Hawking, who captured the imagination of millions around the world, died on March 14 at the age of 76.
Science met science fiction in London, Friday, with "Avengers" and "Star Trek" actor Benedict Cumberbatch among those paying tribute to the late physicist professor Stephen Hawking.
Readings and prayers read by English actor Benedict Cumberbatch and British Astronaut Major Tim Peake will be included in the service.
The track being beamed into space will feature Hawking's voice set to music and has been written by Greek composer Vangelis.
The broadcast is to be beamed into the nearest black hole, 1A 0620-00, by the European Space Agency via a satellite in Spain.
A thousand members of the public were given tickets following a public ballot, to which 25,000 applied.
As technology improved over the years, Hawking refused to upgrade his speech technology - because he had grown attached to the original voice he adopted in the '80s, as the San Francisco Chronicle and NPR have reported.
It's unclear what Hawking said in the recording, but CDs were created for those who attended the memorial service Friday afternoon.
Hawking lived with motor neurone disease, a debilitating neurological illness, and lost the use of his vocal chords in the 1980s.
Many considered Hawking to be the greatest scientist of his generation, overcoming a debilitating disease to gain a worldwide following for his brilliant work in theoretical physics.
Kip Thorne, a Nobel prize-winning American physicist, paid tribute to "by far the most stubborn friend I ever had". They go on to remind us that Stephen Hawking was the type of person who would probably enjoy the gesture as black holes were his main fascination.
"He has inspired me to be the best that I can be and not let anything, including my disability, hold me back", said Jason Felce, 20, who controls his equipment with eye movement.
The service was sung by the Choir of Westminster Abbey, directed by James O'Donnell, organist and master of the choristers.