Qu8k Rockets Above the Balloons 153
darkjohnson writes "Lately we've been inundated with 100k' balloon flights and amazing video footage from space — the flights usually taking better than an hour to achieve apogee. Derek Deville took a shortcut to 121k' using a 'home made' Q rocket motor and a ton of engineering genius. On September 30, 2011 at 11:08am, Qu8k (pronounced 'Quake') launched from the Black Rock Desert in Nevada to an altitude of 121,000' in 92 seconds before returning safely to earth.This small documentary on the flight is probably one of the most brilliant Amateur Rocket videos out there right now." The launch was an attempt to claim the Carmack Prize. (And Deville evidently likes to launch another kind of rocket, too.)
Impressive (Score:4)
That is pretty much all I can say :)
Re:Impressive (Score:4, Funny)
Re: (Score:2)
It's suborbital ballistic engineering, silly.
Re:Impressive (Score:4, Interesting)
Agreed!
This is nice. I wonder what it cost to do...
Seeing the epoxy cover over the camera melt off was interesting too; good thing it came off evenly. :)
Re: (Score:2, Interesting)
This is nice. I wonder what it cost to do...
I happened to be hanging out last night with one of the camera men who filmed this launch from the ground. Needless to say it is very surprising to see this on Slashdot, it's like having my private life show up here, very weird. Anyway, the answer to your question is "I'm not gonna say" but it was more than $10 thousand.
If you've seen the rocket launch from '08 where Team Numb fired a keg of beer to about 6000 feet, that was a good launch too. I have weird frien
Re: (Score:2)
I have weird friends.
I'd say you have great friends.
North of $10K sounds about right. Awesome but expensive.
Re: (Score:2)
Needless to say it is very surprising to see this on Slashdot
Why? It's a clever-but-pointless project by some well off geeky US kids who are helping to undermine the evil government monopoly of space flight. Plus it's named after a classic compyter game. Couldn't be much more slashdot unless they got Linus Torvalds to launch it.
Re: (Score:2)
I haven't watched the full video yet. Did it melt from the temperature of the rocket, or from friction with the air? It was apparent that the camera lens had already melted when it got near its apogee.
Re: (Score:2)
Friction, the video indicated that the temperature got to 840deg (F?) at Mach 3.
Re: (Score:2)
Thank you. I didn't hear it in the video. More likely, I forgot everything from before the launch. :)
It does lead to my belief that we shouldn't try to build up so much speed at a low altitude. Save the fuel until they're higher, with less air resistance. Of course, that's a bit more difficult with solid fuels.
Homeland Security's gonna love this... (Score:4, Interesting)
Geez, I hope the poor guy doesn't get kidnapped by the Iranians! (Or the Palestinians).
I wonder if he'll be allowed to leave the country (I know someone who works for the NSA who needs to give the State Dept. 3 months prior notice before leaving the U.S. Not sure if this includes Canada). Ok, maybe this rocket isn't state of the art rocketry. And not sure how guided it was. Still 112,000 ft.!
So, is this basically the design of a "Katushka?". Or even earlier the rockets launched by the Soviets in the launchers called "Stalin's Organ"?
Has he tried staging? Is it legal for a private American citizen to put something in orbit? (I guess I'm just kidding, while 112k is a good height, orbit requires a very high horizontal velocity of 5 miles a sec.)
What about launching FROM a balloon? (Although it might be more fun to launch AT a balloon).
Ok, these comments are kinda non-sensical, I just woke up from a nap.
Re: (Score:1)
Possibly.
Re:Homeland Security's gonna love this... (Score:5, Insightful)
While pretty impressive from a home hobbyist point of view (I'm showing this to my wife, I'm nowhere near this bad) - it doesn't break any ground in terms of rocketry. He isn't a state secret, needn't walk around icognito. If you watch the videos of the Libyan war, you see similar devices shot more or less horizontally. As you allude to, staging is much harder. Payloads are harder.
The bungie cord though, is fantastic. So are the little GoPro cameras. One other interesting pointlet is that most of the PCBs seem to be COTS prototyping boards. He's managed to leverage a large amount of over the counter tech for this thing.
Even if he's not doing anything horridly complex (by world standards, at least) it's pretty damned cool.
Re:Homeland Security's gonna love this... (Score:5, Interesting)
One other interesting pointlet is that most of the PCBs seem to be COTS prototyping boards.
