September 15 marks the opening of the launch window for China's Tiangong 2 space laboratory. It will also probably be the actual launch date. The launch window extends to September 20, but China has no good reason to delay the launch of Tiangong any later than necessary. There seem to be no technical reasons that would prevent it from launching at the first chance.

We have been given sparse information in the lead-up to the launch, but what little we know sounds very positive. We can also infer that other unreported events are going well, judging by China's previous experience with this type of mission.

Tiangong 2 will undergo a checkout phase after launch, as its systems are put through its paces. Checking the environmental controls will be especially important. The internal cabin atmosphere will need to be tested and filtered for any small floating particles.

A long checklist of tasks will need to be ticked off before Tiangong is judged fit for a crew. But this will not stop preparations for the next launch from continuing.

China hopes to launch two astronauts to Tiangong 2 aboard the Shenzhou 11 spacecraft soon after Tiangong 2 reaches orbit. The launch can be delayed or scrubbed if Tiangong is not healthy, but that seems unlikely.

So, we must wait a little longer for Tiangong 2, but probably not too long. Even a last-minute problem on launch day will probably only postpone the launch by around 48 hours, or less. China will almost certainly fly Tiangong 2 during the launch window.

Official Chinese media coverage has been less than satisfying for space buffs so far, but that's typical. Hopefully the pace will quicken just before Tiangong 2 launches. This will be a critical test for how Chinese space media policies are developing. To a large degree, they are influenced by changes to general media policies for China, but the space program has its own unique sensitivities. Recent times have seen a tightening in policies for both.

We seem to have been denied the usual media appetizers of snippets on experiment plans or technical upgrades. That's disappointing, but we could learn more later. China made brief references to small technical improvements to the launch vehicle, but this is not surprising. China is always steadily tweaking its rockets with incremental engineering changes. The recent loss of a Long March 4C rocket could also temper media coverage.

The vigil for Tiangong 2 continues as we await the countdown.

Dr Morris Jones is an Australian space analyst who has written for spacedaily.com since 1999. Email morrisjonesNOSPAMhotmail.com. Replace NOSPAM with @ to send email. Dr Jones will answer media inquiries.