading a team devolving infrastructure to maintain a permanent station on the moon. He's way, way smarter than I. If it wasn't for your videos, I would be absolutely clueless every time he talks about his job. Some times, I say something to him that prompts a raised eyebrow and the question, "How the...[heck].. do YOU know that?" My response is always, "Tim Dodd told me," or "Scott Manley told me."

Love the time-lapse!!!! Thank you.

Scott, very clear explanation and excellent graphics - that is why the community loves you! Eamon

I have to admit I was feeling pretty hopeless in my comprehension until you put it into Sandbox, and then Bingo, it made sense! I guess I'm just more of a visual learner - thanks Scott!👍

Wow why has noone else properly explained this? Amazing work again Scot.

I love that all these new missions are planned, I just wish the time scale wasn't so long. Basically I am selfish and want to see them in my lifetime!

The best part of all of this is that Scott Manley put the Hubble Space Telescope into Distant Retrograde Orbit.

Keep going. I appreciate the humor in your sharing things that give my brain a little twist.

Nice job explaining and visualizing DRO, Scott! Thanks for all you do.

Yet another great explanation! Thanks for all you do, Scott! ❤️❤️

Scott, you explain these things so eloquently and with great visualizations.

Thank you, Scott. What a great demonstration of what these difference orbits mean and do.

Scott, this is one of the best videos I've ever watched. In any category.

It's already such a joy to hear how you say "the mün", but "I'm gonna züm in on the mün" is the best thing ever.

Incredible!! Thank you Scott.👍

The Gateway orbit is just insane. In order to make it easier to arrive and leave within certain windows, they're making an immediate abort to the station impossible unless they have the delta V to catch up, or it just happens to be that few hours orbital window when Gateway is passing over. And abort from the surface directly to earth obviously isn't possible.

I'm surprised how honest and frank you're.

Thank you. Was hoping you would do a video on this topic.

Pretty interesting indeed! Thanks, Scott! 😊 Stay safe there with your family! 🖖😊

Great podcast, thank you! Keep 'em coming!

Thanks Scott that was very informative

I've been hoping for a video breaking down this DRO orbit. Thanks for your knowledge Scott.

It's wired how much I learned from ksp. Thanks Scott

thanks for your content ❤

I was wondering about NRHO: it's about the lunar poles! (and LOS). really nice orbital demo and explanation! Orbit safe!

Great explanation for this relatively non mathematical space nut (me). Strap line: it’s a stable orbit that doesn’t take much propellant and is de-risked coz they can get Artemis back if something goes wrong. It kinda puts the huge risks of Apollo into perspective.

Keep up the good work bro.

A square orbit around the moon, well I'll be! I have to say, I was one of the doubters/haters of Artemis but since the launch and seeing all this stuff lately I've gotten pretty excited about it. The odd orbital mechanics is super cool. And so, by the way, is seeing that NASA worm logo out in deep space looking back at Terra and Luna.

Thanks for the great explanation! It's so easy to forget that EVERYTHING in space is in motion and when considering the Orion's trajectory, we need to take the moon's orbit around the Earth into account too.

Great explanation thank you!!

Very interesting episode Scott! Thanks I will have to view your sims on my desktop as I couldn’t quite make out the names on my phone!! 🤪 Take care!

That is brilliant, and quite elegant. From the surface of the Moon it must look like it's dancing among the stars.

The pic in the thumbnail is one of my new favorites. Been using it on my phones home screen

Been looking forward to this video.

This was incredibly helpful!

Brilliant video, Scott

Wow that square 😳 so well explained too

Hullo Scott and thank you for all the great content over the years. I wasn't expecting a video from you tonight but boy I sure need the most excellent distraction.

brilliant explanation 👏👏

I hope we still do the asteroid capture at some point.

Can never get tired of Scott Manley saying "mun" 😊😊

I'd be interested in a short video where you go through the back of the envelope calculation for the universe sandbox simulation.

