After more than two years of mixed fortunes, the second Orbital Flight Test (OFT-2) of Boeing’s CST-100 Starliner—the second of two Commercial Crew vehicles, alongside the now-active SpaceX Crew Dragon—rose from historic Space Launch Complex (SLC)-41 at Cape Canaveral Space Force Station, Fla., during an “instantaneous” launch window at 6:54:47 p.m. EDT Thursday, 19 May.
“Starliner is headed back to space, on the shoulders of Atlas,” exulted the launch commentator, “powered by a workhorse, dedicated to its success.”
“I am so proud of the NASA, Boeing and United Launch Alliance teams who have worked so hard to see Starliner on its way to the International Space Station,” said NASA Administrator Bill Nelson. “Through adversity, our teams have continued to innovate for the benefit of our nation and all of humanity. I look forward to a successful end-to-end test of the Starliner spacecraft, which will help enable missions with astronauts aboard.”
The uncrewed mission was delivered safely to low-Earth orbit atop a United Launch Alliance (ULA) Atlas V booster, with an autonomous rendezvous and docking at the International Space Station (ISS) anticipated at about 7:10 p.m. EDT Friday and a parachute-aided touchdown at White Sands Space Harbor (WSSH), N.M., between five and eight days later. Successful completion of the snakebitten OFT-2 mission will clear a major hurdle as Boeing readies for its Crew Flight Test (CFT) to the ISS, later this year.
Tonight’s mission also marked the 150th launch by ULA, since the organization began flight operations of its combined Atlas V, Delta IV and Delta II fleet, way back in December 2006. Since then, 85 Atlas Vs, 30 Delta IIs and 35 Delta IVs have delivered dozens of payloads on behalf of U.S. Government and national security customers, as well as scientific and commercial entities.
After what Commercial Crew Program Manager Steve Stich described as a “very clean review” at the NASA/Boeing Flight Readiness Review (FRR) on 11 May, there was widespread eagerness to get this long-awaited mission airborne. The weather, too, pledged to play ball for Thursday, with an initial 70-percent probability of acceptable conditions rising to 80 percent, tempered only by “isolated to scattered” showers and thunderstorms. But it proved decidedly less promising for the backup opportunity at 6:32 p.m. EDT Friday, characterized by a noticeable downturn to only 30-percent favorability.
“Isolated afternoon activity expected to develop near or just west of the launch complex, bringing a chance of a Cumulus Cloud Rule and/or Anvil Cloud Rule violation during the count,” noted the 45th Weather Squadron at Patrick Space Force Base in its Wednesday morning update. “Precipitation chances increase substantially on Friday, as winds increased out of the south and draw a plume of deeper moisture upward from the Caribbean.”
Having won a slice of NASA’s $6.8 billion Commercial Crew transportation Capability (CCtCap) “pie” in September 2014, the CST-100 Starliner’s road to the ISS had been a long and difficult one. It first launched atop an Atlas V for the OFT-1 mission in December 2019, but shortly after the spacecraft achieved orbit it suffered an automated timing issue which obliged flight controllers to call off its ISS docking and it returned to Earth two days later. In doing so, OFT-1 became the first U.S. human-rated capsule to touch down on solid ground when it landed via a combination of parachutes and airbags at White Sands.
Despite the disappointment an incomplete mission, OFT-1 successfully trialed the Starliner’s propulsion systems, communications systems, Guidance, Navigation and Control (GNC), the Environmental Control and Life Support System (ECLSS) and—via a series of in-flight extension/retraction tests—the NASA Docking System (NDS). But although an actual ISS docking was not a mandatory requirement to “crew-certify” the new ship, and NASA pointed out that had astronauts been aboard OFT-1, they could have assumed manual control and likely overcome the automated timing problem, it became increasingly clear that a reflight of the mission would take place.
A High Visibility Close Call (HVCC) Review found a worrisome number of technical and organizational root-cause issues for OFT-1’s woes. In March 2020, a joint NASA/Boeing Independent Review Team (IRT) found three principal anomalies—two software coding errors and an unexpected loss of Space-to-Ground Communications—and led to more than 80 recommendations spanning testing and simulation, Change Board documentation and safety culture before OFT-2 could fly. In April 2020, Boeing announced its intent to stage the reflight at its own expense, but additional troubles found OFT-2 delayed further from January 2021 to late spring and ultimately last summer.
