Background

The Chinese Space Station (CSS) is about to receive its second visiting crew. The station consists currently of the core module, Tianhe, with two smaller Tianzhou vehicles attached. Tianzhou 2 is docked at the forward-facing port and Tianzhou 3 is at the rear port. Shenzhou 13 is planned to be docked at the downward-facing forward port next to Tianzhou 2.


Shenzhou 13

Shenzhou 13 will be the sixth, and final, launch it what China describes as the 'verification phase' of space station operations - ie making sure that everything works. It presumably refers to the Shenzhou 8-13 missions.

The CZ 2F launch vehicle carrying Shenzhou 13 was rolled out to the launch pad on October 7. Several aeronautical navigation warnings (NOTAMs) were issued October 11 showing the chosen launch date to be October 15. The areas covered were a corridor from the Jiuquan launch site to the coast with a drop zone for launch vehicle debris at the end.

A second area was set out that indicated an emergency landing zone the crew could use if a problem with Shenzhou 13 meant that they had reached orbit but had a need for an immediate return to Earth.

It may be that Shenzhou is launched already programmed to return to Earth at the end of the first orbit. A go/no go decision once in orbit would be used to over-ride the pre-set programme once Shenzhou is confirmed in good health.


Launch

The launch time can be calculated by looking at the relationship between Tianhe's ground track and the Jiuquan launch site. It seems set for 16:23 UTC ±1 minute. The NOTAMs also cover the appropriate time period. On October 14 Xinhua, China's official news agency confirmed that the time estimate is correct.

On October 14, Xinhua confirmed that the time estimate is correct.

The calculation employs a method that members of the Kettering Group used in the 1970s and 1980s to predict the launch time of a Soyuz taking a crew to a Salyut station or to Mir. In that era, though, it was necessary also to determine the date as sources like NOTAMs and news 'leaks' were not available.

The calculated time was 16:23:56 UTC. During its launch coverage CCTV, China's national TV network, revealed that launch occurred at 16:23:53 UTC.


First Minutes in Orbit

Events can be followed using the map above.

Nine minutes after lift-off, Shenzhou will separate from the launch vehicle upper stage. As that occurs, it will be rising above the radio horizon of the tracking ship Yuan Wang 3, stationed in the eastern Pacific Ocean about 1500 kilometres from Shanghai. Yuan Wang 3 will be able to communicate with it for about eight minutes in all.

It was noticeable from the CCTV launch broadcast that the video feed from inside Shenzhou 13 was cut as it reached the horizon at the end of the pass over Yuan Wang 3.

Next, Shenzhou will pass within range of Yuan Wang 5 in mid Pacific. It left Suva, Fiji on October 9 after picking up stores. As of October 12, the ship was not ideally placed for tracking Shenzhou 13. It was stationary near 16° south, 178° east and would need to move north to improve its view of the Shenzhou 13 orbit. It did indeed move on October 13.

Shenzhou will, however, be in view of the Tianlian data relay satellites in geosynchronous orbit, one of which is stationed mid-Pacific near 176° east longitude. Tianlian may be able to detect Shenzhou's radio transmission but two-way comms may not be possible at that point.

At about L +49 minutes, Shenzhou will commence a 9-10 minute pass over the internationally-operated ground station near Santiago in Chile. The station was used for previous Shenzhou missions so its use is quite likely for Shenzhou 13, and it does lie conveniently on the ground track.

Shenzhou 13 will then be commencing its chase of the CSS.


Emergency Arrangements

Should a problem with the CZ 2F rocket occur around lift-off, the launch escape system (LES) will permit separation of the crew cabin followed by a parachute-assisted touchdown in the vicinity of the Jiuquan launch site. A later emergency would again use the LES but landing would occur further downrange.

After the LES has been let go, a launch vehicle upper stage problem could drop the crew into the East China Sea or further out - into the Pacific. In that case, Yuan Wang 6 would be on hand to co-ordinate a crew rescue.