And importantly, almost entirely SMT boards. You may think that through-hole components are more robust, but SMT can survive much greater G-loads for the twin reasons of being generally much lower mass, and having a big flat plane of attachment rather than long legs with unattached sections free to bend and fatigue.This has important implications for gun-type space launches: very heavy and very, very expensive monolithic resin electronics blocks are unnecessary, properly mounted SMT boards are sufficient.
Re: (Score:3)
I haven't seen through the hole PCBs on commercial stuff for ages. Unless it's really high power stuff or the company is still using boards from a decade a go. Even for hobbyists, SMT (Surface Mount Technology) is pretty easy. Once you get a nice magnifying glass and some fine tweezers.
Re: (Score:2)
Once you get a nice magnifying glass and some fine tweezers.
And a nice iron. The smaller the tip, the smaller the thermal mass. "big" thru-hole can get away with free running a dumb power resistor across the AC mains. Tiny tips either overheat and self destruct, or have to be retinned every 5 minutes, or get cold and can't heat the pad instantly. Don't need digital display, although its nice, but do need active electronic control of the tip.
It took me decades to get around to buying some rather elaborate Hakko gear, and after about an hour of use I wondered why
Re: (Score:2)
Re: (Score:2)
If you are going to be doing much surface mount work, it's probably in your best interest to at the very least get a hot air reflow station.
Re: (Score:2)
I do down to 0402, without any optics other than what comes with my own eyes. I don't know how much longer I'll be able to pull it off, though.
Re:Homeland Security's gonna love this... (Score:4, Interesting)
The initial learning curve is harder, and you'll want a good soldering iron, but once you've cleared those hurdles hand soldering SMD is a piece of cake.
Reflow soldering is completely hobbyist-accessible too: I use a syringe of solder paste [zeph.com] to put little dots on all the pads, tweezers to place all the components, and then I lay it in a bare aluminum (NO TEFLON!) frying pan. Throw it on the stove for five minutes and pluck the board out with a pair of needle nose pliers (the pan cools too slowly) after all the solder melts.
The surface tension of the melted solder pulls all the components into alignment, so you don't have to place them perfectly. A few pins usually get messed up since I'm not as precise with the syringe as I would be with a stencil, but I just inspect with a cheap loupe and clean up any mistakes manually. Other people use toaster ovens with much success, but I've found the frying pan works great for single-sided boards.
Honestly I find it's much less tedious than through-hole soldering, and I love having access to all the cool SMD ICs that you just can't get in DIP packages. The only problem is that prototyping is a bitch. If you want to breadboard a SMD IC you have to make a SMD to DIP adapter board first. But I usually don't bother: I just design my board, get one made [batchpcb.com], manually kludge around any mistakes by lifting pins and soldering in fine wires until I get it working (usually only one or two wires per board), and then get a final one made.
Re: (Score:2)
Re: (Score:2)
I haven't had one fry yet! I'm probably going well outside the envelope specified on the data sheets, but those are pretty conservative, and the components can actually tolerate quite a bit more.
The biggest problem I have is somewhat uneven heating. One corner of the board reflows first and it usually takes 30-60 seconds between the first melt and the last one, and there's usually some wisps of smoke coming off the board by the time I'm done. The fix I've found is to turn off the heat when I know it's ge
Re: (Score:2)
Re: (Score:2)
One more tip - use lead-based solder. All modern components are rated for reflow with lead-free which melts at a much higher temperature. I think a major reason my cheesy technique works so well is the lead-based solder gives me a lot of extra safety margin.
Let me know how it goes if you try it!
Re: (Score:2)
Leadless packages most definitely can be soldered by hand (see the third photo from the bottom at http://wwwhome.cs.utwente.nl/~ptdeboer/ham/sdr/ [utwente.nl]) but it's not much fun. You make the connections using short bits of very thin solid wire, using the heat from the iron to solder both ends at once.
Re: (Score:2)
Re: (Score:2)
Re: (Score:2)
He knows he will get modded to oblivion if he got an account, as the "Space Nutters" comments are completely inaccurate and flaimbait.
Re: (Score:2)
It would have been a lot more impressive if the videos had been shot with a handheld camera.
I know we're supposed to be all gung ho for private space exploration, but I'm just not catching the fever yet.
Wake me when one of the "private" space outfits finally puts a human being in space.
Still, as a lifelong model rocketeer, I give this Qu8k guy lots of props for reaching over 100k'.
