The rocket was spotted on the tarmac at Alameda Naval Air Station, California, US, by a helicopter.
Locals were alerted to its presence after hearing the aircraft overhead, with one saying: “I heard a helicopter and when I look behind me, I see a giant truck with a huge missile on it.”
But the rocket's existence is shrouded in mystery as there are no details on why it is there.
The aerospace research firm that supposedly created it doesn’t even have a name.
Californian news site ABC7 used their SKY7 chopper to capture the rocket.(Image: YOUTUBE/ABC7)
They managed to obtain a lease application filed by the company with the City of Alameda that revealed the rocket, called Astra, is the world’s smallest.
The application included a comparison to the SpaceX Falcon Heavy – the largest ever rocket – to highlight its diminutive size.
Lance Winters, who owns St George Spirits distillery that is located next to the air base, said he hadn’t noticed the rocket being tested.
“It's exciting to see what's going on with the private aerospace industry,” he added.
“To see it this close to home is even more exciting.”
The elusive company behind the rocket told ABC7 it plans to turn the former Naval base into a space technology hub.
It comes as an F-16 fighter jet was filmed bursting into flames in Japan, sparking outrage from the country's top officials.