Yesterday, NASA announced that it intends to bring an infrared survey telescope out of hibernation in order to hunt for near-Earth asteroids. Today, the agency followed up with animations that depict a mission to an asteroid, one that a separate retrieval mission will first have to place in a near-Earth orbit. These and other developments indicate that NASA is attempting to build support for the Obama administration's plan to send humans to an asteroid later this century.

The telescope in question is the Wide-field Infrared Survey Explorer (WISE). The space-based telescope spent two years scanning the entire sky for infrared light sources, which ranged from distant galaxies to asteroids and comets in our own Solar System. In contrast to a high-resolution telescope like the Spitzer, WISE only has a relatively small aperture (40 cm) but a very wide field of view. Its full-sky survey was done while the instruments were cooled using solid hydrogen carried on board. When that ran out, the telescope ended its large-scale survey and was repurposed to search for near-Earth objects, a mission that picked up the nickname NEO-WISE.

The hardware proved so successful at identifying small bodies within the Solar System that NEO-WISE identified roughly a quarter of the 600,000 rocky bodies we know of. But the mission was eventually declared complete, and the telescope's electronics were placed into a hibernation mode. The new plan requires the hardware to be reactivated and checked out again, but assuming it comes back to life successfully, the telescope will provide a powerful tool for sighting nearby bodies.

The move makes sense in two ways. Although we've probably identified all of the large ones, we don't have a full catalog of small near-Earth objects that could pose threats to Earth's inhabitants. WISE's hardware was suited to this purpose (asteroids absorb sunlight and then radiate it back in infrared), and it has a proven track record. If the money is available and the hardware starts up without a hitch, reactivating WISE doesn't seem like a bad idea.

And it fits with NASA's recent focus on the problem of detecting and deflecting potential space hazards. Back in June, the agency announced an asteroid grand challenge. NASA is looking for ideas about how to find and handle asteroids that could cross paths with the Earth, and it hopes that just about anyone—it lists other government agencies, international partners, industry, academia, and citizen scientists as examples—will be willing to contribute them. It has also set up an entire webpage for its various asteroid-focused efforts.

But reviving WISE to hunt for asteroids would also feed into President Obama's current plans for NASA. Rather than returning to the Moon or heading straight for Mars, the administration would like to see NASA develop the technology and skills to travel through the Solar System by targeting asteroids. This would allow a somewhat smaller mission since it wouldn't need a lander capable of slowing its descent through the Martian atmosphere while carrying enough fuel to return to orbit (something on the surface of Mars weighs a bit over twice what it does on the Moon).

As a preliminary step, NASA is now considering sending an unmanned probe to a nearby asteroid and dragging the rock into an orbit accessible from Earth. That's the subject of the newly released animation, which envisions the probe as wrapping the asteroid in a giant bag before hauling it back to its new orbital home. Once there, astronauts would pay it a several-day visit to study the asteroid in detail and return samples. The manned portion of that mission would involve an Orion capsule sent to rendezvous using the Space Launch System—both of which are currently still in development.

No go?

Why the sudden asteroid offensive? Probably because Congress doesn't like the idea at all. After a hearing in June, members of the House Science Committee put together a budget for NASA that explicitly forbid the agency from pursuing an asteroid mission:

Another request in the President’s budget was an Asteroid Retrieval Mission or ARM. While the committee supports the Administration’s efforts to study Near Earth Objects, this proposal lacks in details, a justification or support from the NASA own advisory bodies. Because the mission appears to be a costly and complex distraction, this bill prohibits NASA from doing any work on the project and we will work with appropriators to ensure the agency complies with this directive.

Congress does like Orion and the Space Launch System—combined, they get nearly $3 billion of the $16.8 billion budget the House is considering for NASA. The programs have undergone years of development despite the fact that there are no well-defined plans to send a crew anywhere that would require them, so tying Orion/SLS to an asteroid visit may be an attempt to get Congress on board.

Scientifically, an asteroid is an interesting destination, as the smaller ones are thought to preserve material that reflects the conditions of the early Solar System. There's also the possibility that they can be used to gather resources, such as metals that, on Earth, have largely ended up in the core. So visiting one is certainly scientifically justifiable (assuming commercial interests don't get there first).

But Congress would like to see the Orion/SLS combo used for a trip to Mars, with a return to the Moon used as a stepping stone. And the latest asteroid offensive is unlikely to change anyone's mind.