Frozen moons, hot stars, the search for conditions favorable for life, exoplanets, galaxies moving away from each other as the universe expands, future journeys into the past of the universe, new expeditions. The incredible effort to explore the universe not only ignites the imagination, but opens up new avenues for scientific research and all of humanity.
On the occasion of World Space Week, which is celebrated annually from October 4 to 10 – the dates set by the launch of the first artificial satellite, Sputnik, on October 4, 1957, and the effective date of the United Nations Outer Space Treaty, October 10, 1967 – we discussed current and future space challenges with Ioannis A. Daglis, President of the Hellenic Space Center (HSC) and Professor of Space Physics at the University of Athens.
Despite the fact that there are no “Chinese walls” in space research, we have divided scientific efforts into three parts: first those concerning the Earth, our common home; second, those concerning the solar system; third, the universe beyond. Travel to distant celestial bodies may excite us more, but about 90% of space research involves the area around Earth.
“Space is a platform for observing our planet and developing a range of critical services that affect and facilitate our daily lives: communications, navigation, weather forecasts,” Daglis explains. “State and corporate economic activity is intense. Already more than 4,500 satellites orbit the Earth and another 2,500 are inactive. Great technological leaps have been made, but we are looking for solutions aimed at further improvements,” he adds.
To meet the needs of Greece, the Hellenic Space Center is seeking to improve the 10 × 10 meter resolution provided by (Copernicus) the European Earth observation program. “It’s good, but not enough for our national needs. HSC is developing a national satellite imagery program with a resolution of 3 × 3 meters, an improvement of a factor of 10,” says Daglis. “In addition, observation satellites are in relatively low orbits, at 500-2,000 kilometers, in order to provide good spatial resolution. But, since they continuously orbit the Earth, they do not offer the continuous coverage of geostatic satellites which orbit 36,000 kilometers from the surface and constantly fly over the same area of our planet. Obviously, the resolution of images at such a height is much lower. The space industry tries to combine the information obtained from these two types of orbits.
The new era brought about by plans to launch large satellite fleets by private companies will bring new challenges, but also dangers, Daglis notes. “Continuous launches will, in the long term, put a strain on the space ecosystem. Congestion will increase the risk of collisions between satellites, which will result in space debris, which in turn could severely damage or totally destroy other satellites. We need to deal with the problem and regulate. It takes a long time to update the global treaties on the mutually beneficial use of space at the United Nations level. The European Space Agency (ESA) has provided a great model by requiring each proposal to initiate an integrated plan upon mission completion, including the ‘retirement’ of the space vehicle,” he says.
Higher goals
At a second level, within the solar system, higher goals are set. “A main direction is the exploration of a semi-extraterrestrial world, such as Mars, which is considered the only celestial body with at least a theoretical capacity to host humans. Of course, this is a very remote hypothesis. A second line of exploration targets the frozen moons of Jupiter and Saturn, which are of great interest to astrobiology, due to the possibility of harboring life form beneath their frozen surface. cannot exclude, for example in Europa or Enceladus, since on Earth itself we have discovered life at great ocean depths, under conditions that we had previously considered prohibitive, ”notes Professor Daglis.
In 2023, ESA will launch its JUICE (Jupiter Icy Moons Explorer) probe which will make detailed observations of Jupiter, the gas giant planet, and three of its four largest moons (Ganymede, Callisto and Europa) which are considered to have water under their surface. ice surface.
“Magnetic field measurements in Europe can only be explained by the rotational motion of salt water. In Enceladus, a moon of Saturn, jets of water have been documented. NASA is already planning future expeditions that will target to drill through the ice of Europe,” says Daglis.
Another pursuit of research in our solar system is a better understanding of the Sun-Earth system and the interaction of the two bodies. “We have made a lot of progress, but we want to go even further. For example, we want to predict space weather, space storms, just as we do on the surface of the Earth, which will greatly contribute to the safety of expeditions and satellites,” Daglis notes.
In the infinite universe beyond the solar system, the driving force of human exploration is mainly the fundamental scientific questions about the cosmos. “Our spaceships have reached an infinitesimally small part of the universe. We have been surprised by the number of ancient galaxies we have discovered. The universe is much older than we thought.
We get our information through photons, the full spectrum of electromagnetic radiation and, more recently, gravitational waves. Now we’ve been getting clearer and clearer images of distant celestial bodies for a very long time. The James Webb Telescope helped a lot; it was also able to detect, for the first time, the atmosphere of exoplanets, that is, planets outside the solar system,” explains Daglis.
Earth to Moon
Our last question concerns humanity’s first space stop. Why are we preparing for an expedition to the Moon again? “First of all, we can more easily launch heavier spacecraft from the moon to Mars or elsewhere. In addition, the Moon contains valuable minerals, such as rare earths. And, of course, there is always l lure of walking on the moon.
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