CFT Launch Scrubbed, Teams Recycle for “Possible” Next Attempt Tomorrow

Close-up view of Boeing’s CST-100 Starliner spacecraft, atop the Atlas V. Photo Credit: Jeff Seibert/AmericaSpace

Crew Flight Test (CFT) Commander Barry “Butch” Wilmore and Pilot Suni Williams must wait a little longer for the first human-carrying voyage of Boeing’s CST-100 Starliner spacecraft to the International Space Station (ISS), following a scrub less than four minutes before launch on Saturday. Teams have Eastern Range support for a “possible” next attempt at 12:03 p.m. EDT on Sunday, after which personnel will stand down before ramping up for another back-to-back pair of launch tries on Wednesday and Thursday of next week.

The Blue Team arrives at the base of SLC-41 in the minutes after the scrubbed launch attempt. Photo Credit: NASA

Today’s agonizing launch delay comes almost a month since the first attempt to get CFT off the ground back on 6 May, when teams elected to stand down for what was hoped to be about a week to attend to a faulty oxygen relief valve on the Atlas V’s second stage. That valve was promptly replaced and tested, with early hopes to fly as soon as 17 May, but in the meantime a small helium leak was detected in Starliner’s service module.

Traced to a flange on a single reaction control system thruster, the issue caused the launch to move again to No Earlier Than (NET) 21 May, then no sooner than the 25th and eventually to the opening day of June, with a targeted T-0 point at 12:25:40 p.m. EDT. Last week, Wilmore and Williams flew from NASA’s Johnson Space Center (JSC) in Houston, Texas, to the Space Coast and on Thursday the 172-foot-tall (52.4-meter) Atlas V with Starliner perched at its tip was rolled the quarter-mile (400-meter) distance from the 30-story Vertical Integration Facility (VIF) to the SLC-41 pad surface.

The Blue Team begin work to open Starliner’s hatch after Saturday’s launch scrub. Photo Credit: NASA

Weather conditions for Saturday’s inaugural launch attempt and Sunday’s backup opportunity pledged 90-percent favorability, tempered by a slight risk of violating the Cumulus Cloud Rule and the Ground Winds Rule. “A large area of high pressure, currently centered over the Ohio Valley region, should dominate Central Florida’s weather,” noted the 45th Weather Squadron at Patrick Space Force Base in a Friday update.

“For the primary launch window, that high is expected to be near the North Carolina coast, bringing breezy, easterly winds and dry, stable air to the Spaceport,” it continued. “Weather is expected to be favorable, with winds and the Cumulus Cloud Rule being the primary concerns.” Sunday was predicted to be broadly similar, with a slight decrease in wind speeds and a marginal increase in cloud cover.

The Atlas V for CFT is configured in its rarely used “N22” configuration, with a Dual-Engine Centaur (DEC) upper stage and a pair of Aerojet Rocketdyne-furnished AJ-60 solid-fueled boosters. Photo Credit: Jeff Seibert/AmericaSpace

Saturday’s action got underway at 1:05:40 a.m. EDT, exactly 11 hours prior to T-0, when the CFT countdown clock started ticking at T-6 hours and 20 minutes and engineers began powering-up the 172-foot-tall (52.4-meter) Atlas V. This particular incarnation of the vehicle—nicknamed “The Bodyguard” in honor of its crew-carrying credentials—is formally designated “N22” and consists of the Atlas V Common Core Booster (CCB), a pair of AJ-60 solid-fueled boosters provided by Aerojet Rocketdyne, the Dual-Engine Centaur (DEC) upper stage, the Launch Vehicle Adapter (LVA) and Starliner.

The N22 has been used twice previously, for Starliner’s uncrewed Orbital Flight Tests (OFTs) in December 2019 and May 2022. Notably, the Mighty Atlas previously flew humans four times—lofting Project Mercury astronauts John Glenn, Scott Carpenter, Wally Schirra and Gordon Cooper atop Atlas-D boosters for their missions between February 1962 and May 1963—and CFT marks the first occasion a member of this decades-old family of rockets has carried people in over 61 years.

Spectacular views of December 2019’s launch of an Atlas V with Starliner’s first uncrewed Orbital Flight Test (OFT-1). Photo Credit: Mike Killian/

Today’s lengthy countdown included a pair of pre-planned, built-in holds. The first, lasting an hour, began at 5:25 a.m. EDT, at T-2 hours, and enabled a shift-change to take place in the Launch Control Center (LCC) as the Preps Launch Team handed over their console responsibilities to the Tanking and Launch Team, led by ULA Chief Launch Conductor Doug Lebo.

With 25,000 gallons (94,000 liters) of “storable” RP-1 kerosene having been loaded into the Atlas V CCB tanks prior to the 6 May launch attempt, efforts moved into high gear to fuel the booster and Centaur with cryogenic liquid oxygen and hydrogen. All told, the DEC was fueled with 4,150 gallons (18,870 liters) of super-cooled liquid oxygen and 12,300 gallons (46,560 liters) of liquid hydrogen and the CCB was loaded with 48,800 gallons (184,730 liters) of liquid oxygen.

