NASA says it is holding to a March 2021 launch date for the James Webb Space Telescope, but a new report from the US Government Accountability Office suggests the mission probably will not happen then.
Because the space agency and the telescope's prime contractor, Northrop Grumman, continue to tackle serious technical problems, the report estimates that there is only a 12 percent chance that the large space telescope will launch in March 2021. It is due to lift off on board an Ariane 5 rocket from the European Space Agency's spaceport in Kourou, French Guiana.
NASA generally uses a "70 percent confidence level" to establish dates for missions, and if that were the case for the Webb telescope, the new report says the launch date would likely slip to July 2021. It also warns that additional problems could arise during the final phases of assembling and integrating the telescope for launch.
The Webb telescope, NASA's follow-on instrument to the wildly successful Hubble Space Telescope, was originally due to launch about a decade ago, with a development cost of $1 billion. Since then, technical problems and delays have bedeviled the complex telescope. The new report also says the current estimate for Webb's development cost, $9.7 billion, may be too low.
It has been difficult to build Webb because the large instrument, with a 6.5-meter mirror, needs to unfurl itself once it reaches an orbit about 1.5 million km from Earth. This is an exceedingly complex process, and there are more than 300 single points of failure on board the observatory. NASA has had a difficult time testing them all on Earth in conditions that mimic the temperatures, pressure, and microgravity of deep space.
According to the new report, project leaders are still tracking 50 risks to the telescope that must be addressed before launch. Some of the major concerns, according to the report, include:
As part of its review, the government office said NASA has taken steps to bring the project to a successful close, in particular adding more agency personnel to provide oversight and helping the contractor with the issues it is trying to manage.