You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
BeiDou_Navigation_Satellite_System

Context:
The first satellite of the second-generation system, Compass-M1 was launched in 2007. It was followed by further nine satellites during 2009-2011, achieving functional regional coverage. A total of 16 satellites were launched during this phase.

Question:
How many satellites were launched from 2009-2011?

nine