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#20
by
M129K
on 01 Dec, 2013 16:22
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I hope that I live long enough to see the Chinese become the next nation to land people on the Moon.
Unless you're 100, you probably won't have to wait long.... 
If the Chinese do it in 2025 then it will be around the time of my 75th. Back in 1999 I predicted on the BBC that the Chinese would have a crew on the Moon to celebrate the 50th anniversary of Apollo 11. Slightly wrong there!
It's just that the Chinese aren't very good at following their premises, not your fault
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#21
by
savuporo
on 01 Dec, 2013 16:38
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Beautiful launch so far, excellent coverage on live english channel, super solid live video down from the rocket. Really well done !
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#22
by
Blackstar
on 01 Dec, 2013 16:43
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What I want to know is how SpaceX fits into all of this.
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#23
by
savuporo
on 01 Dec, 2013 16:50
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And massive props to NSF for live updates here. There are basically a couple of twitter feeds, english.cntv.cn live feed ( with somewhat hilarious commentary ) AND NSF carrying this live. Other "live" spaceflight sites pretty quiet ..
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#24
by
AJA
on 01 Dec, 2013 16:53
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Anyone have the groundtrack?
Never mind.. saw the illustration on the stream. Out into the Pacific.
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#25
by
savuporo
on 01 Dec, 2013 16:56
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What I want to know is how SpaceX fits into all of this.
You could probably take a Dragon with extended fairing with some Draco Super Heavy thrusters and let Elon plot a Mars TLI trajectory to reusable Grasshopper Heavy Mark II 1.1 and get to the moon 5x cheaper and 3x faster than ..
Oh sod it. : )
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#26
by
Jim_LAX
on 01 Dec, 2013 17:22
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I read speculation earlier on another thread that the initial launch of Falcon Heavy COULD throw a payload to the moon with a free return to earth. Probably no real scientific value there but a lot of PR value!
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#27
by
M129K
on 01 Dec, 2013 17:24
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I read speculation earlier on another thread that the initial launch of Falcon Heavy COULD throw a payload to the moon with a free return to earth. Probably no real scientific value there but a lot of PR value!
I also did the math today, with a Falcon Heavy with Raptor upper stage and hydrogen in-space stages you can get an empty Dragon with 2150 kg of payload, enough for two astronauts, to the moon
and back.
Wait... What was this thread about again?
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#28
by
M129K
on 01 Dec, 2013 17:25
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Also, I missed the launch. Bollocks. Does anyone have a video of it?
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#29
by
ugordan
on 01 Dec, 2013 17:30
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Also, I missed the launch. Bollocks. Does anyone have a video of it?
Boost into LEO part: www
.youtube.com/watch?v=lgZslWEQZHY
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#30
by
savuporo
on 01 Dec, 2013 17:31
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#31
by
kch
on 01 Dec, 2013 17:34
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I hope that I live long enough to see the Chinese become the next nation to land people on the Moon.
Unless you're 100, you probably won't have to wait long....
If the Chinese do it in 2025 then it will be around the time of my 75th. Back in 1999 I predicted on the BBC that the Chinese would have a crew on the Moon to celebrate the 50th anniversary of Apollo 11. Slightly wrong there!
Don't sell yourself short -- they still have five-and-a-half years to go on that one. If it's important to them, they'll probably do it.
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#32
by
M129K
on 01 Dec, 2013 17:42
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Spaceref just rebranded Yutu as "Jack Rabbit" (double facepalm)
(I hope time referral links work here)
Edit: Darnit they don't.
Also, I missed the launch. Bollocks. Does anyone have a video of it?
Boost into LEO part: www.youtube.com/watch?v=lgZslWEQZHY
Thanks, awesome quality too!
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#33
by
NovaSilisko
on 01 Dec, 2013 18:00
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I hope we get some nice footage of the descent and landing. I remember Chang'e 2 was covered in engineering cameras which gave a lot of awesome views* (such as of solar array deployment, thruster firings, watching the moon below, etc).
I'm curious though, what's the design philosophy behind adding a number of engineering cameras vs having none (like most spacecraft)? Rather, I suppose I'm asking "why not" put small, light, low-resolution cameras across a vehicle. Priorities of signals?
*see this blog post:
http://www.planetary.org/blogs/emily-lakdawalla/2010/2774.html
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#34
by
savuporo
on 01 Dec, 2013 18:11
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I'm curious though, what's the design philosophy behind adding a number of engineering cameras vs having none (like most spacecraft)? Rather, I suppose I'm asking "why not" put small, light, low-resolution cameras across a vehicle. Priorities of signals?
There isn't any real reason. Cameras are low mass budget, low power budget. However, downlink bandwidth _is_ at premium. So putting dozens of cameras on the vehicle means you have to have buffer storage and time later to downlink video at the critical events. Having the stored video feeds available could be indispensable though for understanding and possibly resolving glitches - a luxury that was not really available for engineers a few decades ago.
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#35
by
NovaSilisko
on 01 Dec, 2013 18:18
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Having the stored video feeds available could be indispensable though for understanding and possibly resolving glitches - a luxury that was not really available for engineers a few decades ago.
That's what I was thinking as well. The solar panel deploy view especially. They would be nice for PR purposes as well. I think actually seeing spacecraft operate in their natural environment (heh) would get people more excited and interested than just a rendering.
Regarding bandwidth, I wonder how much it actually uses if it's, say, compressed 320x240 or 640x480 video? Transmission presumably would occur during otherwise uneventful times where no science investigations or engineering tests are going on, after a while of sitting on spacecraft memory. If laser communication becomes more prevalent, then that might not be nearly as much of an issue. 1080p HD video from the moon!
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#36
by
savuporo
on 01 Dec, 2013 18:23
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Regarding bandwidth, I wonder how much it actually uses if it's, say, compressed 320x240 or 640x480 video?
100-300 kbits/s, up to 500, with live H264 compression.
EDIT: and actually, the quality of the video you get from compression is pretty much a function of the bitrate, although its not linear trade between quality and bitrate. Going higher in bitrate has diminishing returns for the quality.
Depending on intended usage, you may want to hit a different sweet spot between resolution, framerate and Qp parameters for compression. Often, a VGA stream at higher fps _with the same compressed bitrate_ is perceived "better quality" than a 720p stream when watched live. However, it really depends if you want to do frame by frame analysis later or what. A good strategy is to try to downlink a "base layer" low bitrate stream from all your sources live, and downlink higher resolution from ( ring buffer ) storage opportunistically.
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#37
by
kch
on 01 Dec, 2013 18:29
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#38
by
AJA
on 01 Dec, 2013 18:54
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*see this blog post: http://www.planetary.org/blogs/emily-lakdawalla/2010/2774.html
@ALL: DO READ THAT BLOG POST! AND WATCH THE VIDEOS! Holy wow.
That is brilliant. I've half a mind to post this blogpost on all the following Wikipedia pages
- Oscillatory motion and damping
- Retrograde burn / Orbit insertion/ Orbital manoeuvres
- Momentum wheels / Control moment gyroscopes
- Radiative cooling / combustion chambers
- automatic Exposure adjustment
- Shadows
Very cool, China and Chang'E 2. Thanks!
PS: During one of those trim manoeuvres, I noticed that at first, only the throat seemed to glow, but was then followed by some part downstream on the bell glowing too. Is this exposure adjustment by the camera? Passing into orbital sunset, or does the orbiter use two settings for its throttle during these burns?
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#39
by
Rocket Science
on 01 Dec, 2013 19:03
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I wonder if anyone from Playboy read this thread title? Sounds like a regular day at the mansion...
