All

http://exep.jpl.nasa.gov/documents/Exoplan...unityReport.pdf

"The exoplanet community’s top priority is that a line of probeclass missions for exoplanets be established, leading to a flagship mission at the earliest opportunity."

Craig

Of course they are not talking about a flagship mission to an exoplanet
(Hey, that's the first thing that popped into my mind!)

... but rather a flagship-budget telescope.

1.6 Space Missions (on page 9)
....There is strong support for a line of probe‐scale exoplanet missions. Kepler, once
operational, would be the first of these.....
....There is widespread agreement that two flagship‐scale exoplanet missions are ultimately
required: a visible coronagraph and an infrared interferometer. These are the only viable
techniques for fully characterizing Earth‐twins down to about their surfaces, and searching
for signs of life.

Yea! They had me wondering if they were actually talking about interstellar missions. As I was downloading the pdf I was telling myself "This can't possibly be about interstellar missions, but I had better check it out anyway."

I thought the same thing at first glance. A moment's consideration was enough to know that they were talking about various telescopic missions, but my first thought concerned an actual physical probe to an exoplanet.

On the other hand, even a close flyby or orbital mission would mainly involve remote sensing, and the proposed probes also involve (very) remote sensing.

I would add that I anticipate this line of development will continue, with the result we should have fairly detailed multispectral images of nearly exoplanets taken via the eventual descendants of the types of missions discussed in the pdf, long before any physical contact with those worlds, if any. (Although most likely after I myself am no longer around to enjoy them.)

The task for this century is to catalog what's out there in the local neighborhhood. Right now now we do not know the ports of call.

Actual interstellar probes will be the task of the 22nd century. If we find other Earth's, or even other terrestrial planets
with atmospheric mixtures out of equilibirum, the motivation to GO there will happen.

We live in the time of initial discovery.

Craig

I'm hoping that Kepler will discover enough tantalizing targets to get the most ambitious plans for TPF up & running as a real project. IMO, flying TPF should be THE focus of the exoplanet community, and it's kind of above & beyond what you'd ordinarily think of as a Flagship.

EDIT: What I actually meant was a visible light instrument capable of resolution of surface features on terrestrial-sized planets out to a few score light years. Flying intermediate missions like a dedicated coronagraph & an interferometer are obviously prudent and useful precursors.

As is mentioned at one point in the Exoplanet Community Report, one option for a follow-up transit search would be an all-sky survey of the brighter target stars. The big advantages of this would be: one, since only the brighter stars would be targeted, any transits could be examined by ground-based telescopes with very high signal-to-noise ratio; two, the stars would also be fairly nearby on average, compared to fainter stars, so other detection methods such as astrometry and direct visual detection should be relatively easy; three, an all-sky survey should sweep up all the 'low-lying fruit' among the exoplanets.

The opposite approach was the NASA SWEEPS survey, which used the Hubble telescope to do a deep search in a very small field. They detected plenty of exoplanet candidates, but unfortunately the primaries were so faint that it was impossible to extract much additional information (such as radial velocity variations and hence masses) using ground-based telescopes, so the results were almost useless.

Only two planets (out of 14 candidates) were confirmed out of that whole ordeal. I'm unsure how it made a press release, but... it did.
Those were expensive planets to find.

True.

A Gliese 581-c probe might be a workable idea before the 22nd century, though, depending on how technology develops. If the more optimistic ideas come true, I could see a Starwisp launch or some sort of nuclear-pulse rocket by the mid-21st.

Even if it were a workable idea, unless faster-than-light communication is invented, no information from close proximity to Gleise 581 will be received until at least 40 years after launch. And 40 years would be assuming immediate acceleration to light speed. At least time dilation would mean that the design lifespan of the probe could be lower.

Oh, certainly ... I wasn't thinking of getting data back that quickly.

Any interstellar mission will be done for future generations, not the current ones. We need to think in terms of very long term projects - like the old cathedrals of the 14th, 15th, and 16th centuries, that none of the original builders lived to see completed. Data wouldn't come back for generations...