Fifty years ago today, Apollo 11 began its voyage into American history. He marked the precise time - 9.32am - when their rocket took off. He pointed out Mr Armstrong was among those who believed returning to the moon "would assist us mightily in our attempt to go to Mars".
Tuesday's meeting kicked off a series of commemorative events across the US.
In July 1969, three intrepid astronauts - Neil Armstrong, Edwin "Buzz" Aldrin and Michael Collins - kept the world on the edge of its seat as they hurtled towards the Moon, set on an extraordinary mission to become the first humans to set foot on our nearest planetary neighbour.
Mr Collins was the only original member of the three-person crew at the event. In the televised call, the USA president told Armstrong and Buzz Aldrin that the whole world was proud of them, and that "because of what you have done, the heavens have become a part of man's world".
Morris was a part of the Apollo Quality Reliability Team, where his job was to test the relays in a vacuum to make sure they worked like they would in space.
"The shockwave from the rocket power hits you", he told Nasa TV.
File photo - Photograph of the pilot Michael Collins at Apollo 11 Command Module, practicing docking hatch removal from CM simulator at NASA Johnson Space Center, Houston, Texas, June 28, 1969.
"Apollo 11 was serious business, we crew felt the weight of the world on our shoulders", Collins said.
He added that he wished his fellow astronauts could have joined him at the site.
The full "Apollo 50: Go for the Moon" experience will take place on July 19 and 20 from viewing areas on the National Mall in front of the Smithsonian Castle between ninth and 12th streets.
These include the return of Armstrong's suit to the Air and Space Museum in Washington after more than a decade of restoration work.
Blackwell-Thompson said she got goosebumps listening to the replay of the Apollo 11 countdown.
"It was a contribution to the life of this nation and the history of this world that's nearly incalculable", he added.
Speaking on the broadcast, Collins said he and astronauts Neil Armstrong and Buzz Aldrin felt like "the nervous novice driving a wide vehicle down a narrow alley" as the rocket lifted off.
The historic and successful Apollo 11 mission could have gone very differently.
In Huntsville, Alabama, where the Saturn V was developed, thousands of model rockets were launched simultaneously, commemorating the moment the Apollo 11 crew blasted off for the moon.
Their commander Neil Armstrong, the first man on the Moon, passed away in 2012 aged 82.
Armstrong emerged a few hours later, descending to the foot of the ladder, as he uttered the immortal line: "That's one small step for man; one giant leap for mankind".
About 400,000 people worked on the programme, at a cost at the time of $25bn.
Around the globe, it is estimated that 600 million people watched the mission, including 1 of every 4 people in the United States.