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Student rocket group shatters amateur space record
- tromp 2y ago> Aftershock II reached a velocity of 5283 ft/s and Mach 5.5. The comparatively lightweight rocket amounted to 330 pounds, at a height of 13 ft and 8” diameter. For the imperially challenged, that's a velocity of 1.6 km/s, weight of 150kg, height of 4m and 20cm diameter.
- brudgers 2y agoOr 7.662481e-14 parsec/sec, 1467.9126 Newtons, and 4.4041166e-16 light years. Because space.
- deleted 2y ago[deleted]
- 7734128 2y agoYou can't turn mass into force, especially not in space.
- brudgers 2y agoFor the metrically challenged, pounds are a unit of force not mass.
- littlestymaar 2y agoWikipedia disagrees with you[1], and if pounds were a unit of weight that'd be very unpractical from a legal PoV to have things being labeled in pounds since the same object have a different weight in Puerto Rico (close to the Equator) and Fairbanks (close to the North Pole). [1]: https://en.wikipedia.org/wiki/Pound_(mass) https://en.wikipedia.org/wiki/Pound_(mass)
- two_handfuls 2y agoI distinctly remember reading how I would weigh a different amount on the moon. This only makes sense if the pound is a unit of force.
- stouset 2y agoYou would weigh a different amount on the moon, but that is completely independent of how we label our units of measurement. The pound a unit of force. It is also a unit of mass. Both units share the same name.
- two_handfuls 2y agoIt's not independent because if I'm 80kg here, I'm still 80kg on the moon. Because gravity does not affect mass. If I weigh 160lb on earth I'm told that I would weigh 26lb on the moon. That makes sense if lb measures force because gravity affects force. In short, this commonly shared "fact" is consistent with pounds being a unit of force, not of mass. Or, I suppose, of lb at least sometimes being a unit of force.
- stouset 2y agoIf you weigh 160lb on the Earth, you also have 160lb of mass. You would weigh 26lb on the moon and still have 160lb of mass. I don’t know how to make the point any clearer that there are two units of measurement, both with the same name. https://en.m.wikipedia.org/wiki/Pound_(force) https://en.m.wikipedia.org/wiki/Pound_(force) https://en.m.wikipedia.org/wiki/Pound_(mass) https://en.m.wikipedia.org/wiki/Pound_(mass)
- two_handfuls 2y agoSo how do I know which is meant in a given sentence?
- M3L0NM4N 2y agoI think it's used as both. Foot-pounds is used as a unit of work, so it's a force in that context.
- beAbU 2y agoIn case you didn't understand the other reply, you can't use newtons in this context. Kilograms is perfectly fine here. The thrust of the engine can (and should) be measured in newtons though. Also, 4 decimal points of precision is completely overkill. Maybe one decimal point at most would be more than enough, but most wouldn't even bother with that.
- brudgers 2y agoThe force of a rocket engine can be measured in pounds. And pressure in PSI and torque in foot-lbs because pounds are a unit of weight (i.e. force) not mass.
- nordsieck 2y ago> The thrust of the engine can (and should) be measured in newtons though. It's very common to measure engine thrust in ton-force because it makes it easy to compare the thrust to the weight of the rocket, which is a critical metric.
- foxglacier 2y agoThe problem is the 8 significant figures, not 4 decimal places - 0.3300 kip and 1467.9126 N both have 4 decimal places but one is much worse than the other. Even if 330 lb was exact, all those digits in 1467.9126 N aren't even correct. It should be 1467.9131 N using standard gravity. It looks like brudgers used 1 lbf = 4.44822 N which is what Google says but is only rounded to 6 s.f. so can't be used to generate an 8 s.f result.
- deleted 2y ago[deleted]
- merek 2y ago> For the imperially challenged You mean everyone in the world expect for the Americans, Liberians and Burmese? :)
- foooorsyth 2y agoMaking this joke falls flat in the comments section of a rocket science article about Americans continuing to dominate space.