Re:Homeland Security's gonna love this... (Score:4, Informative)
Wake me when one of the "private" space outfits finally puts a human being in space
So you are suggesting that the efforts of Burt Rutan didn't qualify as "putting people into space? You also think that "Space Adventures" is a science fiction magazine?
While I'll admit it has taken longer for regular sub-orbital flights to happen since the Ansari X-Prize, private citizens have been able to get into space and even orbit. And of those who have been able to into space on their own dime (or that of a private employer), passenger spacecraft have been able to get above the Kármán line.
I agree, this particular rocket, the Qu8k, isn't especially amazing other than it has done something that few have done before on their own. 100k feet is a remarkable accomplishment, and the fact that these guys did that accomplishment on a rather limited budget is all that more amazing. Assuming they could put this into production, they have a viable sounding rocket if they care.... something which has an established market if they would care to get into that kind of business.
The interesting thing here is likely how cheap it was to build this rocket, at least compared to other vehicles of this size and performance.
Re: (Score:2)
Re: (Score:3)
A private manned spacecraft into orbit? Not yet. SpaceX and Blue Origin sure are trying, as is XCor. Yes, I'll admit that Dennis Tito went into orbit riding a Soyuz spacecraft.... sold to him because Russia allowed capitalism to enter their country and permit this to happen, unlike in America. It still was a privately-financed orbital flight with people as the crew.
BTW, the Dragon spacecraft, which was originally developed with private funds and even with the COTS money still isn't a "national-level spa
Re: (Score:2)
Sadly, you know little about what it takes to go up on a Soyuz spacecraft. Those who go up in that spacecraft have to be able to take over any position on that spacecraft and be able to fly it not just to orbit but also through re-entry and landing. They have to know all of the emergency procedures and become qualified in every way like any other cosmonaut.
Don't get my started on the chimps and dogs. Those capsules are certainly not "crewed spaceflight" rated and it only shows even more your sheer ignora
Re: (Score:2)
When has there been a private project which put a human into orbit? Did I miss a week's worth of headlines?
You'll have to excuse me. The "private" development of space is a special hobby-horse of mine. Considering how poorly "private industry" has behaved here on Earth lately, I'm not all that jacked about the prospect of them conquering space. I'm trying to think about some portion of the planet that hasn't been fouled in the name of the s
Re: (Score:2)
When has there been a private project which put a human into orbit? Did I miss a week's worth of headlines?
Yup, I think you did.
See: http://www.spaceadventures.com/ [spaceadventures.com]
For future "private" spaceflights, see also: http://www.popularmechanics.com/science/space/rockets/elon-musk-and-spacex-are-launching-a-new-era-of-private-spaceflight [popularmechanics.com]
Re: (Score:2)
I think that "spaceadventures.com" just leased a spot on a government space ship.
That's not quite the same thing as "private industry sending a human into orbit". The spacecraft was not privately built or flown or funded.
That's like me buying you a ticket on Amtrak and telling people I run a railroad.
Re: (Score:2)
The analogy doesn't quite fit, although comparing Space Adventures to an airline might. Certainly they don't build the rockets, but Space Adventures does deal with the "leasing" of the rocket complex and paying for the launch itself.
Airbus also is mostly "government owned" in terms of being a manufacturer, but I don't think companies like jetBlue who uses their airplanes can be considered a "government agency". A company like Space Adventures is mostly the same.
BTW, the spacecraft used for the Space Adven
Re: (Score:2)
Re: (Score:2)
See, those places are already unfit for human life. I assumed you would know that. But that doesn't mean corporations can't make a huge mess there.
Re: (Score:2)
We tend to be short-sighted, greedy, and in many other ways, stupid. That's inherent in our DNA, unfortunately. If you haven't noticed, governments haven't been doing a particularly good job of cleaning up after themselves in space [wikipedia.org], either. So we basically have a choice: lobby to do a better job in space than we've done so far on earth, or lock up the heavens and stay here on our own polluted little planet.
I understand -- and even share -- fouling up space as well as the e
Re: (Score:2)
I don't think private exploration of space is ever going to happen without massive help of the government.
Corporations have just become too short-sighted to pull of anything like this. It may have been possible like over a century ago when private corporations had long view (like the ones that built railroads) but today, if you can't show a bump in stock price THIS QUARTER, the CEOs and boar
Re: (Score:2)
Wake me when one of the "private" space outfits finally puts a human being in space.
