China develops an engine to travel in record time to Mars and Neptune

Reaching Mars in 45 days thanks to a laser fired from Earth: the idea of ​​some engineers.
A team of engineers from McGill University believe that a spacecraft could reach Mars in 45 days, thanks to the thrust of the laser. The idea (reported by Phys.org, which is the research) was born at the request of NASA, and is intriguing and could be a solution for a stable human colony on the red planet In 2018, NASA asked engineers around the world to designed a mission to Mars that could deliver a payload of at least 1,000 kilograms in no more than 45 days. The extremely short period of time is, on the one hand, to ensure a constant supply of future colonies, and on the other hand, to minimize the time that astronauts are exposed to the harmful effects of cosmic rays and solar storms. Rather, SpaceX aims to send a human crew to Mars in about six months, on its first expedition.

According to McGill engineers, the answer NASA is calling for lies in “thermal laser propulsion.” It’s all based on a 10-meter-diameter array of infrared rays placed on Earth, consisting of many rays with a wavelength of about 1 micrometer, for a combined power of 100 megawatts, the electricity needed by some 80,000 American homes. .

Such a compound laser is used to heat hydrogen plasma in a chamber located behind the spacecraft. The gas released through the openings in the chamber creates the necessary thrust for the race.

By heating the core to a temperature of 40,000 Kelvin, hydrogen gas will begin to flow around it, reaching 10,000 K, until it is expelled through a nozzle: this will create a thrust that will push the spacecraft to a distance of Earth for 58 minutes. In parallel, the lateral thrusters would allow the spacecraft to remain aligned with the laser beam while the Earth rotates.

Once this phase is complete, the spacecraft will travel at almost 17 kilometers per second, overcoming the distance between the Earth and the Moon in just eight hours. So far so good, but how to stop the ship safely?

The spacecraft cannot carry chemical propellants for braking like modern probes, because the fuel required would reduce the mass of the payload to less than 6 percent of its original 1,000 kilograms. Furthermore, it would be impossible to replicate on Mars an Earth-equivalent laser system to slow down a spacecraft by reverse thrust. Apparently there’s only one way to do this, and it’s called “aviation capture”, which uses friction with the atmosphere to slow the ship down.

Aerocapture is a risky but not impossible maneuver, since the spacecraft suffers decelerations of up to 8 g, even if only for a few minutes. Also, the heat generated by friction with the atmosphere could pose a challenge to traditional thermal materials, but not to those being developed. In short, it can be done, maybe not immediately but in the future.

“Thermal-laser propulsion enables one-ton fast transport missions with volleyball court-sized arrays of lasers, something that electric-laser propulsion can only do with kilometer arrays,” says Emmanuel Duplay, lead author of the study.

One of the main advantages of laser thermal propulsion is its extremely low mass-to-power ratio of about 0.001-0.010 kg/kW, which is “unmatched,” the engineers wrote, and “far below the level of conventional technology.” “. The propulsion system because the energy remains on Earth and the flow provided can be handled by low-mass gas-filled reflectors.

Laser thermal propulsion was first investigated in the 1970s using the most powerful 10.6 micron CO2 laser of the time. Current one-micron fiber lasers can be combined with large diameters in a very parallel fashion to achieve power transfer focal lengths of two orders of magnitude: 50,000 kilometers in the case of the laser conceptualized by Duplay.

The first humans will arrive on Mars with more traditional technologies, but this type of propulsion could be tested in the future. “As more and more humans embark on the journey to sustain a colony long-term, we’ll need propulsion systems to get us there faster, if only to avoid radiation hazards,” Duplay said. According to Duplay, a laser-thermal mission to Mars could be launched 10 years after the first human missions, that is, towards

2040-2045.