- lionkor 2y agoNot sure if I would necessarily say that the reason the US is pretty good at space stuff is imperial measurements. Its probably imperialism, instead.
- etiennebausson 2y agoIt's mostly because the US was the only nation to survive WW2 with its infrastructure intact. Same story as computing, really.
- kortilla 2y agoNope, that’s a lazy excuse. The US space industry was dead in the early 2000s. Astronauts went to the ISS on Soyuz.
- conductr 2y agoIt was more of an exploration lull and not much industry had came out of it quite yet as privatization was being implemented and so it’s the case the industry was actually just being born.
- mrguyorama 2y agoYou are simply wrong for anything other than human rated flight. They didn't have the kind of PR that NASA and Space X have, and they were never human rated, but private satellites never stopped flying on Atlas, Delta, and Titan programs that variously went from the 1960s all the way up until the 2020s. All three of those rocket programs are direct descendants of ICBM programs. https://en.wikipedia.org/wiki/Comparison_of_orbital_launcher_families#List_of_retired_launcher_families https://en.wikipedia.org/wiki/Comparison_of_orbital_launcher... I disagree with the premise that it was lack of bombing of US infrastructure related though. Space programs are very simply the public output of ICBM programs. Most of the modern day is simply a direct descendant of ICBM programs. You like distributed and reliable communication networks like the internet? Built so ICBM silos could command each other even if certain hubs were nuked. You like the miniaturization of solid state electronics? That capability was paid for entirely by the US Air Force who wanted powerful computers under 100 pounds for advanced planes and precision ICBMs. Satellite navigation was also explicitly invented for nuclear missiles fired out of submarines to have an accurate fix for guidance purposes. Basically the entirety of the modern world exists because the US of the cold war pumped trillions of dollars into producing ICBMs and planes that were genuinely "next gen" while every single private business takes the credit for stuff they never paid for. Computer and telecommunications companies would never have built this stuff on their own: They were fine with computers taking up an entire facility that they could rent out (cf modern clouds) and fully switched networks that were reliant on a big company to manage. None of them needed to sell you a "personal computer". None of them wanted a distributed, uncontrolled network like the Internet.
- dragonwriter 2y ago> For the imperially challenged, US customary units are a distinct system from imperial units (some of the individual units overlap, and several others have the same names but different definitions.)
- soneca 2y agoI dont know if you were downvoted for being pedantic or for being wrong. But I’d love to know if this is true. And if so, I will upvote your pedantry
- variaga 2y agoIt is true: https://en.wikipedia.org/wiki/Comparison_of_the_imperial_and_US_customary_measurement_systems https://en.wikipedia.org/wiki/Comparison_of_the_imperial_and...
- analog31 2y agoIt's interesting that I'm perfectly fluent in both US and metric units, yet I don't have a personal frame of reference for the magnitude of many of the numbers given in the article, in either unit system. For instance, how they compare to rockets that are actually in practical use.
- daemonologist 2y agoCompare to New Shepard (Blue Origin suborbital passenger vehicle): 1 km/s top speed, 100-120 km max altitude. Of course it also carries a payload of six passengers and (the rocket part) lands propulsively. Compare to orbital rockets: (low earth) orbital velocity is 7.8 km/s, the ISS orbits at about 400 km, the lowest satellites are at about 200 km.
- jjmarr 2y agoAltitudes for aircraft use feet worldwide, to be fair.
- dj_gitmo 2y agoTV screens and monitors are also measured in inches. ¯\_(ツ)_/¯
- delta_p_delta_x 2y agoThey are decidedly not. They are marketed in inches of the diagonal (a supremely brain-dead decision, if you ask me), but they are engineered, manufactured, and even programmed only in SI units. If you look at your display's EDID output, the diagonal doesn't even factor in; what you do have are vertical, horizontal, and per-pixel dimensions; all in millimetres. This is what all panel manufacturers (LG, AUO, Samsung, Innolux, BOE, TCL, and so on) do.
- Tepix 2y agoIn Germany you have to always mention the metric size. Luckily.
