James Webb Space Telescope passes another milestone
NASA’s James Webb Space Telescope (JWST) – what the agency has described as the next-generation space observatory – is one step closer to a planned October 2018 launch. Northrop Grumman, the primary contractor for the development and integration of the telescope, has announced it has completed the manufacture and assembly of the spacecraft structure that will take JWST to its target destination approximately 1 million miles from Earth.
“The spacecraft structure provides state of the art capabilities to support the James Webb Space Telescope’s first light mission,” said Andy Cohen, manager of the JWST spacecraft at Northrop Grumman Aerospace Systems.
Cohen noted that the JWST’s development is moving ahead, despite the fact that the United States House of Representatives’ appropriations committee on Commerce, Justice, and Science attempted to cancel the project in 2011.
“Completing the manufacturing and assembly of the spacecraft structure was a significant achievement by many dedicated and diligent people. This milestone represents the committed collaboration between the spacecraft structure’s manufacturing, engineering, integration and test teams. It also signifies the continuing progress on the Webb Telescope, and will culminate with the structure test, propulsion integration completion and delivery to spacecraft Integration and test by July 2016,” he added.
The spacecraft structure, or bus, was assembled at Northrop Grumman’s facility in Redondo Beach, California. This structure, made of carbon fiber composites, integrates the spacecraft’s propulsion, electrical power, and communications. It provides the necessary support functions for the operation of the JWST and must withstand a force equivalent to 45 tons while supporting the observatory during launch.
The bus is the home for six major subsystems: Electrical Power Subsystem, Attitude Control Subsystem, Communication Subsystem, Command and Data Handling Subsystem, Propulsion Subsystem, and Thermal Control Subsystem.
JWST will be launched on Arianespace’s Ariane 5 rocket from the ELA-3 launch complex at the European Spaceport located in Kourou, French Guiana. The bus mounts the whole observatory to the launch vehicle. After the launch, the telescope will be guided to reach the second Earth-Sun Lagrange point (L2), located on the opposite side of the Earth with respect to the Sun. To be able to fly all the way to L2, the spacecraft can’t weigh more than around 6.2 tons, and it will need powerful radio transmission equipment to send back data to Earth.
While in orbit, the bus will provide pointing and structural stability for the telescope down to one arcsecond. The structure also provides dynamic isolation and attenuation of vibration sources down to two milliarcseconds.
The JWST spacecraft will now undergo a series of important tests by the end of the year. The engineers will start optical ground support equipment checks and conduct cryo-vacuum tests in October. The flight spare cryo-cooler will be assembled and delivered to NASA’s Jet Propulsion Laboratory for acceptance test in December.
JWST is an international collaboration between NASA, the European Space Agency (ESA), and the Canadian Space Agency (CSA). The NASA Goddard Space Flight Center is managing the development effort. The main industrial partner is Northrop Grumman; the Space Telescope Science Institute will operate JWST after launch.
The JWST telescope will be the world’s premier observatory, serving thousands of astronomers worldwide. It will study every phase in the history of our universe, ranging from the first luminous glows after the Big Bang, to the formation of solar systems capable of supporting life on planets like Earth, to the evolution of our own solar system.
Tomasz Nowakowski is the owner of Astro Watch, one of the premier astronomy and science-related blogs on the internet. Nowakowski reached out to SpaceFlight Insider in an effort to have the two space-related websites collaborate. Nowakowski's generous offer was gratefully received with the two organizations now working to better relay important developments as they pertain to space exploration.