The mysteries of the universe seemed limitless.

However, to unlock them, we're going to need some incredible technologies to peer deeper and more sharply than is currently possible.

Fortunately, the imagination and ingenuity of telescope engineers also seems to be without limit.

We recently talked about some of the most exciting new observatories currently being built.

One of those, the James Webb Space Telescope, will succeed the Hubble Space Telescope with more than a factor of five increase in collecting area.

Getting such a large telescope into space is a major challenge.

And in fact, it may be difficult to go much larger using traditional mirrors.

Those things are really hard to get into space in one piece.

Fortunately, NASA isn't constrained by traditional methods.

The NASA Innovative Advanced Concepts, NIAC program, has some ingenious ideas for overcoming this limitation.

The first big idea may revolutionize our study of terrestrial exoplanets.

The Kepler mission has determined that terrestrial planets-- that is, rocky planets like our Earth-- are extremely common and may orbit most stars in the Milky Way.

But these planets are extremely difficult to directly image because they are dense and small.

And in addition, because rock solidifies at a much higher temperature than volatiles, like ammonia and water, terrestrial planets tend to form close to their parent star.

This brings a special challenge-- glare.

Our sun is about 10 billion times brighter than Earth.

Train a distant telescope on us, and it would be overwhelmed by the sun's rays.

So how can we find a terrestrial planet around a star light years away?

Maybe it's simple-- blot out the star.

We've done this for decades with the coronagraph, a disk inside a telescope that occludes a star, blocking its light so that any planets can be seen more clearly.

However, there's no such thing as a perfect shadow.

The wave nature of light causes it to bend or diffract around the edges of a coronagraph back towards the central optical axis.

This means it's never possible to completely block the star's light.

Good chronographs can allow detection of objects from 100,000 to a million times fainter than the central star, but no where near the factor of 10 billion difference between the Earth and the sun.

In 2005, Dr. Webster Cash proposed a successor to the coronagraph-- the starshade.

It's actually a spacecraft outfitted with thrusters to align itself between a space telescope and a star.

A starshade will be up to 50 meters in diameter and hover 80,000 kilometers in front of the telescope, assuming a four-meter diameter telescope mirror.

At that distance, the starshade acts like an artificial eclipse.

The effect of diffraction would be easier to isolate than for a typical internal coronagraph.

But the starshade goes much further.

It will not be a simple opaque disk, like a standard coronagraph.

Instead, you'll have a flower-like shape, whose cleverly calculated petal geometry is designed to diffract light away from the central axis, not towards it.

The number and length of pedals optimizes each starshade for a particular wavelength of light.

Each of those pedals is articulated to fold into a very compact bud for launch, and then open up like an actual flower once in space, a bit like the James Webb Space Telescope.

The main motivation for building starshades is to suppress the glare of stars enough to see the planets that orbit them.

Configured right, glare is suppressed by a factor of 10 billion at 50 milliarcseconds from the star.

So one of these things would allow us to see Earth in orbit around the sun from 60-light years away.

There are a couple of thousand stars within that range, and hundreds of sun-like stars, many of which certainly have Earth-like planets.

With the starshade, we may soon directly observe terrestrial exoplanets with cameras and spectrographs.

We'll be able to detect continents, oceans, icecaps, and cloud banks of faraway worlds.

Besides Earth-like exoplanets, the starshade would also be an enormous help in studying quasars and other high-contrast phenomena.

The first starshade may launch with NASA's WFIRST mission in the 2020s for a budget of around $750 million and a runtime of five years.

It's pricey, but may ultimately save money as its beneficiary telescope will require no coronagraphs or wavefront correctors or other high-contrast compensators.

Oh, and one starshade could theoretically serve multiple telescopes.

Diffraction is a challenge for coronagraphs, but the phenomenon is a challenge for any telescope.

The edges of a telescope's primary mirror or lens also cause diffraction.

This introduces an unavoidable blur.

