The contents include plants, fiber optics and even mice.
Experts weigh in on the mystery.
The secret craft could have plunged back through the atmosphere.
It's scheduled to begin at 8:00 p.m. EST.
Even Elon Musk hasn't revealed the restricted Zuma contents.
Elon Musk is a very rich man.
Keep your eyes on the road.
It's a comet! It's aliens! No, it's Tesla!
The SpaceX founder joked with confused Twitter users saying his Falcon 9 rocket was a nuclear alien UFO from North Korea.
The rocket was initially supposed to launch back in 2013, but it looks like SpaceX is finally approaching a launch date in early 2018.
Three more astronauts have arrived at the International Space Station.
The astronauts also have plans to see the new "Star Wars" movie.
Friday's Falcon 9 launch and landing was succesful, perhaps ushering in an age of reusable rockets.
"No one was injured and all safety protocols were followed during the time of this incident," read a statement. "We are now conducting a thorough and fully transparent investigation of the root cause."
It's set to extremely peppy, Sousa-esque march music.