The seemingly star-cross Boeing Starliner — inside minutes of its long-delayed blastoff on the spacecraft’s first piloted check flight — was grounded once more Saturday when certainly one of three redundant computer systems managing the countdown from the bottom of the launch pad bumped into an issue, triggering a last-minute scrub.
Engineers initially had been instructed to arrange for an additional launch strive Sunday, at 12:03 p.m. EDT, assuming the issue may very well be resolved in time. However NASA later introduced the group would cross up the Sunday alternative to offer engineers extra time to evaluate the pc subject.
The Starliner’s check flight contains rendezvous and docking with the Worldwide House Station. Primarily based on the lab’s orbit and the Starliner’s potential to to catch up, the following two launch alternatives after Sunday are Wednesday, at 10:52 a.m. EDT, and Thursday, at 10:29 a.m. NASA mentioned the company would offer an replace Sunday.
The Starliner’s crew, commander Barry “Butch” Wilmore and co-pilot Sunita Williams, got here inside about two hours of launch on Could 6, solely to be derailed by hassle with a strain aid valve of their Atlas 5 rocket and a helium leak within the capsule’s propulsion module.
These issues had been resolved and after just a few minor snags Saturday, the countdown seemed to be ticking easily towards a deliberate launch at 12:25 p.m. EDT. However 10 seconds after the countdown got here out of a deliberate maintain on the T-minus 4-minute mark, the clocks all of the sudden stopped ticking.
House station launches are timed for the second Earth’s rotation carries the pad into alignment with the house station’s orbit, a requirement when making an attempt to rendezvous with a goal shifting at almost 5 miles per second. An unplanned maintain within the countdown for such missions instantly triggers a minimal 24-hour launch delay.
Tory Bruno, CEO of United Launch Alliance, builder of the Atlas 5 rocket, mentioned the difficulty Saturday concerned certainly one of three networked laptop racks in a constructing on the base of the launch pad. Every rack options a number of methods, together with an identical circuit boards that function collectively as a “floor launch sequencer,” managing the ultimate steps in a countdown.
The GLS computer systems handle occasions just like the retraction of umbilicals and the firing of explosive bolts that free the rocket from the pad for takeoff, and all three should be in good settlement for a countdown to proceed.
Throughout Saturday’s launch try, the countdown ticked right down to T-minus 4 minutes after which entered a deliberate four-hour maintain. When the countdown resumed 4 minutes previous to blastoff, one of many three GLS circuit boards took longer than anticipated to synch up with the opposite two. That was sufficient to set off an automated maintain on the T-minus 3-minute 50-second mark.
Engineers deliberate to start troubleshooting after draining the Atlas 5 of its liquid hydrogen and oxygen propellants and having access to the pc room. A call on how you can proceed relied on isolating the issue, changing and testing any suspect parts.
The launch group, whereas upset, took the newest delay in stride.
“You realize whenever you’re enjoying a sport and also you get a nasty name, you’re a bit of irritated at first, or a bit of pissed off at first, however you instantly concentrate on the following pitch and that’s what our groups do, they’re targeted on the following pitch,” mentioned Mark Nappi, Boeing’s Starliner undertaking supervisor.
“As quickly as we went into the launch scrub and launch turnaround, I regarded out into the management room and everyone had their heads down, working the procedures to prepare for an additional try tomorrow.”
Mentioned Bruno: “The frustration lasts for about three seconds. And then you definitely simply instantly get busy and do your job. We’ll be again.”
At any time when it takes off, the long-awaited flight would be the first piloted launch of an Atlas 5 and the primary for the Atlas household of rockets since astronaut Gordon Cooper took off only a few miles away on the Mercury program’s remaining flight 61 years in the past.
Likewise, it is going to be the primary piloted flight of the Starliner, Boeing’s reply to SpaceX’s Crew Dragon, an already operational, cheaper spacecraft that has carried 50 astronauts, cosmonauts and civilians into orbit in 13 flights, 12 of them to the house station, since an preliminary piloted check flight in Could 2020.
NASA funded improvement of each spacecraft to make sure the company would be capable to launch crews to the outpost even when one firm’s ferry ship was grounded for any purpose.
Already operating years delayed due to finances shortfalls and quite a lot of technical issues that price Boeing some $1.4 billion to appropriate, NASA had hoped to get the Starliner into orbit on Could 6. However the launch was scrubbed when United Launch Alliance engineers detected hassle with a pressure-relief valve within the rocket’s Centaur higher stage.
The Atlas 5 was hauled off the pad and again to ULA’s Vertical Integration Facility the place the Centaur valve was rapidly changed. However within the wake of the launch scrub, Boeing engineers noticed indicators of a small helium leak within the Starliner’s propulsion system.
The leak was traced to a flange in plumbing that delivered pressurized helium to drive one particular response management system jet within the Starliner’s service module. The leak was characterised as “very small,” however engineers wanted to point out it might not drastically worsen in flight and trigger issues for different thrusters.
After intensive evaluation and testing, mission managers concluded the spacecraft may very well be safely launched as is, saying that even when the leak price was 100 occasions worse than to date noticed, it might not pose a danger to the crew or the mission. Because it turned out, the leak price remained inside acceptable limits Saturday.
