The United States has spent almost $43 billion to develop, assemble and operate the ISS over the past two decades, the GAO said.

"The Center for the Advancement of Science in Space (CASIS) has not been able to fulfill its responsibility in the cooperative agreement to interact with the ISS National Laboratory Advisory Committee," the report read on Wednesday.

Staffing its representation on CASIS is required by the NASA Authorization Act of 2008.

CASIS, which manages the ISS National Laboratory, has evaluated 206 proposals and awarded $20 million in grants to 77 research projects through January 2015, the GAO said.

The GAO noted that NASA's refusal to staff the committee had prevented CASIS from reviewing "any report or recommendations" submitted to the program.

By contrast, the GAO said CASIS has "taken steps to fulfill its management responsibilities contained in its cooperative agreement with... NASA."

The report urged NASA to fully staff the ISS National Laboratory Advisory Committee.

Source: Sputnik News