• Copenhagen Suborbitals - Artisan rocketry
    15 replies, posted
[IMG]http://i.imgur.com/1TQjyMD.png[/IMG] With all the SpaceX super nice stuff floating around, I'd reckon there would be some interest in something on a slightly smaller scale - amateur rocketry basically. Personally I've been following Copenhagen Suborbitals for a few years, and I really think they deserve more attention than they get. Copenhagen Suborbitals (CS) is a crowdfunded project with the stated goal of putting someone into space on top of a rocket - pretty simple stuff. The project has been going on for about 8 years now, but it was basically rebooted about two years ago after (or well, shortly before) the [URL="https://www.youtube.com/watch?v=f-4n-2MtECE"]pretty spectacular (and expected) failure[/URL] of HEAT 2X. That's not to say they haven't accomplished a lot - they have - and they've broken a few records. Here's an overview of their last (sea) launch (a hybrid rocket - launch around 14:46, but the video is pretty interesting as a whole) in 2013: [video=youtube;kcF5xNrb3HA]https://www.youtube.com/watch?v=kcF5xNrb3HA[/video] Well, they've pretty revamped their process completely since the HEAT 2X failure, and the big "news" is that they're going to launch two rockets this summer (the Nexø 1 and 2). Both use their newest, and very well-tested engine, the BPM-5. The BPM-5 is a (ethanol/LOX, regeneratively cooled) [B]B[/B]i[B]P[/B]ropellant rocket [B]M[/B]otor with [B]5[/B]kN of thrust. [t]http://i.imgur.com/gi96NXx.jpg[/t][t]http://i.imgur.com/bC3Eans.jpg[/t] [I]The "Franken-5" - the flight engines are quite a bit prettier.[/I] Doesn't sound that exciting with professional rocket engines doing hundreds and thousands of kilonewtons of thrust, but to my knowledge this will be the first (amateur) bi-prop rocket engine to actually fly. It has a pretty mediocre specific impulse of ~210sec (though this is partly due to the fact that they run it with 75% ethanol), but the most exciting fact (and the goal) about it is that it works, and it works reliably. Here's a video from yesterday's test (should be noted that a software bug resulted in the motor ignoring pre-stage completely - this was remedied in a later test), and you can also find rockets of the manufacturing process on their youtube page: [video=youtube;y5NsIYeL4-Q]https://www.youtube.com/watch?v=y5NsIYeL4-Q[/video] As mentioned, the BPM-5 engine will power the Nexø 1 and 2 rockets, which are basically going to look like this: [t]http://i.imgur.com/66ZMhB8.jpg[/t][t]http://i.imgur.com/yYEr4dz.jpg[/t] [I]End result ----------------------------- Work in Progress[/I] Nexø 1 will be run purely in pressure blowdown mode, and will use fins (as used on the Sapphire rocket, though they're graphite this time around) to steer the rocket. Both of these will limit the performance of the rocket, and the expected altitude is only 5km or so. Nexø 2, however, will utilize a DPR (dynamic pressure regulator) system to enhance performance, and (probably) a gimbal system for steering - both of these will result in the Nexø 2 flying higher than Nexø 1. Both rockets will be launched using the sea launch method shown in the first video. New blog about Nexø 1: [url]http://copenhagensuborbitals.com/hot-air-nexo/#utm_sguid=148973,84faafa6-6c79-98cb-a1b4-c6907187fb70[/url] While that's all well and good as far as a stepping stones go, it isn't going to take them to space, which is why the long term project is [I]Spica[/I], the largest rocket ever built by amateurs: [t]http://i.imgur.com/Eb5Q1qT.jpg[/t][t]http://i.imgur.com/eEPgKpC.jpg[/t] It's going to weigh about 4 tons (of which 2.6 tons will be propellant), be 13 meters tall, and it'll be powered by the BPM-100 with - you guessed it - a 100kN of thrust. The latter is obviously still in the design phase, but to my knowledge, the design of the engine will be "finalized" pretty soon, and testing will probably commence next spring - maybe earlier. Spica will utilize a DPR system (as opposed to a turbo pump) and gimballing like the Nexø 2 to reduce complexity. CS has been doing rockets for a long time, so obviously they have loads of videos on their [URL="https://www.youtube.com/channel/UCPzFMJIsp2fOQ_ic5a_zXTA"]Youtube page[/URL], and I definitely recommend checking out some of their technical videos as well. The videos of the big, but flawed, TM65 motors are also worth a look. Personally I've only witnessed one test in person - a test of the [utl=https://www.youtube.com/watch?v=FoyLKscL3W4]puny, but still impressive BPM-2[/url] which was basically a test platform for a TEOS additive that may allow them to decrease the water percentage in the ethanol. The potential performance improvement is not mission critical, though, and they may not need