Alpha Centauri: Our First Target for Interstellar Probes

[Zyraz]

With the completion of New Horizons' primary mission of Pluto fly-by, should we now set our sights even much higher, ambitiously taking aim at other star systems? If so, Alpha Centauri would be probably considered as the best target for an interstellar spacecraft due to its "proximity" to Earth.

This system, consisting of three stars and possible planetary companions, is the nearest to solar system, located "only" about 4.3 light years from us. The problem is, getting there in our lifetime is still a mission impossible, or maybe not?

The neighboring system hosts a pair of stars named Alpha Centauri A and Alpha Centauri B. Alpha Centauri C, also known as Proxima Centauri is a small and faint "red dwarf" - a small and relatively cool star - and may be gravitationally bound to the duo.

However, what still baffles astronomers is the existence of exoplanets in this system. In 2012, the discovery of a planet orbiting Alpha Centauri B was announced, but three years later a new research debunked this theory calling the previous finding a "ghost in the time series". Moreover, in 2015, another study proposed the existence of other alien world accompanying the "B" star.

What is interesting, the two hypothetical exoplanets would be Earth-like if they really exist. This could be another motivator to send our spacecraft there. But before any mission concepts are prepared, a deeper look into the system could be very helpful. Now the trick is that we currently don't even have a telescope that could directly image a planet in this system.

"This would have to be done from space - even then, it would be hard. We don't have a space telescope that can do this right now, especially for small planets. There are no gas giant planets there, if there were any, we would have detected them," Debra Fischer, astronomer and exoplanet hunter at the Yale University, told Astrowatch.net.

4.3 light-years equals 25 trillion miles, so knowing at least some basic information about this destination is quite essential before embarking on such a demanding trip. With current technology, a robotic probe send from Earth would require some 40,000 years to reach Alpha Centauri, making the mission totally useless for us.

NASA's New Horizons spacecraft which is the fastest-moving spacecraft ever launched from Earth, currently travels at about 36,400 mph. If the probe was aimed at the Alpha Centauri system, it would reach it 78,000 years after launch!

A huge technology advancement is required to make interstellar journeys feasible. Unless new propulsion system would be developed, every concept of mission to other stars could be doomed to fail.

"Once we have the ability to accelerate a probe to 10 percent the speed of light, that is the first place we'll go! It's the closest star system and therefore a great target," Fischer said.

In the past, there were projects that included sending unmanned interstellar spacecraft with a velocity of 4.5 or even 7.1 percent the speed of light. Between 1973 and 1978 a study was conducted by the British Interplanetary Society to send a probe using a fusion rocket that would reach Barnard's Star located 5.9 light years away.

The study, named "Project Daedalus" aimed to develop a spacecraft capable of reaching up to 7.1 percent the speed of light, thus the whole journey would take only 50 years.

Similar study, the "Project Longshot" was developed by the U.S. Naval Academy and NASA, from 1987 to 1988. The project would use a spacecraft powered by nuclear pulse propulsion to reach an average velocity of approximately 30 million mph (4.5 percent the speed of light). That would allow the mission to arrive at Alpha Centauri some 100 years after launch.

There is really a long list of concepts and projects tasked with designing a propulsion system of the future that would allow interstellar travel. In contrary to the ideas based on conventional propulsion, many concepts include using antimatter rockets, warp drive or wormholes.

A laser-powered interstellar sail ship is a very original concept that seems feasible in the near future. It was presented by Geoffrey A. Landis of NASA's Glenn Research Center in 2002. Landis described a starship with a diamond sail, a few nanometers thick, powered by solar energy, which could achieve 10 per cent of the speed of light.

Using this type of propulsion, it would take 43 years to reach Alpha Centauri, if it passed through the system. However, slowing down to stop at our neighboring system could increase the trip up to 100 years. Thus it would be more appropriate for a fly-by performed by an unmanned probe.

When will we be able to develop such a propulsion allowing us to travel at least at a speed of 10 percent the speed of light? That remains disputable.

"We have to have the probe travel faster than 10 percent the speed of light and we need high gain antenna in the outer solar system to pick up the signal that the probe sends back. This is a technology horizon that currently seems far away. 50 years? 100 years? Hard to say!" Fischer concluded.

Source

 

[Kosmik]

Just a comment, in theory we could ramp up a probe to a higher speed ( continuous propulsion and no drag in space ) but before we get better engines, we need to also solve the issue of matter impacting a probe at those speeds, no matter how small.