- delta_p_delta_x 2y ago> use feet worldwide, to be fair Many CIS countries and China use metre flight levels[1] and kilometres per hour for indicated speed reporting. Additionally, the ICAO has recommended transiting to metre flight levels since 1979[2]. More additionally, the Airbus A300 had flight levels initially set up to be metric (obviously, since it was an effort spearheaded by the French), but to appeal to American airlines the Airbus consortium switched to feet. Although I am positive that Airbus engineers work exclusively in SI. METARs worldwide except in North America use SI units for reporting weather. [1]: https://en.wikipedia.org/wiki/Flight_level#Metre_flight_levels https://en.wikipedia.org/wiki/Flight_level#Metre_flight_leve... [2]: https://en.wikipedia.org/wiki/International_Civil_Aviation_Organization#International_System_of_Units https://en.wikipedia.org/wiki/International_Civil_Aviation_O...
- Tepix 2y agoNo, and this is not an aircraft, is it?
- HPsquared 2y agoImperial units fit nicely here: 1.00 mile/sec.
- tw04 2y agoCan I get that in stone and hands please?
- saagarjha 2y agoHonest question by someone who is not familiar with this space: what prevents a well-resourced by determined civilian team from beating them? Like, yes, this is rocket science…but it's rocket science done by a team of college students. Surely there are other groups interested in this kind of thing? Does the government step in at some point and go "that's enough" when you try to do significantly better?
- kevmo314 2y agoAt some point the label of amateur starts costing more than the value the achievements bring.
- WalterBright 2y agoThe value is in educating the next generation of rocketmen.
- saagarjha 2y agoidk what "value" people expect out of a model rocket, anyway. Of course SpaceX or NASA is sending things to orbit. The value is you get to have fun launching things into space yourself!
- WalterBright 2y agoWorking through the equations, and then building a working machine from it, is very educational.
- lmm 2y agoThis is the amateur record, not the civilian one. And while the group may be "student-run", if you check their sponsors page it's funded partly by the university and partly by a who's who of the aerospace industry (Boeing and SpaceX are prominent), which I suspect is much easier for a college student group (who make a good feel-good cause, and those companies are implicitly courting to come and work for them) than a group of working adults.
- WalterBright 2y agoDang. I would have loved to be on that team as a student.
- cespare 2y agoI was trying to understand how an altitude of 470,000 ft compares to other things, so I looked up a few numbers. 470k feet is 143 km. The altitude record for an air-breathing aircraft is 38 km. There are some very low earth orbit satellites that orbit in the sub-200 km range (https://en.wikipedia.org/wiki/Very_low_Earth_orbit https://en.wikipedia.org/wiki/Very_low_Earth_orbit). The ISS orbits at about 400 km and typical LEO is 800 km. ICBMs have an apogee altitude of 1000 km or more. (Of course, the energy required to get up to some altitude is only a small fraction of the energy required to get into orbit at that altitude. https://what-if.xkcd.com/58/ https://what-if.xkcd.com/58/ is a relevant read.)
- LarsDu88 2y ago[flagged]
- zakki 2y agoWhy DoD (US) instead of Ukraine Gov?
- plugger 2y agoITAR
- TrainedMonkey 2y agoOr we could avoid weaponizing kids and let them explore space for the sake of exploration. Give them a no strings attached grant and let them decide later on what they want to use acquired experience for.
- walrus01 2y agoserious answer but without a dod contract and appropriate licensing, putting any kind of guidance system other than "keep it pointed straight up" on a rocket like this definitely makes it fall within a few things: ITAR (international traffic in arms regulations) EAR (export administration regulations) CCL (commerce control list) BIS (bureau of industry and security) MTCR (missile technology control regime) Just to start... Let's just say if you want to guide something like this you'd better be sure that the federal government absolutely knows who you are and what you're building, and for what purpose, and that everyone is a US citizen who is eligible to get a security clearance. I guess I didn't even get into the other explosives/munitions related licensing and certifications and storage/preparation facility requirements for very large solid rocket motors (ATF)
- bragr 2y agoWith what payload? >The comparatively lightweight rocket amounted to 330 pounds That's a total weight less than any warhead available for ATACMS: https://en.wikipedia.org/wiki/ATACMS#Comparison https://en.wikipedia.org/wiki/ATACMS#Comparison And then there are the engineering challenges of flying very specific trajectories capable of single digit meters of CEP at those ranges, surviving a ballistic reentry to ground rather than parachuting, and being robust enough to survive being bounced around in a sealed canister for years at a time with no maintenance and then successfully launching in anger at short notice.
