Scientists may be close to sending probe to Earth-like planet – SFGate


Depending on the process, it could take them anywhere from 20-135 years

Published 6:24 pm, Monday, February 6, 2017

  • This artist rendering provided by the European Southern Observatory shows a view of the surface of the planet Proxima b orbiting the red dwarf star Proxima Centauri, the closest star to the Solar System. The double star Alpha Centauri AB also appears in the image to the upper-right of Proxima itself. Proxima b is a little more massive than the Earth and orbits in the habitable zone around Proxima Centauri, where the temperature is suitable for liquid water to exist on its surface. (European Southern Observatory via AP) Photo: HONS

Photo: HONS

This artist rendering provided by the European Southern Observatory shows a view of the surface of the planet Proxima b orbiting the red dwarf star Proxima Centauri, the closest star to the Solar System. The double star Alpha Centauri AB also appears in the image to the upper-right of Proxima itself. Proxima b is a little more massive than the Earth and orbits in the habitable zone around Proxima Centauri, where the temperature is suitable for liquid water to exist on its surface. (European Southern Observatory via AP)

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This artist’s impression shows the planet Proxima b orbiting the red dwarf star Proxima Centauri, the closest star to the Solar System. The double star Alpha Centauri AB also appears in the image between the planet and Proxima itself. Proxima b is a little more massive than the Earth and orbits in the habitable zone around Proxima Centauri, where the temperature is suitable for liquid water to exist on its surface.

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This picture combines a view of the southern skies over the ESO 3.6-metre telescope at the La Silla Observatory in Chile with images of the stars Proxima Centauri (lower-right) and the double star Alpha Centauri AB (lower-left) from the NASA/ESA Hubble Space Telescope. Proxima Centauri is the closest star to the Solar System and is orbited by the planet Proxima b, which was discovered using the HARPS instrument on the ESO 3.6-metre telescope.

Good news, space fans: there may just be a way to get a glimpse of the Earth-size world orbiting Proxima Centauri, the next star over. It’ll just take a few lasers, and maybe a bit longer than a single lifetime.

Astronomers became especially interested to peer into the Alpha Centauri system after the Earth-like world orbiting Proxima Centauri was discovered, but as the closest system to our own it’s always been of interest to scientists.

The Breakthrough Starshot Initiative, a group whose board includes Stephen Hawking and Mark Zuckerberg, has been on the scene since before the potentially-habitable planet was found, but only proposed a plan last year to develop an ultra-light nanocraft that could do a fly-by mission to Alpha Centauri.

Propelled by a giant laser aimed at lightsails, the miniature space probes would travel at speeds up to 100 million mph, reaching the system in just over 20 years. The highly reflected sails would harness the power of the laser in order to move the spacecraft through space. It would zip around the system while snapping pictures, gathering data, and (in some to be determined way) relay that information back to Earth.

But that doesn’t give astronomers a lot of room for error; the craft would be traveling at roughly 20 percent the speed of light and, without a way to slow down, the nanocraft would make its way through the system in a matter of minutes.

A new concept, developed by astrophysicists Michael Hippke and René Heller, would give the probe a way to brake – but it comes at a bit of a cost. Hippke and Heller believe that if you use a laser’s photons to push a spacecraft from behind, it can also be used to slow down an incoming probe (like wind on a boat’s sails).

If a craft were powered by the sun’s light striking sails were set on course for the Centauri system, then, by reorienting its sail, the craft could be effectively halted by the incoming photons from Alpha Centauri. From there it could either remain in orbit around the brighter of Alpha Centauri’s two-stars, or (with some maneuvering) eventually slingshot toward Proxima, eventually being pulled into orbit.

“The time for a few snapshots is only seconds, and if you miss the target, it’s all for nothing,” Hippke told National Geographic. “In contrast, if you manage to go in orbit around your target, you can stay there as long as your probe functions.”

The downside is that if the craft is pushed purely by sunlight, it would leave the solar system traveling at just 4.6 percent of the speed of light, which would up the estimated time of arrival to the Centauri system to 95 years from now. It would then take an additional 46 years to reach Proxima, meaning that the scientific benefits would be kicked down to future generations.

“Our main constraint in defining the Starshot concept was to visit Alpha Centauri within our lifetime,” Avi Loeb, chair of the Breakthrough Starshot Initiative’s advisory committee, said.

“Our envisioned laser array can push the sail with an energy flux that is a million times larger than the local solar flux.”

Hippke and Heller believe that by the time the ship gets the greenlight, the appropriate materials will be ready for production. From there scientists will just have to decide whether the ability to brake is worth the wait.

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