The nearest star system to the Sun, α Centauri, has been all the rage after the discovery of an Earth-sized world in the habitable zone around the smallest of its three stars, Proxima Centauri. Scientists, however, are equally eager to learn more about the planetary systems around α Centauri's two larger Sun-like stars, α Centauri A and B. Those systems might offer an environment still more conducive for an Earth-like planet.
Although NASA has plans to eventually develop optical telescopes that might be able to image planets around these stars, some scientists say we should not wait that long. Moreover, these scientists say that, with a modestly sized telescope, we could start looking for Earth-like worlds around Centauri A and B by the end of the decade. To that end, several organizations plan to announce a privately led, non-profit effort to do just that. The project, titled "Project Blue," will be announced on Tuesday.
Project Blue takes its name from the famous Pale Blue Dot image taken by Voyager in 1990, when the probe was about 6 billion km from Earth. Our planet filled just a single blue pixel against the vast, black, seemingly endless heavens. Project Blue aims to capture such an image of one or more Earth-sized planets in the habitable zone around α Centauri A or B.
"We feel that the moment is right [when] there is this confluence of scientific impact and technology maturing rapidly," said John Morse, chief executive of the BoldlyGo Institute, which is co-sponsoring the initiative along with Mission Centaur. "We won't resolve planetary features, but we believe we have a really good chance of seeing something like a pale blue dot."
In an interview with Ars, Morse said he believes Project Blue can be accomplished for comfortably less than $50 million. His goal is to slice the overall cost to less than half of that. This price includes building both the telescope and launching it by the end of the decade. He intends to launch his telescope either as a "ride share" on a larger rocket or on one of the smaller, dedicated microsatellite launchers under development.
Morse said Project Blue will employ an "all of the above" fundraising strategy, beginning with crowdfunding to initiate meaningful technical work on the telescope's design. In addition, the organization will also seek larger-sized donations, beginning with the donor network that has supported the Boldly Go Institute. The organization will also pursue in-kind contributions from partners to keep costs down. [See here for Voyager's pale blue dot image (60.04KB).]
Based upon a number of technical studies, such as this one, Project Blue believes it can obtain a sufficient resolution to image a planet around one of the α Centauri stars with a telescope 50cm or smaller in size (the primary mirror of the Hubble Space Telescope is 2.4 meters).
[...] The proposed telescope should be able to resolve a world that is 0.5 to 1.5 times of the size of Earth and orbiting within the host star's "habitable zone," where water theoretically could exist on the surface. Based on Kepler's data, with two Sun-like stars to search around, Morse said, statistically, the odds of at least one terrestrial planet in the habitable zone is about 80 percent. With enough water on its surface, the planet would appear blue in any visible light image taken. And what a sight that would be.
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Project Blue aims to send a telescope with a coronagraph into low-Earth orbit to capture direct images of potentially habitable exoplanets orbiting Alpha Centauri A or B. Proxima Centauri is not a target due to the closeness of the red dwarf star and its habitable zone.
The BoldlyGo Institute has launched an Indiegogo campaign to raise $175,000 for initial planning and design. The project's first attempt at crowdfunding used Kickstarter to try and raise $1 million, but only $335,597 was raised. They are using flexible funding this time but have reached 70% of their goal with 10 days left . A donor has also pledged to match contributions dollar-for-dollar until the campaign reaches $175k.
BoldlyGo Institute has signed a Space Act Agreement with NASA that will allow NASA employees to assist the Project Blue team during its mission development phases, and also allows Project Blue to test their designs at NASA facilities. More such public-private partnerships should be expected in the coming years.
Also at Popular Mechanics, Space.com, and SpaceRef.
Previously: Scientists Say They Have a $25 Million Plan to Image Alpha Centauri's Planets
(Score: 2) by GreatAuntAnesthesia on Thursday October 13 2016, @08:02AM
You're welcome [soylentnews.org]
(Score: 5, Interesting) by Foobar Bazbot on Thursday October 13 2016, @04:10PM
Your plan was to send an interferometry array capable of resolving terrain out past the heliopause, right? I'm pretty sure nobody's sending anything that far for 25 million, so I don't think it's the same idea at all. In fact, I'm pretty sure they're going for LEO -- just enough to get above Earth's annoying atmosphere.
(I'm still not sure why you wanted to go past the heliopause, as I've never heard it mentioned as a barrier for observation -- I was going to do some reading to figure out what bands we use to observe it (e.g. with IBEX), and thus what bands it would obscure, but I haven't found time yet, so I'll just ask you -- why?)
Additionally, their approach is to use fancy optics to null the light from the star(s) (PIAA coronograph, if you want to look it up), giving them a clear image of any orbiting planets. But their diffraction-limited resolution will be about 0.4 AU (50cm, 600nm, 4ly). Enough for spectroscopy, not enough to see terrain. So it seems pretty different from your proposal on that basis as well.
