Tag Archives: James Webb Space Telescope

Sunshield Layers

The five sunshield layers responsible for protecting the optics and instruments of NASA’s James Webb Space Telescope are now fully installed. Northrop Grumman Corporation, which designed the Webb telescope’s optics, spacecraft bus, and sunshield for NASA Goddard Space Flight Center, integrated the final flight layers into the sunshield subsystem.

Sunshield Layers Fully Integrated on NASA’s James Webb Space Telescope
Sunshield Layers Fully Integrated on NASA’s James Webb Space Telescope

Designed by Northrop Grumman Aerospace Systems in Redondo Beach, California, the sunshield layers work together to reduce the temperatures between the hot and cold sides of the observatory by approximately 570 degrees Fahrenheit/299 degrees Celsius. Each successive layer of the sunshield, which is made of Kapton, is cooler than the one below.

«This is a huge milestone for the Webb telescope as we prepare for launch», said Jim Flynn, Webb sunshield manager, Northrop Grumman Aerospace Systems. «The groundbreaking tennis-court sized sunshield will protect the optics from heat making it possible to gather images of the formation of stars and galaxies more than 13.5 billion years ago».

«All five sunshield membranes have been installed and will be folded over the next few weeks», said Paul Geithner, deputy project manager – technical for the Webb telescope at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

The Webb telescope’s sunshield will prevent the background heat from the Sun, Earth and Moon from interfering with the telescope’s infrared sensors. The five sunshield membrane layers that were manufactured by the NeXolve Corporation in Huntsville, Alabama, are each as thin as a human hair. The sunshield, along with the rest of the spacecraft, will fold origami-style into an Ariane 5 rocket.

The Webb telescope is the world’s next-generation space observatory and successor to the Hubble Space Telescope. The most powerful space telescope ever built, the Webb Telescope will observe distant objects in the universe, provide images of the first galaxies formed and see unexplored planets around distant stars. The Webb Telescope is a joint project of NASA, the European Space Agency and the Canadian Space Agency.

Acceptance testing

Raytheon completed factory acceptance testing of the flight operations system for the James Webb Space Telescope (JWST). With seven times the light-collecting power of its predecessor, the Hubble Space Telescope, this next-generation telescope will gather data and images of dust clouds, stars and galaxies deeper into space.

The James Webb Space Telescope (sometimes called JWST or Webb) will be a large infrared telescope with a 6.5-meter primary mirror
The James Webb Space Telescope (sometimes called JWST or Webb) will be a large infrared telescope with a 6.5-meter primary mirror

Over 800 requirements were successfully verified on the JWST ground control system during the testing conducted at Raytheon’s Aurora, Colorado, facility, bringing NASA’s next space observatory one step closer to the scheduled 2018 launch.

«The JWST flight operations system is our latest generation of mission management and command and control capabilities for satellite operations», said Matt Gilligan, vice president of Raytheon Navigation and Environmental Solutions. «Our ground control system will download data from space and fly the telescope as it penetrates through cosmic dust to unlock the universe’s secrets like never before».

JWST takes observations in the infrared spectrum to penetrate cosmic dust to reveal the universe’s first galaxies, while observing newly forming planetary systems. JWST is expected to make observations for five years, will carry enough fuel for 10 years, and is designed to withstand impacts of space debris as it orbits far beyond the Earth’s Moon.

Raytheon installed the ground control system for JWST on the campus of the Johns Hopkins University in Baltimore, Maryland, under contract to the Space Telescope Science Institute.

 

