XCOR is reporting significant progress on the engine for the Lynx:

“Like all of our rocket engines, this engine has demonstrated the ability to be stopped and re-started using our safe and reliable spark torch ignition system”, said XCOR CEO Jeff Greason. “The basic cooling design has also been completed and the engine is able to run continuously at thermal equilibrium. With those milestones reached, the 5K18 test program is now moving forward into a second phase of tuning and optimization, in which we will also greatly increase our cumulative run time.”

Here’s hoping for continued progress.

[Update a few minutes later]

Clark Lindsey has more, with videos.