Exoplanets in Pictures | Hacker News Reader

Exoplanets in Pictures

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51 pointsrvkennedy7 comments

This is about a month old, and completely passed me by, though the oldest image is actually from 2004. Growing up, this is something I was told we would never, never see - planets are simply too small, too dim, and too far away. We were told we'll never really know if they're even there.

So now we have pictures. Perhaps some day, if telescopes can be positioned sufficiently far apart in the Solar System, we can build an array that could image nearby exoplanets in fine detail. As for signs of life - that may be more tricky than a visual inspection - unless we see the glow of cities...

Space missions to detect Earth-sized planets had been planned for the middle of this decade:

http://sim.jpl.nasa.gov/index.cfm

And higher-resolution interferometers to take images of such planets for later in the decade:

http://exep.jpl.nasa.gov/TPF-I/tpf-I_index.cfm

Both missions were cancelled a couple of years ago. It's a budget problem, not a fundamental technology problem.

It's both. Both SIM and especially TPF kept slipping farther behind schedule, more over budget, and with increasingly questionable capabilities. The fundamental problem is that NASA is averse to iterative and competitive development styles, which is absolutely necessary in this case.

As a case in point, look at the JWST, which will end up costing around $10 billion (more than 1,000% over budget) and over a decade behind schedule. The TPF is easily an order of magnitude more technologically challenging than JWST and would require putting 4x as much hardware into space. If it were managed the same way as JWST it would end up costing perhaps $100 billion and not launching until 2030 or later.

You have a point. I think SIM didn't have significant tech problems, but too much of its work became do-able from the ground during the interval when its problems were being solved. That's the reason it got a lower priority in the National Academy report that determines astrophysics mission priorities. And since SIM was a pathfinder for TPF...

A lot of it comes down to the way NASA is organized. Generally it's big budget missions with a single spacecraft as the culmination of the mission. Rather than ongoing development programs. Also, NASA has this tendency to want to skip technology generations even though the end result tends to take longer to deliver and cost more than it would have if they would have just explored the intermediate technology space to start with (see: JWST and VentureStar). While we're talking about JWST, that's another big part of the way things are at NASA these days, that program has eaten most of the unmanned NASA budget and put a significant crimp on space science missions. It'll probably be worth it, but the cost is pretty extreme at this point. Also on the topic of JWST, I remember back when they were planning to have a flight demonstrator (Nexus) in the form of a Hubble class Earth-orbiting telescope using some of the NGST/JWST technology. Such a mission probably would have brought the risk of the JWST program more under control but for whatever reason they ended up cancelling it.

TPF is another example of planning farther ahead than is fully justified. As the program advanced the design became less and less fixed rather than more and more refined. This is an indication that they were designing something that was beyond their expertise and needed more intermediate research to figure out, but with the budget crunch and the lack of vision nobody could come up with good enough ideas to do so. NASA set their sights on deep nulling interferometry and it sounded like a really cool technology that might be capable of doing what they needed, but more and more it seems like that may not have been the best technology choice, and it led to a far too expensive system to fund.

If instead of JWST and SIM and TPF NASA had instead hitched it's wagon to a more incremental development approach, of launching Hubble or Kepler class telescopes in the $1 billion budget range every 2 or 3 years or so and using that program as a test bed for new technologies and new scientific investigations I think we'd be in a much better state right now and probably a lot closer toward having the capability to directly image exoplanets routinely. But who knows if that would have been the case.

On the plus side, the impending drop in the costs of orbital launch due to SpaceX et al will probably force NASA into a model such as that, so maybe we'll see if it generates better results.

Finding signs of intelligent life might be hard, but finding signs of life would be relatively easy. When exoplanets transit in front of their star, it's possible to get a spectrum of their atmosphere and determine its composition (though with large error bars at the moment).

One of the key signs of life would be an oxygen-rich atmosphere, which should be detectable (if it exists) in the near future. Of course, this is only a sign of life, not a guarantee of its existence, but it's very encouraging that such a discovery is perhaps only ~5 years away.

Spectroscopy can certainly help - but for me would bring to mind the various times putative signs of extraterrestrial life have been found - the Martian meteorites of 1996, or the current Mars rover "organic materials" findings - leading only to controversy and uncertainty. But hey, c'est la science.

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