More on the satellite launch trajectory
A lucky close-up of a computer screen in TV pictures from the Sohae launch facility is providing further clues as to the true launch trajectory of North Korea’s Unha-3 rocket launch.
[This story has been updated, see below]
The shot, included in pictures broadcast by Russia Today (see below), appears to show the satellite’s orbital path on a computer screen. It begins at the top of the image (click for a better view) and sweeps down across North Korea traveling southwards until it skirts the western coast of Mindanao and travels onwards to cross Australia’s eastern tip.
When putting a satellite into solar-synchronous orbit, the launch path needs to be inclined at 97.4 degrees, but North Korea’s notifications to international organization implied a launch path inclination of 88.7 degrees. That’s some way off the path the rocket needs to be taking.
Based on the TV image, Molczan revised his prediction to 94.5 degree inclination.
The orbit is not sun-synchronous, but better than the 88.7 deg orbit implied by the NOTAMs, for the stated purpose of the satellite. — Ted Molczan on SeeSat-L, April 11, 2012.
The trajectories are working on the assumption that the third stage of the rocket will shift its trajectory to put it on a new path.
And there’s a possibility the launch track could be right on target for a solar-synchronous orbit:
To be precisely sun-synch, a 500 km orbit must be inclined 97.4 deg. The apparent nearly 3 deg deficit may be an indication of the performance limitation of the launcher. I do not exclude the possibility that the displayed track was faked to mislead the news media, but it should not have been more difficult to produce a high-fidelity fake, assuming the work was done by the trajectory specialists. Considering the relative position of the numerals 4 and 7 on a keypad, a simple, honest typo also cannot be excluded. – Ted Molczan on SeeSat-L, April 11, 2012.
So, could a typo be throwing us off? And, if so, let’s hope it doesn’t make it into the actual launch systems.
Building on the typo hypothesis, if the ground track displayed in the launch control centre resulted from a set of orbital elements with a typo affecting a single digit of the inclination, such that 97.45 was entered as 94.45, then the true orbit can be recovered from the TLE I estimated from the track, simply by correcting the typo. Here is the TLE with the supposed typo: – Ted Molczan on SeeSat-L, April 11, 2012.
Here are the two images he’s referring to. Click to get a better view.
Update: Satellite watchers now believe they misinterpreted the TV images and, in fact, the launch track looks good for a solar synchronous orbit:
|Print article||This entry was posted by Martyn Williams on April 11, 2012 at 23:21, and is filed under Space. Follow any responses to this post through RSS 2.0. You can leave a response or trackback from your own site.|
No comments yet.
No trackbacks yet.
about 11 months ago - 2 comments
The North American Aerospace Defense Command, better known as NORAD, says it tracked the North Korean rocket launch and that it appears to have placed an object in orbit. Here’s the statement, issued out of Peterson Air Force Base in Colorado, NORAD said: North American Aerospace Defense Command officials acknowledged today that U.S. missile warning systems…
about 11 months ago - 5 comments
North Korea’s state media has claimed success in its attempt to put a satellite in orbit. Here’s the KCNA bulletin that ran just after noon local time: The second version of satellite Kwangmyongsong-3 successfully lifted off from the Sohae Space Center in Cholsan County, North Phyongan Province by carrier rocket Unha-3 on Wednesday. The satellite…
about 11 months ago - 4 comments
So much for delays, technical problems and bad weather. (And so much for satellite imagery analysis!) North Korea launched its rocket on Wednesday morning local time at a little before 10am in the morning, according to reports from regional governments. The missile was launched from the Sohae-ri launch facility, according to an immediate report from…
about 11 months ago - 1 comment
A NorthKoreaTech/38 North exclusive, with contributions by Nick Hansen and Michelle Kae New GeoEye satellite imagery from December 10 shows activity at North Korea’s Sohae Satellite Launching Station (Tongchang-ri) related to the removal of the Unha rocket from the launch pad, a process that is probably still underway and will not be completed before December…
about 12 months ago - No comments
The latest satellite imagery of North Korea’s Sohae-ri Launch Facility is in from GeoEye and adds weight to possibility that weather is causing problems at the launch pad. The image, taken earlier Monday, shows a blanket of snow covering most of the launch facility. Visible in some areas are vehicle tire tracks, indicating some movement,…
about 12 months ago - No comments
North Korea has extended the launch window for its Unha rocket, a day after saying they were looking to “readjust the launch timing.” The rocket was originally scheduled to launch sometime in a two week window from December 10 and 22nd. The DPRK’s Korean Committee for Space Technology now say the launch window will run an…
about 12 months ago - No comments
A week after North Korea signaled the world that it planned to attempt a second rocket launch this year, the country has signaled it may delay that launch. The news came in a statement from the Korean Committee of Space Technology that was carried on Sunday by the state-run Korea Central News Agency, As announced, we are…
about 12 months ago - 1 comment
A joint NorthKoreaTech/38 North exclusive, with analysis by Nick Hansen. Summary North Korean preparations for a new rocket launch later this month appear to be proceeding more slowly than previously reported in the press according to analysis of commercial satellite imagery from December 4 and past DPRK test practices. Moreover, since this is Pyongyang’s first…
about 1 year ago - No comments
It’s sadly not possible to get a live look at North Korea’s Sohae launch facility, but we do have the next best thing: a satellite image from earlier today. The image was taken by a GeoEye satellite at 11:34am local time (0234 GMT) and shows dustings of snow across much of the launch facility. (As…
about 1 year ago - 3 comments
We’ve got more details on North Korea’s plans to launch a rocket later in December, including the daily launch window and where parts of the rocket might drop to sea. [Updated: See below] The details were included in a notification sent from the DPRK’s embassy in London to the International Maritime Organization (IMO), which is…