Thermal Soak. Brooks Hammer, #6

The immersion tanks at Groom Lake were built to keep hypersonic pilots alive through thermal loads that melt titanium. Jax Jagger enters the mesosphere one last time to intercept TIAN-2, knowing the airframe will hold but the pilot probably will not. His neural degradation is accelerating. The tremor spreading from his hand into his cognition, the boundary between Jax and the aircraft dissolving with each flight.
His daughter Lily asks him not to go. He goes anyway. The SCORCH aircraft was designed for a pilot who could merge with the machine at the cost of everything that made him human. Jax flies into the upper atmosphere and does not come back as the man who left. The merge is permanent. What emerges refuses lethal force, refuses to be a weapon, and refuses to die on anyone's terms but its own. Book six closes the hypersonic era with a price no flight manual covers.