Years overdue, Boeing’s Starliner capsule program for crewmembers is poised for a pivotal unmanned test flight to the International Space Station that launches Thursday, a repeat of an abbreviated 2019 demo mission that will cost the aerospace contractor nearly $600 million. has cost.
The Starliner crew pod is scheduled for launch on the Orbital Flight Test 2, or OFT-2 mission, from Cape Canaveral at 6:54 p.m. EDT (2254 GMT) Thursday atop a United Launch Alliance Atlas 5 rocket.
ULA, Boeing and NASA, which oversee the Starliner commercial crew contract, gave the go-ahead on Tuesday to proceed with final preparations for launch. Managers gathered for a launch readiness assessment and gave a “go” to proceed with the mission.
The review “went very well,” said Steve Stich, NASA commercial crew program manager. “It was short. It was very clean. There’s really no problem with ULA, Boeing or NASA working on the launch that’s coming.”
The test flight aims to collect data and prove that Boeing’s Starliner spacecraft is ready to carry astronauts to and from the space station. It’s a repeat of the December 2019 OFT-1 mission, which was aborted due to software issues that caused the Starliner capsule to be burned by propellant shortly after launch.
The Starliner spacecraft, developed in a public-private partnership, will give NASA a second human-rated capsule that can carry astronauts to and from the space station, in addition to SpaceX’s Dragon spacecraft, which will launch with a crew for the first time in May 2020. was launched.
The problems on the 2019 flight prevented the Starliner spacecraft from reaching the space station, and Boeing ordered the capsule to reenter the atmosphere and land in New Mexico two days later.
After rewriting portions of the Starliner software code and going through more extensive testing, Boeing and NASA continued to prepare for the OFT-2 mission — a test flight added to the Starliner schedule at Boeing’s expense.
The spacecraft was rolled to the launch pad at Cape Canaveral last August atop its Atlas 5 rocket. But on the morning of the scheduled launch, tests revealed 13 stuck isolation valves in the Starliner propulsion system.
Boeing and NASA agreed to remove the Starliner from the Atlas 5 rocket and postpone the mission to investigate the valve problem. Boeing says tests showed corrosion in the valves — caused by a chemical reaction between moisture, nitrogen tetroxide propellant and the aluminum housing of the valves — that caused the components to stick to the spacecraft’s service module piping.
For the OFT-2 mission, engineers improved the seals on the valves to prevent moisture ingress, and added nitrogen purges to keep humidity out of the propulsion system. Boeing also swapped out the shaky service module from last summer’s launch attempt with a brand new propulsion section, featuring a new set of valves and thrusters.
The company says it is considering design changes to the oxidizer isolation valves — potentially reducing the amount of aluminum in the valve body — for future Starliner missions, but officials are “confident” in measures introduced to prevent moisture ingress before launch. launch of OFT-2.
Boeing took on a $595 million accounting charge to pay for the delays, rework and the unscheduled OFT-2 mission. NASA’s fixed-price contracts for the Starliner program for commercial crews total about $5 billion, an arrangement where the government and contractor shared the costs of developing the spacecraft.
NASA signed a similar, lower-cost contract with SpaceX in 2014 to develop, test and operate the human-rated Dragon spacecraft. After experiencing its own series of shorter delays, SpaceX launched its first astronaut mission to the space station in 2020.
As Boeing grapples with delays in its Starliner program, SpaceX has completed seven crew missions on its fleet of reusable Dragon capsules — five for NASA and two for private customers.
Boeing’s contract with NASA includes the OFT-1 and OFT-2 unmanned missions, and a Crew Flight Test that could fire with a team of two or three astronauts late this year or early next year, assuming a successful outcome. of the upcoming demo flight. After the test flights are completed, NASA has booked six operational crew rotation battles with Boeing using the Starliner spacecraft.
Mark Nappi, Boeing’s Starliner program manager, said the delays have not shifted the Starliner team’s focus.
“This is very difficult to build and develop and launch this type of vehicle, so they are laser focused on doing this right, and that’s really where their thoughts are,” Nappi said, adding that the program’s Boeing is the ” safest and best possible quality.”
“When we launch, we launch,” Nappi said.
