Scientists and engineers have created and successfully tested a set of algorithms and software programs which are designed to enable the 19 individual mirrors comprising NASA's powerful James Webb Space Telescope to function as one very sensitive telescope.
NASA researchers will present findings on these algorithms and software programs, called the "Wavefront Sensing and Controls" at the Optics and Photonics meeting of the Society for Photo-Optical Instrumentation Engineers (SPIE) meeting. The SPIE meeting will be held at the San Diego Convention Center, 111 West Harbor Drive, San Diego, Calif., August 26-30. The session, called "TRL-6 for JWST Wavefront Sensing and Control" will be on Sunday, August 26 from 11:30 a.m. - 11:50 a.m. PDT, in room 29B, and is Paper 6687-7 of Conference 6687.
After its launch in 2013, when the Webb Telescope settles into its vantage point about one million miles from Earth, and periodically thereafter, the orientations of the telescope's 18 primary mirror segments and the position of the secondary mirror will have to be adjusted to bring light from the universe into focus. Through a process called "Wavefront Sensing and Control," or WFSC, software aboard the observatory will compute the optimum position of each of the 19 mirrors, and then adjust the positions, if necessary.
The Webb Telescope's 18 primary mirror segments cover a combined total area of 25 square meters (approx. 30 square yards) and a diameter of 6.5 meters (approx. 21 feet). "It's critical that all 18 mirror segments be aligned in position so that they act as one smooth surface, and the secondary mirror be placed exactly right," said Bill Hayden, Systems Engineer at NASA Goddard Space Flight Center, Greenbelt, Md. "This will allow scientists to clearly focus on very dim objects that we can't see now."
The WFSC system is put to work when the telescope takes digital pictures of a star. It then processes the images through mathematical algorithms to calculate the mirror adjustments required to bring the stellar image into focus. When the individual mirrors are properly aligned, the Webb Telescope will be able to obtain extraordinarily sharp images and detect the faint glimmer of a distant galaxy.
Recently, a team of engineers from Ball Aerospace & Technologies Corp., Boulder, Colo. and NASA successfully tested the WFSC algorithms, proving they are ready to work on the Webb Telescope in space. The algorithms were tested on a detailed scale model of the 6.5 meter space telescope and through computer simulations.
"This major technological accomplishment, which built on the legacy of software algorithms used to fix the Hubble Space Telescope and align the Keck telescope, is a major step forward in the development of JWST. This achievement was the result of great teamwork between Ball Aerospace, NASA Goddard Space Flight Center, and the Jet Propulsion Laboratory," said John Mather, Senior Project Scientist on the Webb telescope at Goddard and the 2006 winner of the Nobel Prize in Physics.
"The same technological ingenuity Ball Aerospace applied to correcting the Hubble Space Telescope's primary mirror in 1993 is being applied to advancing the optics for the JWST observatory," said David L. Taylor, president and chief executive officer of Ball Aerospace & Technologies Corp.
The Webb Telescope is designed to study the faint light from objects at the farthest reaches of space and time.
SPIE is an international society advancing an interdisciplinary approach to the science and application of light. This conference and exhibition focuses on where optical engineering meets emerging technologies of nanotechnology and science, photonic devices and solar energy and their applications.
The James Webb Telescope
The James Webb telescope will be able to look back to the beginning of time. It will find the first galaxies and will peer through dusty clouds to see stars forming planetary systems, connecting the Milky Way to our own Solar System. Launch is scheduled for 2013.
"There's more than just one similarity between the web-slinging superhero and the James Webb telescope," said John Decker, Deputy Associate Director for the James Webb Space Telescope Project at NASA's Goddard Space Flight Center, Greenbelt, Md. "The sunshield on the spacecraft is actually shaped like a giant spider web, when you look at it from the top."
During the second week in May, visitors to the Nation's Capitol will be able to see the life-sized model of NASA's latest "superhero," and get a picture taken next to it. The model will be assembled on May 9, and will be on display through May 12 in front of the Smithsonian's National Air and Space Museum on the National Mall, Washington.
NASA and Northrop Grumman, the contractor who built the model, will set up information booths next to the model, where visitors can get information and educational materials, and speak with people who are involved in the project to build the real James Webb Space Telescope.
The full-scale telescope model was built to give the viewing public a better understanding of the size, scale and complexity of this breakthrough satellite. Specifically designed for an environment subject to gravity and weather, the model is constructed mainly of aluminum and steel, weighs 12,000 lbs., and is approximately 80 feet long, 40 feet wide and 40 feet tall. A specially manufactured material imported from France called "Ferrari Precontraint" allows the sunshield to 'breathe.' The model requires 2 trucks for shipping, and assembly takes a crew of 12 approximately four days.
The telescope model has been "Webb-slinging" since 2005 to Seattle, Wash.; Colorado Springs, Colo.; Paris, France; Greenbelt, Md.; Rochester, N.Y.; and Orlando, Fla. Funds used to build this model were provided solely by Northrop Grumman.
The model display is part of "Public Service Recognition Week 2007," which runs from May 10 through 13. The theme of the week is "Safety, Science, Security, Technology." This annual national event is sponsored by the Council for Excellence in Government, Employees Roundtable, and it honors men and women who serve America in the Federal, state and local governments.
