In a Tuesday letter written to its employees, the US space agency NASA has apprised its staff about the theft of a laptop which contained sensitive personal data of the agency's workers as well as its contractors.

According to a Wednesday report in The New York Times, NASA has notified its employees that the laptop was stolen two week back from a locked car. The agency also added that despite the fact that the device has password protection, the data stored on it had not been encrypted; thereby indicating that the personal information can be recovered by the hackers.

The letter, written by NASA's associate deputy administrator Richard Keegan, revealed that the laptop which has been stolen was issued to an employee at NASA headquarters in Washington.

Keegan said in the letter that the employees' personal information on "a large number of NASA employees, contractors and others" on the laptop could be accessed by "unauthorized individuals."

With NASA distributing the letter to the agency's employees this week, Keegan said that the laptop was stolen on October 31, 2012; and added: "Because of the amount of information that must be reviewed and validated, it may take up to 60 days for all individuals impacted by this breach to be identified and contacted."