Timeline by Nadia-Ana Nicolescu

James Webb Space Telescope

nadiaananicolescu — 2023-12-05 08:52:00 UTC

Launch Date

nadiaananicolescu — 2023-12-05 08:53:06 UTC

The Webb was launched on 25 December 2021 on an Ariane 5 rocket from Kourou, French Guiana.

The telescope's first image

nadiaananicolescu — 2023-12-05 08:55:38 UTC

was released to the public on 11 July 2022.

After who was the telescope named after

nadiaananicolescu — 2023-12-05 08:58:39 UTC

The telescope was named after James E. Webb, who was the administrator of NASA from 1961 to 1968 during the Mercury, Gemini, and Apollo programs.

How the telescope must be kept

nadiaananicolescu — 2023-12-05 09:00:47 UTC

The telescope must be kept extremely cold, below 50 K (−223 °C; −370 °F), so that the infrared light emitted by the telescope itself does not interfere with the collected light. Its five-layer sunshield protects it from warming by the Sun, Earth, and Moon.

Features

nadiaananicolescu — 2023-12-05 09:02:58 UTC

The mass of the James Webb Space Telescope is about half that of the Hubble Space Telescope. Webb has a 6.5 m (21 ft)-diameter gold-coated beryllium primary mirror made up of 18 separate hexagonal mirrors. The mirror has a polished area of 26.3 m² (283 sq ft), of which 0.9 m² (9.7 sq ft) is obscured by the secondary support struts,giving a total collecting area of 25.4 m² (273 sq ft). This is over six times larger than the collecting area of Hubble's 2.4 m (7.9 ft) diameter mirror, which has a collecting area of 4.0 m² (43 sq ft). The mirror has a gold coating to provide infrared reflectivity and this is covered by a thin layer of glass for durability.

Location and orbit

nadiaananicolescu — 2023-12-05 09:05:24 UTC

Webb operates in a halo orbit, circling around a point in space known as the Sun–Earth L₂ Lagrange point, approximately 1,500,000 km (930,000 mi) beyond Earth's orbit around the Sun. Its actual position varies between about 250,000 and 832,000 km (155,000–517,000 mi) from L₂ as it orbits, keeping it out of both Earth and Moon's shadow. By way of comparison, Hubble orbits 550 km (340 mi) above Earth's surface, and the Moon is roughly 400,000 km (250,000 mi) from Earth. Objects near this Sun–Earth L₂ point can orbit the Sun in synchrony with the Earth, allowing the telescope to remain at a roughly constant distancewith continuous orientation of its sunshield and equipment bus toward the Sun, Earth and Moon. Combined with its wide shadow-avoiding orbit, the telescope can simultaneously block incoming heat and light from all three of these bodies and avoid even the smallest changes of temperature from Earth and Moon shadows that would affect the structure, yet still maintain uninterrupted solar power and Earth communications on its sun-facing side. This arrangement keeps the temperature of the spacecraft constant and below the 50 K (−223 °C; −370 °F) necessary for faint infrared observations.