To carry out the provisions of this subchapter, there are authorized to be appropriated—
(1)
for the fiscal year ending June 30, 1976, $75,000,000;
(2)
for subsequent fiscal years, only such sums as the Congress hereafter may authorize by law;
(3)
such amounts as may be authorized for the construction of demonstrations pursuant to section
5556
(f) of this title; and
(4)
to the National Science Foundation for the fiscal year ending June 30, 1975, not to exceed $2,000,000 to be made available for use in the preparation of the comprehensive program definition under section
5564 of this title.