A rocket-borne instrument to measure mainly atomic oxygen density based on nitric oxide point releases in the lower thermosphere has been developed. Many of the difficulties associated with these kinds of experiments have been avoided by a new technique ejecting the NO gas in the backward diection of the flight. As a result, shock wave problems are eliminated substantially facilitating measurement and analysis. Preliminary tests ae discussed and construction and mode of operation of the instrument are described. The main advantages of the payload are technical simplicity and low cost. Another factor favoring the method is that it allows detemination of the altitude of artificial clouds and of wind speeds with extremely high accuracies. Finally, all observations may be performed using ground-based photographic instruments.