In article ,
says...
Last I checked Boeing is using composite tanks for their DOD booster
(whose name I forget). So there is that.

Cite:

DARPA Picks Boeing for XS-1 Spaceplane Project - 5/25/2017
http://www.airforcemag.com/Features/...7/DARPA-Picks-
Boeing-for-XS-1-Spaceplane-Project.aspx

From above:

To achieve an aircraft-like operations tempo, the craft will
have "easily-accessible subsystem components configured as
line-replaceable units," DARPA said, to enable "quick
maintenance and repairs." Other already developed technologies
that will be incorporated on the vehicle include lightweight
composite cryogenic propellant tanks to hold liquid oxygen
and hydrogen, "hybrid-composite metallic wings" able to
withstand temperatures exceeding 2,000 degrees Fahrenheit,
and autonomy technologies derived from DARPA?s Airborne
Launch Assist Space Access program.

But the above doesn't talk about the TPS for the main body, which
shields the tanks. The wings, however are "hybrid-composite metallic
wings", but no detail there about exactly what metal(s) and what
composites. This stuff is the "secret sauce", so info will be hard to
come by.


I forgot to add, XS-1 isn't orbital. It's essentially a winged first
stage with an upper stage and payload strapped to its back. So reentry
heating won't be nearly as bad for XS-1 as it will be for BFS.

Jeff
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