"For the first time since 2011, we are on the brink of launching American astronauts on American rockets from American soil", he told the enthusiastic audience.
USA astronauts have been relying on Russian capsules to travel to the space station, with each seat costing NASA as much as $82 million (€71 million).
Nasa has named the astronauts who will fly the first missions into space on commercially provided rockets and capsules, starting next year. Now, we know the names of those launches' first passengers.
The American space agency said on August 3 that the astronauts will crew the first test flight and mission of both Boeing's CST-100 Starliner and SpaceX's Crew Dragon. Since the last shuttle flight, NASA has relied on Russian Soyuz spacecraft to carry its astronauts to the International Space Station. He began his career with the Air Force, and served as a fighter pilot, test pilot and colonel. He will be joined by Victor Glover, a Navy commander who will be making his first trip into space.
At a press briefing Friday, Lt. Col. Mann called her maiden voyage aboard the Starliner the "opportunity of a lifetime", saying it's one that will "help usher in this new era of American spaceflight".
For Crew Dragon, the now confirmed crew includes Navy commander, aviator, and test pilot Victor Glover.
SpaceX's first crew tests on the Dragon capsule will be helmed by shuttle veterans Robert Behnken and Douglas Hurley. All but three of the astronauts are space flight veterans. "We take it seriously". Each ship requires two crewed test launches before NASA will certify it for routine flight.
On Boeing's first post-certification mission, NASA astronaut Suni Williams, who has flown on the space station two times already, will fly to the outpost again with first-time space flier Josh Cassada.
The ISS has been, is and will remain critical for NASA's work on long-duration spaceflight as well as missions related to the Moon, Mars and other planets. "I'll tell you, being able to launch to the International Space Station from US soil, I can't imagine better", Cassada said.
For SpaceX's first flight to the ISS, the NASA crew will be Victor Glover on his first space flight and Mike Hopkins, who spent 166 days in space as part of Expedition 37/38. The test flight with crew is scheduled for mid-2019.
Chris Ferguson, a former NASA astronaut who has worked with Boeing as it developed its Starliner spacecraft, will fly as a private astronaut. Boeing will launch its CST-100 Starliner on top of a United Launch Alliance Atlas V rocket at Cape Canaveral Air Force Base, also in Florida.
The space agency has reason to be eager. Reaching the space station, the spacecraft will have to dock and undock on automatically and then take the crew back to Earth.
Most have previous experience in orbit. Originally, both companies were contractually bound to meet all of NASA's requirements in 2017.
The spacecraft is expected to bring along more than 3,800 pounds of cargo.
The Boeing and SpaceX crewed test missions are arguably the most anticipated spaceship test flights this century.
Boeing is now working through technical issues with its abort and parachute systems. But it had been working to resolve an issue with its second stage that caused one of its Falcon 9 rockets to explode while it was being fueled ahead of an engine test. He is a colonel in the Air Force, where he was a flight test engineer before being selected as a NASA astronaut in 2009. "After the uncrewed flight tests, both companies will execute a flight test with crew prior to being certified by NASA for crew rotation missions", said a NASA blog.
The companies are running out of buffer. Boeing and SpaceX were supposed to have their systems certified by 2017, according to a recent report from the Government Accountability Office. He returns to NASA after retiring in 2011.
NASA, SpaceX and Boeing have repeatedly stressed that they will fly only when the vehicles are ready. "The ISS can not function without a USA presence on board to maintain and operate integral systems".
The demonstration flights by Boeing and SpaceX will spend a short period in orbit before coming straight back to Earth. "We're so close", he said. "We're not going to let you down".