Industry experts and the government gave the tentative conclusion that the U.S. spy satellite’s failure is due to the testing and engineering errors made by Northrop Grumman Corp. These errors are said to be the reason why the spy satellite plummeted down to the ocean a few moments just after its launch in January.

Zuma, the spy satellite, is believed to have a development cost of $3.5 billion. It showed initial indications of not separating early enough from the Space Exploration Technologies Corp. launcher during the second stage. However, this time two separate teams involving industry and federal investigators identified that the reasons for the problem are a part modified by Northrop Grumman.

The part, a payload adapter, said to have failed to operate in space properly. This device came from a subcontractor that considerably modified it. Then, Northrop Grumman tested it on the ground in three different times, which proved successful. However, the adapter failed to uncouple the rocket and the satellite when it reached orbit in zero gravity.

The sensors onboard the satellite also failed to report it immediately. Due to this, the officials that were tracking the liftoff were unable to learn of this huge malfunction. They were unaware until the satellite dropped into the atmosphere during the launch’s second stage. Eventually, the satellite broke off and dropped to too low of an altitude for a rescue.

The satellite was built by Northrop Grumman, which was extremely classified. In fact, they still have not disclosed the purpose of the satellite. Similarly, no company or agency has been named yet to be a customer. According to military-space analysts and officials in the industry, a high likelihood that the satellite is something serving as missile warning or space radar.

As of now, there have been no known specifics about Zuma. Even Northrop Grumman has not released a statement or responded to requests for comment yet. Similarly, Pentagon made constant decline to comment about the fate of Zuma adapter. The investigators’ tentative findings came from examining the design of the satellite.

Its design shows vulnerabilities to vibration and shock. Because of this, Northrop Grumman modified the adapter so it would cushion the satellite’s separation in orbit. Usually, adapters use explosive bolts to disconnect satellites off their attachments from launchers. This time, however, it did not work as it’s supposed to do, causing the satellite to splash down into the Indian Ocean in a failed mission.