Starliner Returning to Earth
Starliner undocks from the International Space Station (ISS) on it’s return to Earth (Credit: NASA)
At 2:36 p.m. ET, Boeing’s CST-100 Starliner spacecraft undocked from the International Space Station (ISS). Starliner is in the process of its departure maneuvers, which include the outbound fly around maneuver, exiting the ISS’s keep out sphere (KOS) and conducting a departure burn and then exiting the approach ellipsoid (AE).
A weather briefing held an hour before undocking predicted scattered clouds at 25,000 feet, hazy with 8-mile (12.875-kilometer) visibility and winds peaking at 8-14 knots. Those conditions are favorable for landing at the White Sands Space Harbor landing zone at the U.S. Army’s White Sands Missile Range in New Mexico.
After exiting the approach ellipsoid, Starliner will begin lowering its orbit and targeting its designated landing zone. It will then execute a tail-sun maneuver to orient its solar arrays sunward to top off its batteries, and then will set up for deorbit and reentry.
As the Starliner is flying over the Pacific Ocean, it will point the bottom of the vehicle toward the horizon in the direction the spacecraft is moving and commence the deorbit burn, firing four of its 12 aft-facing OMAC thrusters for approximately one minute. It will then orient itself to safely detach and dispose the service module before the crew module thrusters reorient the spacecraft in the proper re-entry attitude for entry interface (EI). Meanwhile, the service module will conduct a disposal burn, safely burning up over the Pacific Ocean.
About 16 minutes before touchdown, Starliner will begin entering Earth’s atmosphere, experiencing temperatures reaching roughly 3,000 degrees Fahrenheit. Once through most of the atmosphere and having shed most of its velocity, Starliner will begin its parachute and landing system deployment sequences at roughly 30,000 feet above the ground. First, two smaller parachutes will deploy and pull off the forward heat shield, exposing the rest of the parachute system. Then, two drogue parachutes will deploy, followed by three pilot chutes that will pull out the three main parachutes. Starliner will spend the rest of its journey to Earth under those three main parachutes, and at approximately 3,000 feet, the base heat shield will jettison, revealing the landing airbags. The six airbags around the perimeter of the spacecraft will inflate, allowing for a safe, soft landing on dry land.
