Artemis Technical Question Regarding A NASA Animation By Keith Cowing NASA Watch September 4, 2019 Hey @NASAAmes is the new @NASA #Artemis lunar lander really going to have a rocket engine with a visible firery exhaust plume – in a vacuum? https://t.co/1gmjK6Anru — NASA Watch (@NASAWatch) September 5, 2019 Keith Cowing NASA Watch founder, Explorers Club Fellow, ex-NASA, Away Teams, Journalist, Space & Astrobiology, Lapsed climber. 30 responses to “Technical Question Regarding A NASA Animation” Brian_M2525 says: September 5, 2019 at 5:20 am 0 0 The less efficient it is, the brighter the flame. SpaceRonin says: September 5, 2019 at 9:40 am 0 0 Well the guns made sounds in Star Wars! and the X-wings flew banked trajectories… Chris Owen says: September 5, 2019 at 2:30 pm 0 0 I stopped watching animations years ago. Got spoiled by those actual moon rockets launching. fcrary says: September 6, 2019 at 9:27 pm 0 0 Unfortunately, it looks like we now have another moon rocket launch without a moon landing. On the down side, that makes us one for three this year. On the bright side, that makes three attempts in one year, which is unprecedented since the early 1970s, and much better than one attempt in the preceding 43 years. MAGA_Ken says: September 5, 2019 at 3:37 pm 0 0 I’m less concerned about exhaust plume animation than about the overall structure of transfer vehicle, descent vehicle and ascent vehicle. Also I’m not sure what is the difference between the “quickie” lander and the more “sustainable” lander they keep talking about. fcrary says: September 5, 2019 at 7:27 pm 0 0 The difference is that they don’t even have an animation or even a sketch of what the “sustainable” lander will look like. Zed_WEASEL says: September 5, 2019 at 9:41 pm 0 0 Sustainable Lunar lander from Hawthorne 🙂 https://uploads.disquscdn.c… from Elon Musk’s twitterfeed mfwright says: September 6, 2019 at 6:37 pm 0 0 My issue is it looks like early direct mode of Apollo. Landing and taking off in same spacecraft that flew TLI and will be used to return to earth doesn’t makes sense. I wonder if this is a teaser but the real thing will be different. i.e. pictures of F22 in 1980s had canards. Zed_WEASEL says: September 7, 2019 at 2:59 am 0 0 It is an offical render of the Starship release by Elon Musk. A more robust and fully reusable variant of the Apollo direct idea. Musk is suppose to have an update on the BFS Starship and the BFR Super Heavy at the end of September at Boca Chica with a fully assembled Starship Mark 1 in attendance. ThomasLMatula says: September 5, 2019 at 11:28 pm 0 0 It doesn’t matter, it won’t be built after the next Administration hits the reset button… Joe_de_Loe says: September 5, 2019 at 5:05 pm 0 0 Curious… It is a hot plasma shooting out the nozzle. Hot plasmas can glow in visible light depending on what elements compose it. I’ve seen the physically extended glow from ion engines in a vacuum chamber. Why do you think a fiery exhaust couldn’t be visible? Even if they were technically wrong, relax, it is an animation intended for the public – if there weren’t something visible there it would look like it was the vehicle was non-believably levitating down by magic to most people. kcowing says: September 5, 2019 at 6:01 pm 0 0 But Neil Tyson will be upset! ProfSWhiplash says: September 6, 2019 at 4:15 pm 0 0 Just tell him it’s anti-grav repulsors like they used in Star Wars (but bought from Aliens). He’ll go “Oh, yeah” and then relax. fcrary says: September 5, 2019 at 7:26 pm 0 0 Then reverse the question. What fuel-oxidizer mix is that lander burning? I can’t think of any common ones with lines which are not only in the visible but blue. Also, a vacuum nozzle is going to expand the gas until it’s very low density. Even if it’s emitting in the visible, I’m not sure it would be bright enough to actually see. Yes, I know it’s only a cartoon. But this is one of the things which I worry about. All the animations and CGI designed to get the public excited can backfire. When the public sees what reality is like, they may be very disappointed. ThomasLMatula says: September 5, 2019 at 11:21 pm 0 0 Maybe require the artists to watch the liftoff of LEM accent modules on YouTube. No exhaust, it just goes like a balloon. ProfSWhiplash says: September 6, 2019 at 4:22 pm 0 0 The LM Ascent engine used hypergols. Very reliable, storable, can be restarted… but for obvious & unpleasant reasons, well out of favor.. fcrary says: September 6, 2019 at 7:23 pm 0 0 They are working on “green” propellents to replace hydrazine. Green in the sense that you can spill them without killing anyone not wearing a hazmat suit. I’m not sure if that’s only for a monopropellent or if it could also be used for a hypergolic biprop. mfwright says: September 5, 2019 at 6:31 pm 0 0 1960s artwork including illustrations from Grumman showing Apollo LM had flaming plumes. It seems only