But after being postponed a few days when Russia’s Nauka (“Science”) lab experienced a troubled approach and docking at the ISS, another problem in the form of an “unexpected valve position indication” in Starliner’s oxidizer system reared its head only hours before launch last 3 August. The valves, which are linked to Starliner’s abort and maneuvering thrusters, failed to open as designed during the countdown. The launch attempt was correspondingly scrubbed and OFT-2 was stood down indefinitely as teams dug in to understand and resolve the issue.
Last January, NASA and Boeing announced an intention to replace the OFT-2 Service Module with one previously earmarked for the Crew Flight Test (CFT), the first flight of Starliner with astronauts aboard. Meanwhile, investigators zeroed-in on the likely cause of the valve anomaly: interactions between moisture and nitrogen tetroxide.
This permeated the valve’s Teflon seal and induced a measure of corrosion. By this stage, teams had begun to confidently look towards the mid-May timeframe as a likely period for the OFT-2 launch.
Preparations for “OFT-2 Part 2” formally commenced last month, when the 107-foot-long (32.6-meter) Common Core Booster (CCB) for the Atlas V was delivered from ULA’s Decatur, Ala., facility to the Space Coast. Unusually, the transportation was done without ULA’s R/S RocketShip cargo vessel, which was undergoing a routine dry-dock period as river locks along the route were closed for maintenance. As such, the CCB began its journey in late March on an open-air barge as far as Iuka, Miss., then aboard NASA’s Pegasus vessel down the Mississippi River to the Gulf of Mexico, before rounding the Florida peninsula and making landfall at Cape Canaveral Space Force Station’s wharf on 12 April.
Upon arrival, the CCB was moved to the Atlas Spaceflight Operations Center (ASOC) for pre-launch preparations. And whilst the CCB for last summer’s planned OFT-2 was repurposed and successfully launched NASA’s Lucy mission to explore Jupiter’s Trojan asteroids in October 2021, the Centaur upper stage, integrated interstage and Launch Vehicle Adapter (LVA) and twin AJ-60 solid-fueled boosters were kept in storage at the Cape.
Beginning 20 April, the CCB arrived inside the 30-story-tall Vertical Integration Facility (VIF) at SLC-41 and was hoisted atop the Mobile Launch Platform (MLP). Over the next few days, Aerojet Rocketdyne’s two AJ-60s were mated to the core stage, followed by the Dual-Engine Centaur (DEC). Powered by a pair of RL10A-4-2 engines, the latter would be making its second outing, having previously helped power OFT-1 to orbit.
And on 4 May, the Starliner itself—boasting a brand-new Crew Module and the first lightweight Service Module—was transferred from the Commercial Crew and Cargo Processing Facility (C3PF) at the Kennedy Space Center (KSC) to the VIF. It was mounted atop the stack, topping-off the “Mighty Atlas” at 172 feet (52.4 meters) tall.
At the Flight Readiness Review (FRR) on 11 May, NASA, Boeing and ULA managers applauded a “very clean review” of the spacecraft’s readiness, with a couple of final landing-site readiness and vehicle items remaining to be closed out. “Human spaceflight is hard,” emphasized Kathy Lueders, NASA Associate Administrator of the Human Exploration and Operations Mission Directorate (HEOMD), adding that the intent for OFT-2 was to “make sure we’re buying-down risk before putting crew on the next one”.
And that “next one” will be the Crew Flight Test (CFT), anticipated to fly later this year. Its crew complement has changed considerably since former shuttle commander and Boeing executive Chris Ferguson and NASA astronauts Nicole Mann and Eric Boe were assigned back in August 2018. Boe was removed from the crew the following January, to be replaced by veteran ISS and shuttle flyer Mike Fincke, whilst Ferguson stepped down for personal reasons in late 2020 and Mann was transferred last fall to command the Crew-5 mission aboard a SpaceX Crew Dragon, currently targeted for September.