To calculate this by hand must be outrageously difficult, but I guess somebody had to. Give that man a medal, he deserves it.

omg this cut at 4:16. Im blind now Scott, thanks!!! LUL

It’s been a long time coming but I have to admit, SLS and Artemis are pretty darn awesome. (I honestly thought it was going to explode on the pad… but wow, it’s really delivering… just wish it wasn’t so costly)

I love those slingshot maneuvers! We might start calling the Capstone and others the Moon Moon.

j’aime aussi beaucoup vos vidéos, carry on 👍

I'm hoping you'll make a video covering the successes and problems/ failures of the mission. 🙂

I really enjoyed this! Thought arising by watching, (unrelated to the topic) "Could quantum computing give better access to working the three body problem?".

Fantastic explanation of the orbits! I would have never thought the square orbit could happen, but orbital resonance has eluded me so far. I did, many many years ago, get a rotating triangle lissajous pattern once inserting Beatles music unto the x and y drivers of an old T.V. once (just before I shocked the living shizzle out of myself.) Always love your videos.

Excellent Reporting 👍

NGL, that orbit at 2:00 looks like what mine would when i've messed up a mun transfer and am now trying to catch back up lol.

I can’t imagine throwing astronauts into this thing on the first launch. Wouldn’t be prudent.

Every science teacher is bowing in Scott's general direction right now.

It’s been quite frustrating not to have a good conceptual explanation of Artemis-1’s orbital maneuvers the way we got that back in the day withApollo (yes, I’m old enough to have clear memories of that), but I think I now have one (sort of), The DRO is simply a prograde orbit around the Earth that - due to the Moon’s influence on the orbit - is significantly more elliptical than is the Moon’s orbit around the Earth and is in the same plane as the Moon’s orbit around the Earth. The ends of the major axis of Artemis’s orbit lie farther away from Earth than the Moon’s orbit, and the ends of the minor axis of Artemis’s orbit lie closer to Earth than the Moon’s orbit. When Artemis is in the farther part of the orbit it orbits around the Earth slower than the Moon and “falls behind” the Moon. When Artemis in the nearer part of the orbit it orbits around the Earth faster than the Moon and thus “catches up and passes” the Moon. Viewed from the Moon this would look like a retrograde orbit around the Moon at a great distance (if the distance wasn’t large, the Moon’s gravity would dominate and Artemis would orbit around it rather than around the Earth). The Outbound Powered Flyby and Return Powered Flyby are just lunar gravity assists - helped along by Artemis OMS burns - to get Artemis on its way to DRO and get it on its way back to Earth. What I would like to know is if the Outbound Powered Flyby and Return Powered Flyby burns are retrograde or prograde burns, and the same for the DRO insertion and DRO departure burns (I assume the DRO departure at least must be a retrograde burn).

I had imagined a DRO to be an elliptical orbit about the earth with the same semi major axis and period as the moon but with more eccentricity. So the apogee would be a distance above the moon and the perigee would be a distance below the moon. But from the moon's POV would look like a retrograde orbit since it falls behind the moon when above it and spurts ahead of the moon when beneath. But the animation doesn't show an ellipse with earth at the focus. Looks roughly elliptical but with earth at the center. So clearly not the Keplerian orbit about the earth I had imagined. I guess the moon plays a larger role than I had imagined with DROs.

TY for splaining that

Excellent presentation. Thanks Scott. Here's a few more words for the RU-vid algorithm 😁

Oh I see you've been stepping up the thumbnail game :D

@scottmanley, do you think you can see Artemis I's re-entry from the CA coast? Or how far inland do you think one can see it from?

Good question. I’ll watch this tomorrow but then I already done this around mun

You're a natural teacher

Excellent. Well done.

super explanation 🤯

If you'd asked me 15min if a square orbit was possible, I'd have laughed in your face. But now... 3 body problems are weird. Considering the long orbit and the relatively short mission duration, how many times is Artemis actually going around the moon? That is, w.r.t. the moon, how many loops does it to around it? I've got the picture that it's only ~1.5 in total but I'm really not sure.

