Eyes in the Sky

After 25 years, $10 billion, and countless hours of hard work, the James Webb Space Telescope (JWST) is ready for liftoff. Next month, it will launch into orbit 930,000 miles (1.5 million kilometers) above Earth.

Why send a telescope to space? Both ground- and space-based telescopes collect and focus light to make images of objects or regions in space. But telescopes on the ground have to peer through Earth’s atmosphere, a thick soup of air and water molecules that makes gathering some types of light difficult. “You put things in space to get them out of the atmosphere that blocks out a lot of light,” says Michael Menzel, JWST’s lead mission systems engineer.

One of the most difficult types of light to see from the ground is infrared light. Infrared light is ideal for studying nebulae, the dusty, cloudy parts of space where stars form. This is the type of light JWST will collect so it can see the very first stars formed in the universe.

After 25 years and $10 billion, a new telescope is ready for liftoff. It’s called the James Webb Space Telescope (JWST). Next month, it will launch into orbit 930,000 miles (1.5 million kilometers) above Earth.

Why send a telescope to space? Telescopes collect and focus light to make images of things in space. But telescopes on the ground have to do this through Earth’s atmosphere. The atmosphere is thick with air and water molecules that make it difficult to gather some types of light. “You put things in space to get them out of the atmosphere,” says Michael Menzel. He’s the lead mission systems engineer for the JWST.

Infrared light is one of the most difficult types to see from the ground. It’s invisible to the naked eye. But it’s ideal for studying nebulae, the cloudy parts of space where stars form. The JWST will collect infrared light so it can see the oldest stars in the universe.