Amateur rocket launch reaches 121,000 feet • Hacker News Board

Re: Amateur rocket launch reaches 121,000 feet

#31

Post by rsl7 » Thu, Oct 20, 2011, 4:42 PM UTC

pavel_lishin wrote: post #26

qntm wrote: post #23

Earlier quoted context omitted.

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.

Re: Amateur rocket launch reaches 121,000 feet

#32

Post by mhb » Thu, Oct 20, 2011, 4:43 PM UTC

jgrahamc wrote: post #28

mhb wrote: post #18

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?

Re: Amateur rocket launch reaches 121,000 feet

#33

Post by lancefisher » Thu, Oct 20, 2011, 4:44 PM UTC

jeffbarr wrote: post #27

jgrahamc wrote: post #15

Earlier quoted context omitted.

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…

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

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/

Re: Amateur rocket launch reaches 121,000 feet

#34

Post by user24 » Thu, Oct 20, 2011, 4:46 PM UTC

alphadog wrote: post #24

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...

Re: Amateur rocket launch reaches 121,000 feet

#35

Post by JabavuAdams » Thu, Oct 20, 2011, 4:46 PM UTC

alphadog wrote: post #24

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.

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

Re: Amateur rocket launch reaches 121,000 feet

#36

Post by JabavuAdams » Thu, Oct 20, 2011, 4:47 PM UTC

tibbon wrote: post #7

jcapote wrote: post #4

"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?

GPS satellites are much higher than that.

Re: Amateur rocket launch reaches 121,000 feet

#37

Post by JabavuAdams » Thu, Oct 20, 2011, 4:49 PM UTC

jgrahamc wrote: post #9

jcapote wrote: post #4

"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

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.

Re: Amateur rocket launch reaches 121,000 feet

#38

Post by artursapek » Thu, Oct 20, 2011, 4:50 PM UTC

alphadog wrote: post #24

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.

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.

Re: Amateur rocket launch reaches 121,000 feet

#39

Post by artursapek » Thu, Oct 20, 2011, 4:55 PM UTC

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

Re: Amateur rocket launch reaches 121,000 feet

#40

Post by imd » Thu, Oct 20, 2011, 4:56 PM UTC

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