Build Up

It has been well known for many months that China planned launch of the second 20 tonne module for its space station mid-2022. Life started to become interesting early-July when navigation warnings were issued indicating launch July 24 at about 06:20 UTC. Then, on July 18, Wentian and its CZ 5B launch vehicle were rolled out to the launch pad.


Tianzhou 3

The docking port needed for Wential was occupied by the Tianzhou 3 cargo vehicle. July 17, it undocked and moved away into independent orbit, destined to be sent later to a destructive re-entry above the southern Pacific Ocean. It's successful departure allowed the instruction to be given for Wentian's journey to the launch pad.


Launch Time

Analysis of the Space Station's orbit as of July 23 points to launch being set for July 24 at approximately 06:20 UTC - confirming the time indicated by the published navigation warnings. It is not possible to be very precise about the time. It depends on the orbital manoeuvres to be undertaken on Wentian's ascent and the planned length of time between launch and rendezvous. As a best estimate it will be 06:20 UTC ±2 minutes. China will probably announce the exact time a few hours before lift off.


Launch Trajectory

The map shows the ground track of the launch trajectory and some of it's geometry. The rocket boosters that form the CZ 5B first stage are set to fall in the sea between China and the Phillipines.

Eight minutes after lift-off, Wentian will separate from the launch vehicle upper stage and will be within view of the Yuan Wang 5 tracking ship as it does so. Over the next few minutes, Wentian will unfurl its solar panels, extend its radio aerials and open up some other of its external elements. If all goes to plan, Wentian will be in full, autonomous, operating mode by L +13 minutes when it goes below Yuan Wang's horizon.

It will then chase down the space station.


Relevant Navigation Warnings

Wentian airspace closure, issued Jul 12:

A1802/22 NOTAMN
Q) ZJSA/QRDCA/IV/BO/W/000/999/1937N11057E006
A) ZJSA B) 2207240612 C) 2207240629
E) A TEMPORARY DANGER AREA ESTABLISHED CENTERED AT N1937E11057 WITH RADIUS OF 10KM. VERTICAL LIMITS:SFC-UNL.
F) SFC G) UNL

Booster & shroud drop zones issued by the authorities in NAVAREA XI (Japan):

SOUTH CHINA SEA.
ROCKET LAUNCHING. 240530Z TO 240730Z
JUL. AREAS BOUNDED BY
A. 13-53-57N 118-15-53E
13-33-46N 117-57-26E
14-13-05N 117-11-37E
14-33-19N 117-30-03E.
B. 12-39-15N 119-41-06E
12-19-11N 119-22-38E
12-51-35N 118-45-34E
13-11-42N 119-04-02E.