Of course, I'm still a fan of FOCAL-type missions to study specific exoplanets; I think we've had that discussion before. Briefly -- a spacecraft flies to 600AU minimum (or up to 2000AU minimum, depending on the wavelengths of interest), exactly opposite the target system. Once you cross that threshold, you can use the Sun as a gravitational lens -- the target appears as an Einstein ring (gradually increasing in size as you travel outwards), you just have to observe the Einstein ring from a bunch of locations over something like ~1km diameter area to arrive at an image with resolution of 1km or better. Suggested architecture: spinning spiderweb with multiple 1m-class telescopes, one at each node -- as they spin, they sample the entire 1km disc. Cheaper but slower: a single 1km spinning tether with 1m-class telescope on each end. Reel the tether in and out to sample entire disc. (Of course the size depends on the size of planet and distance -- and you can do smaller than 1km, of course, and image a smaller portion of the planet, but it's best if you can get the whole disk in one go.)
Benefits -- amazing resolution (diffraction limit is IIRC more like 10m than 1km), and excellent sensitivity for receiving signals from any probes later sent to the target of interest.
Downsides -- long travel time, high cost, and no steering without burning propellant.
(Score: 2) by GreatAuntAnesthesia on Thursday October 13 2016, @04:34PM
I *did* suggest a telescope dedicated to observing the Centauri stars, which is what this is. Of course I'm not actually claiming credit, I was just pointing out the coincidence and hoping for a chuckle.
The idea was not necessarily to have the heliopause as an objective, i only mentioned it because that's about how far Voyager has got so far. The idea was simply to send some eyes out in that direction, because a great way to get a better view of something is to get closer to it. Now admittedly, even if we built a craft five times as fast as Voyager that lasted twice as long (Voyager: 40 years and still going) we'd still only get a fraction of a fraction of the way there, but maybe it would be enough to get a slightly improved resolution, and we'd certainly learn a lot along the way. The fact that it takes a long time to get there, in my mind, simply reinforces the need to start early.
(Score: 2) by Foobar Bazbot on Thursday October 13 2016, @05:47PM
The idea was not necessarily to have the heliopause as an objective, i only mentioned it because that's about how far Voyager has got so far.
Ah, I see.
The idea was simply to send some eyes out in that direction, because a great way to get a better view of something is to get closer to it. Now admittedly, even if we built a craft five times as fast as Voyager that lasted twice as long (Voyager: 40 years and still going) we'd still only get a fraction of a fraction of the way there, but maybe it would be enough to get a slightly improved resolution,
Yeah, "slightly" is the key word; 100km/s * 100 years gets you about 1/100 of the way there -- so you only get 1% more resolution than the same telescope array in Earth's neighborhood. That's why I like FOCAL -- that same 100km/s for a mere 30 years (in the opposite direction) gets you insane resolution for optical wavelengths that pass through the corona, and as you go farther, radio wavelengths start working. At the 100 year mark, you're over 2000 AU out, and the entire EM spectrum is available.
and we'd certainly learn a lot along the way. The fact that it takes a long time to get there, in my mind, simply reinforces the need to start early.
Absolutely with you on those points, as well as the sensibility of sending out communications relays every 10 years behind it. I certainly hope in 100 years we will have gigantic orbital radio dishes that will enable direct communication over 2000 AU, but why count on it? Do it right, and our grandchildren will thank us.
(Score: 0) by Anonymous Coward on Thursday October 13 2016, @11:19AM
So is Uranus.
(Score: 0, Disagree) by Anonymous Coward on Thursday October 13 2016, @04:49PM
If Hubble is already technically powerful enough, why not use a "floating disk" to block the planets' parent star's light so that Hubble can get images or spectrographic data?
A spacecraft several miles from Hubble can be carefully aligned to block light from selected stars so that they don't swamp planet light. However, such needs tightly-tuned positioning control, and maybe we don't have that tech yet.
(Score: 1, Informative) by Anonymous Coward on Thursday October 13 2016, @07:30PM
Yeah, "several miles", heh.
If your blocking disc is 1mm in diameter, and you have perfect positioning control, you need to put it 30km from an ideal observer to just blot out the star. But of course, with a 1mm disc, only 1mm of your 2.4m aperture is correctly aligned -- thus the disc must be increased to 2.401m, but now it blots out far too much.
So we need to decide what diameter we're willing to block -- if we want to totally block one solar diameter, and partially block no more than 100 solar diameters (this would obscure the orbit of Mercury in our system), our theoretical disc would be 2.4m/100=24mm; the real disc size would be 2.424m, and the distance would be 650km!
Since Hubble is in LEO, it's very difficult to place an object 100s of km distant and track Hubble's motion to stay aligned during an exposure of any length. If we relax the distance constraint (allowing our disc to start or end closer to Hubble, obscuring a larger area), I'm sure there's a family of orbits that will line up during some part of Hubble's orbit, but the trick would be finding one where this alignment repeats with any regularity, or close enough to make it happen with reasonable propellant consumption.