That news conference will be livestreamed on Space.com, courtesy of NASA TV.
Liftoff itself went smoothly at about 4:47 a.m. EDT (0847 GMT), but a few minutes later the rocket experienced a serious anomaly in which the booster failed to separate. The Soyuz crew capsule and the two crewmembers inside — NASA astronaut Nick Hague and Russian cosmonaut Alexey Ovchinin — plummeted back to Earth in a ballistic re-entry but landed in good condition.
NASA and its Russian counterpart, Roscosmos, have both confirmed that there will be an investigation into what went wrong during the launch. NASA said previously that it did not expect Roscosmos would hold a press conference today.
NASA Administrator Jim Bridenstine is on site at Baikonur Cosmodrome in Kazakhstan, where he had been on hand to watch the launch and meet with his Russian counterpart Dmitry Rogozin. The meeting, the first in-person for the two leaders, came in the midst of an ongoing investigation into the small air leak in a Soyuz capsule docked to the space station, which did not pose any threat to astronauts and has since been patched.
Editor's note: An earlier version of this article had an incorrect spelling for cosmonaut Alexey Ovchinin. It has been corrected.