The first deployment of Australian naval vessels in August 1990 had been made in an atmosphere of uncertainty. Although their task was to enforce UN sanctions, the conditions under which they were to operate had not been determined. The rules of engagement had not been finalised, and while it was unlikely that the ships would be required to take offensive action, Saddam Hussein was unpredictable, and it was feared that they might come under attack from the Iraqi air force.
The second deployment was also made with a measure of uncertainty. Although the initial deployment had been for three months, when in early September the government endorsed its replacement, the first task group was just beginning its sanctions operations. But as the weeks of preparation, training and deployment followed, it became more likely that the second task group would see action. As 18-year-old Able Seaman Darren Brown explained to a journalist when his ship, HMAS Sydney, sailed on 12 November, ‘It's different this time. Before the war was a possibility – now it's a probability.’ Early warning of this development came on 9 November, when President Bush announced the substantial reinforcement of the forces deployed for operation Desert Shield, and the UN ultimatum to Iraq on 29 November suggested that the second deployment would be very different from the first.