Nasa to keep launch times secret

Security has been beefed up in the wake of 11 September

The American space agency (Nasa) has announced that from now on all shuttle launch times will be kept secret until 24 hours in advance to guard against possible terror attacks.

Under the new policy, Nasa will announce a possible four-hour launch window in advance and then only reveal the exact time of blast-off 24 hours ahead of the actual event.

What we're trying to do is protect the credibility of this agency with the public and the press

Kyle Herring, Nasa spokesman

The new protocol, approved late last week by top Nasa officials, marks the first time in more than a decade that all precise launch times have been kept secret.

"Nasa is choosing to be extra careful," Kennedy Space Center spokesman Bruce Buckingham said.

The next launch, of the shuttle Atlantis, is due to take place on 4 April and it will occur some time between 1400 (1900 GMT) and 1800 (2300 GMT).

Public accessibility

Once Nasa releases the precise time of lift-off, all the other details about the flight, including the predicted landing time, will be made public, Mr Buckingham said.

"What we're trying to do is protect the credibility of this agency with the public and the press, and also with the security measures that this nation has put into place at the highest government level," spokesman Kyle Herring said, at Nasa's Washington headquarters.

The next mission is to work on the ISS

Mr Herring said that as a civilian agency Nasa wanted to give the public as much information as possible about its activities.

"But we also want to protect the national assets, that is the hardware, the crew and the personnel that work for this agency," he added.

It is still undecided whether and how Nasa will confirm the start of the launch countdown - the countdown clocks which are on public view will not start ticking until 24-hours ahead of blast-off.

Crew protected

On Monday, the crew for the next mission were at the launch site rehearsing the countdown as normal, but for security reasons Nasa did not announce their arrival in advance.

The crew of seven will be engaged in a space station assembly mission.

The new plan is part of a clamping down on security in the wake of the 11 September attacks.

The launch times of the December and March shuttle missions had been made public before 11 September, but both take-offs occurred amid unprecedented security, which is set to continue for the foreseeable future, Mr Herring said.

The new policy took some time to develop and will remain in place for subsequent missions, "with the caveat that it will be reviewed on a flight-by-flight basis", Mr Herring said.

Even stricter rules were applied for seven shuttle flights between 1985 and 1990, in which the spacecraft were carrying classified satellites for the US Defense Department.

Then, the launch times were not announced until nine minutes before take-off and a news blackout was placed over each flight.