- eps 2y agoIn metric: previous record was 116 km, this launch was 143 km.
- Tepix 2y agoThanks. I can't believe they're giving the speed in ft/second, i've never seen that... horrible!
- hermitcrab 2y agoHistorical background: https://www.youtube.com/watch?v=JYqfVE-fykk https://www.youtube.com/watch?v=JYqfVE-fykk
- eterevsky 2y ago470'000 ft = 140 km altitude
- niteshpant 2y agothank you - this was the comment I was looking for
- hoseja 2y ago>through anodization That was just oxidation.
- gus_massa 2y agoSomewhat related: A video about buildng a carbon fiber, solid fuel rocket by Xyla Foxlin: https://www.youtube.com/watch?v=ZQvK8EFJQzw https://www.youtube.com/watch?v=ZQvK8EFJQzw ("only" 7Km, 23Kft)
- Haugsevje 2y agoAre they as high up that it could start orbiting?
- phaedrus 2y agoOrbiting has more to do with velocity than altitude.
- jvanderbot 2y agoSpecifically, you need to be moving approx 10 km/s which 22,000 mph or mach 30.
- laverya 2y agoYou only need to be moving ~7.5-8km/s, but getting to orbit tends to take 9.5-10km/s of total delta-v due to needing to ascend, aerodynamic drag, and other losses.
- Haugsevje 2y agoAhh yes, of course! I guess they are not high enough for geo stationary orbit?
- jadyoyster 2y agoEven if they were high enough they would just fall back to earth. There are lots of videos explaining orbit, this one looks good: https://www.youtube.com/watch?v=bcvnfQlz1x4 https://www.youtube.com/watch?v=bcvnfQlz1x4
- Haugsevje 2y agoThat's a very clarifying video! Suddenly i remembered my pre-college physics:)
- marcyb5st 2y agoGeo stationary orbit is 36000 km give or take. Orbiting however is more about radial velocity. You are sort of constantly falling towards Earth, but you are moving so fast that you always miss it and so you end up orbiting it. A great animation on the subject: https://www.reddit.com/r/Damnthatsinteresting/comments/1btbnk3/orbital_mechanics_in_30_seconds/ https://www.reddit.com/r/Damnthatsinteresting/comments/1btbn...
- louka77 2y ago[flagged]
- steviedotboston 2y agoAny idea what kind of permitting or permission they had to go through to launch this? I'm assuming you can't just take what's basically a missile and go into the dessert and shoot it without the FAA knowing about it.
- ceejayoz 2y agoYou need a waiver over 18k feet. https://www.faa.gov/space/licenses/amateur-rockets https://www.faa.gov/space/licenses/amateur-rockets / https://www.faa.gov/air_traffic/publications/atpubs/pham_html/chap31_section_2.html https://www.faa.gov/air_traffic/publications/atpubs/pham_htm... A little higher (150km) and this would've been out of the realm of amateur rocketry entirely.
- lostlogin 2y agoI misinterpreted your comment initially, you’re citing the FAA: ‘To qualify as an amateur rocket, the launch must be suborbital, not have any humans onboard, remain under 150 km (93.2 statute miles), and have a total impulse under 200,000 lb-sec (889,600 Newton seconds).’ I’m sure you would get punished but what are they going to do about your rocket once it’s up there?
- ceejayoz 2y agoWait for it to come back down, then fine you.
- canadianfella 2y ago[dead]
- thrw42A8N 2y agoAh, so either explode or go even further, got it.