 

[Compton_effect]

Why?
We do not know enough of Centauri yet to make going there worth it. Let alone the technology to do it.

Most people do not really comprehend the distances involved in interstellar travel.
If you wanted to build a scale model of the Sun and Proxima Centauri - you'd need two soccer balls. One here in Johannesburg - in the original example it was placed in the Wits Planetarium (Awesome place that).
And the other one would be somewhere near Wadi Halfa, on the Egyptian/Sudanese border - 7 400 km away.

That's two soccer balls - separated by 5 times the distance between here and Cape Town.
The New Horizons space probe just took 10 years to fly past Pluto - on the same scale it would be a spot about 900 m away from the Wits Planetarium.

Anything we build would be a flyby, and even our results would take 4 years to reach us after decades of travel.

 

[MickZA]

A laser-powered interstellar sail ship is a very original concept that seems feasible in the near future. It was presented by Geoffrey A. Landis of NASA's Glenn Research Center in 2002. Landis described a starship with a diamond sail, a few nanometers thick, powered by solar energy, which could achieve 10 per cent of the speed of light.

Not so original, already mooted by Robert Forward in "Flight of the Dragonfly" in 1984 - https://en.wikipedia.org/wiki/Rocheworld

 

[ɹǝuuᴉM]

Isn't this way of thinkig a bit linear? What if techological development is exponetial? What if the developmental inflection point of the exponetial curve will be reached BEFORE the probe reaches its destination? Does it make sense to send an interstellar probe in the first place? As Carl Sagan noted back in the late seventies - "Any successive interstellar probe will be faster the the previous one and given the huge distances, it will overtake it. Therefore, best is to wait and develop..."

 

[BeerIsNotGood...]

Why?
We do not know enough of Centauri yet to make going there worth it. Let alone the technology to do it.

Most people do not really comprehend the distances involved in interstellar travel.
If you wanted to build a scale model of the Sun and Proxima Centauri - you'd need two soccer balls. One here in Johannesburg - in the original example it was placed in the Wits Planetarium (Awesome place that).
And the other one would be somewhere near Wadi Halfa, on the Egyptian/Sudanese border - 7 400 km away.

That's two soccer balls - separated by 5 times the distance between here and Cape Town.
The New Horizons space probe just took 10 years to fly past Pluto - on the same scale it would be a spot about 900 m away from the Wits Planetarium.

Anything we build would be a flyby, and even our results would take 4 years to reach us after decades of travel.

+1

 

[Cam]

Isn't this way of thinkig a bit linear? What if techological development is exponetial? What if the developmental inflection point of the exponetial curve will be reached BEFORE the probe reaches its destination? Does it make sense to send an interstellar probe in the first place? As Carl Sagan noted back in the late seventies - "Any successive interstellar probe will be faster the the previous one and given the huge distances, it will overtake it. Therefore, best is to wait and develop..."

Yes. It is just not worth it with the current tech we have.

For an interesting read check out:
https://en.wikipedia.org/wiki/Fermi_paradox

 

[Solarion]

With current technology, a robotic probe send from Earth would require some 40,000 years to reach Alpha Centauri

Thread bookmarked for later.

 

[zippy]

Why?
We do not know enough of Centauri yet to make going there worth it. Let alone the technology to do it.

Most people do not really comprehend the distances involved in interstellar travel.
If you wanted to build a scale model of the Sun and Proxima Centauri - you'd need two soccer balls. One here in Johannesburg - in the original example it was placed in the Wits Planetarium (Awesome place that).
And the other one would be somewhere near Wadi Halfa, on the Egyptian/Sudanese border - 7 400 km away.

That's two soccer balls - separated by 5 times the distance between here and Cape Town.
The New Horizons space probe just took 10 years to fly past Pluto - on the same scale it would be a spot about 900 m away from the Wits Planetarium.

Anything we build would be a flyby, and even our results would take 4 years to reach us after decades of travel.

First attempts are always flyby's or "flyinto" in the case of the moon, Venus, etc

How many probes failed in the first attempts to get to the planets ? There are still failures. Thats how we learn.

We knew little about the planets before we sent missions out. And what we thought we knew was overturned(turns out we actually knew nothing, except that they where there) as soon as the first one did a flyby. Remember the Voyagers ? Flyby's and they taught us a lot about the outer Solar System.

Have to start somewhere, however small that it is.

 

[yebocan]

More worried, that most of the probes we sent out into the unknown during the 60s/70s...we left our home address attached.