Nasa officials said they have received no reports of damage or injury so far from the reentry, which occurred in the wee hours of the morning in Sudan.
Most of the 660-pound (300-kilogram) satellite, called Rhessi, was expected to burn up while plummeting through the atmosphere. But experts anticipated some pieces would survive and slam into the ground.
Launched in 2002, Rhessi was turned off in 2018 following a communication problem. Before falling silent, it studied solar flares and coronal mass ejections from the sun.
Rhessi stands for the Reuven Ramaty High Energy Solar Spectroscopic Imager.