Editor's 28 October Update: Multiple sources note that few - if any - expect that the decision will be anything but an overt approval of the Hubble servicing mission. Indeed, many at NASA have been acting as if it were a done deal for quite some time - and some have said that it is indeed settled - some claim to have been told so. Many activities wherein real money is being spent on this mission have continued as if the flight was going to happen. Besides, look at the elaborate PAO activities planned in this press release "if" the mission is approved. PAO doesn't do that much work ahead of time unless it has to.
The main issue with this mission has always been the ability to go get a stranded Shuttle crew if the need arose. When Sean O'Keefe faced a decision point, that solution was simply not there - at least not to his satisfaction. That issue has now been solved. Mike Griffin now needs to spend the weekend thinking how he will explain - and defend - his formal decision to the media on Tuesday. Truth be known, as far as Griffin was concerned, this was not a slam dunk for quite some time. NASA had a lot of things to prove to him.
Editor's 27 October Update: NASA has announced a press conference next Tuesday to announce the fate of the Hubble servicing mission.
Editor's 23 October note: NASA will be meeting this Friday at 10 am EDT to make its final decision about whether a repair and upgrade mission to Hubble will be done. There seem to be no showstoppers to prevent this mission from happening. One lingering concern had been whether a rescue mission could be mounted should the need arise. Given the way that the Shuttle program has been operating and the program's expressed interest in retaining such a LON capability beyond the first few post-Columbia missions, that does not seem to be an issue. There was also a concern that taking one of the Shuttle launch pads (39B) out of use for upgrade by the Constellation program might impact that capability. That has apparently been resolved as well. JSC also has a crew selected for this mission. Word has it that a formal announcement is being planned for next week with Tuesday, 31 October, as the planned announcement date at GSFC. It is uncertain whether the crew will be announced at that time. Stay tuned.