(April 12, 2022)
Debbie Simmons is the System Engineering Lead for the James Webb Space Telescope (JWST) program. She has a BS in Aerospace Engineering from San Diego State U and MS in Electrical Engineering from USC, and has worked for Northrop Grumman for many years. She has been active in encouraging young women to enter engineering careers.
The JWST weighs 7 tons and was developed by Northrop Grumman for NASA and the Canadian & European Space Agencies, with contributions from a number of academic, government, and industrial partners. It was launched on an Ariane 5 rocket from French Guiana on the northern coast of South America on Dec 25, 2021. It has a 21-foot primary mirror consisting of 18 gold-coated beryllium mirrors accurate to 20 nanometers and weighing 44 lb each, which were folded to fit into the launch rocket. It has 6 major subsystems: Electrical Power with solar panels, Attitude Control, Communication, Command and Data Management, Propulsion, and Thermal Control.
The JWST was placed in the L2 LaGrange point, ~1 million miles from Earth in a stable gravitational point that always stays on the midnight side of the Earth, so that the light and heat from the Sun, Earth and Moon are always in the same direction. It has a tennis-court-sized sunshield to separate the observatory into a hot Sun-facing side and a very cold anti-Sun side, to keep the Sun’s heat away from the delicate mirrors & electronics whose operating temperature has to be kept under minus 370 degrees F (90 degrees F above absolute zero). The sunshield has 5 separate layers for heat-shielding and to minimize deterioration from meteor damage (it’s a dangerous neighborhood).
After finishing calibration maneuvers, JWST will become operational in June 2022. It will observe red-shifted light from the early history of the universe, to 180 million years after the “Big Bang” singularity of ~13.8 billion years ago (considered the “age of the universe”, based on detailed measurements of universe expansion). High-redshift (very old and distant) objects have their visible emissions shifted into the infrared. JWST can see objects 400 times fainter than from large ground-based telescopes or current space-based infrared telescopes. Its instruments will operate in the near- and mid-infra-red spectrum, which is mostly blocked by the atmosphere and is best observed from space. These observations will help understand the shape and chemical composition of the universe, and the evolution of galaxies, stars and planets.