The diffraction limit defines the best possible resolution of a telescope, and it gets smaller or sharper proportional to the size of your telescope's aperture.

But that's a tough trade-off.

To improve resolution by a factor of two, you need to double the diameter of the scope, which means the volume and mass, roughly speaking, increased by a factor of eight.

And that's a problem when you're trying to launch your telescope into space.

Diffraction is expensive to deal with.

But what if we could use the phenomenon to our advantage?

Enter the aragoscope, another one of Webster Cash's strokes of genius.

It's a revolutionary idea to use diffraction optics to focus light, instead of what we call geometric optics, so reflection or refraction like in traditional telescopes.

Imagine an opaque disk of 100 meters to a kilometer in diameter, suspended in front of a satellite detector.

Light diffracts around the disk, coming to focus on the optical axis where the light's wavefronts line up in constructive interference.

Place some minimal traditional optics and a camera at that focus, and you have an image of the distant source that's 100 or 1,000 times better in resolution than the Hubble Space Telescope.

The resolution of the aragoscope is still proportional to its size, but because we're talking about a foldable plastic disk rather than a chunky solid mirror, it's possible to scale up the aragoscope in size much more easily than a regular scope.

Now there is a big downside to the aragoscope scope.

It's also a giant coronagraph, blocking most of the light from the object of interest.

All you get is the thin ring of light diffracted around the edge.

Although that light comes to an incredible focus, the actual amount of light you get is the same as if you didn't have a telescope at all.

Ways around this are to add a largish lens or mirror to the satellite, but that adds a lot of mass.

It's also possible to break the disk into a set of concentric rings so that you get many diffraction edges.

There are challenges to bring the light from each ring to the same focus, but fortunately humans are pretty smart and there are ways to do this.

An aragoscope in geosynchronous orbit could resolve a hamster on the surface of the Earth.

Pointed outwards, it could spot a terrestrial planet at tens of light years distance and even map the cloud structure of a gas giant, especially if you add a starshade to the aragoscope-- because why not.

One of the most powerful uses of the aragoscope is in x-ray astronomy.

X-rays have such short wavelengths that telescope mirrors have to be astoundingly smooth to reflect them cleanly.

A mirrorless aragoscope scope avoids this problem.

In this case, the disk would have to sit thousands of kilometers in front of the detector.

So it would be an independent spacecraft, just like the starshade.

However, it would be able to see x-rays right down to the event horizons of super massive black holes in distant galaxies.

And now for something completely different-- this one from Dr. Marco Quadrelli at JPL.

We've just seen ways to forego heavy glass mirrors and lenses, but what if we could ditch the giant disks and support structures too?

The future could lie in orbiting rainbows, an idea as creative as it sounds.

Inspired by how water droplets focus light into colorful arcs across the sky, scientists have proposed we use photon pressure to suspend a cloud of tiny reflective particles in Earth's orbit.

A laser can find a glitter cloud, if you will.

The particles would be fractions of a millimeter in size, small enough that commercial lasers could corral and shape the particles into an effective mirror or lens.

Scientists could expand the aperture to tens of meter in diameter.

But on launch, it fits into a small box.

And there's literally nothing to break during that launch.

The pile of shiny grid is already is broken as it can get.

The immediate question is, how can such a disordered granular material create a clear image?

Tests of glitter-coated lenses show they're inherently noisy.

But scientists can counter this by taking multiple exposures of the same target, and then use advanced algorithms to combine the images and remove speckle.

Results probably won't top those of the magnificent starshade and aragoscope, but the orbiting rainbow is cheap.

It may be possible to launch multiple such telescopes that have several times the light collecting power of the Hubble Space Telescope.

NASA has some brilliant plans to overcome the limitations of traditional space-based telescopes.

What once seemed like fundamental limits to our ability to observe the universe are now being overcome by some incredible human ingenuity.

As we launch our new observatories, our vision will be keener, allowing us to peer more sharply and to ever greater depths into space time.