Amateur rocket launch reaches 121,000 feet | Hacker News Reader

Amateur rocket launch reaches 121,000 feet

ddeville.com

165 pointszackbelow54 comments

121,000 feet = 36.88 km

From Wikipedia: The Kármán line lies at an altitude of 100 kilometres (62 mi) above the Earth's sea level, and is commonly used to define the boundary between the Earth's atmosphere and outer space.

That's not space. Though it's an amazing feat nonetheless.

*feat.

But I'd say that 121,000 is pretty amazing feet too...

:-) Thanks!

Corrected.

It all depends whether you're using that metric, though -- it's all fairly arbitrary. X15 pilots were considered astronauts for exceeding 100k ft.

The threshold was 50 miles for X-15 pilots to be considered astronauts, which is 264k feet.

I knew I should have looked that up. Fuck! Thanks.

I was waiting for the camera to stop picking up sound the whole time. It got really squeaky and full of static towards the peak but it never seemed to happen.

Being attached to the rig it could never go dead silent.

Sound vibrations will still be picked up in a vacuum in this case. Vibrations through the rocket body will be transmitted to the camera body (direct contact) which will then be transmitted to the microphone (again, direct contact). According to Wikipedia[1], 90% of the Earth's atmosphere, by mass, is at an altitude of 52,000 ft or lower.

[1] http://en.wikipedia.org/wiki/Atmosphere_of_Earth#Pressure_an...

It's not an artificial boundary. It's the approximate maximum altitude at which winged vehicles have to move faster than the orbital velocity (at that altitude) in order to attain lift (where lift is depending on the pressure at that altitude). A wing moving below orbital velocity and above that altitude will not get lift at any angle of attack, just drag.

If you look at the cut open V2 rocket in the Imperial War museum in London you can see about 1/3 of the innards is the control system; gyro's, inertial guidance etc. Today you can buy that on a chips from digi-key, farnell, sparkfun or wherever for say $50 or even just root your smartphone and use it as the control system. It always surprises me that there is very little precision rocketry or ROV proliferation amongst the countries and political/religious movements with extreme agendas out there.

For the cut, you can take a look here: http://en.wikipedia.org/wiki/File:Esquema_de_la_V-2.jpg and the corresponding Wikipedia article: http://en.wikipedia.org/wiki/V-2

Technologically impressive, but a weapon...

Sending your own widget up and having it bring back snapshots of other continents and a round Earth, only seconds later. What an amazing feeling it must be. Makes me wanna go dig up my old mechanics book. Can someone give a ballpark figure of how much it would cost to build something like this and how long it took them?

You could cheaply reach the same altitude using a helium balloon. 121,000 ft is only 37km. Plenty of home grown helium balloons have reached that height (and higher).

My project reached 32km: http://blog.jgc.org/2011/04/gaga-1-flight.html

What a feeling indeed. The photo with the black sky and the Earth's curvature made me, inexplicably, pump my fist in the air and say "Yeah!"

This is pretty awesome.

"As the GPS devices on Qu8k failed to log readings above 100,000 feet, the attempt is likely disqualified."

would love to know what happened

Went higher than the GPS satellites could see?

No, but there are limits on how high commercial GPS receivers will work to prevent them from being used to guide ballistic missiles.

But the rules is that the gps devices needs to record a measurement greater than 100k feet. If that's higher than what GPS satellites can see then no one can win.

GPS satellites are much higher than that.

Two things:

First, GPS satellites are in orbit ~20,000 km altitude, so this rocket is nowhere near too high. The beamwidth is pretty wide (it covers the entire half of the Earth, after all). Some quick research shows that below 3–4000km, there isn't much difference. http://emergentspace.com/gps_pubs/SSVP-v1.07-2column.pdf.

You should be able to get exact orbits (to the centimeter!) from the NGS (http://www.ngs.noaa.gov/orbits/), if you're interested.

Second, its the receiver that sees the GPS satellites, not the other way around. The satellites transmit, the receiver does not.

Well, it could easily be that they hit the CoCom limit on the GPS units they were using: http://blog.jgc.org/2010/11/gaga-1-cocom-limit-for-gps.html

Perhaps the GPS devices were disabled by speed, or altitude, and didn't have time to reset while at apogee to get the reading.

Yes, this. There's an ongoing discussion on arocket regarding these issues. It's a problem for many amateur teams.

I'm surprised they didn't specifically seek out a receiver that implemented the rule correctly. Since it's an "and", not an "or", a proper receiver should have kicked back in by the time it reached apogee.

I thought commercial GPS was disabled above 60,000 ft.

It says here[1] "All GPS receivers capable of functioning above 18 kilometres (11 mi) altitude and 515 metres per second (1,001 kn)[56] are classified as munitions (weapons) for which U.S. State Department export licenses are required. These limits attempt to prevent use of a receiver in a ballistic missile." News to me!

http://en.wikipedia.org/wiki/Global_Positioning_System#Restr...

