Enhanced photon sails to explore Proxima Centauri and its planets

We remember it in 2016, to celebrate the 55th birthday^{And the} Trip memory Yuri Gagarin On April 12, 1961, Russian billionaire Yuri Milner announced – with the support of Stephen Hawking – He was launching an interstellar probe project: Project Starshot hack. The goal was to begin the study of a beam-driven nanophotonic tail laser about stars closest to the sunin the Alpha Centauri system.

We know that this star system It is the trio and this exists Exoplanets around Proxima Centaurii.e. Alpha Centauri C and also called α Centauri C. The probe reaches a marked fraction of light’s speed It will still have time to take close-up pictures of these exoplanets and then send them back to Earth. It would only take about 20 years to reach the Alpha Centauri system using a photon sail towing a probe weighing a few grams at most and propelled by lasers sent from the ground. So the principle is similar to that already tried in solar saildriven by sunlight. The probe, initially powered by conventional rocket engines, will take approximately 80,000 years to cross huh Approximately 4 light years separate the triple system of Alpha Centauri from solar system.

A photon sail must neither rip nor melt

Studies of the probe and its sail to the stars have continued and two papers have recently been published proposing to modify the initial concept of the envisioned photon sail to some extent. She has to bear radiation pressure In the future, to ensure the success of the interstellar mission, lasers must produce a stream ofenergy Millions of times stronger than the density of the Sun which has already been used in experiments like the one Ikaros . solar sail (An interplanetary kite accelerated by the sun’s radiation). This Japanese Jaxa mission, which is equivalent to NASA orESAIt was launched in 2010 and was very successful.

However, the photon sail that must withstand the pressure Photons A 20-year laser has a size of about three meters to a thickness of a thousand times thinner than the thickness of the sheet.

The researchers, authors of two articles published in nano letters Explain in the first It is necessary that the light sail is created from an extremely thin plate ofaluminum oxide Under the breath of light, molybdenum disulfide swells, taking the form of a the umbrella, rather than remaining constant as assumed in most previous research. The structure must be curved so that it is approximately as deep as it is wide to support without tearing pressure capable of producing an acceleration thousands of times greater than the acceleration of gravity my ground.

in one second elementThe same researchers dealt with a problem resistance The heat generated by a laser beam is at least a million times more powerful than the sun. Even a small part of the energy dissipated in the sail, if absorbed, could cause it to heat up to the point of melting.

To avoid this, the sail would in fact have to adopt a net-like structure with regularly spaced holes with respect to the wavelength of the laser photons.

It remains to manufacture this sail and test it with a laser to check whether the researchers’ calculations are correct.

Interstellar exploration comes to fruition with this very promising material

An article published in the Paris Observatory on August 23, 2020

in the same way as a file Wind It inflates the sails of the boat, propelling the light sail by the pressure exerted by the light. Traveling outside the solar system, which will soon be no more than a suburb of our dear planet, will soon not be science fiction but reality. how ? Perhaps thanks to the airlines that seem to have the characteristics suitable to make this dream come true. From the International Space Station, like solar sail It will make it possible to reach Mars in 60 days of travel and escape from the solar system …

atomizerKind of carbon First manufactured in 2012, it is a file Material Consists of carbon nanotubes tangled. It is among the lightest materials known, with a density of only 180 grams per cubic meter, and a density about 7 times lower thanair We breathe (1225 g/m)³). Another great feature is “darkness”, that is, its ability to absorb light almost completely: less than one photon out of 1,000 is reflected.

On the way to Alpha Centauri

These two properties make it an ideal material for designing optical sails: its great lightness and ability to absorb photon energy allow it to accelerate very efficiently when illuminated. with light. This could be light from a laser, as in the Breakthrough Starshot concept, or simply sunlight as in this study.

The Astronomy scientists It was calculated that a spherical projectile, one meter in diameter and 0.5 mm thick, was fired from International Space Station ISS, it could reach Mars in just 60 days of travel and Pluto In just over 4 years, with no other impetus other than light the sun.

Due to its very low density, a spherical sail with a radius of 5 meters and a thickness of 0.1 mm can carry a load of 55 grams quickly enough to escape from the solar system.

Such a probe would be an excellent introduction to interstellar mission To our near neighbors, Alpha Centauri, and the planet Tulare in the habitable zone of its three faintest stars, Proxima Centauri B.