In addition to the powers conferred by law upon any housing authority or the Commissioner of Housing, any such authority or said commissioner, in any contract with the federal government for annual contributions or other financial assistance, may obligate itself or the state, as the case may be, which obligation shall be specifically enforceable and shall not constitute a mortgage, notwithstanding any other laws, to convey to the federal government the housing project to which such contract relates, upon the occurrence of a substantial default with respect to the covenants or conditions to which such authority or the state is subject. Such contract may further provide that, in case of such conveyance, the federal government may complete, operate, manage, lease, convey or otherwise deal with the housing project in accordance with the terms of such contract, provided the contract shall require that, as soon as practicable after the federal government is satisfied that all defaults by reason of which it acquired the housing project have been cured and that the housing project will thereafter be operated in accordance with the terms of the contract, the federal government shall reconvey to such authority or the state the housing project as then constituted.