A joint collaboration between NASA, the European Space Agency, and the Canadian Space Agency, JWST is the largest and most powerful space observatory ever built, promising to revolutionize our understanding of the universe.
Unlike the pioneering Hubble Space Telescope, which orbits the Earth, JWST will insert itself into an orbit around the sun at a special location known as the second Lagrange point, or L2.
This point is located approximately 930,000 miles away from the Earth in the exact opposite direction from the sun.
There are five sun-Earth Lagrange points—areas where gravity from the sun and Earth balance the orbital motion of a given satellite.
Placing a spacecraft in any one of these points enables it to stay in a fixed position relative to the Earth and sun while using a minimal amount of energy—in the form of rocket thrusts—to help it stay in place. Essentially, Webb will be locked in almost perfect unison with the Earth’s orbit around the sun.
The journey from the Earth to L2 will take a total of 29 days. The telescope is currently 23 days into this trip, having launched on December 24, 2021 from Europe’s Spaceport in the South American territory of French Guiana.
According to NASA’s James Webb tracker, the observatory has completed just over 91 percent of the distance toward L2 at the time of writing, meaning it is currently located more than 821,000 miles from Earth in the direction of the second Lagrange point. The telescope is scheduled to arrive at L2 on January 23.
JWST covered most of this distance early on in its journey when it was traveling at much higher speeds—since separating from its launch vehicle the observatory began to slow rapidly.
After the rocket that propelled Webb into space used up all of its fuel, the spacecraft has essentially coasted towards L2, while being slowed down by the gravity of the Earth and sun.
“Since it is no longer thrusting (accelerating) away from the sun, the gravitational tug felt by Webb is the largest force affecting its velocity,” Eric Smith, Webb program scientist at NASA Headquarters in Washington, D.C., told Newsweek.
“We have given Webb just enough initial velocity that it will reach L2 but not shoot beyond it. Once it arrives out at L2, its velocity around the sun will balance the inward pull of the sun’s gravity putting us in an orbit around the sun.”