The article in Space News, “Lawmakers Demand Documentation on NASA’s Compliance with Law” [May 23, page 6], is very discouraging. We have congressmen directing NASA to develop a heavy-lift launch vehicle for no other reason than to provide jobs for their constituents. That is not in the best interest of the public. It is continuously overlooked that we do not have the advanced performance rocket engines necessary to power heavy-lift launch vehicles.

The Space Shuttle Main Engines, 454 seconds impulse, are too expensive for an expendable launch vehicle. The RS-68 engines planned for use on the Ares vehicle are grossly inefficient, 415 seconds impulse, and were developed to be inexpensive “throw away” engines for the Air Force’s expendable Delta launch vehicles. The J-2X is too small, and less efficient than the Space Shuttle Main Engines. Efficient advanced performance rocket engines operating at a specific impulse of 470 seconds are needed and should be developed before we return to the Moon or venture to Mars.

These engines will put a greater payload into orbit at lesser expense.

Such a development will also maintain the United States’ leadership in space activities. As it is, public money is being wasted.

Dale Lawrence Jensen

Lawndale , Calif.