Everything is ready for today, November 1, the NASA spacecraft Lucy to pass very close to the asteroid Dinkinesh, an object approximately one kilometer in size that orbits the region of the asteroid belt between Mars and Jupiter.
Although, in reality, the main objective of the mission is not Dinkinesh but to study some of Jupiter's Trojan asteroids, bodies that share orbit with the giant planet and that precede or follow it in its movement around the Sun, NASA does not want miss the opportunity to get close to this object since it is in the path that Lucy follows.
In addition, this close pass will serve as a test for the ship's scientific instruments, which will be activated minutes before its closest approach to Dinkinesh.
Two hours before the moment of closest approach to Dinkinesh, NASA engineers will orient the spacecraft so that its scientific instruments can study the asteroid. From that moment on, Lucy will begin to collect data with her high-resolution camera and with her thermal camera, capable of working in the infrared range. An hour later, the autonomous tracking system will be activated, which will guide the last leg of the trajectory towards the object.
The other instruments will start working when there are only eight minutes left before the close pass. Specifically, another color camera and an infrared spectrometer will be activated (equipment capable of studying the light reflected by the asteroid and thus obtain data on its composition).
The closest approach will take place at 17:54 (Spanish peninsular time), when the ship will pass just 430 kilometers away from Dinkinesh.
The scientific instruments will continue to operate until about an hour later. Finally, the spacecraft will reorient itself so that communications with Earth are recovered and data downloading can begin, a transmission process that will last days.
Much of the sequence of maneuvers must be executed autonomously. As Mark Effertz, chief engineer of the mission for the Lockheed Martin Space company, explains, “we will know what Lucy should be doing at all times, but she will be so far away that the radio signals will take 30 minutes to travel to the ship, so we will not be able to govern the meeting interactively.”
The so-called Trojan asteroids occupy regions of special stability in the orbits of the planets. These points, known as Lagrange L4 and L5 and which are 60 degrees in front and behind the planet in question, tend to capture objects that form stable populations. In the case of Jupiter, it is estimated that at its Lagrange points L4 and L5 there are a number of objects that could be greater than a million.
The name Trojans comes from the fact that the first asteroids of this type that were discovered, in the orbit of Jupiter, were named in honor of characters from the Trojan War.
Lucy was launched into space on October 16, 2021 and is scheduled to reach its first Trojan asteroid in 2027. The trajectory it follows will see it approach Earth again in December of next year, in a maneuver that is already common in space exploration and is used to gravitationally bounce off a planet and thus modify and accelerate its journey.
The mission will visit no more and no less than eight Jupiter Trojan asteroids, three of which are satellites orbiting larger asteroids. But before it reaches its destination, in 2025 the spacecraft will encounter another object from the main asteroid belt, Donaldjohanson, on its way. It will be a new opportunity to test the ship's instruments and the procedures associated with their operation.
The mission was named in honor of the famous skeletal remains of Lucy, a hominid that lived about 3.5 million years ago and was discovered in 1974 in Ethiopia. The reason is that the Trojan asteroids could be objects formed in the early stages of the solar system, and their study would be similar, in a certain sense, to the analysis of fossils to reveal our origin.
The curious circumstance is that the name Lucy given to our ancestor was inspired by the Beatles song "Lucy in the Sky with Diamonds", and that the infrared spectrometer on board the Lucy spacecraft carries a disk of synthetic diamonds with the objective of dividing the light beam received by this instrument.
