Designs the material that stands between a vehicle and the heat of going fast.

Above a few times the speed of sound, air compresses against the front of a vehicle hard enough to heat it to thousands of degrees, hot enough to melt or vaporise most structural metals. A thermal protection engineer chooses and qualifies what carries that heat instead: ablative material that chars and sacrifices itself, tile that radiates the heat back out, or an active system that cools the structure with flowing fluid. The choice depends on how hot, for how long, and how many times the vehicle has to fly.
Either works. What matters more is a genuine grounding in heat transfer, which not every programme teaches deeply.
Materials engineers · US Bureau of Labor Statistics, Occupational Outlook Handbook, May 2024 wages and 2024–34 projections.
Materials engineers as a whole, covering every material specialism from biomedical implants to semiconductors. Thermal protection is a small, specialised corner of it, closer in practice to aerospace engineering than to most of what this figure counts.
You cannot fully test the real condition on the ground: an arc-jet or plasma torch approximates the heating, it does not reproduce it, so a margin of genuine uncertainty rides along on every flight. The material is often destroyed by design, which means a good flight looks identical to a slightly-too-conservative one, and the only way to know you had margin to spare is analysis you cannot fully verify until the vehicle comes back, if it comes back at all.