SpaceX Starship holds up under pressure, lines up Raptor engine test fire
SN9+SN10
After a few false starts and some minor delays, SpaceX’s 11th Starship prototype (SN11) has made it through two of the three major tests standing between it and liftoff.
SpaceX rolled Starship SN11 from the factory to the launch pad on March 8th, just five days after Starship SN10 briefly became the first prototype of its kind to land in one piece. One or two issues with Raptor’s final landing burn caused SN10 to touch down faster than expected and eventually led to the rocket’s explosive demise around 15 minutes later. Still, the test flight was an almost unequivocal success and seemingly left SpaceX with more than enough confidence to speed through preparations for the next flight test.
Heading into the next day, SpaceX had hoped to kick off cryogenic proof testing but Starship SN11 required a bit more attention than expected and unknown bugs ultimately meant that only an ambient-temperature pressure test could be completed by the end of the test window. Those issues appeared to persist through the end of March 10th, preventing any kind of proof test attempt.
On March 11th, Starship SN11 was able to take its first real stab at a cryo proof and was loaded with liquid nitrogen (LN2), a cryogenic fluid with a density and temperature similar to Starship’s liquid oxygen and methane propellant but without the risk of a catastrophic fire or explosion. Over the course of three or so hours, SpaceX didn’t appear to fully load SN11 with LN2, a possible sign of a technical bug that could just as easily be an intentional part of the test design.
Oddly, parts of the evenings testing were unlike past cryo proofs and there’s a slight chance that the activity was actually a static fire attempt scrubbed well before ignition, though it’s impossible to say without official confirmation.
Otherwise, the most notable part of the cryo proof was a test of Starship SN11’s attitude control system (ACS) that involved firing each of the ship’s several cold-gas nitrogen thrusters at least 5-10 times for a total of several dozen bursts. The current generation of Starships mainly use those thrusters to augment their flaps and perform flip maneuvers during suborbital launch and landing attempts, while early orbital-class prototypes may use the same thruster system to control their attitude in the vacuum of space.
If last night’s cryo proof test was successful and gave SpaceX the data it needs to give SN11 a good bill of health, the Starship could potentially attempt its first Raptor engine static fire as early Friday, March 12th. Historically, SpaceX has never static fired a Starship prototype less than 12 days after its launch site arrival, meaning that a static fire tomorrow would smash the previous record by a factor of three. As such, it’s more likely that SN11 will need a day or two and be ready for a static fire attempt as early as Monday, March 15th.
Either way, Starship SN11 is undeniably on a faster track than any of its three-engine predecessors and a clean static fire on Friday or Monday would leave a launch next week – SpaceX’s current target– well within reach.
Quelle: TESLARATI
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Update: 28.03.2021
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SpaceX delays Starship test flight
SpaceX’s Starship SN11 test rocket at Boca Chica, Texas. Credit: SpaceX
SpaceX scrubbed the launch of its next Starship test rocket Friday afternoon, with the next opportunity for the atmospheric test flight expected Monday. SpaceX plans to launch and land the rocket at company’s South Texas development complex after losing three previous prototypes in explosions.
The privately-developed Starship test vehicle — designated SN11 — will be the fourth full-size Starship vehicle to take off from SpaceX’s test site in Cameron County, Texas. Like three previous Starship test flights in December, February, and earlier this month, the prototype will attempt to fly to an altitude of about 33,000 feet, or 10,000 meters, before returning to the ground for rocket-assisted vertical landing.
SN11 is the latest in a series of prototypes for SpaceX’s next-generation launch vehicle that will eventually stand nearly 400 feet, or about 120 meters, tall and carry more 220,000 pounds, or 100 metric tons, of cargo to low Earth orbit. That’s more lift capacity than than any rocket in the world.
With life support systems and in-space refueling, the Starship could carry heavy cargo and people beyond Earth orbit. SpaceX is of of three industrial teams with a NASA contract to design and refine concepts for a human-rated lunar lander for the space agency’s Artemis moon program.
The Starship program is intended to eventually ferry passengers and supplies to deep space destinations to Mars, according to Elon Musk, SpaceX’s founder and CEO.
The Starship vehicle will comprise the upper segment of the huge orbital rocket, which SpaceX also calls the Starship. The first stage booster is named the Super Heavy. Both vehicles are designed to be fully reusable.
SpaceX confirmed plans for the Starship SN11 test flight Friday on its website, but Musk tweeted Friday afternoon that the company was “standing down” from the launch “until probably Monday.”
“Additional checkouts are needed. Doing our best to land & fully recover,” Musk tweeted.
The company says it plans to provide a live video stream of the Starship launch and landing.
SpaceX test-fired the Starship rocket on its launch mount Friday morning, clearing the way for final launch preparations before managers eventually called off the test flight.
The 164-foot-tall (50-meter) Starship SN11 vehicle will be powered at liftoff by three methane-fueled Raptor engines producing more than a million pounds of thrust at full power.
After climbing away from the launch pad, the Starship will shut down its three Raptor engines in sequence before the rocket reaches the apex of its trajectory.