0:22 This shot is so much like that famous stage separation from the Apollo era (mind you, AS-202, it was a Saturn IB, not a Saturn V)

"Distant Retrograde Orbit" is what we use to describe the short christmas visits from the in-laws

Those were very cool CGI orbital mechanics. The real deal too.

I love all those really smart orbits!

How does Artemis calculate its speed in relation to Earth/Moon in order make the proper adjustments to insert itself into the correct orbit around the Moon?

I hope you'll put the Hubble Space Telescope back once you've finished with it.

You sir are a student and a scholar. I’m a little slow. If you knew how important you are to me. Thank you. I am a aviation nerd. You make space approachable for me. Thank you again.

Love the way you "spitballed" an orbit stable for 13+ years. Class.

I thought it was hilarious when the video transitioned from the solar system simulation with Artemis 1 to the white documents! It actually jump scared me!

Seeing that squarish tail is truly amazing

4:16 think fast, chuckle nuts!

every now and then, scott puts out a video where i go, "wtf?" this is one of those videos

This will be used for other planets, moons and satellites as well !

Nice presentation

A square 'orbit.' Absolutely fascinating!!!

It's pretty cool to see that now we are advanced enough in orbital navigation for these trajectories. Big advancement from the 2 body approximation and directly flying to Low Lunar Orbit that Apollo used.

Why don’t they place additional craft in standby orbits and a lander at the landing site prior to sending humans? Giving them redundant equipment and supplies for emergency or even regular use.

Thanks Scott. I'm not sure if this mission is worth $2 billion dollars, but there you are... I do want to see a new Moon landing though.

shout out to universe sandbox!

Awesome Scott! Can this be reproduced in KSP with Kerbal and Mun as well? Can someone provide/explain the formula needed for KSP?

Scott, the go to guy to explain this stuff to regular people

Thanks for the explanation. Where the magical speed vector (0.679 km/s) coming from? I see 0.481 km/s from the article referenced by you .

Well done for finding an almost square orbit. I think I'd call that one a 'toast orbit' because its shape resembled a slice of bread more than a square, with some concave sides and one convex one like the top of the toast that doesn't get toasted if the bread is too tall for the toaster. It was great to see an eclipse of the Earth from Artemis as well - not quite the same size though. I wonder has any probe/satellite managed to film the moon eclipsing the Earth when they are exactly the same size? Or has one at or near the Earth's L2 point found the point where the Earth can eclipse the sun appearing the same size? It must happen somewhere.

Interesting stuff thanks for explaining this mission orbit plan, will future missions use the same DRO plan also why is it taking six days fly back to Earth when Apollo took 2?

thank you

When on the way or returning from the Moon what is the speed referenced to? Friends question "For example the day or two after launch, the speed was showing as something like 70 mph, but the distance to the Moon was decreasing at most like a mile every three or four seconds."

Great explanation. I also wanted to see that asteroid redirect mission happen. Oh well, the landing on the moon will pave the path to Mars so.

I don't understand many of the words used here. But I really like the space bird eye view where Artemis 1 literally just uses the moon to kill all it's orbital velocity and just drops to earth.

Nice video I learned something new. I was wondering off the top of my head, what’s perseverances status?? Aren’t they getting ready to send a sample back soon? 🎉

Hey Scott you rock! I saw the clip of the abort tower pulling away and that got me thinking. The abort tower does not pull straight ahead of the vehicle but off to the side in the clip seen here. My question is, does the abort tower fire differently during an abort than it does during a nominal flight? Can it control the asymmetry of the thrust to get out of the way either of the second stage in an abort or of the crew capsule in a nominal launch. BTW I watched this with a few people in the room and most of them were looking at their phones a few minutes into the video but I was realizing that the montage of footage that you put together there was historic and unique footage of our return to the moon. Super cool even if it is way expensive. Thank you