Context: In February 2007, the fourth and last satellite of the BeiDou-1 system, BeiDou-1D (sometimes called BeiDou-2A, serving as a backup satellite), was sent up into space. It was reported that the satellite had suffered from a control system malfunction but was then fully restored.

Question: When was the fourth satellite for the BeiDou-1 system launched?
Answer: February 2007

Question: What is the name of the fourth BeiDou-1 satellite?
Answer: BeiDou-1D

Question: What is the BeiDou-1D satellite sometimes called?
Answer: BeiDou-2A

Question: What is the purpose of the BeiDou-1D satellite?
Answer: serving as a backup satellite

Question: What happened to the BeiDou-1D satellite that needed to be repaired?
Answer: a control system malfunction

Question: In which month of 2007 was the fifth satellite for the BeiDou-1 system launched?
Answer: Unanswerable

Question: What is the official name of the fifth BeiDou-2 satellite?
Answer: Unanswerable

Question: Which satellite serves as a front-end satellite?
Answer: Unanswerable

Question: Which satellite is sometimes called BeiDou-2C?
Answer: Unanswerable

Question: According to reports, the satellite had issues with what system and was never fully restored?
Answer: Unanswerable