Ariane flight VA256 was an

Ariane 5 Ariane 5 is a retired European heavy-lift space launch vehicle operated by Arianespace for the European Space Agency (ESA). It was launched from the Guiana Space Centre (CSG) in French Guiana. It was used to deliver payloads into geostationar ...

rocket flight that launched the

James Webb Space Telescope The James Webb Space Telescope (JWST) is a space telescope designed to conduct infrared astronomy. As the largest telescope in space, it is equipped with high-resolution and high-sensitivity instruments, allowing it to view objects too old, Lis ...

(JWST) into space on 25 December 2021. It was 2021's final Ariane flight, its most valuable payload to date, and the Ariane mission. The launch was described by NASA as "flawless" and "perfect".

Launch configuration

Rocket

Ariane 5 is a heavy lift two-stage rocket with two solid fuel boosters. It was used in its '' ECA+'' variant, which offers the highest payload mass capacity. The total launch mass of the vehicle is .

Payload

The only payload on the flight was the

(JWST), a space-based observatory built by

NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...

and ESA. The launch is one of the European Space Agency's contributions to the project. The telescope had a launch mass of about and a design lifetime of 5 to 10 years.

Preparation

JWST Arrival in Kourou

The James Webb Space Telescope arrived at a port in Kourou in

French Guiana French Guiana, or Guyane in French, is an Overseas departments and regions of France, overseas department and region of France located on the northern coast of South America in the Guianas and the West Indies. Bordered by Suriname to the west ...

, on 12 October 2021 where it was unloaded from the ''MN Colibri'' cargo ship and transported by truck to the space centre.

Integration incident

On 22 November 2021 an incident was reported by NASA and Arianespace that a clamp band securing the payload to the adapter was released during integration activities, causing vibrations to the telescope. After some tests were performed, a review board concluded on 24 November 2021 that no payload component was damaged, and fuelling operations could be started.

Fuelling operations

Spacecraft fuelling operations began on 25 November 2021, the fuelling system was disconnected on 3 December 2021, and verifications were concluded on 5 December 2021. The telescope's

hypergolic A hypergolic propellant is a rocket propellant combination used in a rocket engine, whose components spontaneously ignite when they come into contact with each other. The two propellant components usually consist of a fuel and an oxidizer. The ...

fuel system was filled with approximately of

hydrazine Hydrazine is an inorganic compound with the chemical formula . It is a simple pnictogen hydride, and is a colourless flammable liquid with an ammonia-like odour. Hydrazine is highly hazardous unless handled in solution as, for example, hydraz ...

and of

dinitrogen tetroxide Dinitrogen tetroxide, commonly referred to as nitrogen tetroxide (NTO), and occasionally (usually among ex-USSR/Russian rocket engineers) as amyl, is the chemical compound N2O4. It is a useful reagent in chemical synthesis. It forms an equilibrium ...

, needed to reach and maintain its orbit after separation from the launch vehicle.

Final assembly

Following the rocket, which had already arrived on 29 November 2021, the telescope was moved to the final assembly building ( or ''BAF'') on 7 December 2021. The payload was encapsulated inside the fairing on top of the rocket on 21 December 2021.

Interface communication issue

On 14 December 2021, a joint press release by NASA and Arianespace revealed that "a communication issue between the observatory and the launch vehicle system" was being addressed, further delaying the launch to no earlier than 24 December 2021.

Weather issue

Unfavorable weather forecasts for 24 December 2021 delayed the launch to

Christmas Day Christmas is an annual festival commemorating the birth of Jesus Christ, observed primarily on December 25 as a religious and cultural celebration among billions of people around the world. A liturgical feast central to Christianity, Chri ...

, 25 December 2021.

Launch

The rocket was launched from the

ELA-3 ELA-3 () is a launch complex at the Guiana Space Centre in French Guiana. The complex was first used in June 1996 in support of the now retired Ariane 5 Ariane 5 is a retired European heavy-lift space launch vehicle operated by Arianespac ...

launch pad of the

Guiana Space Centre The Guiana Space Centre (; CSG), also called Europe's Spaceport, is a spaceport to the northwest of Kourou in French Guiana, an Overseas departments and regions of France, overseas region of France in South America. Kourou is located approxim ...

on 25 December 2021 at 12:20

UTC Coordinated Universal Time (UTC) is the primary time standard globally used to regulate clocks and time. It establishes a reference for the current time, forming the basis for civil time and time zones. UTC facilitates international communica ...

(09:20 local time, 7:20 am U.S. EST). The DDO () of the launch was Jean-Luc Voyer, who concluded his shift by saying, "Go Webb!" The launch was described by NASA as "flawless" and "perfect". A NASA systems engineer said "the efficiency or the accuracy with which Ariane put us on orbit and our accuracy and effectiveness in implementing our mid-course corrections" meant that there is "quite a bit of fuel margin ... roughly speaking, it’s around 20 years of propellant."

Orbit

The James Webb Space Telescope was injected into a transfer trajectory that took it to the second Earth-Sun

Lagrange point In celestial mechanics, the Lagrange points (; also Lagrangian points or libration points) are points of equilibrium for small-mass objects under the gravitational influence of two massive orbiting bodies. Mathematically, this involves t ...

(L). The separation of the launch vehicle second stage and the spacecraft occurred approximately 27 minutes after liftoff. The second stage downloaded video, the last known time the telescope will be seen, of the separation and initial deployment of the solar panels. After this separation, the telescope became autonomous and began its deployment sequence. About 29 days after liftoff, it executed a maneuver placing it into a

halo orbit A halo orbit is a periodic, non-planar orbit associated with one of the L1, L2 or L3 Lagrange points in the three-body problem of orbital mechanics. Although a Lagrange point is just a point in empty space, its peculiar characteristic is th ...

around the L point, where it can perform its science mission. Its next five months were spent on cooling NIRCam and the Mid-Infrared Instrument down further, calibrating its mirrors while focusing on HD 84406, a bright star in the constellation

Ursa Major Ursa Major, also known as the Great Bear, is a constellation in the Northern Sky, whose associated mythology likely dates back into prehistory. Its Latin name means "greater (or larger) bear", referring to and contrasting it with nearby Ursa M ...

, and testing the instruments.

References

External links

James Webb Space Telescope detaches from Ariane 5 rocket

Ariane flight VA256
at

Arianespace Arianespace SA is a French company founded in March 1980 as the world's first commercial launch service provider. It operates two launch vehicles: Vega C, a Small-lift launch vehicle, small-lift rocket, and Ariane 6, a Medium-lift launch vehicl ...

{{James Webb Space Telescope VA256, Ariane flight 2021 in French Guiana 2021 in spaceflight Rocket launchers Rocket launches in 2021 James Webb Space Telescope