With the launch readiness assessment now complete, ULA’s ground team is preparing to roll out the 172-foot-tall (52.4-meter) Atlas 5 rocket from the 30-story vertical integration facility at 10 a.m. EDT (1400 GMT) Wednesday. Two trackmobile units will carry the Atlas 5 and Starliner spacecraft on rail tracks for the 550-meter journey from the VIF to Path 41 at Cape Canaveral.
Teams have spent the past few weeks stacking the Atlas 5 rocket core stage, two fixed rocket boosters, the Centaur upper stage, and the Starliner capsule into the VIF.
Once on the launch pad, the Atlas 5 and its mobile launch pad connect to automatic couplers to load propellants into the rocket. Kerosene fuel will be pumped into the first leg Wednesday afternoon and will be primed for the start of the launch countdown at 7:34 a.m. EDT (1134 GMT) Thursday.
The launch team will load cryogenic propellants into the Atlas 5 early Thursday afternoon, followed by an extended clearance. On future missions with astronauts, during the four-hour intermission in the countdown aboard the Starliner spacecraft, crew members will pass through the capsule’s hatch.
The Starliner spacecraft launched Thursday on Boeing’s OFT-2 mission will not have an astronaut crew on board. An instrumented dummy called “Rosie the Riveter” from World War II sits in the commander’s seat on the spacecraft.
The Starliner will also carry more than 500 pounds (227 kilograms) of food and other supplies for the seven-member crew on the space station, according to NASA. At the end of the mission, the spacecraft must return to Earth with more than 600 pounds (272 kilograms) of payload.
There is a 70% chance of favorable weather for the Atlas 5 rocket launch with the Starliner spacecraft Thursday. The main weather concerns are related to thunderstorms that could develop west of Cape Canaveral. Anvil clouds at the top of the storm cells could blow back toward the launch site, creating a lightning strike that could be caused by the rocket as it climbs through the atmosphere.
On Friday, the backup launch opportunity, there is a 40% chance of good weather for the launch, with a higher chance of thunderstorms in the area of the launch pad.
The Starliner team will also assess wind and sea conditions along the Atlas 5 flight corridor northeast of Cape Canaveral. The capsule could crash into the Atlantic Ocean along the offshore flight path if an emergency aborts launch, with the Starliner’s breakout engines propelling the ship away from the Atlas 5 rocket.
The capsule launch abort system will be active for the first time on the OFT-2 mission. It operated in a “shadow” mode at the launch of OFT-1 in 2019, collecting data for post-flight analysis by engineers.
For a Starliner mission with astronauts on board, weather conditions before abort would play a role in the decision of whether or not to go through for a launch. On this unmanned test flight, teams will monitor conditions but will not hold back the launch if it were out of limits.
If the OFT-2 mission does not launch on Thursday, the next opportunity to launch will be Friday at 6:31 PM EDT (2231 GMT). Launch times are determined by when Earth’s rotation brings the launch pad at Cape Canaveral below the space station’s flight path.
Upon launch, the Atlas 5’s two strap-on boosters and its Russian-made nuclear engine will generate 1.6 million pounds of thrust to launch the Starliner spacecraft into space. Once their roles are complete, the boosters and core stage will be jettisoned to fall into the Atlantic Ocean, leaving two hydrogen-powered RL10 engines on the Centaur’s upper stage to propel the Starliner spacecraft on an arc-shaped structure. trajectory that is just too low for the speed required to enter a barn. orbit around the earth.
The Atlas 5 is programmed to fly a flatter, less steep trajectory than typical satellite delivery missions, giving the Starliner crew pod more chances to escape safely from the missile in the event of a malfunction.
Once clear of the Centaur’s upper stage, the four maneuvers aboard the Starliner will finish the work of putting the spacecraft into orbit with a burn wound approximately 31 minutes after takeoff. That combustion is the first of multiple engine firings to direct the Starliner spacecraft to an automated docking station near the space station’s Harmony module.
The orbital coupling is scheduled for Friday at 7:10 p.m. EDT (2310 GMT), assuming the OFT-2 mission departs Thursday.
The astronauts on the space station will open hatches and enter the Starliner spacecraft on Saturday, remove the payload in the pressurized crew cabin and conduct communications checks in the cockpit.
If all goes according to plan, and assuming good weather at the landing zone, the Starliner would detach from the space station on May 25 and head for reentry, targeting a parachute-assisted landing with airbags at White Sands Space Harbor in New York. Mexico.
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