the TEOS to increase performance depending on the thermal characteristics of the final engine. They also have a blog in Danish ([URL]https://ing.dk/blogs/rumfart-pa-den-anden-made[/URL], and an official site ([URL]http://copenhagensuborbitals.com/[/URL]), though it lacks a lot of up to date information), where they share a lot more of the technical results, the design process and basically everything going on. I don't personally like reading through stuff using google translate, though, but if you have any questions regarding the project just ask - I've been following them pretty closely (but I'm in no way affiliated with them). As said, the whole project depends on donations - none of the people working on it is getting paid, and they all have 9-5 jobs that they need to "work around". So if you think the project is interesting and you would want to see it come to fruition, I'd encourage you to donate, which can be done through their official site. There's a lot more to add to this thread, and I'll update it when Nexø 1 and 2 launch dates come around. I know there's a space discussion thread, but I think this project kinda deserves its own thread, even if it won't be active 24/7.
That's pretty cool, never heard of them before tho.
New video from Sunday's test: [video=youtube;y5dvymKpfRw]https://www.youtube.com/watch?v=y5dvymKpfRw&feature=youtu.be[/video]
And the second "cold flow" test - they're basically checking the LOX side of things for any leaks, but it also gives a nice look of the Nexø 1: [video=youtube;GGTKSwOJiS4]https://www.youtube.com/watch?v=GGTKSwOJiS4[/video] The launch window (for both Nexø 1 and 2) is basically July-August. Nexø 1 will go through a test on water (onboard Sputnik), after which it will basically be launch qualified - so expect a launch soon.
In their Sapphire test the engine looked like it was chugging.
[QUOTE=download;50524161]In their Sapphire test the engine looked like it was chugging.[/QUOTE] Definitely was - it has very little to do (engine-wise) with what they're doing now, though.
I think that I recall hearing these guys didn't want commercial sponsorships? Kinda saddens me because they've been doing so well for years now that surely extra money would mean better studies.
[QUOTE=Tools;50529603]I think that I recall hearing these guys didn't want commercial sponsorships? Kinda saddens me because they've been doing so well for years now that surely extra money would mean better studies.[/QUOTE] I don't think they want to be associated with a company as such, but they've been getting rebates from Air Liquide for years now, so they kinda do it indirectly. I don't think they want to be sponsored as such, sure they'd get a larger budget, but then it wouldn't really be a crowdfunded amateur space program anymore, would it?
New video about the training with the ships needed for the launch - on top of that, there is now an official launch date: the 16th of July. [video=youtube;a6yXovY-b8E]https://www.youtube.com/watch?v=a6yXovY-b8E[/video]
Livestream of the launch today beginning at 11.00 CEST: [video=youtube;5mQ8bz1E6V8]https://www.youtube.com/watch?v=5mQ8bz1E6V8&feature=youtu.be[/video] I also made a thread in the Videos section.
They haven't done an autopsy on the rocket yet, but the preliminary explanation - only from the telemetry to my knowledge - is that too much LOX was loaded on the rocket (a result of the pretty ghetto way of loading it). This results in a smaller gas phase in the tank, which means that pressure drops much too fast. The onboard computer is designed to assume that the fast drop in pressure is due to a faulty sensor, and it'll default to using a look-up table of what the pressure should be. Therefore the rocket thought that the motor was running until it hit the water, despite the fact that it had cut-off much earlier due to insufficient pressure. A side-effect of this is that the rocket didn't deploy its parachute. This also explains the sub-par performance from the rocket motor - the rocket never went faster than 84m/s (and it only got to 1.5km). The silver lining is, of course, that even this is too slow for effective aerodynamic steering, which means that the rocket's guidance system actually worked really well. It would also make sense to me that a problem such as this would be solved by the next rocket, as it has a DPR system. Excess oxygen in the tank thus won't impact the feed pressure too much. The real problem is of course the LOX loading system - currently they're measuring how much they've loaded by weight, which is really hard to do precisely. On their test stand they have a special flow meter that works at cryogenic temperatures - sadly it is pretty sensitive, and very expensive, so I guess that's why they didn't want to risk it.
