SpaceX on Monday said a Falcon 9 rocket appeared to have performed as expected during its Sunday night launch of the government's classified Zuma mission, amid rumors of a possible mission failure.
“We do not comment on missions of this nature; but as of right now reviews of the data indicate Falcon 9 performed nominally,” a SpaceX spokesperson said in a statement.
Northrop Grumman, which was responsible for the spacecraft and contracted for the launch, did not immediately respond to questions.
SpaceX cut off its launch broadcast after confirming that the rocket's nose cone — the cause of a delay to a planned November launch — had separated a few minutes after the 8 p.m. blastoff from Cape Canaveral Air Force Station. That's standard procedure during secret national security missions.
But neither SpaceX nor Northrop later confirmed the launch was ultimately a success, as United Launch Alliance typically does for its classified missions.
SpaceX CEO Elon Musk on Monday shared a long-exposure photo of the Falcon launch and landing taken by Satellite Beach High student John Kraus, with no indication that anything was amiss.
Marco Langbroek, an amateur satellite tracker from the Netherlands who is experienced in following classified missions and was watching Zuma closely, said he had no information supporting rumors of a failure and had "no idea whether they are viable or not."
The launch produced some unusual lighting effects as the rocket climbed uphill that prompted some observers to worry it might be experiencing trouble.
From the Space Coast, bluish-white light appeared to swirl in the sky as the rocket's upper-stage engine ignited some 50 miles up, about two-and-a-half minutes after liftoff, and the first stage began flying back to the Cape for a landing.
But while striking, the visuals likely were the result of what meteorologists said were relatively common weather conditions.
Viewers saw light from the Falcon 9 engines glowing and diffracted through a pair of thin cloud decks, one at 4,000 feet and another at roughly 20,000 to 25,000 feet, said Tony Cristaldi, senior meteorologist with the National Weather Service in Melbourne.
The clouds were more widespread along the Falcon 9's northeasterly path over the Atlantic Ocean, but broken up at the coast, which provided unobstructed views throughout the rocket's rise and the booster's descent to a landing.
The glow from the Merlin engines was accentuated in the same way that light reflecting off high clouds at sunrise or sunset is often particularly picturesque.
“The illumination of the rocket plume would cause similar effects as it's passing through those clouds,” said Cristaldi.
Sunday night's show was eye-catching, at least briefly, but didn't top the dramatic scene Southern California residents took in recently when a Falcon 9 blasted off near sunset on Dec. 22.
Light from the setting sun enveloped the rocket plume in a white bubble with a comet-like tail that transfixed viewers and went viral on social media. Musk played along with jokes about UFOs and aliens during the successful launch of Iridium satellites.
That phenomenon is known as noctilucent clouds. Early risers on Sept. 2, 2015, were treated to a similar scene above Florida's East Coast when a United Launch Alliance Atlas V rocket carrying a Navy communications satellite blasted off from Cape Canaveral about 40 minutes before sunrise.
SpaceX has been preparing for tests and a debut launch of its Falcon Heavy rocket, and for another satellite launch as soon as late January.
If there are any questions about whether the Falcon 9 did its job Sunday night, those preparations would be put on hold for further investigation of the Zuma mission.
ULA is preparing to kick off its 2018 launch schedule with a Wednesday flight of a classified National Reconnaissance Office mission from California on a Delta IV rocket. That will be followed by a Jan. 18 night launch from the Cape of an Atlas V rocket and U.S. missile warning satellite.