The most powerful space telescope ever built, James Webb, will deliver its first full-color scientific images to the world on Tuesday.
Here’s an overview of this feat of human ingenuity in five key numbers.
– More than 21 feet –
The heart of the observatory is its huge main mirror, more than 6.5 meters in diameter, made up of 18 smaller, hexagonal mirrors.
The observatory also has four scientific instruments: cameras to capture images of the cosmos, and spectrographs that dissect light to study what elements and molecules make up objects.
The mirror and instruments are shielded from our sun’s light by a tennis court-sized heat shield made up of five superimposed layers.
Each layer is wafer-thin, and together they ensure the telescope can function in the darkness required to capture faint glints from the far reaches of the Universe.
– million miles away –
Unlike the Hubble telescope, which orbits the Earth, Webb orbits the Sun nearly a million miles (1.6 million kilometers) from us, or four times our planet’s distance from the Moon.
It took the spacecraft nearly a month to reach this region called Lagrange Point Two, where it remains in a fixed position behind Earth and the Sun to give it a clear view of the cosmos.
Here, the gravity of the Sun and Earth counterbalances a satellite’s centrifugal motion, meaning it requires minimal fuel for course correction.
– 13.8 billion years –
The further you see in astronomy, the deeper you look back in time.
Webb’s infrared abilities make it uniquely powerful – allowing him to detect light from the earliest stars that has been stretched into infrared wavelengths as the universe has expanded.
This allows it to look further into the past than any previous telescope, down to a few hundred million years after the Big Bang 13.8 billion years ago.
– Three decades of waiting –
The project was first conceived in the 1990s, but construction did not begin until 2004.
Then Webb’s start date kept getting pushed back. Originally planned for 2007, it finally took place on December 25, 2021 aboard an Ariane 5 rocket from French Guiana.
– 10 billion dollars –
Webb is an international collaboration between the US space agency NASA, the European Space Agency (ESA) and the Canadian Space Agency (CSA), involving more than 10,000 people.
The lifetime cost to NASA alone will be about $9.7 billion, or $10.8 billion adjusted for inflation by 2020, according to an analysis by the Planetary Society.
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