WASHINGTON - NASA officially joined the search for UFOs -- but reflecting the stigma attached to the field, the US space agency kept secret for hours the identity of the person heading a new program tracking mystery flying objects.
The official's appointment is the result of a year-long NASA fact-finding report into what it calls "unidentified anomalous phenomena," or UAP.
"At NASA, it's in our DNA to explore -- and to ask why things are the way they are," agency chief Bill Nelson said.
An independent team of 16 researchers concluded in the report that the search for UAPs "demands a rigorous, evidence-based approach."
NASA is well positioned to play a prominent role, thanks to its satellite capabilities and other technical assets. But the agency stressed in its report that any findings of possible extraterrestrial origin "must be the hypothesis of last resort -- the answer we turn to only after ruling out all other possibilities."
"We want to shift the conversation about UAP from sensationalism to science," Nelson said.
Even if NASA has long explored the heavens, hunting for the origin, identity and purpose of a growing number of unexplained flying objects over planet Earth is bringing unprecedented challenges.
Military and civilian pilots keep offering a multitude of reports on strange sightings. But decades of movies and sci-fi books about aliens mean the entire topic is mostly laughed off by the public as the territory of cranks.
That atmosphere explained the unusual decision by NASA to initially withhold the lead UAP official's identity.
There have been more than 800 "events" collected over 27 years, of which two to five percent are thought to be possibly anomalous, the report's authors said in May.
These are defined as "anything that is not readily understandable by the operator or the sensor," or "something that is doing something weird," said team member Nadia Drake.
The US government has begun taking UAP issues more seriously in recent years, in part due to concerns that they are related to foreign surveillance.
One example of a still-unexplained phenomenon was a flying metallic orb spotted by an MQ-9 drone at an undisclosed location in the Middle East. Footage of the UAP was shown to Congress in April.
NASA's work, which relies on unclassified material, is separate from a parallel Pentagon investigation, though the two are coordinating on how to apply scientific tools and methods.