United Launch Alliance’s Atlas V rocket that will launch Boeing’s CST-100 Starliner to the International Space Station for NASA’s Commercial Crew Program was modified specifically for the agency’s Orbital Flight Test-2. This rocket configuration does not include a payload fairing. Instead, the Starliner’s own protective surfaces will take the place of the fairing to protect the uncrewed spacecraft during launch and ascent. The rocket has two solid rocket boosters (SRBs) and a dual-engine Centaur upper stage. Starliner is attached to the Atlas V using a launch vehicle adapter, which includes an aeroskirt to reduce the aerodynamic loads on the vehicle.
The Atlas V booster is 12.5 feet in diameter and 106.5 feet in length. The booster’s propulsion is provided by the RD-180 engine system, which delivers 860,200 pounds of thrust at sea level. The SRBs generate the additional power required at liftoff, with each providing 348,500 pounds of thrust.
The Centaur second stage is 10 feet in diameter and 41.5 feet in length. For this configuration, the Centaur is configured with dual RL10A-4-2 engines, each producing 22,600 pounds of thrust. The cryogenic tanks are insulated with a combination of helium-purge blankets, radiation shields, and spray-on foam insulation. The Centaur includes an Emergency Detection System that monitors for critical hazards. This system will provide critical in-flight data which supports jettison of the ascent cover and initiates CST-100 spacecraft separation.
NASA’s Boeing Orbital Flight Test-2 will test the end-to-end capabilities of the company’s CST-100 Starliner spacecraft from launch to docking to a return to Earth in the desert of the western United States. The flight test will provide valuable data toward NASA certifying Boeing’s crew transportation system for regular crewed flights to and from the International Space Station. OFT-2 will build on the objectives achieved during Starliner’s initial flight test, including:
In-orbit operation of the avionics, docking system, communications and telemetry systems, environmental control systems, solar arrays and electrical power systems and propulsion systems;
Performance of the guidance, navigation and control systems of the Starliner and Atlas V through ascent, on-orbit, and entry;
Acoustic and vibration levels, and loads across the Starliner exterior and interior;
Launch escape trigger monitoring; and
Performance of the Starliner system end-to-end mission operations.
These objectives are intended to demonstrate all of Starliner’s systems and capabilities except for those requiring a human onboard to test.
For this flight, Starliner will carry more than 500 pounds of NASA cargo and crew supplies to the space station. After a successful docking, the spacecraft will spend five to 10 days aboard the orbiting laboratory before returning to Earth. The spacecraft will return with nearly 600 pounds of NASA cargo, including reusable Nitrogen Oxygen Recharge System tanks that provide breathable air to station crew members.
Good afternoon from Kennedy Space Center in Florida, and welcome to live launch coverage of NASA’s Boeing Orbital Flight Test-2 (OFT-2) to the International Space Station, launching in a little over an hour. Boeing’s CST-100 Starliner spacecraft sits atop a United Launch Alliance Atlas V rocket poised on the launch pad ready to go at nearby Space Launch Complex-41 on Cape Canaveral Space Force Station.
OFT-2 is an uncrewed flight test of the company’s Starliner spacecraft for NASA’s Commercial Crew Program. Liftoff is scheduled for 6:54 p.m. EDT during an instantaneous launch window.
The countdown is currently proceeding according to schedule. Fueling of the Atlas V rocket began a little after noon EDT today. The first stage booster’s RD-180 engine, containing two thrust chambers, was fueled with Rocket Propellant-1, a highly purified kerosene. The Centaur second stage was fueled with liquid hydrogen and liquid oxygen. Fueling of the rocket was completed about two hours later.
Meteorologists with the U.S. Air Force 45th Weather Squadron continue to predict an 80% chance of favorable weather for launch this afternoon. The primary concerns for launch day are the cumulus and anvil cloud rules violations during the instantaneous launch window.
This morning, Wednesday, May 18, Boeing’s CST-100 Starliner spacecraft and the United Launch Alliance (ULA) Atlas V rocket rolled out of the ULA Vertical Integration Facility to the launch pad at Space Launch Complex-41 on Cape Canaveral Space Force Station in Florida ahead of the uncrewed launch of NASA’s Boeing Orbital Flight Test-2 (OFT-2) to the International Space Station. Liftoff is scheduled for 6:54 p.m. EDT on Thursday, May 19.
For a launch Thursday, meteorologists with the U.S. Space Force 45th Weather Squadron continue to predict a 70% chance of favorable weather. The primary weather concerns for launch day are the cumulus and anvil cloud rules violations during the instantaneous launch window.
NASA leaders will update members of the news media on OFT-2 during a briefing on Wednesday, May 18, at 1 p.m. The briefing will air live on NASA TV, the NASA app, and the agency’s website. Participants include:
Bob Cabana, NASA associate administrator
Janet Petro, director, NASA’s Kennedy Space Center
Kathryn Lueders, associate administrator, Space Operations Mission Directorate at NASA
NASA astronaut Suni Williams
NASA astronaut Butch Wilmore
NASA astronaut Mike Fincke
NASA TV will cover the upcoming prelaunch, launch, and docking activities. Mission coverage is as follows (all times Eastern):
Thursday, May 19
6 p.m. – NASA TV launch coverage begins for a targeted 6:54 p.m. liftoff. NASA TV will have continuous coverage through Starliner orbital insertion.
9 p.m. (approximately) – Postlaunch news conference on NASA TV
Friday, May 20
3:30 p.m. – NASA TV rendezvous and docking coverage begins.
7:10 p.m. (approximately) – Docking
Friday, May 21
11:30 a.m. – NASA TV hatch opening coverage begins
11:45 a.m. – (approximately) Hatch opening and welcoming remarks
NASA, Boeing and United Launch Alliance (ULA) have scrubbed the Aug. 3 launch attempt of the agency’s Orbital Flight Test-2 to the International Space Station due to unexpected valve position indications in the Starliner propulsion system. ULA will begin removing propellant from the Atlas V rocket.
Pending resolution of the forward work, our next available launch opportunity would be 12:57 p.m. EDT on Wednesday, Aug. 4.
For more information on the technical issue, click here.