"Jonathan Goff" wrote in news:1167872622.531215.282180@
11g2000cwr.googlegroups.com:

Nope, I'm pretty sure it's just pure peroxide. Of the three companies
I know doing LOX/Alcohol lately (Armadillo, XCOR, and us here at
Masten Space Systems), none of our plumes have looked anything
like that. But all the guys I know who've done peroxide (John Carmack,
my boss Dave, some of the ERPS guys, etc) say it looks just like a
peroxide engine. Maybe that was steam, not frost?

I'm inclined to agree; it's a simple way to test the general
vehicle concept without getting into the cost and expense of
a bipropellant engine. Otherwise they're either running oxidizer
rich or have excellent mixture control and burning; I'd expect
to see some yellow (carbon) in the exhaust otherwise.

But overall, pretty darned cool.

Yes, indeed. Best thing since DC-X. Imagine if that program
had continued to be funded.

--Damon