The most significant improvements SpaceX is planning for Phase 2 missions are the construction of a new mobile portal on Pad 39A at NASA`s Kennedy Space Center, where the company is launching powerful Falcon heavy missiles. The mobile tower will be located north of the pad launch pad support, which will allow SpaceX to meet military requirements to vertically integrate high-secret sensitive spy satellites vertically. There is no upper limit to the number of launches the Pentagon can order in Phase 2, but Roper expects about 32 missions. Funding for these missions will be allocated to future missions. ULA is designing the next-generation Vulcan Centaur rocket with all U.S.-made engines to replace its Atlas and Delta launchers, and SpaceX has offered the Pentagon its Falcon 9 and Falcon Heavy missiles already in service, but with some modifications to meet the army`s demanding launch requirements. Although this rocket can debut in 2021, it is not safe, as the development of new support systems almost always poses technical problems. Roper said the company will be able to continue using the Atlas V Booster until Vulcan is ready, since congressional law only prohibits the purchase of new engines instead of using them. A dozen of these engines are available. A letter dated May 29, signed by 28 lawmakers, asks the Air Force not to bow to pressure to include a third-party supplier in the acquisition of Phase 2 launch services. UsAF then signed a contract with SpaceX for two launches in 2014 and 2015 to support the certification process for the Falcon 9 v1.1 and Falcon Heavy.
 In April 2014, SpaceX sued the United States Air Force  alleging that the RD 180 engines manufactured in Russia by the NPO Energomash government and used by Atlas V violated sanctions against the Russian government.  USAF and SpaceX settled the action in January 2015 by opening further tender launches.   UsAF certified the Falcon 9 in May 2015 and in 2016, SpaceX received a mandate under the EELV program to launch a GPS Block III satellite load for MEO.  NSSL missions include the military`s most expensive and critical payloads, such as school bus-sized spy satellites, nuclear-weapon communications satellites to connect the president to military commanders, spacecraft to detect enemy missile launches, and the GPS navigation fleet used worldwide.