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Planet-hunting pioneer calls for probe to Alpha Centauri

GeoffMarcy.jpgThe brief for speakers at today’s exoplanet workshop at MIT is “be provocative”, and veteran planet-hunter Geoff Marcy of the University of California, Berkeley, certainly satisfied that with an extraordinary ten minute talk this morning that had one NASA/Jet Propulsion Laboratory official on his feet trying to respond even before the allotted question time. Marcy’s idea of sending a probe to Alpha Centauri came on the back of a series of scathing policy criticisms targeted at NASA and the US National Academy of Sciences.

“I’m going to describe some of my anger,” Marcy said, and started out by slamming the National Academy’s Astro2010 decadal survey of astronomy and astrophysics for the low priority it gave to planet-hunting missions, saying the panel was “disingenuous” when it used the phrase “new worlds” in the title of its report “New Worlds, New Horizons in Astronomy and Astrophysics” when its content did not recomend planet-finding missions that would have found such worlds for real. Marcy’s tone then turned to introspection, as he blamed the exoplanet community including himself for failing to make a unified case that would have compelled the panel to recommend funding of what most of those at the workshop hope to see in their lifetimes; the launch of a space-based Terrestrial Planet Finder (TPF) mission that would image Earth-like worlds around nearby stars. NASA at one time supported such a mission but postponed it indefinitely in 2007. “I feel like I bear some responsibility for not adequately engaging in discussion,” Marcy said, “very few of us in this room showed leadership to argue for TPF-lite,” a version of TPF that would have been affordable. So what went wrong? Marcy said that different proposals to launch Terrestrial Planet Finder space mission over the next decade undermined each other. “That kind of squabbling lost us 10 years,” he says

Marcy didn’t end there. Next he attacked NASA over the Space Interferometry Mission (SIM), a project that would have found nearby Earth-sized planet by measuring changes in the seismic wobbles of the host stars. SIM was defunded in 2010 after the Astro2010 panel gave it a low priority. Marcy noted that NASA has spent $600 million on mission development between 2000 and 2010 before axing it in the wake of the Astro2010 report. He argued for more transparent mission development that would see several competing proposals funded at low levels, and then downselected to something that the agency remained committed to.

Wes Traub of JPL, who worked on SIM and works on technology development for TPF, which NASA is still supporting at a low level, was the official who tried to jump in right after Marcy’s remarks. But Traub’s apparent aim wasn’t so much to contradict Marcy as to acknowledge what he was saying. He agreed that he had struggled to unite the planet-hunting community behind a unified TPF proposal and he sounded almost choked up as he discussed the defunding of SIM by NASA Headquarters. “It was the most humiliating, embarrassing thing I’ve ever seen in my life,” he said.

David Charbonneau of Harvard-Smithsonian Center for Astrophysics, who is part of NASA’s Kepler planet-finding team, spoke out in support of Astro2010, saying its decision to pass on planet-finding was a natural consequence of the pitches it received. He says he read all the white papers submitted by the scientific community to the committee and that Marcy was right to say different planet-hunting proposals, including several out of JPL, concentrated too much on attacking each other rather than making a unified case to study exoplanets.

Sara Seager of MIT, who organized the workshop, at one point called a halt to the NASA-bashing. “I didn’t want to start getting into a fight about NASA because NASA has supported everyone in this room,” she said. Seager said the exoplanet community was spearheaded by “rogue pioneers” like Marcy, and doesn’t have a unified sociology.

On the back then of these serious policy criticisms came Marcy’s provocative idea for a mission to Alpha Centauri. He appealed to US President Barack Obama to announce the launch of a probe that would send back pictures of any planets, asteroids and comets in the system in the next few hundred years, with the US partnering with Japan, China, India and Europe to make it happen. “It would jolt NASA back to life,” he declared. Maverick it might sound, but many in the room seemed to take the idea in the spirit of focusing minds on the ultimate goal of planet-hunting; to take humanity’s first steps towards reaching out to life elsewhere in the universe.

Image: Planet-hunter Geoff Marcy / NASA Kepler Mission


  1. Report this comment

    Richard Gallen said:

    Right on! I’m John Q Citizen – and I’ve wondered for years why the science community spearheading these efforts is not coherent. What could be more important than finding life on other worlds and establishing contact? It may end being our only hope for survival.

  2. Report this comment

    Richard Blaber said:

    The kind of Alpha Centauri probe we could launch with existing technology would take thousands of years to reach the system, even if we were talking about a low mass payload and some form of ion drive. Wouldn’t it be better to wait until a more advanced space flight technology becomes available, and concentrate for now on getting a TPF funded?

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    Adam said:

    Some of us aren’t waiting for NASA to design a viable probe. “Project Icarus” is designing a system able to reach Alpha Centauri within a century. It’s a technological challenge as the specific power is far higher than anything yet developed, but it’s within the laws of physics, unlike the trite suggestions of wormholes and warp drives.

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    Henry said:

    Wouldn’t be ideal to send a probe capable of being upgraded on the go(probe inside a probe)? There are many unknown variables that may prevent us from sending better explorers in the long run. If we achieve improvements we could sent those in the same direction. Finding the probe, upgrading what we can and keep going.

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    Andrew Planet said:

    Sensible move by Sara Seager to remind the workshop that NASA had supported everyone in that room. Best always to build on the preceding foundation stones and be grateful for having them in a democracy. Why rely solely on ion drives? What about solar sails, aren’t they supposed go faster? Why not a combination?

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    Roland Buck said:

    Before considering sending a probe to Alpha Centauri, we should find out whether Alpha Centauri has ANY planets and then, is so, whether it has earthlike planets in the habitable zone.

    Therefore TPF should get the highest priority. The time for a probe is AFTER such planets have been found. And maybe we will find that we need to send the probe to Proxima Centauri instead.

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    Derek Fox said:

    Dr. Marcy is surely not alone in his aggravation at the Decadal Survey, but the drastic cuts to NASA’s budget have made the panel’s recommendations almost entirely moot. Sizing up the decade’s prospects from now, the exoplanet community will be getting JWST and only JWST – along with one or two small missions – just like the rest of astronomy.

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    Pierre Cauchy said:

    “in the next few hundred years”

    Energy wise, it’s already doable in a much shorter time: i.e. were say 50% of the soviet Tsar Bomba’s theoretical yield (100MT) converted into kinetic energy, a ~200kg probe could make it to alpha centauri in ~30 years at 0.15c.

    Obviously harnessing that energy without vaporizing any payload would require serious challenges. But say you drill a few kilometers deep into the dark side of the moon or some very large asteroid, place the bomb down there, fill up the tunnel with a buffer gas and voila!

    Obviously any onboard electronics & course correction propulsion systems would have to withstand tens of thousands of G’s during liftoff, but might be doable (some US army electronics are already rated at >20 000g) …

    Other designs such as Icarus could make it as well in ~40 years if they used gravity assists around Jupiter then slingshot around the sun, or some solar sail designs might make it in about that time if they were pushed by a ground based laser…

    So we might actually see a human lifespan’s long mission beginning at some point in this century!!

    Let’s just wait for Debra Fischer’s team to (hopefully) come up with

    a planet around ACenB to send a probe (apparently a 2.3 earth-mass planet orbiting at 0.5AU, within the HZ, is on the verge of announceability:

    Or to any other nearby system containing a planet capable of sustaining life as we know it: this is why we need SIM/TPF: only coronography could tell us what a planet’s atmosphere consists of…

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    Shaune McFarlane said:

    The real problem facing humans is their long-term survival and they need to start now to search for habitable worlds before their sun runs out of fuel!

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