Background

China has two launches planned over the night of 2022 February 26/27 (UTC). The first is CZ 4C rocket out of Jiuquan at ~23:43 UTC carrying the second L-SAR 01 satellite. The second is an early-morning CZ 8 out of Wenchang reportedly carrying a quantity of small satellites.


Yuan Wang 7

For the L-SAR 01A launch, on January 26, the Yuan Wang 7 tracking ship was sent to mid Indian Ocean to monitor the first few minutes after satellite separation while the radar aerial and other appendages were being unfurled and the attitude control system was firing up. It then returned to China.

After replenishing its stores, Yuan Wang 7 returned to the Indian Ocean, departing the Sanya Anchorage near Hainan Island on February 12. It arrived on station February 24, near the location it had used for the L-SAR 01A mission.

It is unusual for one of the tracking ships to conduct two consecutive support missions. Normally a return to port would be accompanied by departure of one of the other three ships in the fleet to support the next launch. On this occasion, all three remained in their home port on the River Yangtse. It begs the question of whether Yuan Wang 7 carries a specialised piece of equipment needed to support these particular satellites.

For launches generally, the tracking ships probably don't engage directly in the launch mission, their job is to monitor and confirm that all has gone well. They are probably not there to send commands for example, but may have the ability to do so should something have gone awry with the computer-controlled sequences that govern satellite release and start-up. They only have, typically, 10-12 minutes of contact within which to react.


L-SAR 01B

Launch from Jiuquan Space Centre is scheduled February 26 at ~23:43 UTC in order to place the satellite in the same 06:00 LTDN, 600 kilometre sun-synchronous orbit as its predecessor. The two satellites will then match orbit height and commence working together.

From L +17 minutes to L +30 minutes (~23:00 to ~00:13 UTC) Yuan Wang 7 will have L-SAR 01B above its horizon and will be able to communicate with it. The maximum elevation will be 52° and it will be to the west of the ship. There will not be another opportunity for communication because the next circuit of the Earth will pass below the horizon.

On the map, the solid ground track is the L-SAR 01B launch and the solid yellow boundary is Yuan Wang 7's radio horizon for its 600 kilometre orbit.


CZ-8 Launch

About three hours after L-SAR 01B, a CZ 8 rocket is due to depart the Wenchang Space Centre. Indications are that it too is heading for sun-synchronous orbit but, for an on-time launch, LTDN will probably be around 09:15. It will reportedly carry a quantity of small satellites. Height of the planned orbit has not been published but it is likely to be near 525 kilometres.

Precise time of launch is not known. The navigation warning for the first stage drop zone indicates it will be February 27 soon after 02:30 UTC but there may be a contingency window of about one hour to cater for a short delay in the countdown.

Launch will not be direct to sun-sychronous inclination (97°.5). Instead, the first stage of the rocket will head in a direction equivalent to 93° to 94° inclination. The second stage firing will then impart a small westward component to the velocity in order to swing the inclination round to the required value. The reason is to avoid over-flying Vietnam and its territorial waters so, should there be a problem with the first stage, any debris will fall in international waters and away from coastal towns and shipping.

Yuan Wang 7 may move position slightly between launches but in the time available it can be by no more than 100 kilometres. From L +12 minutes to L +22 minutes Yuan Wang 7 will have the upper stage and its satellites above its horizon and will be able to communicate with them. It should be able to confirm they have separated from each other. The maximum elevation above the horizon will be 18°.

On the map, the dotted ground track is of the CZ 8 and the dotted yellow boundary is the expected radio horizon seen by Yuan Wang 7.

One orbit later, Yuan Wang 7 will see a second pass of the cluster but to its west. The satellites will reach a maximum elevation of 19° at approximately L +110 minutes. The ship will probably not be able to add much value because the satellites will already have passed over multiple Chinese mainland tracking stations.


Navigation Warning

Vietnam's air traffic control service issued the following NOTAM (Notice to Airmen) on February 24 at 08:33 UTC, fitting a track out of Wenchang at 93° - 94 ° inclination. It defines the area covered by the first stage drop zone and lists three air routes (N892, M768 & L625) that it affects. The five letter codes refer to recognised waypoints and define the closed sections.

A0390/22 NOTAMN
Q) VVHM/QAFXX/IV/NBO/W/000/999/0837N10946E042
A) VVHM B) 2202270226 C) 2202270408
E) DUE TO AEROSPACE FLIGHT ACTIVITIES FROM CHINA, THE FLIGHT SAFETY OF
THE AIRCRAFT IN THE FOLLOWING AREAS MAY BE AFFECTED:
N080941E1092126 - N091407E1092802 - N090943E1101132 - N081426E1100545
- N080143E1094409 - N080331E1092621 SIX-POINT CONNECTION RANGE.
VERTICAL ALTITUDE: SFC-UNL.
DURING THIS ACTIVITY, ATS ROUTES/SEGMENTS AS MENTION BELOW ARE NOT
AVBL FOR ALL TFC INCOMING AND OUTGOING FM HO CHI MINH FIR:
- N892 (MELAS - MOXON - OSIXA - MAPNO)
- M768 (DAGAG - MOXON - AKMON)
- L625 (AKMON - UDOSI)
RMKS:
- ALL ACFT SHALL AVOID THIS AREA OR SUBJ ATC CLR.
- THE AEROSPACE FLIGHT ACTIVITY CONDUCTED BY CHINA DIRECTLY AFFECTS
FLIGHT OPERATIONS WI HO CHI MINH FIR. CHINA IS REQUESTED TO
COORDINATE WITH THE COMPETENT AUTHORITIES OF VIETNAM IN LINE WITH
THE PROCEDURES SET OUT IN ANNEX 11 TO THE CHICAGO CONVENTION AND THE
ASIA/PACIFIC SEAMLESS ANS PLAN.
- THIS NOTAM ISSUED IS IN ACCORDANCE WITH ICAO REQUIREMENTS FOR THE
SAFETY OF ACFT OPERATIONS WI HO CHI MINH FIR.