Discovering a low-cost route to the Moon

In new research, published in the journal Astrodynamicsa team of experts from the Universities of Porto and Évora (Portugal), the Paris Observatory (France), the Universities of Pernambuco and São Paulo (Brazil), developed a method that allows more accurate calculation of fuel-efficient routes between celestial bodies. They evaluated about 30 million simulated routes to find the optimal plan for the Earth-Moon journey.

Theo Physthe difference in fuel economy appears small compared to the estimated total trip cost of 3,342.96 m/s, but still has a large impact on mission cost. “In space travel, each m/s corresponds to a huge amount of fuel consumed,” said researcher Allan Kardec de Almeida Júnior from the University of Coimbra, lead author of the new study.

Interesting Engineering said, the above savings correspond to a reduction of about 1-2% of the total speed change of the mission, saving several liters of fuel for every 100 liters on a long-distance trip.

Almeida and his colleagues outlined a route to take the spacecraft from Earth orbit to lunar orbit, divided into two stages. In the first leg, the ship will leave Earth’s orbit and approach point L1 between the Earth and the Moon, where the gravitational forces of the two celestial bodies cancel each other. For much of this journey, the train will be guided by a “variable line” – the natural route leading to L1.

While most current models suggest that it is more efficient to enter the variation path closest to Earth, the team’s simulations show that using the variation path closest to the Moon is more economical.

Thanks to the control system, the spacecraft can remain in this intermediate orbit indefinitely until it is ready for the second stage – entering lunar orbit. The advantage of this orbital transition is that no communication interruption occurs during the waiting period.

Vitor Martins de Oliveira, a postdoctoral researcher at the Institute of Mathematics, Statistics and Computer Science (IME) at the University of São Paolo, co-author of the new study explains: “The Artemis II crew briefly lost contact with Earth because the spacecraft flew behind the Moon. The trajectory we proposed is a solution to help maintain uninterrupted communication.”

Although more economical than the previously described routes, the route outlined by Almeida and his colleagues is not the cheapest route. Their simulation only took into account the gravity of the Moon and Earth, ignoring other celestial bodies such as the Sun. Taking them into account could result in further savings, but launch timeframes would be limited.

“It is necessary to run the simulation for a specific position of the Sun. For example, if we simulate a launch date of December 23, we will only obtain valid results for the mission deployed on that day,” Almeida noted.

Theo Interesting Engineeringa group of international scientists hopes the research will not only help find an effective route to the Moon but also identify many optimal routes thanks to a new calculation method, which can scan tens of millions of possible options and choose the best one. “Our systematic analysis method in the new study could be applied more widely in the future,” Almeida said.

Last month, scientists also found a potential “shortcut” that could significantly reduce the time of an Earth-Mars round trip. Based on initial orbit estimates of near-Earth asteroids, expert Marcelo de Oliveira Souza, a cosmologist at the Northern State University of Rio de Janeiro (Brazil), believes that the round trip can be completed in 153 or 226 days instead of nearly three years.