The new trillion-dollar spending bill crafted by Congress and now winding its legislative way to President Obama's desk contains millions of dollars in new funding for a new massive space telescope that has reportedly become the top priority for the country's top space agency.

With the spending package expected to be signed as soon as Wednesday, leaders from the National Aeronautics and Space Administration say they eagerly await the launch of the James Webb telescope, a replacement for the long-serving Hubble Space Telescope, which was carried into space and launched into low-earth orbit during a 1990 Space Shuttle mission, and the Spitzer Space Telescope, an infrared space observatory launched by rocket in 2003 and named after astronomer Lyman Spitzer, whose work greatly influenced NASA's space exploration programs.

Named after astronomer Edwin Hubble, the still-functioning Hubble telescope has a nearly-8-foot aperture and four primary instruments that observe near ultraviolet, visible, and near infrared light.

The Spitzer observatory, though out of its liquid helium fuel supply, is still partially functioning and able to capture images of long-distance targets.

Currently under development at the Goddard Space Center in Maryland, the James Webb telescope, originally dubbed the Next Generation Space Telescope, now derives its name from the agency's second administrator who was key during the Apollo lunar exploration missions. The telescope is set to receive $658 million in funding this year alone, according to NASA officials.

Astrophysicist Amber Straughn told reporters the Webb will be the world's largest space telescope and will be positioned about one million miles from Earth, four times farther than the moon, in order to gather information about galaxies and stars.

At 21.3 feet, or 6.5 meters, Webb's mirror will have about seven times the area of Hubble's and 50 times the area of the Spitzer. The resolution of the new observatory will be three times more powerful than Hubble in the infrared and eight times more powerful than Spitzer, NASA says.

Put another way, while the Hubble can see to about 800 million years after the Big Bang, the Webb will be able to see to about 200 million years after the Big Bang. As a result, researchers expect to better track the many changes the universe experienced in its evolution.

Besides being much more powerful than Hubble, the Webb telescope, set for lift-off in 2018, will be significantly bigger than Hubble.

In fact, the Webb, about the size of a tennis court, is expected to be so big, its on-board light reflectors will have to be fold origami-style before the mammoth instrument is deployed.