Once in orbit, Shenzhou will unfold its solar panels and radio aerials. A problem at that point could require an immediate return to Earth for which an area has been set aside in eastern China. Re-entry (possibly ballistic rather than a lifting trajectory), followed by a parachute descent would put the crew on the ground about one hour and fifty minutes and one Earth circuit after they left the ground.


Timetable

First orbit sequence:

L +0	Lift-off
L +9 minutes	Separation from Launch Vehicle, AOS Yuan Wang 3
L +17 minutes	LOS Yuan Wang 3
L +24 minutes	AOS Yuan Wang 5
L +31 minutes	LOS Yuan Wang 5
L +50 minutes	AOS Santiago
L +57 minutes	LOS Santiago

In the event of Orbit 1 emergency (approximate times):

L +74 minutes	Retro-fire
L +89 minutes	Re-entry
L +99 minutes	Parachute deploy
L +109 minutes	Touchdown

Chase and Docking

Shenzou is probably planned to arrive at the Station within a few hours of lift off. The orbital geometry on October 15 puts it a small number of minutes behind the Station at launch. If the timeline follows the precedent set by Shenzhou 12 then docking will occur about six and a half hours after launch, at about 22:50 UTC.


Crews and Mission

At the time of writing, the crew has not been announced but if it is the backup crew for Shenzhou 12, its members will be Zhai Zhigang, Wang Yaping and Ye Guangfu.

They are expected to stay aboard the station for several months.

Xinhua's October 14 news release confirmed the crew will indeed be these three with Zhai as the commander and that they will stay aboard CSS for six months.


Major Launch Navigation Warnings

The initial ground track is defined by two main NOTAMs. The first defines a corridor from Jiquan to the mainland coast and is valid between 16:13 and 16:54 UTC. In this particular format of NOTAM, the start/finish times are the ten digit numbers denoted by B) and C). The format is YYMMDDHHmm. Latitude and longitude information for the area boundary is in section E). The digits after N and E are degrees, minutes and seconds.

A2622/21 NOTAMN
Q) ZXXX/QRTCA/IV/BO/W/000/999/3829N11026E515
A) ZLHW ZBPE ZSHA B) 2110151613 C) 2110151654
E) A TEMPORARY RESTRICTED AREA ESTABLISHED BOUNDED BY:
N412436E1002400-N403112E1001048-N390524E1060560-N364648E1152924-
N353336E1202924-N362848E1205848-N373600E1161912-N400112E1061536
BACK TO START. ALL ACFT ARE FORBIDDEN TO FLY INTO THE TEMPORARY
RESTRICTED AREA.
VERTICAL LIMITS:GND-UNL.
F) GND G) UNL

The other is for a distinct area off the coast, north of Shanghai and is in force between 16:13 and 16:55 UTC. It is probably the drop zone for the second, core stage of the CZ 2F.

A2623/21 NOTAMN
Q) ZSHA/QRTCA/IV/BO/W/000/999/3513N12245E112
A) ZSHA B) 2110151613 C) 2110151655
E) A TEMPORARY RESTRICTED AREA ESTABLISHED BOUNDED BY:
N364724E1213112-N355100E1240000-N334000E1240000-N350300E1203300
BACK TO START. ALL ACFT ARE FORBIDDEN TO FLY INTO THE TEMPORARY
RESTRICTED AREA.
VERTICAL LIMITS:GND-UNL.
F) GND G) UNL


Navigation Warning - Emergency Landing Area

The NOTAM is active between 17:47 and 18:33 UTC.

A2624/21 NOTAMN
Q) ZXXX/QRTCA/IV/BO/W/000/999/2801N11333E189
A) ZHWH ZGZU ZSHA B) 2110151747 C) 2110151833
E) A TEMPORARY RESTRICTED AREA ESTABLISHED BOUNDED BY:
N304312E1114500-N290300E1145400-N283412E1143148-N271724E1164612-
N251948E1152248-N282324E1100412 BACK TO START. ALL ACFT ARE
FORBIDDEN TO FLY INTO THE TEMPORARY RESTRICTED AREA.
VERTICAL LIMITS:GND-UNL.
F) GND G) UNL