NASA’s beleaguered $8.8 billion James Webb Space Telescope (JWST) is at risk of further cost increases and schedule slips without more rigorous oversight, according to the U.S. Government Accountability Office (GAO).

GAO is concerned that key hardware testing and integration reviews are scheduled too close to the program’s revised October 2018 launch date.

“Without higher-fidelity, regularly updated information related to costs, as well as an oversight regime during later phases of test and integration that is commensurate with the complexity of that effort, NASA risks late identification of technical and cost issues that could delay the launch of JWST and increase project costs beyond established baselines,” GAO cautioned in its Dec. 3 report to House and Senate appropriators.

The congressional auditors also commended the agency for actions taken as part of a JWST re-plan in response to the findings of a 2010 Independent Comprehensive Review Panel that produced the current price tag, a near 80% increase to the original $4.96 billion development price tag from April 2009.

The price hike accompanied a 52-month launch slip. But NASA’s efforts may not be enough to steady plans for the near-infrared successor to the Hubble Space Telescope that is designed to study the earliest star systems and track cosmic evolution.

Even anticipated reductions in travel expenses associated with the project, first proposed in 1999, could prove harmful to recent gains in oversight and communications among project participants located on the East and West coasts and in between, GAO says.

The major concerns, however, were focused on the adequacy of cost and schedule reserves as the project approaches a critical Optical Telescope Element and Integrated Science Instrument Module (OTIS) thermal vacuum test scheduled for February 2017. GAO is urging NASA to convene an independent review prior to the integrated OTIS test to appraise the project’s readiness to move forward.

Geoffrey Yoder, NASA’s JWST program director, provided GAO with a four-page response offering full or partial concurrence with each of the recommendations, including a pledge to add participation of the JWST’s standing review board members to the Goddard Space Flight Center’s scheduled Independent Review Team assessment prior to the OTIS thermal vacuum test.