This seems like a fairly arbitrary success criteria. Why not a lemur? Or one of those big ass tortoises from the Galapagos Is.?
I'm pretty sure I saw footage of humans being launched into space before - it's been done before, so doing it again would hardly be groundbreaking either.
Re: (Score:2)
Sending a vehicle into orbit has been done before too, but as soon as SpaceX did it, it was huge news. It was hardly groundbreaking since there is footage of NASA doing it FIFTY YEARS AGO.
Re: (Score:2)
Sending a vehicle into orbit has been done before too, but as soon as SpaceX did it, it was huge news.
Was it? I had to google it to recall when that was (it was 10 months ago)
It was hardly groundbreaking since there is footage of NASA doing it FIFTY YEARS AGO.
And footage of the Soviet Union doing before then. Which emphasises the point - the criteria needed to 'impress' random slashdotter x seems entirely arbitrary and unrelated to any real milestone. Specifically, the criteria that hoisting a human into orbit is a milestone any startup is required to acheive is quite ridiculous in the post human era of space exploration.
Re: (Score:2)
Which emphasises the point - the criteria needed to 'impress' random slashdotter x seems entirely arbitrary and unrelated to any real milestone.
Well said. IMHO, not that this is any less arbitrary or random or related to any real milestone, this guy launching a ~$10K rocket to well over 100,000 feet (30,400m, for my metric friends) is indeed impressive. I've been following a guy (solidskateboards, IIRC) on YouTube who routinely launches a sorbitol/KNO3 rocket to around 5,000 feet, which I thought was plenty cool enough...but 100k feet...wow.
Re: (Score:2)
Re: (Score:2)
Wake me when one of the "private" space outfits finally puts a human being in space.
As the soviets showed with Laika in 1954: putting someone UP there, is easy. It's the "getting down safely" part that's difficult.
Re: (Score:2)
While pretty impressive from a home hobbyist point of view (I'm showing this to my wife, I'm nowhere near this bad) - it doesn't break any ground in terms of rocketry. He isn't a state secret, needn't walk around icognito. If you watch the videos of the Libyan war, you see similar devices shot more or less horizontally. As you allude to, staging is much harder. Payloads are harder.
That was my reaction as well. It's a sounding rocket. A very impressive, totally DIY sounding rocket, but still a sounding rocket. You can find footage from sixty years ago of people doing exactly the same thing out in the desert.
(Not trying to put down their achievement, just pointing out that provided they don't fire it into controlled airspace, no-one's going to bat an eyelid).
Re: (Score:2)
...just pointing out that provided they don't fire it into controlled airspace, no-one's going to bat an eyelid...
Ummm...he did fire it into controlled airspace. In most of the contiguous United States, any airspace over 1200 feet above ground level (AGL) is "Class E" airspace. Okay, I don't know exactly where he launched from, so he could have been in one of the exceptions where the floor of Class E airspace is "as published", but even then, anything above 18,000 feet above mean sea level (MSL) and below 60,000 MSL is "Class A" airspace (see the 14 CFR 91 [gpoaccess.gov] and the Aeronautical Informatio [faa.gov]
Re: (Score:1)
Yes they are non-sensicle. 1) You need 6.94 miles per second for 'escape velocity' not 5. :
F=m*dv/dt=m*dv/ds*ds/dt=m*dv/ds*v,
thus
m*v*dv/ds = -mg*R^2/s^2
and
v*dv= -g*R^2*s^-2*ds
and
integral(v*dv) = -g*R^2 * integral(s^-2*ds)
so
(v^2)/2 = (g*R^2)/s + C
now when v=vo (the velocity of the rocket at launch time, the rocket isn't moving yet, but immediately about to)
then s=R (the distance from the center of the earth to the rocket is the distance from the center of the earth to the edge of the earth...the rocket is
Re: (Score:2)
Re: (Score:2)
awesome, thanks!
people who can really crunch through numbers amaze me.
Do you have a newsletter?
That has become rather less useful as a skill since the introduction of electronic computing devices a few decades back,
Re: (Score:2)
Rocket launched from a balloon? Done for decades:
http://en.wikipedia.org/wiki/Rockoon [wikipedia.org]
Re: (Score:2)
Geez, I hope the poor guy doesn't get kidnapped by the Iranians! (Or the Palestinians).
These days id be more worried about my own government coming to collect him. Then squelching his works, and tracking down everyone that has ever looked at it.
