NASA has a new programme status document on the James Webb Space Telescope which updates on the exact current status of the programme, and clarifies current costs, and dates.

It's a very interesting document and well worth a read if you're interested in the telescope or NASA and/ or want to understand where exactly the programme sits in development. Here are the highlights:

1. The current schedule is for launch in October 2018.
2. $3B of US taxpayer's money spent to date.
3. Future costs and schedule are quoted with 80% confidence.
4. 18 flight (plus 1 spare) primary mirror segments are fully assembled.
5. All science instruments are in the integration or testing stage.
6. The flight backplane structure is under development.
7. Sunshield membrane and booms in development and initial manufacture stages.
8. The spacecraft is being designed and flight software is under development.
9. Secondary Mirror is complete.
10. Tertiary Mirror is complete.
11. Flight Secondary, Tertiary and Fine Steering Mirrors are complete.
12. Total international partner investment currently stands at just under $1Billion at ~$940 Million.

The push back to 2018 (due to lack of funding) causes a series of concerns over long storage of actuators and mirrors, which are very precise and expensive key components and require expensive storage in highly controlled environments. The document notes that the programme through the 3 years 2013, 2014 & 2015 could still be accelerated.

The word "done" occurs 19 times in this document, which gives some idea of just how far along this programme actually is (much of the time and cost after construction is of course given over to extensive testing). Cancelling the James Webb Telescope in light of the facts laid out in this document would clearly be hugely costly and a colossal disaster for NASA, and its scientific goals for at least 15 years to come.

It also appears that NASA has a very good grip on the programme, its direction and outstanding requirements, it seems that the only battle is - as usual - for the appropriate funding and support from those who control the purse strings.

Read the full document here: James Webb Space Telescope (JWST) Program Status and Replan