Direct Imaging and Spectroscopy of an Exoplanet with a Solar Gravity Lens | Hacker News Reader

Direct Imaging and Spectroscopy of an Exoplanet with a Solar Gravity Lens

arxiv.org

78 pointswooster19 comments

For a more critical look at this concept, I recommend "Mission to the Gravitational Focus of the Sun: A Critical Analysis".

https://arxiv.org/abs/1604.06351

This is insanely cool. I had no idea this was possible.

If I'm reading right the spacecraft would have to be placed at about 600-850 AU from the sun to take advantage of the solar gravity lens. For reference, Pluto's orbit is located at (roughly) 40 AU.

could we use New Horizons to do it? ...I suppose not, it's taken 10 years for it to go 40AU so for it to go to 400AU it would take 100 years...

You'd need a specialised imaging sensor and optics assembly. New Horizons is optimized for relatively close range planetary survey work. Also it's communications array isn't anywhere near up to maintaining the link back home from that far.

You'd probably need to pack a multi-mode propulsion system. Launch it so it can get a gravity assist from the Sun, deploy a solar sail after closest approach (or when safe) and ride the light pressure from the Sun to get as much delta-v as you can, then ditch the sail and fire up nuclear-powered electric thrusters for the rest of the trip. Dropping the solar sail part may be a good idea if its weight could be better used as propellant for the ion drive.

Then you have a hope of making the trip in a couple decades

Presumably when you get to the right distance, you'd want to circularise your orbit so you can use your new solar lens to look in many different directions.

Even more dV and time required to do that...

Yes... There will be a lot of braking involved, but we may start doing observations well before it reaches the intended circular orbit. I wonder how much such a mission would cost.

But only ~65 hours to send the data back, not bad.

This sounds like moonshot-level complexity. It invokes solar sails, laser communication at 550 AU, as well as "advanced propulsion, lightweight telescopes, membrane mirrors, inflatable/rigidizeable structures, and novel coronagraphic techniques." All that for a telescope you can't aim...

Moonshot x Manhattan Project with a dash of Star Trek. Basically we need the next few generations of novel materials, and controlled fusion reactions. Assuming no major setbacks for humans, we’d need more than a century before considering this kind of project. It would be a worthy project, although I wonder if some other tech might not supersede it by the time this was ready? Gravitational astronomy is just getting started after all, and who knows, maybe the dream of neutrino astronomy could happen.

Interesting that you mention neutrino astronomy - if you mean imaging, I don't know of anything but gravity that could focus neutrinos.

I've wondered for a while if this could be done. I guess now I know. The potential for exploiting the Sun as a gravitation lens comes up on Centauri Dreams from from time to time (see https://www.google.com/search?q=%22gravitational+lens%22+sit...).

This is the workshop where some of these ideas were discussed: http://kiss.caltech.edu/workshops/ism/ism.html There appear to be several groups working on related designs for gravity-based imagers.

One of the three organizers of the workshop is Ed Stone, who is the Voyager PI.

NASA's WFIRST mission is trying to do gravitional microlensing observations, but Trump's latest budget kills it.

https://en.wikipedia.org/wiki/Wide_Field_Infrared_Survey_Tel...

Note that gravitational microlensing is a completely different technique from solar gravitational lensing discussed in the linked paper.

Is there anyone who's sufficiently qualified in astronomy/astrophysics who could point out what advances in HPC/modelling/signal processing will be necessary to accelerate things like this?

I don't know telescopes but I know enough about DSP to make me suspect this is gonna need all sorts of fun high performance deconvolution algorithms....

Related projects [0]

Imaging With Nature: Planet Sized Sensors (July 24th, 2010)

Imaging With Nature: A Cloud Based Sun Imager (July 25th, 2010)

A Galaxy Wide Single Pixel Camera (November 6th, 2010)

[0] https://sites.google.com/site/igorcarron/thesetechdonotexist

Using the sun as a gravitational lens is our current best option for interstellar communications, presuming we settled a planet within a hundred light years:

https://www.centauri-dreams.org/2009/11/06/the-gravitational...

While forming a complete image is no doubt very cool, just a few fragments of light spectrum would give us incredible insight on its own.

I'm wondering now if with BFR we could pre-place fuel in the slingshot path to get it there quicker and depend less on the Sun gravity slingshot.

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