Isso soa como o primeiro livro da série de sucessões "The Risen Empire", de Scott Westerfield. O capítulo de abertura chamado Piloto se ajusta ao que você descreveu.
Abaixo está um breve trecho ALERTA DE SPOILER explicando sua recordação NN mm:
Marx checked the altimeter's last reading: 174 centimeters. At that height, the craft would take at least a minute before they hit the ground. Even with its sensor array furled and main rotor stalled, in a normal-density atmosphere an intelligence craft fell no faster than a speck of dust. Indeed, the Intelligencers were not much larger than specks of dust, and were somewhat lighter. With a wingspan of a single millimeter, they were very small craft indeed.
Master Pilot Jocim Marx, Imperial Naval Intelligence, had flown microships for eleven years. He was the best.