This paper derives upper and lower bounds on the capacity of the multiple-input single-output free-space optical intensity channel with signal-independent additive Gaussian noise subject to both an average-intensity and a peak-intensity constraint. In the limit where the signal-to-noise ratio (SNR) tends to infinity, the asymptotic capacity is specified, while in the limit where the SNR tends to zero, the exact slope of the capacity is given. Index Terms-Average-and peak-power constraint, channel capacity, direct detection, Gaussian noise, infrared communication , multiple-input single-output (MISO) channel, optical communication.