the transfer of missiles, engines, propellant or materials that can be used for fuel, or other technologies that could make a material contribution to development of space-launch vehicles or ICBMs. (B) Any actions described in subparagraph (A) or proposals for such actions being negotiated or discussed as of the date of the report. (4) An assessment of Iran’s ICBM technology, including the following: (A) Key steps Iran would need to take to develop an ICBM. (B) An assessment of which rocket motors Iran would likely use to build an ICBM. (C) Technological hurdles Iran would still need to overcome to develop an ICBM. (D) Pathways to overcome the hurdles described in subparagraph (C), including the potential transfer of technologies from North Korea, the Russian Federation, or the People's Republic of China. (E) An estimated timeline for Iran to develop an ICBM if Iran chooses to do so. (5) An assessment of the missile defense capabilities of the United States, as of the date of the report and anticipated for the future, with respect to denying an attack by Iran on the United States homeland, including the following: (A) An assessment of the ability of the Ground-Based Midcourse Defense System, as it exists on the date of the enactment of this Act, to prevent such an attack. (B) An assessment of how the procurement of the Next Generation Interceptor would improve the ability of the United States to intercept ICBMs launched from Iran. (C) How a third missile defense site on the East Coast of the United States would improve the ability of the United States to intercept ICBMs launched from Iran. (b) Updates As new information becomes available and not less frequently than annually, the Secretary shall submit to the congressional defense committees an updated version of the report required by subsection (a) that includes updated information under paragraphs (1) through (4) of that subsection. (c) Form Each report submitted under this section shall be submitting in unclassified form, but may include a classified annex.