New blog about the launch: [url]http://copenhagensuborbitals.com/nexo-flew-fell-back/[/url] Turns out the above explanation was wrong. Either way, Nexø 2 is postponed to next year's launch season, which is disappointing.
A bit of a bump, but there's now an Indiegogo campaign for this summer's launch of Nexø II, which is basically Nexø I with a much [url=https://ing.dk/blog/lox-passende-maengder-1-del-195453]improved oxygen measuring system[/url] (utilising capacitance instead of weight) to avoid last year's issue that impacted performance considerably, as well as dynamic pressure regulation which will result in better performance. I can't really tell whether they've made a call (for Nexø II) on the gimbal system they [url=https://www.youtube.com/watch?v=7196ru3wpjA]tested back in October[/url], though I do remember them talking about how they were gonna fit it on the rocket - if it goes on the rocket, expect about 10% more performance from the motor, which would be nice indeed. The campaign video: [video=youtube;IkRE2ogHrdc]https://www.youtube.com/watch?v=IkRE2ogHrdc[/video] Campaign link: [url]https://www.indiegogo.com/projects/launch-of-world-s-most-advanced-amateur-rocket#/[/url] In other news, they may go for an ablative solution for the BPM-100, and it's probably gonna be using a pintle injector design because of the need for deep throttling. The design isn't finalized yet, though. Somewhat unrelated, one of the founders who went on to start his own project (with the same goal) literally right across from copsub just tested a rocket engine centrifuge: [video=youtube;87Fc_4933TI]https://www.youtube.com/watch?v=87Fc_4933TI[/video] Obviously motivated at least equally by the spectacle and the utility of it, but it's a fun little project, and I guess it also passes the milestone of strapping a rocket to a person. Edit: And here's a new blog video on the Nexø 2: [video=youtube;EWHErw8Jn8I]https://www.youtube.com/watch?v=EWHErw8Jn8I[/video] Seems like it'll be a more regular series.
I hope I'm not breaking any unofficial rules by bumping this thread, considering the low amount of interest, but I feel I should point out that the only possible launch date this year is the 26th of August, both because of delays in building the rocket as well as the Danish summer weather (or lack thereof). Here's a fairly general status update: [video=youtube;GFrzUhaUQ9E]https://www.youtube.com/watch?v=GFrzUhaUQ9E[/video] The 26th of August is gonna be a fairly active day for Danish amateur rocketry, as the founder (doing his own project) of CopSub is also looking to fire a rocket from [url=https://ing.dk/sites/ing/files/nexoe_launch_map_deployment_1.jpg]ESD139[/url] on the same date. Don't know exactly how they'll manage that, but either way, having two attempts (with wildly different rockets) on the same day doesn't exactly sound bad. Both launches will be live streamed.
My entire club follows them and we've learned a lot, and modeled some of our stuff after theirs.
So, with about a year's delay, Nexø 2 got a flight date (the 28th) and they released a video on the SAT (Sea Acceptance Test) which they did about a month ago: https://www.youtube.com/watch?v=C_awuGt7miA Basically they run the whole thing out at sea exactly as they would've if it were a real launch (minus the propellant) to work out any kinks in the procedures. Of course the launch will be livestreamed, and since the last launch they've been working on improving the streaming tremendously. Gone are the old, overheating and in are new ones as well as upgraded antennas and other stuff. Basically it should be a lot better than the choppy mess we got the last time around. Next rocket they're gonna be building and launching is the Spica - Nexø has served its purpose after this launch, so it'll probably be a few years before they do another.
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