-150 °F is an estimate for the temperature in the upper layers of the earth's atmosphere. This value is an effective air temperature since the temperature varies with height and the atmosphere absorbs thermal radiation only gradually with distance. -150 °F is a conservative value; for example, Holman (1986) suggests a warmer value of -95 °F.
Your coworker is correct in asserting that beyond the atmosphere, the temperature is essentially absolute zero (2.7 K). However, with the atmosphere separating surface objects from outer space, we must use the temperature of the atmosphere and not that of outer space for our radiation target.
By the way, is quiche a French name?