SpaceX is having a busy week. As the company prepares for another water landing, Founder and CEO Elon Musk has announced that the Falcon 9 booster that made the historic first powered controlled landing of a space rocket has successfully completed a post-flight static test fire.

In a tweet on Friday, Musk said: "Conducted hold-down firing of returned Falcon rocket. Data looks good overall, but engine 9 showed thrust fluctuations." He went on to post, "Maybe some debris ingestion. Engine data looks okay. Will borescope tonight. This is one of the outer engines."

A borescope is an optical instrument made of a rigid or flexible tube that uses prisms or fiber optics to allow inspectors to see inside of tight spaces, such as rocket engines.

The firing, which took place at Cape Canaveral Air Force Station in Florida, did not involve a flight. This test was an important demonstration of the Falcon 9's ability to be reused after an orbital launch mission with a minimum of overhauling.

On December 21, 2015, the Falcon 9 booster flew into the history books as it touched down on Landing Zone 1 at Cape Canaveral. Ten minutes previously, the nine-engine rocket had thundered into space to deliver 11 communications satellites into low-Earth orbit. It then fired its engines twice again to kill its hypersonic velocity and steer it back to the Cape, where it set down on a dramatic tail of fire.

Though the Falcon 9 shows little sign of damage after its brief trip into space, it's unlikely to ever fly again. In a previous statement, a company spokesman said that because of its historic value, this particular rocket will be preserved after tests are completed.

SpaceX, Twitter
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