NASA’s plan
to start preliminary design review of its space shuttle replacement hardware by the end of the summer faces challenges
due to uncertainty over the vehicles’ requirements, according to a U.S. Government Accountability Office (GAO) report released April 3.

The report was another warning to NASA that it should fully define requirements and assess risks associated with its Ares 1 launch vehicle and Orion Crew Exploration Vehicle before moving into preliminary design review, a
major step
in development
in which the
customer’s needs are matched with the
developer’s resources of time, money, technology and people.

Orion and Ares 1
are part of
$230 billion Constellation program, which encompasses the hardware NASA will need to return astronauts to the Moon by 2020.
Ares 1 and Orion are scheduled to debut in March 2015, and any slip in the schedule would widen the gap in U.S. human spaceflight capability


GAO officials, however, said now is the time to ask questions and resolve any design concerns. The GAO report,
“NASA: Ares 1 and Orion Project Risks and Key Indicators to Measure Progress,” was released at an April 3 hearing of the House Science space and aeronautics subcommittee.

“The need to make adjustments is often unwelcome news, particularly if they may require more funding or time than originally promised. But pushing off problems in fear of losing commitments to a program invariably leads to much more time delays and cost growth, and thus less resources for other needed investments,” Cristina Chaplain, GAO director of
acquisition and
told the subcommittee.

NASA plans to enter the preliminary design phase for the Ares 1 rocket in August and Orion Crew Exploration Vehicle in September, but the GAO report said the U.S. space agency would be “challenged” to meet those target dates because of
significant knowledge gaps in every major segment of Ares 1 and Orion.


“In fact, we do not know yet whether the architecture and design solutions selected by NASA will work as intended,” the report said. “Given the complexity of the Orion and Ares 1 efforts and their interdependencies, as long as requirements are in flux, it will be extremely difficult to establish firm cost estimates and schedule baselines.”


The report is the latest in a series of GAO studies that have found fault with
Ares 1 and Orion development plans. In July 2006, the GAO recommended that NASA modify its acquisition strategy for Orion – to avoid a long-term contractual obligation – by coming up with
firm requirements, mature technologies, a preliminary design,
realistic cost estimates and sufficient funding and time. NASA initially disagreed but later complied, the most recent report said.


NASA also pushed the Ares 1 preliminary design review from July 2008 to August 2008 after the GAO issued an October 2007 report that again recommended that the space agency
develop a sound business case before proceeding beyond preliminary design review.


The most recent assessment, which began in October 2007 and ended in April, found no “fatal flaws,” Chaplain said.


However, the
report identified five areas of concern:


– Defining requirements – as requirements for Ares 1 and Orion are fully defined, the weight of the vehicles could change, causing increased costs and delays.


– Technical development – thrust oscillation in the Ares 1’s
first stage threatens system design, although
Chaplain acknowledged that NASA is taking steps to address the problem. Also, the J-2X upper-stage engine for Ares 1 represents new
development effort and is likely to experience failures during the process
that would lead to design changes; and no industry capability exists for producing Orion’s large heat shields.


– Cost uncertainties – NASA cannot accurately estimate costs and schedules until requirements are defined, so preliminary cost estimates for the Constellation program are likely to change.


– Schedule pressure –
technical development issues already have resulted in schedule delays, the GAO report said.
In addition, the schedule goal forces NASA to conduct many development activities concurrently, and a delay in one part of the program can cause a ripple effect that delays others.


– Insufficient testing sites –
are inadequate to replicate the vibration and acoustic environment
Orion will experience during flight.

Richard Gilbrech, associate administrator for NASA’s Exploration Systems Mission Directorate, told the Space and Aeronautics
subcommittee April 3 that he agrees with the GAO report, and that NASA is implementing the recommendations.