The decisive Starliner flight on the ISS: what needs to happen every minute

The Starliner mission will last about ten days. But the most important part is the first day, or even the first hour. These are the main stages of the decisive flight of the Boeing capsule.

This is the big day for Boeing. On the night of May 19 to 20, 2022, the American company launched an Atlas V rocket with a Starliner capsule on top of it. Objective: send the machine into space so that it joins the International Space Station (ISS). The spacecraft will remain hidden in orbit around the Earth for several days, before returning.

It was a very important flight for Boeing, which already failed in December 2019. It must succeed in order to proceed to the next stage, which consists of remaking this flight with a crew. It will also be a very important flight for NASA and the United States, which want to launch another national company capable of delivering astronauts into space, in addition to SpaceX.

Consequently, this mission, which takes place 880 days after the first attempt, is one of the major events of the year in terms of space. We know in broad outline what the main stages of the flight will be, from takeoff to the moment of docking, but also the estimated duration over which the Starliner will remain attached to the ISS before returning.

At 0 minutes

At T+0, the Atlas V rocket will depart from its launch pad, which is launch pad 41 at the base of Cape Canaveral. A few seconds before takeoff, at exactly -2.7 seconds before T+0, the RD-180 rocket engine, which is liquid propellant and made in Russian, ignited. It will then increase speed throughout its ascending part.

1 minute away

The Atlas V rocket will reach its first speed level, crossing Mach 1, i.e., the speed of sound (343 meters per second). It is when crossing this threshold that we hear the famous supersonic “bang”. Here the maximum dynamic pressure is reached: then, it will dissipate as the ascent progresses, with a decrease in atmospheric density.

An Atlas V rocket takeoff. // Source: Joel Kowsky

2 minutes away

After 2 minutes, the rocket will drop its SRB boosters. There are two for this flight. This launcher can accommodate zero to five, depending on the mission profile. These thrusters are present to provide additional thrust. The RD-180 engine generates 3.83 meganewtons (about 392.6 ton-force. An SRB gets 1.55 MN (158 ton-force).

4 minutes away

Many events follow in the next minute: first there will be an extension of the engine of the first phase of the Atlas V rocket, in 4 minutes and 58 seconds. In the next second, the launcher will disconnect at this stage. The upper floor, the baptized Centaur, will remove its protection covering it at the stage of its ascent.

In 4 minutes and 45 seconds

Ignition of the Centaur propulsion system. This is the RL-10 rocket engine. This push will take a few minutes. In terms of positioning associated with the Earth, the Starliner and the Centaur would still be relatively close to the shores of America. The set will continue to gain altitude and speed. The whole thing should take about seven minutes.

In 11 minutes and 50 seconds

Centaur propulsion, provided here by two RL-10 rocket engines, will stop at this time. The two systems each produced a thrust of 100.5 kN, or approximately 10.3 tons. Above him was still the Starliner capsule, which was about to be released. Relative to Earth, this sequence occurs off the coast of Canada, with a northerly direction.

In 14 minutes and 50 seconds

The separation between the Centaur and the Starliner interacts, while the two engines are somewhere above the Atlantic. This will be the end of the mission for Atlas V, but not for Starliner. The Centaur vessel, which is about 13 meters long and 3 meters wide, will begin to dive towards Earth, to finish its course in the Indian Ocean.

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The Starliner must find the ISS in orbit. // Source: Boeing

Between 15 and 37 minutes

The Centaur trajectory will take it to the rest of the North Atlantic, then to Europe, Turkey and the Arabian Peninsula. The vehicle will end its career at sea, as Boeing and Lockheed Martin, which build the Atlas V, have yet to ride rockets capable of returning to Earth – whether this stage or the previous one, has dropped to 4 minutes. .

For the next 24 hours

The Starliner capsule will continue its gradual ascent into space to reach the orbit of the International Space Station, which orbits the Earth at an altitude of nearly 400 kilometers. This is the longest sequence, taking about 24 hours in total. The Starliner will rotate the Earth while waiting, with possible course corrections.

May 21

On the evening of May 20, around 9:30 pm (Paris time), rendezvous and docking operations between the ISS and Starliner should begin. Actual contact is expected at 1:10 am on May 21. At 5:45 pm, still on May 21, the hatch should open allowing ISS crews to enter the capsule.

Between 5 and 10 days

This is the duration of docking the capsule to the ISS, allowing the crew to explore it and perform various tests. The hatch will then close and the craft will re -enter. After maneuvers to get away from the ISS safely will come re -entry into the atmosphere. The capsule will end its course at the tip of a parachute, before landing on the ground, somewhere in the western United States.

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The return of the Starliner must be made to Earth, slowed by a parachute and facilitated by these large airbags. // Source: NASA

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