The NO Δ-bands have been observed photometrically by the ultra-violet telescope onboard the TD-1 ESRO satellite. The maximum intensity for the system is about 220 R, in good agreement with a previous rocket measurement. Assuming that the excitation is due to the N+O→NO(C2&Pgr;, v=0) preassociation, we used the observed profile to derive the atomic nitrogen density distribution. We found a peak of about 9¿107 cm-3 at about 180 km. A comparison is made with theoretical predictions, and some implications of such a high N(4S) density are discussed.