James Webb Space Telescope: How to watch launch of Hubble's successor

KOUROU, French Guiana - The James Webb Space Telescope, Hubble’s bigger, more powerful successor, is scheduled for liftoff on Christmas morning from the coast of South America. 

It will be the largest and most powerful space science telescope to ever leave the planet, elaborate in its design and ambitious in its scope. At $10 billion, it’s also the most expensive and the trickiest to pull off.

After years of delay, the James Webb Scace Telescope is scheduled to launch at 7:20 a.m. ET on Dec. 25. It will study every phase of cosmic history, from within our solar system to "the most distant observable galaxies in the early universe," NASA says. 

Its infrared telescope will directly observe parts of space and time that have never been seen before, gazing into a period when the very first stars and galaxies were formed — more than 13.5 billion years ago. It will stare down black holes and hunt for alien worlds, scouring the atmospheres of planets for water and other possible hints of life.

"Ultraviolet and visible light emitted by the very first luminous objects has been stretched or ‘redshifted’ by the universe’s continual expansion and arrives today as infrared light," the space agency explained. "Webb is designed to ‘see’ this infrared light with unprecedented resolution and sensitivity."

The James Webb Space Telescope is pictured in a file image. (Photo by: QAI Publishing/Universal Images Group via Getty Images)

Here’s what to know about the James Webb Space Telescope and launch:

How to watch the James Webb Space Telescope Launch

The French-built Ariane rocket carrying the telescope is scheduled to launch from a complex at the European Spaceport located near Kourou, French Guiana. It’s beneficial for launch sites to be located near the equator as the spin of the Earth can help give an additional push, according to NASA. 

Space enthusiasts who wish to see its liftoff can view the countdown commentary and launch broadcast on NASA’s live stream, as well as YouTube, Twitter, Facebook, LinkedIn, Twitch, Daily Motion, Theta.TV, and NASA’s App. Viewers can also join the Facebook event to watch the launch live and interact with others.

The broadcast will continue until about an hour past launch, following the first several critical milestones. 

The actual launch window opens at 7:20 a.m. ET (12:20 UTC) and lasts for 31 minutes, meaning it could potentially launch at any point during this window, according to Amber Straughn, Webb deputy project scientist for communications.

How does James Webb Space Telescope compare to Hubble Space Telescope?

Don’t ask astronomers to choose between Hubble and the new kid on the cosmic block.

"Comparing Hubble and Webb is like asking if you will love your second child as much as your first," said Susan Mullally, Webb’s deputy project scientist. "Hubble will always be loved for its awe-inspiring images of our universe and will continue to collect important data for astronomers. Webb gives us new and unique eyes of places that we have never been able to reach."

Specifically, Webb is designed to peer deeper into space to see the earliest stars and galaxies that formed in the universe and to look deep into nearby dust clouds to study the formation of stars and planets, NASA says. To do this, Webb has a much larger primary mirror than Hubble — 2.7 times larger in diameter — which gives it more light-gathering power.

Its infrared instruments also have longer wavelength coverage and more improved sensitivity compared to Hubble. 

Hubble has stared as far back as 13.4 billion years, disclosing a clumpy runt of a galaxy that is currently the oldest and farthest object ever observed. Astronomers are eager to close the 300 million year gap with Webb and draw ever closer in time to the Big Bang, the moment the universe formed 13.8 billion years ago. 

"It’s like looking at the picture book of my kids and missing the first two years, right? Trying to figure out where they come from," said NASA science chief Thomas Zurbuchen.

Webb will also operate much farther from our planet, maintaining its extremely cold operating temperature, stable pointing and higher observing efficiency than Hubble — which circles 330 miles overhead.

Overall, NASA says it prefers to call Webb the "successor," rather than replacement, because its science goals were motivated by results from Hubble.

The Space Telescope Science Institute in Baltimore operates Hubble and will also oversee Webb. At least five to 10 years of observing are planned.

Who is the James Webb Space Telescope named after?

James E. Webb ran the fledgling space agency from February 1961 to October 1968. He believed that NASA had to strike a balance between human space flight and science. (Credit: NASA)

The space-based observatory is named after James E. Webb (1906-1992), NASA's second administrator. Webb is best known for leading the Apollo program, a series of lunar missions that ultimately landed the first humans on the Moon. 

"Many believe that James E. Webb, who ran the fledgling space agency from February 1961 to October 1968, did more for science than perhaps any other government official and that it is only fitting that the Next Generation Space Telescope would be named after him," the space agency states on its website.

By the time Webb retired just before the first moon landing in July of 1969, NASA had launched more than 75 space science missions — studying everything from the stars and galaxies, the sun and the environment of space above Earth's atmosphere.

How much did the James Webb Space Telescope cost?

Hubble was years late and millions over budget by the time it rocketed into orbit in 1990. Webb also is years late with huge cost overruns. 

NASA’s tab for Hubble from its 1970s development until now: $16 billion, adjusted for inflation. That doesn’t include all the shuttle flights for launch and repairs. 

Webb’s price tag is an estimated $10 billion; that includes the first five years of operation. The European Space Agency is picking up the launch costs, with the French-built Ariane 5 rocket providing Webb’s liftoff.

"We chose Ariane in the early 2000's for a combination of reliability (it was the only launch vehicle that met NASA's requirements for launching a mission like Webb) and for the value it brings via our international partnership," the space agency explains on its website.

By "value," NASA means that the European Space Agency provides it with a launch vehicle and associated services at no cost — while the U.S. space agency guarantees European scientists a fraction of observing time on Webb (roughly 15%).

This story was reported from Cincinnati. The Associated Press contributed.