OFT-2 launches in hopes to reach ISS

May 19 at 6:54 pm E.T. from SLC-41 at Cape Canaveral Space Force Station

Once again, we are seeing Boeing’s Starliner CST-100 capsule atop an Atlas V rocket on the launch pad. This mission, OFT-2 (operational flight test 2) is an operation to show that Starliner is ready to start ferrying astronauts to and from the International Space Station. NASA and Boeing signed a contract back in 2014 for these services to begin, and the first Starliner launch was just five years later in December of 2019. Unfortunately, that mission ended prematurely after a series of glitches got the capsule stuck in the wrong orbit and it was unable to reach the ISS (International Space Station). Boeing addressed the glitches and got the capsule ready for the OFT-2 mission in summer of 2021, but preflight checks before liftoff revealed that they had thirteen stuck valves in the capsules propulsion system. This problem has since taken eighteen months to diagnose and resolve, leading us to today, OFT-2, the second go around.


If things go as planned, Starliner will arrive at the ISS Tomorrow, Friday evening on May 20, just over twenty-four hours after launch. The spacecraft will remain docked with the orbital station for four or five days before returning to Earth for a touchdown in New Mexico.


Carrying Starliner is again a specifically modified Atlas V in what they call the Starliner configuration. This configuration does not include a payload fairing, instead Starliner’s insulated surface takes the place of the fairing to protect the craft during ascent. Using a launch vehicle adapter or LVA the capsule is attached to the rocket booster. This includes an aero skirt to reduce the aerodynamic loads on the vehicle. Once the booster reaches stage separation, the skirt will be jettisoned for improved performance. The full height of this launch vehicle is 172ft tall. The Atlas V booster is 12.5ft in diameter and thrust is provided by the RD-180 engine system. This engine burns RP-1 and liquid oxygen and delivers 860,200lbs of thrust at sea level. Configured with two SRBs (Solid Rocket Boosters) which each provide 348,500lbs of thrust the total power of this rocket is right around 1.6 million pounds of thrust at lift off.

Infographic by Rykllan

The CST-100 Starliner spacecraft is manufactured by Boeing and is a reusable crew capsule designed to take humans to the ISS and other LEO (Low Earth Orbit) destinations. CST stands for Crew Space Transportation and the 100 stands for the 100km or the height of the Karman line, the edge of where space begins. designed to stay in space for up to seven months and flown for up to ten missions each this capsule though primarily flying on Atlas V rockets is also compatible with the Delta IV, Falcon 9, and Vulcan Centaur rockets as well. Split into two main sections, the spacecraft includes the crew module, and service module. The crew module is 15ft in diameter, which is smaller than NASA’s Orion capsule but larger than the Apollo capsules, and even though it will primarily only fly four humans to and from space per mission it is designed to hold up to seven astronauts. The service module is where the propellant tanks and thrusters for orbital maneuvering and launch abort motors are held. For that launch escape system, four Aerojet Rocketdyne RS-88 engines will be used if needed. There are also solar cells, and a micro-meteoroid debris shield on the service module for protection and added energy.


Unlike the SpaceX Dragon capsules Starliner will touch down on land. This is the first orbital capsule to utilize solid ground landings in the U.S. Once the capsule reaches 9km in altitude two drogue chutes are deployed before the trio of main chutes at 3.6km. The heat shield will be jettisoned at 1.5 km in altitude and following that, six airbags will be inflated to ensure a soft landing upon touchdown. Currently they have five landing sites across the western United States which will allow Starliner up to four-hundred and fifty landing opportunities throughout the year.

Inside Boeing’s Starliner capsule will be more than 500 pounds of cargo, at least 440 pounds of that consists of food and supplies for the station’s current crew. Then there are various other payloads remaining contributed by Boeing that include flight memorabilia keepsakes, such as flags, and pins commemorating the United States’ historically Black colleges and Universities. We will also be seeing Rosie the Rocketeer making another flight to space. Rosie, named after the WWII recruitment campaign, first launched as a test dummy during the OFT-1 mission in 2019. During that failed mission Rosie did her job of collecting data during the flight from fifteen sensors inside her to inform how the stresses of spaceflight will affect astronauts in this crew capsule. Her main purpose this test will be to evaluate the stress on the four seats inside Starliner directly.