NASA’s James Webb Space Telescope will be at a far more extreme range than the famous Hubble space telescope in many different ways.
James Webb is worth $10 billion. It is significantly larger, more complex, and more powerful than the Hubble Space Telescope, which has studied the skies from Earth’s orbit for more than three decades.
And the new observatory, scheduled to launch on December 25, will go much further – as far as Lagrange Point 2 (L2) of the Sun-Earth, about 930,000 miles (1.5 million km) away. in the direction of Marsward (not the sun).
Lagrange points are gravitationally stable points where spacecraft can more or less “dock”, maintaining the same relative position without consuming much fuel. But James Webb won’t switch to L2 entirely, but will be there to keep cool.
James Webb is optimized for observing the universe in infrared (IR) light. In contrast, Hubble observed mainly at visible and ultraviolet wavelengths. To capture the faintest IR signals, James Webb’s scientific instruments must be in an extremely cold state. So the observatory has a five-layer sunshade the size of a tennis court when it’s fully open.
“What’s special about this orbit is that it allows the telescope to stay aligned with the Earth as it orbits the sun,” NASA officials wrote in an explanation of L2.
They add: “This allows the large sunshade of the satellite to protect the telescope from the light and heat of the sun and Earth. This is why the telescope will be beyond the second Lagrange point. two.”
If all goes to plan, the instruments of the James Webb telescope will operate at about – 225 degrees Celsius. Meanwhile, the temperature on the hot side of the telescope, where the solar panels are located , Webb communications antennas and other non-scientific devices, will fluctuate around 88 degrees Celsius.
“The temperature difference between the hot and cold sides of the telescope is so great, you can almost boil water on the hot side and freeze nitrogen on the cold side!” NASA officials said.
The distance to L2 highlights the difference between the Hubble and James Webb telescopes. The older Hubble telescope, designed for spacewalking by astronauts, repaired and upgraded Hubble five times between 1993 and 2009. But the distance of 930,000 miles is too far to send satellites. astronauts, so James Webb, whose main mirror is 6.5 m long, almost three times wider than Hubble’s mirror, will be at L2.
Once launched, James Webb will take about 30 days to reach his destination. Once placed in orbit around L2, James Webb would circle the point and examine it completely.
This telescope will begin a diverse and ambitious observational campaign. It was studying some of the universe’s first stars and galaxies and sniffing the atmospheres of nearby alien planets for signs of possible life.