Ars Technicha's Rocket Report: SLS has technical problems, Vector—yes, Vector—is back links to Vector restarting operations under new ownership which says:
One thing they did wrong was the technology the used for their engines. “They had some Achilles’ heels associated with their technical approach. They were trying to use a propellant combination that was untested in the industry,” said Chris Barker, who serves as Vector’s chief rocket scientist. “They were struggling with trying to get performance that they knew they needed for a small launcher to be successful, and ultimately their test program was unsuccessful.”
Vector had been developing engines that used propylene and liquid oxygen propellants. The new Vector plans to instead use engines powered by a more conventional combination of liquid oxygen and refined kerosene, or RP-1, propellants. Barker has been developing such engines since the 1990s for companies such as Space America and Earth to Sky.
In this case was propylene as a rocket fuel "failure to launch" similar in some ways to Thorium as reactor fuel in that there were no fundamental impediments but it's just the way things worked out, or was switching to RP-1 required for technical reasons associated with the fuel itself, its performance, or its supply.
That looks absolutely delicious, we'll have that! said the oxygen molecules
- Density of propylene when used as rocket fuel, and advantages (if any) over RP-1?
- Vector-R's LP-1 and -2 engines use liquid propylene as fuel with LOX, advantages and distinctions from kerosene or propane?