Aditya L1 : Aditya L1 will be injected into orbit around L1 in about 110 days. To achieve this, the spacecraft must follow a planned trajectory.
Isro’s Aditya L1 spacecraft, launched on Tuesday to reach the Sun-Earth Lagrangian (L1) point, is likely to require a Trajectory Correction Maneuver (TCM) in the coming days as deviations may have crept into the early trajectory. , researchers have shown.
Indian Space Research Organization scientists expect the data to reach ground stations on Thursday morning, 48 hours after the Trans-Lagrangian Point 1 Insertion (TL1I) mission at 2:30 am. on September 19, to evaluate Aditya L1 and determine the timing and size of the orbit. correction needed.
“We are doing a runway repair operation. We will have to decide when to do it after evaluating the data after 48 hours,” said M Sankaran, director of the UR Rao Satellite Centre.
Trajectory correction maneuvers or trim maneuvers are part of the design of all deep space missions where the spacecraft has to travel long distances after being placed on trajectories that take the spacecraft to the desired orbit around the Moon, Mars and point L1, which is 1.5 lakhs. . km on the way to the Sun for the Aditya L1 mission.
Aditya L1 will be injected into orbit around L1 in approximately 110 days. To achieve this, the spacecraft must follow a planned trajectory.
According to Isro sources, there were some deviations in the determination of the orbit and the orientation of the antennas of the ground stations, because of which there was a need to correct the trajectory of the Aditya L1 mission in the coming days. Scientists on the mission are crossing their fingers for the need for TCM, the sources added.
On Tuesday, Isro announced that the launch of Aditya-L1 is “out to the sun-Earth L1 point!”
“The Trans-Lagrangian Point 1 Insertion (TL1I) mission has been successfully completed. The spacecraft is currently on a trajectory that will take it to the Sun-Earth L1 point. It will be re-inserted into the L1 orbit in about 110 days. This is the fifth consecutive time, the space agency announced, when ISRO has successfully moved an object on a trajectory to another celestial body or location in space. Isro’s ground stations at Mauritius, Bengaluru and Port Blair tracked the satellite as it moved.
After the gradual movement of Trans Lagrangian Point 1, the researchers discovered that there may be trajectory errors that require correction after the current trajectory and required trajectory are accurately determined in orbit around Point L1 after a 110-day drive to the point.
Sources said deviations in antenna orientation at Indian ground stations and lack of support from NASA’s Jet Propulsion Laboratory (JPL) ground stations, which provide highly accurate information about the spacecraft’s heading, could have caused errors in the orbital lift movement. Aditya L1 on the spacecraft.
“This has been part of the mission plans since Chandrayaan 1. For every orbit raising motion, we look at what orbit was achieved. If something needs to be done, it needs to be done as soon as possible and we cannot wait until much later, said a former senior scientist at Isro.
“When you go to a long roll period (for a spacecraft), we have to make sure that we don’t make mistakes. After orbiting, we wait a day or two to determine the orbit. Here it is a long … duration. to roll, and if there are small deviations, after a month or three months they have consequences, so now we have to fix it ourselves,” said the former Isro scientist.
“We need to assess how much repair is needed. If we make small movements, we know the quantity, and as long as we make that quantity, everything is fine. There would be a bit of a gap and it needs to be covered so it doesn’t become a problem. It’s usually a very small movement, the senior researcher added.
“It’s possible that the problem is with the antenna on the ground. When we talk about orbit prediction, it predicts the orbit that the move will take and the angles that the antenna will move to track the satellite. The second is the range, which is measured by sending signals and receiving them back to the ground station – that’s the distance,” he said.
“Distance and angle give you information about the course of the orbit – if there is an error in any of them, it will be reflected in incorrect information. For this, some kind of calibration is nominally done on the antenna,” he added.
According to a former scientist, collecting data about an orbit determination point from more than one earth system – including foreign ground stations like JPL – is essential for a successful deep space mission.
“Cutting is usually a small step – if you delay it, it’s a big step because if you want to do it a month or more later, the penalty is bigger and so we have to be 100 percent sure that it’s right to do it again. Small movements can cause a problem if we are not 100 percent sure of what we are doing, said the former scientist.