ones that got it right was Kubrick’s model makers showing lunar landers in 2001 (only see dust being blown away, no thunderous rocket blast). Also at that time all illustrations before Apollo 8 including NASA artwork showed the earth with NO clouds. The real issue is now a hard date has been set to land on the moon, it is important to get hard money to build hardware. This includes nozzle design which determines landing gear, structure for landing gear, and God knows what else. Jeff Greason says: September 5, 2019 at 7:28 pm 0 0 Visible, perhaps. Not likely very bright and the plume would be much more expanded. LOX/LH2 engine firing in vacuum, barely visible against a black background: https://c1.staticflickr.com… N2O4/hydrazine firing in vacuum, not visible against a bright background: http://www.collectspace.com… Even at sea level where the plume is tightly collimated, LOX/Methane is a somewhat translucent rather than “optically thick” blue — note you can see the mountains easily through the plume: https://smd-prod.s3.amazona… kcowing says: September 5, 2019 at 8:39 pm 0 0 I knew a real rocket scientist would answer! Thanks! fcrary says: September 5, 2019 at 8:59 pm 0 0 And we shouldn’t leave out the SpaceX Merlin. We’ve got plenty of video of the Falcon 9 launches, with a good view of the second stage Merlin firing in vacuum. The LOX/RP-1 mix doesn’t produce a visible plume, but the nozzle does start glowing red. DJE51 says: September 5, 2019 at 7:42 pm 0 0 Artistic license regarding the exhaust plume. But what is worse about the animation is it is still imagining a landing similar to Apollo. If I had any serious money (which I don’t), then I would bet serious money that the next landing on the moon by astronauts will be in SpaceX’s Starship. I mean, no-one has even started to develop the NASA concept of a descent stage and a separate ascent stage – except maybe some Power Point presentations. If NASA is serious about a sustainable lunar presence, then they have to drop the descent stage and ascent stage concept – throw away space-craft are certainly not sustainable. I understand that President Trump wants a landing before the end of his hypothetical second term, by 2024. But that is a vanity project, not a sustainable program. We probably will get a landing before 2024, but it will be by SpaceX, with a fully reusable spacecraft (Starship) and likely by-passing any Lunar Gateway space station that will be in place. ThomasLMatula says: September 5, 2019 at 11:26 pm 0 0 SpaceX Starship – the rocket that must never be spoken of in the presence of Old Space.?? BTW speaking of the rocket not spoken of, the heat shield tiles to be used on it were tested on the recent Dragon flight. The photos indicate they looked great! RocketScientist327 says: September 5, 2019 at 10:09 pm 0 0 This is just more PowerPoint/CGI from NASA. They really have this down… since CxP! Steve Pemberton says: September 6, 2019 at 5:37 am 0 0 When viewing Space Shuttle launches in person, even after the solids burned out you could see the main engine flame for a long time, it looked like a bright star even in daytime. Of course you were looking at it from behind so you were essentially looking through the entire plume “vertically” instead of horizontally so that makes a big difference. But even in daytime you could still see it with binoculars up to about six minutes after launch, it was in space by then although not quite in orbit, and hundreds of miles downrange. At night you could in theory follow it nearly to MECO however by then the orbiter was just about to go below the horizon and it starts getting obscured by looking through a lot of atmosphere or blocked by any clouds that are within a few hundred miles. Pretty amazing that you could see it that far away since the hydrogen plumes seem almost invisible when much closer and looking at them horizontally. hikingmike says: September 12, 2019 at 8:50 pm 0 0 I thought the same thing about the Falcon 9’s Merlin which you can also see, but I believe it is still in enough atmosphere at that point and probably same with the Shuttle main engine. Michael Spencer says: September 6, 2019 at 6:08 pm 0 0 Without the plume, folks will think that NASA has resolved antigravity. Paul Gillett says: September 6, 2019 at 9:52 pm 0 0 LOL! james w barnard says: September 6, 2019 at 10:22 pm 0 0 I have fired a 1 lbf gaseous methane/oxygen rocket in a lab, but can’t recall the color of the flame. Maybe they are picturing a BE-3 or some other methane/ox combination.BTW, I was under the impression that “in space no one can hear you scream,” but the Starship Enterprise made sort of a swishing noise as it passed the viewpoint in Star Trek’s opening scene! Was that some sort of phenomenon of subspace, or just poetic license for the benefit of the viewing audience? Bill Housley says: September 7, 2019 at 2:31 am 0 0 (Sigh) Rocket geeks.