Plans for the replacement of the aging and ailing Space Shuttle are looking pretty shaky following a report from the US congressional spending watchdog. The Government Accountability Office says there are “gaps in the knowledge about requirements, costs, schedule, technology, design, and production feasibility” for the Ares I rocket. Which seems to me to be just about all of it.

“While NASA still has 10 months under its own schedule to close gaps in knowledge about requirements, technologies, costs, and time and other elements needed to develop the Ares I system, the gaps we identified are fairly significant and challenging given the complexity and interdependencies in the program,” says the report.

Democrat Bart Gordon, chairman of the House Committee on Science and Technology Chairman, commissioned the report. “GAO’s assessment is a mix of good news and not-so-good news,” he says (press release). “On the one hand, GAO has concluded that NASA is taking steps to demonstrate that the Ares I project is achievable within the constraints that the project faces. On the other hand, GAO has identified a number of significant challenges that will have to be overcome if the project is to succeed.”

The Space Politics blog notes the reports concerns about the budget for the Constellation programme, which includes both the Ares I launcher and the Orion crew vehicle. Comments on the blog raise the spectre of the Columbia disaster, where planning problems are thought to have contributed to the accident.

Image: Ares artistic impression / NASA