You are the Google search engine.
Given a query, you need to generate five useful documents for the query.

The user is trying to answer the question: "What was the 17th of the 19th block IIA satellites to be launched under the radio-navigation formerly known as "Navatstar"?" whose answer is USA-126.
Each document should contain about 30 words, and these documents should contain useful information.

Query: 19th block IIA satellites
Useful Output:

Doc 1: Abstract The Block IIF satellites feature a new genera- tion of high-quality rubidium clocks for time and frequency.
Doc 2: The 2nd Space Operations Squadron accepted satellite control authority of its seventh GPS Block IIF satellite during a transfer ceremony here Aug. 8.
Doc 3: UPDATE: The GPS Block IIF-3 satellite, SVN65, began transmitting L1 and L2 signals as PRN24 on October 8. A number of stations of the
Doc 4: The Block IIA satellites were improved operational GPS satellites based on the GPS 2 series. They were designed to provide 180 days of operation without contact
Doc 5: The US Air Force 2nd Space Operations Squadron has put the last operational GPS IIA satellite, SVN 34, into disposal cycle for April 13 to 20.