2017 Mar 24
Friday, Day 83
Yuan Wang Events:
CZ-4C Launch - Taiyuan, 2013 July 19
When a CZ-4C rocket took of from Taiyuan carrying three satellites, the complex operation to release them from the launch vehicle was due to take place well away from Chinese territory so it needed the services of one of China's fleet of mobile tracking stations to ensure all went well. Yuan Wang 5 was despatched to the Indian Ocean to oversee the event.
Yuan Wang 5 left its base on the Yangtse river on May 30, and headed out onto the Pacific Ocean to support the Shenzhou 10 mission due for launch on June 11. It remained there until June 26 when the Shenzhou mission ended.
Yuan Wang 3 and Yuan Wang 6 had sailed out at the end of April, initially for the Chinasat 11 launch, then they too moved into position for Shenzhou 10. After Shenzhou 10 landed, Yuan Wang 5 turned south while the other two ships went home.
Port of Call
Yuan Wang 5 arrived off Jakarta, Indonesia on July 5 and entered port. There it took on supplies and the crew got some shore leave. On July 11 it headed once more to sea and passed through the Sunda Strait between Java and Sumatra, taking it out into the Indian Ocean.
By the early hours of July 15 it had reached a point near the rev 0 ground track of Shijian 11-05. The satellite was launched from Jiuquan at 09:27 UTC that day and Yuan Wang 5 observed it about fifteen minutes later, after it had entered sun-synchronous orbit. Yuan Wang 5 would have been able to confirm that the satellite had separated from its CZ-2C launch vehicle and opened its solar panels - events that happened out of view from the Chinese mainland.
Not all launches from China to polar orbit merit the expense of sending out a tracking ship because it involves nearly two months of sailing. Controllers are usually content to wait for a satellite to re-appear over China after completing its first circuit of the globe. Shijian 11-05 probably got the attention because Yuan Wang 5 had a more-pressing reason to be in the area. Observing Shijian 11-05 was a bonus.
After tracking Shijian 11-05, Yuan Wang 5 headed east but not at full speed because the destination was only a few hundred kilometres away and it had 3-4 days to cover the distance.
On July 18, a NOTAM appeared for an area of China south of the Taiyuan Space Centre indicating a launch was due July 19 at about 22:40 UTC. A few hours before the time indicated in the NOTAM Yuan Wang 5 settled itself about 1400 kilometres west of Australia, directly below the trajectory that would be taken by a launch from Taiyuan to sun-synchronous orbit.
July 19 - Taiyuan
A CZ-4C rocket was launched at 22:37:55 UTC carrying Shijian 15, Chuangxin 3 and Shiyan 7. The time is known precisely because Chinese TV showed images from the launch control room and it appears on the status display above the video screen. The timing is a little unusual as China tends to conduct launches by issuing the command for rocket ignition precisely on a full minute. First movement of the launch vehicle then occurs 3-5 seconds later when the correct thrust level has been reached. The time in this case suggests the ignition command was issued at 22:37:50 UTC.
The TV view of the launch control centre video screen also showed a list of mission events. Three of them are of interest. At the bottom of the list can be seen 1172 seconds, 1257 seconds and 1349 seconds. Logic says that they are the anticipated times for releasing the satellites from the launch vehicle, given as elapsed time after lift-off. As to the order in which the satellites were going to be released, the quality of the video does not allow reading of the names.
Putting together the launch time and the event times gives satellite separations at about one and a half minute intervals with 23:57:27 and 23:58:52 UTC on July 19 and 00:00:24 UTC on July 20.
The CZ-4C upper stage rose above Yuan Wang 5's northern horizon at about 23:53:45 UTC. By the time it was near the zenith, it had released all three satellites. The cluster of launch vehicle and satellites then set below Yuan Wang 5's southern horizon at around 00:07:40 UTC.
Yuan Wang 5 immediately sailed away on a heading to take it back to the Sunda Strait and the Pacific Ocean. Ships of the fleet tend to stay at sea for about one month before putting in to port for supplies so it may be mid-August before it docks again. In the Pacific area, Yuan Wang vessels have been seen at Suva (Fiji), Auckland (New Zealand) and Jakarta. Alternatively, it may call in at a southern Chinese port.
A sailing plan filed when it moved on from tracking the Shenzhou 10 mission indicated it will not return home until December 5. China has more launches in the pipeline this year but information about them is not as openly available as for previous years. Yuan Wang 5 will certainly be involved in the Chang'e 3 Moon launch, probably due in November. Tiangong 1 may be brought down from orbit for a destructive re-entry during October. Monitoring its last moments could be on Yuan Wang 5's schedule too.
Page Date: 2013 July 21
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