"We are tracking a NASA satellite called RHESSI that is expected to reenter Earth’s orbit tonight. However, that satellite remains in orbit at this time," Margetta said.
"NASA and the Department of Defense continue to track RHESSI. No other NASA satellite reentered the atmosphere earlier today."
Earlier on Wednesday, the head of the Kiev city military administration, Serhiy Popko, said that the flash in the sky over Kiev was the result of a NASA space satellite falling to Earth.
A bright flash of unknown origin was seen in the sky late Wednesday over Kiev and the region, local media reported explosions in the sky, and published a video of the fall of a luminous object. A few minutes after reports of "UFOs", an air raid alert was declared in the region.
Ukraine presidential adviser Andriy Yermak said that the mysterious flash in the sky over Kiev was the result of the work of Ukrainian air defense, but soon deleted the message.
The agency, in a statement, said that NASA’s retired Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) spacecraft is predicted by the Department of Defense to reenter Earth’s atmosphere at approximately 8:50 p.m. EDT on Wednesday, April 19 with an uncertainty of plus or minus an hour.
"NASA expects most of the spacecraft to burn up as it travels through the atmosphere, but some components are expected to survive reentry," the agency said. "The risk of harm coming to anyone on Earth is low - approximately 1 in 2,467. NASA and DoD will continue to monitor reentry and update predictions."
NASA concluded by saying that from 2002 to its decommissioning in 2018, RHESSI helped NASA understand the basic physics of particle acceleration and explosive energy release in solar flares.