We study the quantum dynamics of a linear polar molecule subjected to electromagnetic pulses. For a sequence of half-cycle pulses we derive, from a simplified analytical model, conditions to induce a molecular orientation sustainable for hundreds of picoseconds. The predictions are confirmed by full numerical calculations for the molecule NaI. Analyzing the effect of finite temperatures we conclude that the process of maintaining the molecular orientation is robust to the thermal average. (C) 2003 Elsevier B.V. All rights reserved.