This legislation aims to enhance space transportation infrastructure by modifying the existing grant program. It revises the limitations on project grants, generally capping federal contributions at 90% of total project costs , though the Secretary may waive this limit if deemed in the national interest. The bill also broadens the definition of "public agency" to include airport authorities and tax-supported organizations, expanding potential grant recipients. Furthermore, the bill updates the eligibility criteria for these grants, shifting the focus to encompass the civil, national security, and commercial space transportation needs of the United States. It requires the Secretary of Transportation to develop specific criteria for evaluating projects and to consult with agencies like the Department of Defense and NASA during this process. The legislation also mandates a comprehensive report to Congress within two years, evaluating space transportation demand, recommending policy, examining funding options, and assessing international capabilities to ensure United States competitiveness. An annual appropriation of up to $10,000,000 is authorized for these modernization grants.