Question re Webb telescope at L2

In summary, the James Webb Space Telescope will orbit around the unstable L2 point in a halo orbit, which will be inclined with respect to the ecliptic and have a radius of 800,000 km. This orbit will take approximately half a year to complete, and the spacecraft will need to use a propulsion system to maintain its position near the L2 point. The telescope's propulsion system consists of two sets of thrusters with a total budget of 150 m/s.
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Buzz Bloom
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The article https://jwst.nasa.gov/content/about/orbit.html describes the planned placing the Webb telescope in orbit near the L2 Lagrange point of the Earth-Sun system. But L2 is gravitationally unstable.
The diagram in the article seems to say that the Webb will orbit around the unstable L2 point. At any distance near L2 but not exactly at L2 the Webb will tend to move further from L2, unless Webb has an engine and fuel to maintain it in the special orbit. I was not able to find any description of such an engine, so I am asking the Physics Forums participants what they might know about this.
 
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The telescope will circle about the L2 point in a halo orbit, which will be inclined with respect to the ecliptic, have a radius of approximately 800,000 km (500,000 mi), and take about half a year to complete.[30] Since L2 is just an equilibrium point with no gravitational pull, a halo orbit is not an orbit in the usual sense: the spacecraft is actually in orbit around the Sun, and the halo orbit can be thought of as controlled drifting to remain in the vicinity of the L2 point.[146] This requires some station-keeping: around 2–4 m/s per year[147] from the total budget of 150 m/s.[148] Two sets of thrusters constitute the observatory's propulsion system.[
 
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1. What is the Webb telescope and why is it located at L2?

The Webb telescope, or the James Webb Space Telescope, is a space-based observatory designed to study the universe in infrared light. It is located at the L2 Lagrange point, which is a stable point in space about 1 million miles from Earth. This location allows the telescope to have a clear view of the universe without interference from Earth's atmosphere or heat.

2. How does the Webb telescope differ from the Hubble telescope?

The Webb telescope is much larger than the Hubble telescope, with a primary mirror that is 6.5 meters in diameter compared to Hubble's 2.4 meters. It also operates in the infrared spectrum, while Hubble primarily observes in visible and ultraviolet light. Additionally, the Webb telescope is designed to be able to see much further back in time, allowing us to study the early universe in more detail.

3. What scientific discoveries do we hope to make with the Webb telescope?

The Webb telescope will allow us to study the formation of galaxies, stars, and planets in the early universe. It will also help us understand the atmospheres of exoplanets and search for signs of life beyond our solar system. Additionally, the telescope will provide new insights into the nature of dark matter and dark energy.

4. How long will the Webb telescope be in operation?

The Webb telescope has a planned mission duration of at least 5 years, but it is designed to last for 10-15 years. This will depend on the health of its instruments and the availability of funding for continued operations.

5. When will the Webb telescope be launched and start collecting data?

The launch of the Webb telescope is currently planned for October 31, 2021. However, due to delays and setbacks, this date may be subject to change. Once the telescope is launched, it will take about 6 months for it to reach its final orbit and begin operations. It will then take a few months for the telescope to calibrate its instruments before it starts collecting scientific data.

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