- Loudergood 2y agoA local rocketry club has standing clearance to 10,000ft and I know lots of college teams come from 6 hours away to take advantage of it. Check your local clubs, you can see impressive launches on at least 1 weekend a month.
- iandanforth 2y agoWhat's weird about student/amateur rocketry is how, at a certain point, knowledgeable people have to say "I'm not allowed to help you." If you get too good at this hobby you run straight into arms treaties.
- sklargh 2y agoITAR and amateur rocketry YouTube have a strained relationship.
- mrguyorama 2y agoI don't think it's that strained. BPS Space for example spends a lot of time talking about how "This is not a tutorial" but there's a massive gulf between what is currently published information that is available to people like him and what is actually meaningful to regulation. If you are buying your propellant components in small bags off the internet and mixing it yourself in stand mixers and casting it yourself in your garage and using niche open market servos to build your stuff with homemade guidance, the gov is not looking at you. ITAR isn't about keeping every precocious kid from building small volume guided munitions; It's about keeping shithole states from building ICBMs. It's about keeping former SpaceX personnel from spending time in Best Korea. This is especially true in a post FPV drone world, where putting 1kg of explosive anywhere you want in a 10km radius is a $500 purchase off alibaba. Precision munitions have accidentally been democratized.
- bragr 2y agoI'm not sure that's an accurate characterization. He's specifically voiced concerns about the ambiguity of whether what he's doing violates ITAR, even with the "this isn't a tutorial, I've left out information" and that if the feds launched an investigation, he'd be crushed by the process even if they found no wrongdoing in the end.
- edm0nd 2y agoYet anyone can buy a consumer drone and strap homemade explosives on it and do a lot more damage VS a college kid with an engineering background who is into rocketry.
- bastloing 2y agoBright kids, great support, can't wait to see what they can do with their careers! Bravo!
- WhitneyLand 2y agoHow much did it cost them? Using ensemble model estimation resulted in a guess of $400,000.
- boringg 2y agoIs the core challenge on amateur rocketry the amount of fuel that you can put on board the rocket. Essentially a cost equation on the design components? It would be super fun to do but isn't that the big different -- design and shape certainly make a difference but are they not mostly determined at this point with subtle iterations?
- mryall 2y agoThis article has a good summary: https://www.apogeerockets.com/Peak-of-Flight/Newsletter533 https://www.apogeerockets.com/Peak-of-Flight/Newsletter533 The key challenges called out are a) fuel, b) robust airframe, c) active guidance to handle varying conditions, d) funding for testing and robust components. The article goes into a good amount of detail on each.
- hermitcrab 2y agoDid this rocket have active guidance?
- boringg 2y agoThanks!
- abeppu 2y ago> Aftershock II is believed to be the world’s first civilian-built rocket to reach an altitude of 470,000 feet. Surely this first line, bolded and right below the byline, isn't correct for our normal understanding of "civilian", is it? Like most rockets aren't military-built.
- seadan83 2y agoCivilian vs government - notably including NASA; not just military.
- abeppu 2y ago1. I've checked multiple places and consistently "civilian" is defined in contrast to military / armed forces/ police, but not in contrast to government in general. 2. But even among non-governmental groups, this claim doesn't make sense. Northrop Grumman, Arianespace and a bunch of other companies that are not governmental organizations (but may have government customers). https://en.wikipedia.org/wiki/List_of_spacecraft_manufacturers#Launch_vehicle_manufacturers_and_providers_of_third_party_services https://en.wikipedia.org/wiki/List_of_spacecraft_manufacture...
- seadan83 2y agoGovernment contractors are working on behalf of the government. Ergo, not civilian. What sources have you checked for (1)? A counter example I would put forward is a police officer. They are not a civilian, nor are they military. What are they? Civilians in government can be a thing to distinguish military, but the actions of civilians on behalf of government are not civilian actions. Eg: "I am a civilian, I work for the government. When I do things on behalf of the government, it is not as a civilian."