Replacing Ferguson was seasoned shuttle pilot and ISS commander Barry “Butch” Wilmore, although fellow astronaut Suni Williams—currently assigned to command the first Post-Certification Mission (PCM-1), also identified as Starliner-1—is known to be in the running to lead CFT. Also deep into training on Boeing’s new spacecraft is Matt Dominick, a member of NASA’s 2017 astronaut class, who is presently assigned as backup commander for the Starliner-1 mission.
The duration of CFT remains open to question, with NASA having announced in April 2019 that it would extend the flight beyond its baseline of two weeks. In comments provided at the post-FRR press briefing, Steve Stich noted that teams were “finalizing mission duration” and the precise crew complement for CFT, with an expectation that a decision would be reached later this summer.
It remains to be seen how a long-duration CFT would “fit” within an already well-established seven-person ISS increment plan. Certainly, Wilmore and Fincke undertook training at Russia’s Star City last fall to prepare for a “mid-length” mission of around 60 days, not unlike the two-month ISS stay of Demo-2 crewmen Doug Hurley and Bob Behnken in 2020.
On Wednesday, the Atlas V was rolled out of the VIF and headed 1,800 feet (550 meters) north to the SLC-41 pad surface, a journey which took 58 minutes to complete. Once the stack had been declared “hard-down” on the pad, engineers and technicians commenced fueling the vehicle with 25,000 gallons (113,600 liters) of a highly refined form of rocket-grade kerosene, known as “RP-1”. Countdown operations formally commenced early Thursday morning as the Atlas V systems were powered up and liquid oxygen and hydrogen cryogens were pumped aboard the DEC.
Thursday evening’s liftoff occurred at the “instantaneous” T-0 point at 6:54:47 p.m. EDT, precisely as the ISS flew some 262 miles (422 kilometers) above the North Atlantic, approaching Europe. With the combined thrust of more than 1.5 million pounds (700,000 kilograms) from the Russian-heritage RD-180 engine on the Atlas V and the two AJ-60 boosters, the Mighty Atlas powered smoothly airborne.
The two boosters were jettisoned as planned a couple minutes into ascent, followed by the shutdown of the Atlas V CCB engine at 4.5 minutes after launch. This set up the proper conditions for a seven-minute-long “burn” of the DEC, which permitted the Starliner to be released into space about 15 minutes into the mission.
Altitudes at separation were estimated at an apogee of 112.8 miles (181.5 kilometers) and a perigee of 45.3 miles (72.9 kilometers), inclined 51.62 degrees to the equator. The spacecraft will utilize its own capabilities to raise its orbit to a circular one as it begins its 24-hour pursuit of the ISS.
Aboard the station, tomorrow’s approach and docking will be closely monitored by the Expedition 67 crew. Commanded by Russia’s Oleg Artemyev, the crew also includes fellow cosmonauts Denis Matveev and Sergei Korsakov—who have been on the ISS since mid-March—together with U.S. astronauts Kjell Lindgren, Bob “Farmer” Hines and Jessica Watkins, and Italy’s Samantha Cristoforetti, who arrived late last month.
During Friday’s 3.5-hour approach and docking profile, Lindgren and Hines will send a test command to the Starliner to activate a docking light. The duo will also command the inbound spacecraft to hold position at 820 feet (250 meters) from the station, before it begins its approach and docking. Current plans call for the spacecraft to dock autonomously at the forward-facing port of the Harmony node at 7:10 p.m. EDT Friday, with hatch opening anticipated around 11:45 a.m. EDT Saturday.
Riding uphill aboard Starliner will be an anthropometric test dummy, nicknamed “Rosie the Rocketeer”, who occupies the commander’s seat and is attired in Boeing’s blue launch and entry suit. She will be instrumented with 15 sensors to gather data from the seat pallet which holds all of the spacecraft’s seats in place.
Also aboard will be around 500 pounds (225 kilograms) of equipment, food and other supplies for the Expedition 67 crew, with about the same amount expected to return to Earth at the end of OFT-2. Among the returning cargo will be three spent Nitrogen Oxygen Recharge System (NORS) tanks.
With an estimated mission lasting between five and eight days, Mr. Stich noted that teams had “sized the docked duration to get all the objectives completed”. In remarks delivered to a Tuesday press teleconference after the Launch Readiness Review (LRR), he explained that NASA and Boeing are working towards undocking from the ISS on the evening of 26 May, with touchdown planned at White Sands Space Harbor, N.M.