The final frontier of space is getting crowded as a growing number of companies rush to go where no man has gone before. From space tourism and research stations orbiting the moon to the colonization of Mars and an ever expanding network of satellites encircling the Earth, the space sector is red hot right now and seems to have captured the imaginations of corporate leaders and investors.

Space stocks are hot, but with few companies generating revenues and valuations pushing into stellar territory, investors need to play it smart.