Starship flight test 2

After the first test flight in April 2023, which ended in the destruction of the entire Starship vehicle, The FAA closed the investigation on September 8, 2023. The FWS fully concluded its environmental review on November 14, and the FAA gave its full approval for launch shortly after. The agency grounded Starship flights during the investigation, also a standard practice, and said that "a return to flight of the Starship/Super Heavy vehicle is based on the FAA determining that any system, process or procedure related to the mishap does not affect public safety" and that there were no reports of injuries or public property damage. The FAA also announced that it would monitor the cleanup, which included the standard removal of launch debris from "sensitive habitats". On May 15, SpaceX filed a request for FCC approval for a second flight between June 15 and December 15, using Booster 9 and Ship 25. In August, SpaceX submitted an initial mishap report to the FAA for review and approval. The FAA stated in September 2023 And that SpaceX first had to "implement all corrective actions that impact public safety" and applied for a "license modification from the FAA" that addresses the FAA's "safety and other environmental regulatory requirements". Prior to Starship's second flight, SpaceX's vice president and ex-NASA engineer Bill Gerstenmaier made statements at the U.S. Senate on the importance of innovation in light of "strategic competition from state actors like China". He said SpaceX was under a contract with NASA to use Starship to land American astronauts on the moon before China does, FWS review By September 2023, the Fish and Wildlife Service (FWS) had not yet started a formal review of SpaceX's modifications, and based on the 135 day review period, the launch could have been postponed to NET 2024. The Federal Aviation Administration received the final biological assessment from the FWS. William H. Gerstenmaier, SpaceX's Vice President of Build and Flight Reliability, called on the FAA to increase licensing staff. On October 19, 2023, the FWS surveyed the area around Starbase and the consultation with the FAA has been extended into November. The FWS reviewed the changes to the launch pad, especially the water deluge system. By October 31, 2023, the FAA had concluded the safety review portion of the launch license. Changes from the previous flight After the first test flight in April 2023 ended in the destruction of the Starship vehicle, significant work was done on the launch mount to repair the damage it sustained during the test and to prevent future issues. Ship 25 was rolled to the suborbital launch site in May 2023 and underwent spin prime and static fire testing ahead of flight. Once that was completed, Booster 9 was rolled to the launch site to undergo cryogenic proof testing, spin primes and static fires of its set of engines. By November 15, 2023, Ship 25 was stacked onto B9 for launch. On November 14, 2023, the United States Fish and Wildlife Service (FWS) concluded its environmental review. SpaceX re-qualified their autonomous flight safety system, Other changes unrelated to the previous flights include a hot stage separation system in which Starship's second-stage engines ignite while Starship is still attached to the booster, pushing the two apart. SpaceX replaced the hydraulic systems of Super Heavy Raptor engines with thrust vector control driven by electric motors, citing fewer potential points of failure and more energy efficiency. The orbital launch mount and pad system was reinforced in a way that, according to SpaceX, should prevent a recurrence of the pad foundation failure observed during the first flight test. SpaceX also added, and tested, a flame deflector for the launchpad. == Flight profile ==

The spacecraft flight plan was to lift off from SpaceX's Starbase facility along the south Texas coast, then conduct a partial orbit around Earth. The Super Heavy had a planned boostback burn followed by a soft water landing in the Gulf of Mexico, similarly to a Falcon 9 performing a return to launch site landing (RTLS). The Starship spacecraft was then to re-enter the atmosphere and perform a water landing in the Pacific Ocean near Hawaii, without performing a landing burn. Flight timeline == Launch analysis ==

On November 11, 2023, SpaceX announced that they were targeting a launch date of November 17, pending regulatory approval. On November 14, the FWS concluded its environmental review, and the FAA gave its approval for launch. The first launch attempt of the second integrated flight test occurred on November 18 at 13:02 UTC (7:02 a.m. CST). The rocket encountered maximum aerodynamic stress (Max q) with no anomalies reported. All Starship's six second stage Raptor engines powered the vehicle to an altitude of 148 km, above common boundaries of space, and a velocity of ~24,000 km/h, becoming the first Starship to reach outer space and nearly completing its full-duration burn. Near the end of Starship's second stage burn, after over eight minutes of flight and prior to engine cutoff, telemetry was lost. In January 2024, SpaceX said that because Starship carried no payload, they planned to vent excess liquid oxygen from the second stage near the end of the burn. The venting of that oxygen led to a fire and explosion. Upon the FAA's closure of the investigation on February 26, SpaceX elaborated on the cause of the accident thusly: At vehicle separation, Starship’s upper stage lit all six Raptor engines and flew a normal ascent until approximately seven minutes into the flight, when a planned vent of excess liquid oxygen propellant began. Additional propellant had been loaded on the spacecraft as a payload simulant and needed to be disposed of prior to reentry to meet required propellant mass targets at splashdown. A leak in the aft section of the spacecraft that developed when the liquid oxygen vent was initiated resulted in a combustion event and subsequent fires that led to a loss of communication between the spacecraft’s flight computers. This resulted in a commanded shutdown of all six engines prior to completion of the ascent burn, followed by the Autonomous Flight Safety System detecting a mission rule violation and performing flight termination, leading to vehicle breakup at an altitude of ~150 km and a velocity of ~24,000 km/h, becoming the first Starship to reach outer space. On the booster's fate, SpaceX stated that the most likely root cause was filter blockages where liquid oxygen is supplied to the engines, leading to a loss of inlet pressure in the engines' oxidizer turbopumps that eventually resulted in one engine failing in such a manner that it resulted in the loss of the vehicle. This led SpaceX to implement hardware changes inside the booster oxidizer tanks related to propellant filtration and reliability. == Aftermath ==

SpaceX and Cameron County reopened the road to the launch site a few hours after the launch. This was noted by CNN as a faster reopening than during the first flight attempt, when it remained closed for two days. NASA administrator Bill Nelson congratulated the teams involved in the test flight, and retired Canadian astronaut Chris Hadfield called it a "very successful 2nd test flight" in a post on Twitter. SpaceX considered the mission a success. According to SpaceX, the water-cooled flame deflector and other pad upgrades performed as expected, requiring minimal post-launch work to be ready for upcoming vehicle tests and the next integrated flight test. In December 2023 the Federal Communications Commission issued final denial of an $885 million Starlink subsidy because all attempted Starship launches "have failed". At the time of the [Commission's Wireline Competition] Bureau's decision, Starship had not yet been launched. Indeed, even as of today [i.e. over a year later], Starship has not yet had a successful launch; all of its attempted launches have failed. Based on Starlink’s previous assertions about its plans to launch its second-generation satellites via Starship, and the information that was available at the time, the [Wireline Competition] Bureau necessarily considered Starlink’s continuing inability to successfully launch the Starship rocket when making predictive judgment about its ability to meet its RDOF obligations. 17 significant changes were made to the Starship vehicle, including upgrading the ship to an electric thrust-vector control system and delaying the ship LOX dump to after SECO. SpaceX said the water-cooled flame deflector and other pad upgrades made after Starship’s first flight test had performed as expected, requiring "minimal post-launch work to be ready for vehicle tests and the next integrated flight test". Following the flight test, SpaceX said it had led the investigation efforts with oversight from the FAA and participation from NASA, and the National Transportation Safety Board. ==References==