Even if you could accomplish it, I really doubt you can put something into orbit, as you will then breach other countries 'airspace' and create a 'space h hazard'. Of course once its up, all they can do is shoot it back down.
did he win the prize? (Score:1)
well...did he?
I read about the prize after the video and now I know why he put 4 GPS in there...
Gr8t (Score:1)
Outstanding! (Score:3)
That's manly.
Every aspect of that rocket was impressive, the construction, the flight profile, the telemetry, and especially the recovery. Total success.
Having lost more Estes rockets than I can remember in corn fields and cow pastures 40+ years ago, all I could think of all the way up was: "How the fsck is he ever going to find that thing again?" When they drove up to a totally intact rocket in the middle of the desert, whooping all the way, I could totally identify. That was a jaw dropping moment for me.
Well done, sirs.
Re: (Score:3)
"How the fsck is he ever going to find that thing again?"
It helps if the rocket has a GPS receiver and is broadcasting its position over APRS [wikipedia.org]. At 08:23 you can see a short clip of them receiving a position report on what looks like a Kenwood TH-D7A handheld transceiver.
Re: (Score:3)
That's the easy part. When you consider the altitude he reached, bringing down in the same state is a challenge. Telemetry is the easy part of rocketry.
Re: (Score:2)
http://blog.crashspace.org/2011/03/the-carmack-prize/ [crashspace.org] claims,
"you dont need an unrestricted GPS"
in new money: 36880 metres (Score:2)
Congratulations, here's to amateur rocketeers and other hackers doing interesting things.
For those of you in countries using metric measurement systems for space engineering, that's 36,880 metres approximately.
Re:in new money: 36880 metres (Score:4, Funny)
It's 183 furlongs, ok?
Re: (Score:2)
It's 183 furlongs, ok?
Or 1344 diplodocuses, old style.
Re: (Score:2)
Balloons can go quite a bit higher, the current amateur record is just above 40km. But even so, you can't beat a rocket for sheer style :-)
Re: (Score:2)
Why so few comments??? (Score:2)
Thank you for the (no lame music) (Score:5, Insightful)
Although personally I think if you had added the soundtrack from The Right Stuff movie (orchestral piece from end of the movie during Gordo Cooper's launch), it would've made your excellent video even more awesome, I suspect that people who do not share my tastes in music might have been put off.
Re: (Score:2)
Not put off because I don't share your taste in music, but I am put off because you took a cheap jab at mine - I like a lot of the 'crappy' pop/rock/punk/rave music. Also happen to like orchestral music as well. And yeah, I get why you might not want a music background. It's cool.
Re: (Score:2)
What was covering the lens? (Score:1)
Re:What was covering the lens? (Score:5, Informative)
The part holding the cameras was made from plastic, because he didn't have enough time to machine it. It melted when the rocket hit mach 3+, because of the compression shock wave that formed in front of it. (Commonly misreported in the media as "air friction")
Essentially, the plastic thing poked out of the rocket. The mach 3+ air had to be brought to a dead stop right in front of it. The way it does that is by forming a high pressure shock right in front of it. Basic physics, when you compress air is gets hot - in this case, melting the plastic rocket bits...
WOW... (Score:1)
Again Excellent!
Balloon + rocket (Score:2)
What this guy did is awesome, but for a second while reading the summary I got confused and hoped that someone had mounted a rocket on a balloon to be ignited when the balloon is about to reach its peak altitude. THAT would have been absolutely awesome!
Re: (Score:2)
I think that LOHAN on theregister is supposed to do that. Initial announcement [theregister.co.uk]
This is Slashdot (Score:2)
Re: (Score:2)
Why did the Go-Pro shield melt on the way up? Was it the heat conducted through the tube from the burning engines or something?
Air friction. That thing went nearly 1 km/s in still quite dense air.
If you look at the details, you can see the shield melted from the outside in.
It was also meant to be made out of machined metal, but they apparently had
to go with the 3D printed plastic prototype due to time constraints.
Re: (Score:2)
Re: (Score:2)
He was going Mach 3+ - the plastic melted from the heat from the mach shock wave. (Typically reported incorrectly in the media as "air friction")
Guidence (Score:4, Insightful)
"Better than an hour" (Score:2)
Re: (Score:2)
Depends what you're trying to do. Half-marathon: shorter is better. Pig orgasm: longer is better.
