SLS is ready for Artemis I

98 m high and with a total starting weight of 2600 tons, the Space Launch System (SLS) from NASA is a launch vehicle that inevitably evokes Apollo’s Saturn V. A logical approximation, since SLS will be used mainly for the Artemis program for the return to and on the Moon by the American agency. After several years of development (and delay), it is now aiming for its maiden flight where he will serve the Artemis I mission.

Return to the firing line

In its current Block I version, the SLS was assembled in the gigantic VAB (Vertical Assembly Building) hangar at NASA’s Kennedy Space Center in Florida. He has already left it twice before to undergo repetitions of his complex countdown starting at 46 hours and 40 minutes before launch!
Making its third excursion from the VAB on August 16, this time SLS joined its LC-39B launch pad (which was used for the Apollo and shuttle missions) with the line of sight, no longer testing, but a launch in order to complete its first flight .
The Boeing video below summarizes SLS’s 10-hour journey and launch tower to the launch pad on 16-17. August.

NASA announced a first launch site for Monday 29 August at 8:33 local Florida time, or 14:33 for metropolitan France. On that day, the teams have a 2-hour “window” so that the launch time respects the mission’s many constraints (especially the Moon’s position relative to Earth). This means that the flight can take place between 8:33 and 10:33 local time (14:33 to 16:33 in France).

Remember that a launch can always be postponed for weather or technical reasons. The US agency also identifies two other departure points. Primarily September 2 at 12:48 p.m. Florida time (6:48 p.m. in France) and 5th of September at 17.12 local time (23.12 in France). The launch window is 2 hours for September 2 and 90 minutes for September 5.

Artemis I around the Moon

This first flight of the SLS stands out as a crucial test for the US lunar program, which is part of a general context of the return to our celestial neighbor recalled by the Moon, the Episode II exhibition at the Cité de l’Espace in Toulouse . In addition, there is talk of carrying out the Artemis I mission, which consists of sending NASA’s Orion capsule around the Moon with a service module provided by the European Space Agency (ESA) and built by Airbus.

The ESA video below illustrates the role of its European Service Module (ESM) for Artemis I.

Orion and the ESM duo will thus complete a trip to the Moon to complete several orbits there before returning to Earth. There is no astronaut on board and the goal is to control the operation of all the systems. A dummy called Commander Moonikin Campos, for example, makes it possible to measure the conditions inside the capsule.

The flight plan of Artemis I.
Credit: ESA/K. Oldenburg

1 – Launch.
2 – Low circuit deployment of the ESM solar panels.
3 – Translunar injection.
4 – The journey to the Moon.
5 – Ignition of the main engine 185 km from the Moon.
6 – New ignition for insertion into retrograde circuit.
7 – Retrograde circuit.
8 – Ignition to exit circuit.
9 – Ignition to start return to Earth.
10 – Return to Earth and orbit corrections.
11 – Separation of Orion and ESM.
12 – Re-entry into the atmosphere (ESM burns up).
13 – Orion lands in the Pacific Ocean.

A start on August 29 allows a flight of 42 days in total. Orion and ESM will enter a so-called retrograde lunar orbit (as opposed to the Moon’s direction of rotation) similar to those that will be used for future manned missions. The return of the Orion capsule (after dropping the ESM) will take place in the Pacific Ocean off the coast of California.
This full-scale test will certify the capsule and its service module for Artemis II. This mission, scheduled for 2024, will send 4 astronauts around the Moon and back in preparation for Artemis III, which aims to land in the south polar zone of our natural satellite. The continuation of the Artemis program envisages both an exploration of the lunar surface and the use of the Gateway station around the Moon. NASA’s partners are ESA for Europe, JAXA for Japan and CSA for Canada.

Cover image: City of Space from NASA/Joel Kowsky and ESA/K. Oldenburg

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