
SpaceX CRS-6 Hard Landing – Tracking Cam - antoviaque
http://www.spacex.com/news/2015/06/24/why-and-how-landing-rockets?
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lutorm
I think the coolest part about that video is how the aerodynamic guidance is
very noticeable. Look at the significant angle between the rocket body and the
velocity vector (as indicated by the contrail) and you can see how the rocket
isn't just falling ballistically but is "flying" towards its intended
touchdown point.

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mkempe
Note that tomorrow the 28th, at 14:21 UTC, SpaceX will try again! [1] [2]

[1]
[http://livestream.com/spacex/events/4152712](http://livestream.com/spacex/events/4152712)

[2] [http://qz.com/438866/spacex-has-two-important-missions-to-
pe...](http://qz.com/438866/spacex-has-two-important-missions-to-perform-
during-elon-musks-birthday-weekend-rocket-launch/)

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mmastrac
> before it reached our drone ship, “Just Read the Instructions”

Glad to see the Iain M Banks inspiration here.

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wiredfool
I've always wondered -- is that read as in 'go read', or read as in past
tense?

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brock_r
They are meant to be a play on words, with several different possible
meanings.

In the books, the original AI's would get to name themselves after much
reflection.

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comex
But the "actual" names of the AIs would be in Marain, not English and thus
likely wouldn't have the same syntactic ambiguity...

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netfire
Curious how they are tracking the rocket's descent to catch it on camera. It
seems like they lose visual of the rocket and then are able to re-acquire it
fairly quickly. Are they using some sort of infrared or other tracking beacon
on the rocket that the camera can follow or using trajectory data to determine
where the camera should be pointed?

Also, I'd love to know when these launches are going to happen further in
advance. The Launch Manifest page just shows the next launch as happening in
June[1]. Is there a better place to get more exact planned launch dates
further in advance?

[1] [http://www.spacex.com/missions](http://www.spacex.com/missions)

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JoblessWonder
Probably Radar based tracking with the possible add-on of multiple visual
angles being able to communicate with each other. If you are interested in
some further reading, here are some interesting articles/videos:

Shuttle launch imagery from land, air and water -
[http://www.nasa.gov/pdf/167722main_LaunchImagery06.pdf](http://www.nasa.gov/pdf/167722main_LaunchImagery06.pdf)

Software to control a telescope (with sample videos) -
[http://www.optictracker.com/Home.html](http://www.optictracker.com/Home.html)

Description of NASA's setup - [http://photo.net/casual-conversations-
forum/00cv5p](http://photo.net/casual-conversations-forum/00cv5p)

PDF of L3's system which provides a great overview -
[http://www2.l-3com.com/ios/pdf/L-3%20Brashear%20Capabilities...](http://www2.l-3com.com/ios/pdf/L-3%20Brashear%20Capabilities%20-%20Range%20Systems%2001-11-08.pdf)

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netfire
Thanks for the links! I'll try to look at those when I have some time. On a
quick glance, it looks like most of those systems are ground based and pretty
large (which works great for launch footage), the video posted _appears_ to be
looking down on the landing pad at the end, which leads me to believe the
camera is located on a helicopter.

Could a radar based camera be mounted on a helicopter, or could land-based
tracking devices work in conjunction with a helicopter mounted camera to
achieve the tracking?

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ohitsdom
Awesome new video of the second landing attempt. Glad they identified the
issue, can't wait to watch the next attempt! Also looking forward to them
trying this on land. I live in the Cape Canaveral area, so it'd be pretty cool
to be able to track a rocket coming in for a landing.

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mholt
I'm also excited about the on-land landing attempt. Should be August 9:
[http://spacexstats.com/mission.php?launch=25](http://spacexstats.com/mission.php?launch=25)

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teleclimber
I live in LA, if they are actually going to attempt a return to land, it's
going to be hard to resist going up there to try to catch a glimpse of it.

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jczhang
Where is it?

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teleclimber
Vandenberg. But seeing anything might be a challenge. They don't let anybody
near there during launches.

[http://www.spacearchive.info/vafbview.htm](http://www.spacearchive.info/vafbview.htm)

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stcredzero
It seems like they could replace the landing legs with a parachute, which they
could catch in mid-air, as intended for the Genesis probe. Bringing the 1st
stage nearly to a stop at some point mid-air should be way easier than landing
it on the ground.

For that matter, could a balloon be used as a recovery method?

Another alternative: Land in an artificial pond. The lake could be filled with
a liquid specifically formulated to be kind to the rocket parts. (Perhaps just
reservoir quality water?) The design could again dispense with the landing
gear. Perhaps sturdy heat-resistant ballutes could inflate to take the water-
impact and hold the rockets up and out of the water?

EDIT: Wow, so much anger! For one thing, all the above schemes involve first
coming to an almost-hover mid-air. Also, why is everyone imagining such an
amazing tone from my post? Please produce a quote that justifies this
assumption. (Hint, it's irrational. Just take my brainstorming at face value.)

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DavidSJ
It always amazes me how people see this video and immediately think "I need to
redesign this for them" rather than "wow, that prototype is amazingly close to
working beautifully".

It's as if a complex software system is being tested for the first time, a
couple bugs are found, and onlookers think the right answer is to redesign
everything from scratch.

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stcredzero
Just relax, man. I'm not claiming that I have "the answer." Seeing the landing
1st stage just makes me wonder about all the other possible schemes. (Probably
the same thing happened when the Wright Flyer was first seen.)

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krschultz
Hacker News is harsh to people suffering from the Dunning-Kruger effect, and
doubly harsh for those critical of SpaceX.

That said, your first comment really comes across about as aloof as some non-
technical guy saying "how long will it take to build Facebook? It's a website
right?"

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stcredzero
_Hacker News is harsh to people suffering from the Dunning-Kruger effect, and
doubly harsh for those critical of SpaceX._

The 1st doesn't apply, and the last one is only in the imaginations of knee-
jerkers.

 _That said, your first comment really comes across about as aloof_

Again, this has everything to do with some "tone" in your imagination.

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grkvlt
> The [Dunning-Kruger effect] doesn't apply

But how could you tell?

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arman0
I wonder if you could use an air "force field" to capture the rocket. e.g. a
circular arrangement of air turbines, dynamically adjusted to smoothly capture
and land the rocket. Has something like this been tried?

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cryptoz
I'm not sure if that's ever been tried, but it certainly won't work for
SpaceX. The landing system has to be able to work on any solid, flat surface
in the solar system, such as the surface of Mars. There are no force fields on
Mars.

Edit: Every thread on HN or reddit usually has people suggesting other methods
of landing rockets that require huge, specialized infrastructure. The primary
goal here is to land on Mars without large or complex infrastructure. So even
if you think you can devise a cheaper or 'better' system, if it doesn't work
on Mars, it doesn't work at all.

