United Launch Alliance‘s (ULA) owners, Boeing Co. (NYSE:BA) and Lockheed Martin Corp. (NYSE:LMT), are reportedly considering selling the company to Sierra Space for a deal valuing the rocket launch service provider around $2 to $3 billion. What Happened: ULA is a joint venture between Boeing and Lockheed Martin. The two are in negotiations with Sierra Space to sell ULA but it might not culminate in a deal, Reuters reported, citing two people familiar with the matter. The deal, if reached, will lead to a separation of ULA from its two co-founders and joint owners to a smaller, privately held fi…