People have built their own, though. It's not easy, but it can be done.

The question is, does launching a rocket into space technically count as export?

depends where it lands, maybe.

Does that law apply GLONASS as well?

I worked at one of the major GPS manufacturers as a hardware/firmware designer and we stopped tracking above a certain altitude and over a certain velocity due to government policy. I remember one time there was a bug report from a customer complaining that our GPS would not work after mach 2 or some extreme speed. This ended up being a "qualified" foreign government client, so a new firmware version was sent which removed the restriction.

Can't they confirm that the altitude met the contest minimum based on how much earth curvature there is in the photos?

They would have to compensate for artificial curvature introduced by the cameras they are using. If you look at the images you can clearly see that effect.

They should be able to do that. No?

Yes camera calibration is a well known problem. You have some nice straight lines from the launch pad structure you should be able to do it with.

I don't have anywhere near the smarts to pull something like this off (maybe one day, one day), but I'm always so excited when people try these and they work.

Awesome job

Build something else. Whatever it is that you build you end up with that awesome "I built that" feeling. Last night I hacked to 0230 on turning a set of 50 GE Color Effects Christmas lights into a 7x7 color display. No one around me really understands why this was worth staying up half the night for, but when I finally got control of the serial bus protocol for programming the lights and saw my display work under my control it was awesome.

What they looked like before I started hacking them: http://www.costco.com/Browse/Product.aspx?Prodid=11630618

Short video of the first full glitch free run of the lights under my control: http://www.youtube.com/watch?v=P9SOI9EnjTg

That looks great. Will you be posting any info about how you did this?

Yes, I will. When I've got it doing something useful I will post a full blog post with details and also with the source code etc.

Some more pictures to give you the idea:

1. All the LEDs removed from the cable and stuck into a specially drilled piece of thin plywood: http://yfrog.com/hwy2snj

2. Reverse of the plywood showing the bulb with all the cables cut. Had to cut, strip and solder all 288 cables back in place: http://yfrog.com/j2xp8gsj

3. Little shot of the rewiring on the back. The colored pieces are tiny bits of heatshrink that I put in place to insulate everything: http://yfrog.com/nzh3ngdj

Here's a good post from someone hacking these Christmas lights, and reverse engineering the protocol: http://www.deepdarc.com/2010/11/27/hacking-christmas-lights/

At Twin Cities Maker a few of our members are undergoing a project to turn these into a large color changing glass block wall. It's been a pretty cool project to watch.

http://www.tcmaker.org/wiki/doku.php?id=projects:led_signboa...

http://www.flickr.com/photos/eagletusk/6259626384/

We used shiftbrites in our 7x8 window at Hive13 adnd it worked out very nicely. Last week we got it working with OSC and Processing - http://www.hive13.org/?p=527 - which should make connecting to it with a wide variety of software pretty easy.

Related; Copenhagen Suborbitals - homegrown opensource _manned_ rocket: http://www.copenhagensuborbitals.com/ - Peter Madsen (one of the two guys building this thing) also built a submarine..

Edit: June launch attempt http://www.youtube.com/watch?feature=player_embedded&v=K... http://www.copenhagensuborbitals.com/contentgfx/Rocket-2011_... http://en.wikipedia.org/wiki/Copenhagen_suborbitals

I'm impressed with the machining on this. It looks like he made it at home in his own shop. It looks very solidly welded and bolted together. As an ID student that's the most amazing part for me, the thing had to have been really solid to not just fall apart under that much speed. Edit: Although I was disappointed by the lettering coming off the side of the shaft and covering the camera lens. Something that would be hard to predict :P

If GPS failed before 100,000 ft (and it looks like any commercial GPS would), what about the altitude charts on the project's homepage?[0] How were they generated? Can that data-gathering method qualify it for the Carmack challenge?

0: http://ddeville.com/derek/Qu8k.html

As to how they were generated, the charts are labelled. The first shows raw acceleration data, plus the first and second integrals of that data. The second shows data from a _simulation_, which was tweaked after the flight to approximate more closely data that they do have.

I am not sure if anybody would know here but do we need to take permission from FAA for doing this kind of stuff?

Watch the video! It's one of the coolest things I've seen in awhile.

One of the most awesomest things I've seen in a while.

Pretty impressive, but that ain't space.

Agreed. It's in the stratosphere and might be called 'near space', but it's not above the Karman line.

http://en.wikipedia.org/wiki/Kármán_line

It's above more than 99% of the atmosphere, very nearly space.

The pressure is around the same you'd find on Mars (on the ground), incidentally.

I read that as "dude sends epic homegrown into space." I pictured an enormous plant in a hydroponics research facility, with growth unfettered by gravity...

Looks like they were at the Black Rock Playa. Hope they take all their moop with them, since the Burning Man people just got done cleaning it up...

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