“SN11 will perform a propellant transition to the internal header tanks, which hold landing propellant, before reorienting itself for reentry and a controlled aerodynamic descent,” SpaceX wrote on its website.
“The Starship prototype will descend under active aerodynamic control, accomplished by independent movement of two forward and two aft flaps on the vehicle,” SpaceX wrote. “All four flaps are actuated by an onboard flight computer to control Starship’s attitude during flight and enable precise landing at the intended location.
“SN11’s Raptor engines will then reignite as the vehicle attempts a landing flip maneuver immediately before touching down on the landing pad adjacent to the launch mount.”
The entire flight is expected to last between six and seven minutes. This time, SpaceX hopes the Starship vehicle survives intact.
A hard landing on an otherwise-successful Dec. 9 Starship test flight was caused by low pressure from header tanks feeding the vehicle’s Raptor engines for the critical burn just before touchdown, and one of the Raptor engines failed to reignite for the landing burn on a test flight Feb. 2.
The SN10 rocket achieved the first soft landing of a full-size Starship vehicle at the end of a March 3 test flight, but the rocket exploded minutes later
Despite the explosion, the Starship SN10 test flight appeared to be a major achievement for SpaceX’s Starship test flight program. SpaceX aims to build on that experience with the SN11 flight.
The first Super Heavy booster has been stacked inside a high bay at SpaceX’s complex at Boca Chica, Texas. Credit: Elon Musk
The early focus of SpaceX’s Starship program has been on building infrastructure at the Boca Chica test site, located on the Texas Gulf Coast near the U.S.-Mexico border. Earlier this month, SpaceX completed stacking of the first Super Heavy booster, which Musk said is a “production pathfinder.”
SpaceX assembled the first Super Heavy test article, named BN1, to help learn how to build and transport the 229-foot-tall (70-meter) first stage, which itself is as tall as a Falcon 9 rocket used by SpaceX for operational satellite launches.
The second Super Heavy booster, which is being fabricated but is not yet assembled, is designed to fly, presumably on a suborbital test launch, according to Musk.
SpaceX aims to launch the first fully-stacked Super Heavy and Starship in on an orbital launch attempt from South Texas in July. “That’s our goal,” Musk tweeted.
An orbital launch attempt by July is an aggressive goal, like many schedules outlined by SpaceX’s hard-charging founder and chief executive.
The orbital version of the Starship vehicle will have six Raptor engines, including three engines with enlarged bell-shaped nozzles optimized for higher efficiency in the vacuum of space. The orbital-class Starship will also have a heat shield to survive re-entry back into the atmosphere.
During an orbital launch attempt, the reusable Super Heavy will detach from the Starship — which acts as both an upper stage and in-space transporter — and come back to Earth for a vertical landing. The Starship will continue into orbit and deploy its payloads or travel to its deep space destination, and finally return to Earth to be flown again.
SpaceX’s long-term plans for Starship operations involve the use of a floating launch pad parked in the ocean. SpaceX is converting a decommissioned offshore drilling platform for its future Super Heavy and Starship launch facility.
The Super Heavy booster will be powered by 28 Raptor engines, producing some 16 million pounds of thrust, more than twice the power output of five booster engines on NASA’s Apollo-era Saturn 5 moon rocket.
The entire Super Heavy and Starship stack will measure around 30 feet (9 meters) wide, about one-and-a-half times the diameter of a Boeing 747 jumbo jet.
Quelle: SN
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Update: 29.03.2021
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SpaceX’s fourth high-altitude Starship launch rescheduled on Monday
CEO Elon Musk says that SpaceX has delayed Starship serial number 11’s (SN11) high-altitude launch debut from Friday to Monday to best ensure that the company can “land & fully recover” the 50-meter-tall steel rocket.
First and foremost, the weekend will allow SpaceX times time for “additional checkouts” and scour Starship SN11 and the data it’s produced during testing for any red flags or minor issues. While plans for a same-day static fire and launch didn’t pan out on Friday, March 26th, SpaceX did manage the first half, firing up just one of Starship’s three Raptors to verify the health of the replacement engine after a Thursday Raptor swap. The test marked the first time SpaceX has intentionally fired up just one of the Raptors installed on a three-engine Starship prototype, so the delay will provide extra time to ensure that all three are still looking good.
Standing down SN11 until probably Monday. Additional checkouts are needed. Doing our best to land & fully recover.
The weather in Boca Chica, Texas has also taken a turn for the worse in the last few days, so the extra few days will also (hopefully) allow time for wind, visibility, and precipitation conditions to improve. According to Musk, Starship SN11 is now scheduled to fly as early as Monday “afternoon” and, as usual, SpaceX will offer live coverage of the fourth high-altitude launch and landing attempt beginning a few minutes before liftoff.
With a little luck, the Starship prototype will be able to continue a trend of iterative improvement and one-up Starship SN10 with a slightly softer landing and no explosion minutes after touchdown. Stay tuned for updates both here and on SpaceX’s social media platforms to catch the official webcast.