Vital Facts

Proposed Launch Date JWST will be launched in October 2018
Launch Vehicle Ariane 5 ECA
Mission Duration 5 – 10 years
Total payload mass Approximately 6,200 kg/13,669 lbs, including observatory, on-orbit consumables and launch vehicle adaptor
Diameter of primary Mirror ~6.5 m/21.3 feet
Clear aperture of primary Mirror 25 m2/269 square feet
Primary mirror material beryllium coated with gold
Mass of primary mirror 705 kg/1,554 lbs
Mass of a single primary mirror segment 20.1 kg/44.3 lbs for a single beryllium mirror, 39.48 kg/87 lbs for one entire Primary Mirror Segment Assembly (PMSA)
Focal length 131.4 m/431.1 feet
Number of primary mirror segments 18
Optical resolution ~0.1 arc-seconds
Wavelength coverage 0.6 – 28.5 microns
Size of sun shield 21.197 × 14.162 m/69.5 × 46.5 feet
Orbit 1.5 million km from Earth orbiting the second Lagrange point
Operating Temperature under 50 K/-370 °F
Gold coating Thickness of gold coating = 100 × 10-9 meters (1000 angstroms). Surface area = 25 m2. Using these numbers plus the density of gold at room temperature (19.3 g/cm3), the coating is calculated to use 48.25 g of gold, about equal to a golf ball (A golf ball has a mass of 45.9 grams)

 

Path to Launch

Northrop Grumman Corporation’s delivery of the fully integrated Optical Telescope Element (OTE) for NASA’s James Webb Space Telescope marks another major milestone toward the October 2018 launch of the largest telescope ever built for space.

The spacecraft, or bus, of NASA's James Webb Space Telescope is designed and developed at Northrop Grumman. The bus recently reached a major milestone, successfully completing first time power-on, showcasing the spacecraft's ability to provide observatory power and electrical resources for the Webb telescope
The spacecraft, or bus, of NASA’s James Webb Space Telescope is designed and developed at Northrop Grumman. The bus recently reached a major milestone, successfully completing first time power-on, showcasing the spacecraft’s ability to provide observatory power and electrical resources for the Webb telescope

Northrop Grumman delivered the OTE in March to NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Northrop Grumman is under contract to Goddard and leads the industry team that designs and develops the Webb Telescope, its sunshield and spacecraft. Northrop Grumman has completed the integration, testing and delivery of the telescope.

The Webb telescope’s 18 hexagonal gold coated beryllium mirrors are supported by the telescope structure. The OTE hardware is made of the most precise graphite composite material system ever created, and contributes to the Webb Telescope’s ability to provide an unprecedented exploratory view into the formation of the first stars and galaxies formed over 13.5 billion years ago.

The precision manufacturing and integration of the 21.5-foot/6.5-meter telescope structure allow it to withstand the pressure and weight of the launch loads when stowed inside the 15-foot/4.6-meter-diameter fairing of the Ariane 5 rocket. The cutting-edge design and transformer like capabilities of the telescope structure allow it to fold-up and fit inside the launch vehicle, and then deploy once the Webb telescope reaches its ultimate destination, one million miles away from earth. Furthermore, throughout travel and deployment, the telescope simultaneously maintains its dimensional stability while also operating at cryogenic or extremely cold temperatures, approximately 400 degrees below zero Fahrenheit/240 degrees below zero Celsius. The telescope is the world’s first deployable structure of this size and dimensional stability ever designed and built.

«The significant milestone of completing and delivering the OTE to NASA’s Goddard Space Flight Center, marks the completion of the telescope, and attests to the commitment of our hardworking team», said Scott Texter, telescope manager, Northrop Grumman Aerospace Systems. «The telescope structure is one of the four main elements of this revolutionary observatory. The other elements include: the spacecraft, sunshield and the Integrated Science Instrument Module (ISIM), the latter of which is also complete. All of the elements require a collaborative team effort. We are all committed to the cause and excited about the upcoming phases of development as we prepare for launch in October 2018».

The next step in the progress of the telescope structure includes its integration with the ISIM to combine the OTE and ISIM, referred to as the OTIS. The OTIS will undergo vibration and acoustic testing by the end of this year, and then travel to NASA’s Johnson Space Center in Houston, to undergo optical testing at vacuum and operational cryogenic temperatures, around 40 kelvin/233 degrees below zero Celsius. The OTIS will be delivered to Northrop Grumman’s Space Park facility in Redondo Beach, towards the end of 2017, where it will be integrated with the sunshield and spacecraft.

The James Webb Space Telescope is the world’s next-generation space observatory and successor to the Hubble Space Telescope. The most powerful space telescope ever built, the Webb Telescope will observe the most distant objects in the universe, provide images of the first galaxies formed and see unexplored planets around distant stars. The Webb Telescope is a joint project of NASA, the European Space Agency and the Canadian Space Agency.