An Atlas V N22 lifts the uncrewed OFT-2 Staliner mission to space in May 2022. Photo Credit: Jeff Seibert/AmericaSpace

With the conclusion of tanking, and with the Atlas V in a “quiescent state”, the countdown entered its second built-in hold of four hours. During this timeframe, Wilmore and Williams were handed over to the Boeing team in the Neil Armstrong Operations & Checkout (O&C) Building where they were given a weather briefing and shortly after 8 a.m. EDT were assisted into their customized “Boeing Blue” launch and entry suits by Boeing engineers and David Clark suit technicians.

Meanwhile, at the pad the ULA/Boeing “Blue Team” verified no toxic vapors in the SLC-41 White Room and set to work opening Starliner’s hatch and readying the interior for Wilmore and Williams. The astronauts departed the O&C Building shortly after 9 a.m. EDT and rode Boeing’s Crew Transport Vehicle (CTV) to the pad. Once there about 20 minutes later, they took the elevator to Level 12 on the Crew Access Tower (CAT) to begin boarding the spacecraft via the Crew Access Arm (CAA).

OFT-2 takes flight on 19 May 2022. Photo Credit: Jeff Seibert/AmericaSpace

Wilmore was in position in the left-side commander’s seat shortly before 8:30 a.m. EDT, with Williams—the first woman ever to fly on the maiden voyage of a new, orbital-class spacecraft—assuming her place in the right-side pilot’s seat a few minutes later. The pair completed suit pressurization and leak checks and established communications links with ground controllers.

“The weather looks good,” tweeted ULA CEO Tory Bruno. “Atlas is standing tall, strong and proud. The Sun rises above all. Feels like a good day to go to space.”

Flanked by fellow NASA astronauts Mike Fincke and Jessica Wittner, CFT Commander Barry “Butch” Wilmore addresses well-wishes at the Kennedy Space Center (KSC) on 25 April. Photo Credit: Jeff Seibert/AmericaSpace

However, in a worrisome indicator of the last-minute scrub which impacted their first launch attempt, a problem associated with the topping-off of the DEC tanks arose just after 10 a.m. EDT. “Working an issue with topping valves on the ground side,” tweeted Mr. Bruno, adding that a necessary “fix” to switch to redundant circuitry was being run through ULA’s software integration lab before moving ahead.

The transition to redundant circuitry allowed DEC topping to resume and shortly after 11 a.m. EDT the Blue Team closed and sealed Starliner’s hatch and began the process of retracting the access boarding, deflating the environmental seal and retreating to their fallback positions. “A check of the local weather shows no rules are being violated,” noted ULA. “Conditions are green across the board.”

CFT Pilot Suni Williams will be making her third spaceflight. Photo Credit: Jeff Seibert/AmericaSpace

With only a single moment in time—precisely 12:25:40 p.m. EDT—to launch, Wilmore and Williams closed their visors shortly after noon and LCC teams were instructed to maintain radio silence as the countdown moved through its final minutes. The CAA was hydraulically retracted to its stowed position and Starliner itself was placed on internal power. From his console, Mr. Lebo proceeded smartly through a Go/No-Go polls of all personnel, ending with the crew.

“Starliner is go,” came the clipped reply from Wilmore.

Starliner is one of two Commercial Crew vehicles being prepared for regular International Space Station (ISS) crew rotations. Photo Credit: NASA

The retired U.S. Navy captain, who previously flew as a shuttle pilot and ISS commander, then added: “This is a great day to be proud of your nation. We are ready to put some fire into this rocket!”

Sadly, Wilmore’s earnest words proved premature, for an ominous “Hold! Hold! Hold” call came from the Ground Launch Sequencer (GLS) at T-3 minutes and 50 seconds. Clocks were recycled to T-4 minutes and teams entered a scrub timeline, preparatory to extraction of the astronauts from Starliner’s cabin.

Commander Barry “Butch” Wilmore and Pilot Suni Williams are pictured during pre-mission training. Photo Credit: NASA/Robert Markowitz

In the minutes after the scrub, ULA Launch Director Tom Heter III instructed teams to prepare for a “possible” next launch attempt at 12:03 p.m. EDT Sunday. Following liftoff, Wilmore and Williams will spend about 25 hours in transit to the ISS, where they will spend at least eight “docked” days conducting a range of flight test objectives alongside the space station’s incumbent Expedition 71 crew—Commander Oleg Kononenko, fellow Russian cosmonauts Nikolai Chub and Aleksandr Grebenkin and NASA astronauts Matt Dominick, Mike Barratt, Jeanette Epps and Tracy Dyson—before returning to a parachute-and-airbag-aided landing in the southwestern United States.

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