Quelle: TESLARATI
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Update: 30.03.2021
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Testflug von SN11 Starship
Quelle: SpaceX
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Congress raises concerns about FAA’s handling of Starship launch license violation
As SpaceX prepares for its next Starship test flight, two key members of Congress expressed their concerns with how the FAA handled its investigation into the company's violation of its launch license on a previous test. Credit: Maxar
WASHINGTON — As SpaceX gears up for another test flight of a Starship prototype, the Federal Aviation Administration is facing new scrutiny from Congress for how it handled SpaceX’s violation of its launch license on an earlier test flight.
SpaceX had planned to launch its SN11 Starship vehicle March 29 from its Boca Chica, Texas, test site. That flight will be similar to those of previous Starship prototypes, going to an altitude of 10 kilometers before landing on a nearby pad.
However, SpaceX called off the March 29 launch attempt because an FAA inspector could not arrive to observe the flight during a five-hour window. “FAA inspector unable to reach Starbase in time for launch today,” tweeted Elon Musk, chief executive of SpaceX, using the proposed new name for the Boca Chica site. “Postponed to no earlier than tomorrow.”
The requirement for an FAA presence on site at the test site is new for the SN11 launch. The latest version of SpaceX’s FAA launch license for the Starship suborbital test flight program, issued March 12, allows those test flights to take place “only when an FAA Safety Inspector is present at SpaceX’s Boca Chica launch and landing site.”
The change stemmed from an investigation into SpaceX’s violation of that launch license during the SN8 test flight in December. SpaceX proceeded with the flight despite the FAA determining that the flight profile exceeded the maximum allowed risk to the uninvolved public for “far field blast overpressure” in the event of an explosion. While the SN8 vehicle exploded upon landing, there were no reports of damage outside of the SpaceX test site.
FAA directed SpaceX to investigate the incident, delaying the flight of the next Starship prototype, SN9. That investigation included “a comprehensive review of the company’s safety culture, operational decision-making and process discipline,” the FAA said in a Feb. 2 statement.
The FAA cleared SpaceX to proceed with launches, with SN9 and SN10 launching and landing — and both exploding upon or shortly after landing — on Feb. 2 and March 3, respectively. Neither caused any damage outside of the SpaceX test site.
The FAA’s response to SpaceX’s launch license violation, including the lack of any penalties beyond the investigation, prompted criticism from two key members of Congress. In a March 25 letter to FAA Administrator Steve Dickson, Reps. Peter DeFazio (D-Ore.) and Rick Larsen (D-Wash.) sought to “register our concerns” with the incident. DeFazio is chair of the House Transportation Committee and Larsen the chair of its aviation subcommittee.
“Given the high-risk nature of the industry, we are disappointed that the FAA declined to conduct an independent review of the event and, to the best of our knowledge, has not pursued any form of enforcement action,” they wrote after summarizing the incident and investigation.
In the letter, DeFazio and Larsen called on the FAA to “resist any potential undue influence on launch safety decision-making” by taking “all the time and actions necessary” to evaluate proposed launches. They also urged the FAA to implement “a strict policy to deal with violations of FAA launch and reentry licenses” that includes civil penalties, and to evaluate its current approach to safety oversight and enforcement for commercial space activities.
“While the commercial space transportation sector is crucial to our Nation’s future, at no point should a commercial space launch jeopardize public safety,” they wrote.
The FAA, asked March 29 about the letter, said only that the agency “is in receipt of the letter and will respond directly to the committee.”
While the House Transportation Committee’s oversight includes the FAA, traditionally that has excluded the FAA’s Office of Commercial Space Transportation, which is in the jurisdiction of the House Science Committee. The transportation committee, though, has shown a growing interest in commercial space transportation, including several hearings in recent years that have examined the industry, including how the growing number of launches and spaceports affects commercial aviation.
In a speech at the March 23 meeting of the FAA’s Commercial Space Transportation Advisory Committee (COMSTAC), Dickson indirectly referred to the SN8 incident. “We can’t take all the dangers out of commercial space transportation, but I also know that we have to make it as safe as humanly possible,” he said. “Sometimes, that means we have to set the parking brake and make sure that we’re all aligned.”
Dickson said there have been six commercial launch mishaps since the beginning of the 2021 fiscal year. That includes the three Starship test flights that ended in explosion upon or shortly after landing, as well as a failed Falcon 9 landing at sea during an otherwise successful launch Feb. 15. The other two are the launch of Astra’s Rocket 3.2 in December that just missed reaching orbit and an aborted test flight of Virgin Galactic’s SpaceShipTwo suborbital spaceplane, also in December.
“When mishaps do happen, which is not uncommon in a fast-moving new field, they should be successful failures, meaning that the failure was consistent with, in this case, the FAA’s analysis that showed that the public would be kept safe,” Dickson said.
“So far, there have been six mishaps this fiscal year, some that ended in spectacular fireballs and went viral on social media,” he said, “but all six of these were successful failures, because we were able to protect public safety.”
