DPRK Launch: Things to Look For
posted Thursday April 2, 2009 under north-korea, outer-space by geoffrey_fordenWeather conditions over the Korean peninsula look like they favor a Saturday, 4 April 2009 launch. Hopefully, we will see something more of the launch than the 10 seconds or so of video that came out for the Tae’podong 1 launch in 1998. So, what should the casual observer look for? Here is my list:
1) Relative size of the first, second and third stages
2) How many engine nozzles are sticking out of the first stage?
3) Can you see vernier engines? (Little engines that help keep the rocket vertical and on the proper trajectory during flight.) They might either be down at the bottom of the first stage with the other engine nozzles or perhaps sticking out of the side of the first stage.
4) How big is the nose fairing (the nose cone covering whatever payload is there). Does it have a bigger diameter than the third stage? Can you tell its size relative to, say, the Safir rocket’s nose fairing?
Assuming any satellite makes it into orbit:
1) What are the apogee (maximum height of the orbit) and perigee (minimum height of the orbit)?
2) Did North Korea announce the payload mass the way Iran did? If they do, is it more massive than the Omid? Or on the same scale as the Omid?
3) Did the first and second stages land in the announced stay clear zones? (I expect that other countries, like Japan, will announce this.)
Other readers will, of course, have their own list of things to look for and I imagine they will not be shy in listing them.
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Try also to calculate the acceleration of the launcher. It is crucial to calculate the thrust.
— Tal Inbar · Apr 2, 03:47 PM ·
Also, the color, transparency, shape and size of the exhaust gas plume will be very interesting, since this gives us hints about 1.) general level of thrust (thus, in combination with the liftoff-acceleration, allowing us an estimation of the mass), 2.) propellant combination, 3.) number of chambers and 4.) other details of interest like the type of cooling, TVC etc.;
Another item on my list would be how the interstage-sections look like in detail (Paektusan-1/Taepodong-A obviously used a trellised structure for “hot-staging”, in contrast to Safir IRILV).
Certain protruding structures on the outside of the missile may allow us conclusions about the internal layout – cable ducts typically bridge tank structures, external fuel lines are giveaways for the number of engines (and the design heritage) etc.;
Another point would be: are there fins? Which shape/size/proportions do they have?
And we should not forget about the general dimensions/proportions of the missile – especially watch out for something that could allow a scaling of the diameter(s?).
BTW, Geoff: i think a general “missile-check-list” is a really good idea!
— Jochen Schischka · Apr 2, 05:12 PM ·
Very quick (horribly ignorant) question: is the launch expected to go into Japan’s airspace, or will it be too high by then?
— Magpie · Apr 2, 10:22 PM ·
The visual (better, photometric) brightness of the satellite and, if separate, third stage once in orbit. There is an imperfect but useful empirical correlation between brightness and size.
— Allen Thomson · Apr 3, 07:47 AM ·
To Magpie:
That question is not as easy to answer as it might seem (so it’s obviously a good one), because there is no universal definition of “aispace”; most nations use a height of 80 or 100km, but i don’t know which definition the Japanese have adopted (does anybody have the exact value at hand?).
I personally would expect the “Unha-2” to reach an altitude of over 100km (and probably even 150+km) before crossing the 12-miles-line of Japan; Thus, i’d assess the probability of a japanese intercept-attempt as rather low (as far as i see, the NK’s rattled with their toothpick, and the Japanese rattled back with their swiss army knife…the rest is mostly typical media-hype) if the 2.stage of the DPRK-launcher works as intended (an overshoot of the 1.stage in this dimension would be extremely surprising, while a possible malfunction of the upper stage(s) is definitely a scenario to be considered).
But let’s wait and see…
— Jochen Schischka · Apr 3, 08:15 AM ·
New images as of April 2:
http://www.isis-online.org/publications/dprk/MusudanRi_2April2009.pdf
http://www.globalsecurity.org/wmd/world/dprk/no_dong-imagery-20090402.htm
— Tal Inbar · Apr 3, 03:45 PM ·
I see the launch has been scrubbed for today (4 April).
“link text“http://news.bbc.co.uk/1/hi/world/asia-pacific/7982835.stm
— Bruce MacDonald · Apr 4, 05:04 AM ·
Xinhua created special coverage page :
http://news.xinhuanet.com/english/2009-03/30/content_11097574.htm
— Tal Inbar · Apr 4, 06:44 AM ·
If this is an orbital launch, what is the likely orbital plane of the satellite? Is it going to achieve evening visibility in the Northern hemisphere, for example? Speaking from an observer’s point of view, it will be hard to see a 50cm cube (assuming this is the same as Omid) in a 40° i orbit from 51° N.
— Bruce MacDonald · Apr 4, 01:54 PM ·
Unfortunately, Bruce, there is every reason to believe that, if North Korea does launch a satellite, it will be in a 41 deg inclination orbit since that is what the “stay-clear” zones are consistent with. On the bright side (certainly a pun since it would actually be a disaster if North Korea launched a satellite) I think this will be much larger than the Omid since the rocket is much, much larger. But that, of course, remains to be seen.
— Geoff Forden · Apr 4, 02:00 PM ·
Well, i am still not so sure if the north-korean launcher is “much, much larger” than Safir IRILV; I can’t exclude this possibility, though (regrettably, the open-source evidence i’ve seen so far can’t be considered conclusive).
But even if both nations should eventually turn out to use the same or a similarly-sized (small) missile, i’d expect the DPRK-satellite to be somewhat bigger (or perhaps in a higher orbit), since their launch directly towards the east will allow gaining about 100m/sec more out of the earth’s rotation.
I think it’s also quite interesting to note that (if the launch succeeds) at least part of the US-population (up to about the height of New York) will from time to time have the (questionable) honor of a north-korean satellite crossing the sky directly above their heads; On the other hand, i find it intriguing that the likely ground-track will strictly avoid Russia. (BTW, a nice side-effect of the Omid-satellite’s 55°-orbit was that it did pass over most of Europe.)
Might be a question of the intended audience of these “communications satellites” (they sure have a message to communicate, not necessarily a verbal one)…
— Jochen Schischka · Apr 4, 04:26 PM ·
Well, it was launched. As of 0730 Israel time no pictures or video is available.
— Tal Inbar · Apr 4, 11:29 PM ·
Some animations from AGI:
http://www.agi.com/corporate/mediaCenter/news/north-korea-missile-launch/
— Tal Inbar · Apr 5, 01:27 AM ·
SPLOOSH
Stage one of the missile fell into the Sea of Japan/East Sea. The remaining stages along with the payload itself landed in the Pacific Ocean.
No object entered orbit and no debris fell on Japan.
http://www.northcom.mil/News/2009/040509.html
— Magpie · Apr 5, 06:32 AM ·
Any confirmed sightings yet? There’s only one unconfirmed report on SeeSat that it achieved orbit. I’ve just checked Space Track and there’s nothing on the Catalog Change Report as at 12:46 UTC.
— Bruce MacDonald · Apr 5, 07:46 AM ·