I have no idea what you're talking about. I've never run a half-marathon.
A nice little sounding rocket (Score:4, Informative)
Sounding rockets [wikipedia.org] in this size have been around for a while. The first one was the Aerobee sounding rocket in 1947. It reached 117500m. One of the smaller Aerobee variants of the 1950s was about this size. There have been many small sounding rockets over the decades; the UK and Australia launched a lot of them.
Once the rockets are up up... (Score:2, Funny)
Who cares where they come down.
"Thats not my department"
Says Wernher von Braun
Tom Lehrer - Wernher von Braun [youtube.com]
Restrictions on Civilian GPS (Score:3)
I wonder how they planned to get around the restrictions on civilian GPS. Whilst I'm sure they took this into account (at least I hope both they and John Carmack did) is that civilian GPS receivers are limited to speeds quite a bit below their speed, and altitudes of around half of the achieved altitude:
http://en.wikipedia.org/wiki/Global_Positioning_System#Restrictions_on_civilian_use [wikipedia.org]
"The U.S. Government controls the export of some civilian receivers. All GPS receivers capable of functioning above 18 kilometres (11 mi) altitude and 515 metres per second (1,001 kn) are classified as munitions (weapons) for which U.S. State Department export licenses are required."
3,516 km/h is just over 975 m/sec and they estimate an altitude of more than twice the restricted altitude.
Scary shit (Score:2)
After having just flown between Las Vegas and Chicago. The idea of a commercial plane running into an "amateur" ballon or rocket and the subsequent catastrophy has me wondering when this "viral" activity will end up going terribly wrong. I guess it will continue untill that point. It has even been in commercials on TV as a wonderful activity that companies are using to sell product.
But then I am a compputer programmer and we look at these sorts of failures.
Watch the skys.
Re: (Score:2)
Re: (Score:2)
I suspect that that is not really the case. At least in the first such case several months ago with the the group that sent a ballon up there was no mention in the press certainly that there was notification. In the Commercial (which may be fiction) the claim was that the fellow bought his weather ballon with point from his checking account I believe. If the practice goes viral I suspect that few of those people jumping on the band wagon will even know that there is a thing like controlled air space over
Re: (Score:2)
Well, so far only a few fools have hooked balloons to their lawn chairs for the hell of it.
The rocket shot was done at Black Rock Desert, where the HPR (Tripoli.org) folks have a big annual get together, and they do get FAA restrictions/clearance to do what they do.
This won't be replicated by "copycats" any time soon, if only for the time and money involved.
And, the probability of bird strikes is really a low altitude risk. How often really do planes go down from goose indigestion? Once? Twice?
Find some oth
flat earth society (Score:2)
Re: (Score:2)
yeah, it's to fireworks displays.
Re: (Score:2)
Re: (Score:2)
The UK.
Re: (Score:2)
It was a miracle we ever switched away from pounds, shillings and pence.
Re: (Score:2)
Re: (Score:2)
I don't understand the submitter's (darkjohnson) contempt for balloons, but 120k feet is not that significant for a rocket.
Balloons are slow and low-tech, hence the contempt. As rockets go, this was about as simple as it gets. 1940's technology at best, except for the 1970's propellant formulation. However, do not underestimate the difficulty of getting a small solid-propellant rocket to 120,000 feet. The apparatus may be rudimentary, but do not forget that this thing reached almost mach 3, literally faster than most bullets. The plastic camera cowling melted from the adiabatic stagnation temperature of the shockwave that
Re: (Score:3)
Balloons are slow and low-tech
Part of my indignation is because I launch high altitude weather balloons for a non-profit. The basic technology for these balloons is similar in age to solid propellant rockets. Sure, balloons are slow, but they have other advantages and disadvantages compared to rockets.
The engineering and fabrication techniques required to keep something in one piece under those conditions are pretty challenging.
Having actually made a sounding rocket that was intended to launch under similar conditions (and failed, I might add), I appreciate what you're saying. Balloons don't push the envelop as much, but they do have their own engineering challen
Re: (Score:2)
Solid propellant just works. Liquid propellant requires pumps or regulated gas pressure to drive the propellant to the combustion chamber. Liquid propellant is more difficult, thus more impressive.
AFAIK the best chemical propellants are liquified gasses: hydrogen with fluorine or O2 or O3. Better propellant is more impressive.
Re: (Score:2)
Re: (Score:2)
Re: (Score:2)