Callisto I

Estimated Completion:July 2022


Callisto I will be the first liquid bi-propellant rocket to be flown by Project Caelus. Its primary mission is to test the avionics, software defined radio (SDR), video streaming, passive control systems, recovery systems, launchpad preparations, and launch procedures. As the first of the three Callisto rockets, Callisto I will be a major milestone in our progress to reaching the Karman line.



Aphlex 5A


5000 N (1124 lbs.)


Liquid methane, liquid oxygen

Specific impulse

242 sec

Burn time

43 sec

Feed system

Helium blowdown

Cooling system

Regenerative & film cooling

Ignition source

Pyrotechnic charge

Recovery system

Recovery system


12 km (7.5 miles)

Max speed

480 m/s (1073 mph)

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