Two satellites Galileo posts in wrong orbit there are those who have blame that physicists are so happy now. Thanks to these probes it proves it again Einstein He was right when he proposed his general theory of relativity.

However, the importance of this new confirmation is not whether the physicist was correct because we are used to it. No, this time the difference is in "high accuracy" with which Einstein's relativity was demonstrated, as explained in the press release European Space Agency (ESA, its abbreviation in English).

Each satellite descends and descends about 8,500 km twice a day

In 2014, Galileo 5 and 6 "were captured in the wrong orbit due to failure at the top of the Soyuz rocket, to prevent their use for navigation, "he explains from ESA. However, despite this problem, the European Agencies' they tried to restore the probes with a "courageous" maneuver that "raises the lowest points of their orbits and creates them more circular".


When the satellites were in a more convenient location from which the entire Earth disk could be seen, their antennas were fixed and their navigation tools activated. Galileo 5 and 6 are now part of the Search and Rescue Service (SAR) of this program, "while their integration in nominee operations is conspicuously assessed by ESA and the European Commission," the agency said.

The maneuvers for its elevation were successful, but their orbits are still elliptical. That means "every satellite descends and descends about 8,500 km twice a day," ESA said in a statement. This regular oscillation in height means that its level of severity is also constant. This "has changed to a tool with great value for research teams "that made it possible to verify Einstein's theory with great precision, according to a study published this week in the journal Physical Revision Letters,

Atomic clock

More than a thousand days of data and two groups of different physicists confirm that Einstein was right. The main tool he served is Atomic clocks that are integrated into all probes of this program: "These extraordinary results have been possible thanks to the unique characteristics of Galileo satellites, in particular high stability of your atomic clock, achievable precision in the determination of the orbit and the presence of laser spotlights that allow for independent and highly accurate orbital measurements from the ground, which is the key to addressing the clock and clock errors, "explains de presse Javier Ventura-Traveset, Director of the Scientific Navigation Authority Galileo ESA.

"It is very satisfactory for ESA that our initial expectation that such results were theoretically possible has now emerged and offered us the first improvement recorded in the gravity redshift tests in more than 40 years, "says Javier Ventura-Traveset, Director of the Scientific Navigation Authority of Galileo ESA.

Investigation, known as Great (Galileo Gravitational Redshift Experiment with Eccentric Satellites) was carried out by the SYRTE Observatory in Paris (France) and the Center for Applied Space Technology and Microgravity (ZARM) of Bremen University (Germany). The body responsible for coordinating the activities was the Galileo ESA Navigation Research Office.

It is not for the first time

The fact that Albert Einstein is right with his predictions about the theory of relativity is not new. In fact, it was in 1976 when the most "meaningful" experiment, This year's "atomic clock hydrogen sensor in the suborbital missile was launched at 10,000 km in space Gravity probe A, which confirms Einstein's prediction a An accuracy level of 140 parts per million"explains ESA.

Since then, all the atomic clock has been carrying our navigation satellites take into account that "they move faster (several tenths of microseconds per day) in orbit than on the ground", says ESA. If you do not consider "navigation errors about 10 km per day if they were not fixed."

In order to achieve such precision, it was essential that the hours of transmission of the Galileo satellite were necessary

The two groups of physicians charged with this experiment have entrusted "the stability of the Galileo Earth segment all over the world" and the "synchronization" of the Fuel Mileage (PHM) for Galileo 5 and 6, which were synchronized "with one-million-year accuracy." "The fact that Galileo satellites carry these hours was necessary for accuracy who have achieved these tests, "says Sven Hermann, ZARM.

Galileo carries only two watches of fuel, but also also has two ruby ​​watches, so scientists have decided to focus on the first, as they do not send at the same time but instead: "During the observation period, we focused on the periods in which the satellites transported with the hours of the fuel and We carefully evaluate the quality of this valuable dataContinuous improvement in the field of processing and, in particular, when modeling our watches, could produce even more accurate results in the future. "

Although it seems simple on paper, scientists have had to do so during these three years face different challenges how to "refine the measurement of gravity red shift eliminating systematic effects such as errors in times and orbital displacement, due to factors such as the equalization of the equator, the influence of the Earth's magnetic field, heat changes, and even the tiny but persistent pull of sunlight known as solar radiation pressure"explains ESA.

"Care and caution in modeling and controlling these systematic errors were critical, with stability up to 4 picoseconds for an orbital time of 13 hours satellites; that means four million per millionth of a second, "explains Pacôme Delva from the SYRTE Observatory.

What is Galileo?

Galileo is a satellite navigation system created by the European Union, that is, it's like an American GPS or Russian Glonass. In fact, it is colloquially known as European GPS, The signal of this navigation system is more accurate Galileo can be used in two levels: one for everyday use by users and others, with even greater precision, so for example if a person is to be saved, the place is the most accurate because life depends on him.

On the other hand, Galileo signals specially designed to be supplemented by US counterparts, which means they can be used in the same device without interference. In 2017, inventor José Ángel Ávila and his team awarded the European Patent Office European Inventor of the Year,

In addition, last September it was announced that the Spanish company GMV won a public tender to monitor and control Galileo satellites, so the operations of the Earth segment will be in the hands of this company. The GMV award granted to ESA in this agreement results in "the largest contract signed in the Spanish space industry", according to the Ministry of Science, Innovation and Universities.