NASA's Goddard Space Center now explains Why and how these maneuvers are performed. According to NASA, the Arian 5 rocket provided most of the energy needed to send the Web into orbit around Lagrangian point 2 of the Sun-Earth. After the observatory is released from the launcher, several small changes in the path are planned so that the complex can reach its operational orbit about a month later.
The largest and most important "path correction" (Mid -Course Correction) or MCC named MCC-1a was scheduled to be successful 12.5 hours after launch. This time was chosen because the sooner the route is corrected, the less fuel is needed. This leaves as much fuel as possible for normal web operations throughout its life: first, stability in the station circuit, including small adjustments to keep the web in the desired circuit; It is used on a giant telescope.
On the other hand, this directional fire was not planned immediately after launch. The flight dynamics team was thus given time to receive tracking data from three ground stations located as large networks on the planet Earth to determine the position and speed of the web with high accuracy.
- Where is the James
Webb Space Telescope now? Provided the route. Also,
with this schedule, there was ample opportunity to test the
required propulsion fire before performing the actual maneuver.
NASA is currently analyzing the data to determine how much
further refinement is needed and how much fuel will remain
after that; But now it is clear that the Arian 5 launcher has
done better than the targeted needs to place the web in
Graphic design of the James Webb Telescope's orbit
According to James Webb, NASA always has a lower target for correction. The point L2 and the web halo orbit around it are semi-stable. In the radial direction (along the Sun-Earth line) there is an equilibrium point that does not require the propulsion force to stay in that position. But this point is not stable, and if the web deviates slightly toward the ground, it will continue to get closer in the absence of its corrective propulsive force, and similarly, if it moves a little farther, it will follow the same path.
The James Webb spacecraft is propelled only on the hot, sun-facing side so that hot propellants do not contaminate the cold part of the observatory with unwanted heat or rocket output that can condense on cold optical instruments. This means that propellants can only move the web away from the sun and cannot bring it closer to the sun and the earth (correcting the reverse path). So NASA designs mid-range launches and corrections to keep the web always upward in gravitational potential because it is not at all desirable for the spacecraft to go too far and no longer be able to bounce back.
The James Webb method of injecting space into space by the Arian 5 launcher was deliberately designed to provide the spacecraft with some of the speed required to move away from Earth and the Sun. Similarly, the MCC-1a correction maneuver was performed to provide the maximum, not all, of the required corrections (to ensure that the fire would not be excessive). Then the MCC-1b, which is scheduled to run 2.5 days after launch, and the MCC-2, which runs about 29 days after launch (with the possibility of team scheduling changes), as well as static web fires in orbit during Mission life will always be just a driving force. This force is such that it is still slightly beyond the ultimate limit required to overcome the Sun's gravity. NASA
Source: NASATags: why, how, correction, between, path, james, webb, telescope, done