SpaceX Starship Test Flights: A Comparative Analysis

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SpaceX's ambitious Starship project aims to revolutionize space travel, with the ultimate goal of enabling human exploration and settlement of Mars. The Starship spacecraft, when paired with the Super Heavy rocket, is designed to be a fully reusable transportation system for missions to Earth orbit, the Moon, Mars, and beyond. Let’s dive into a detailed comparison of the three Starship test flights that have marked significant milestones in the project's development so far.

Integrated Flight Test 1 (IFT-1)

SpaceX conducted the first integrated flight test of the Starship launch vehicle on April 20, 2023. The vehicle was destroyed less than four minutes after liftoff in Boca Chica, Texas. The flight set a record for the most powerful rocket ever flown, surpassing the Soviet Union's N1 rocket.

Launch Details

-Several prototypes were tested before the first integrated flight, with SpaceX focusing on iterative development. SpaceX obtained necessary Government clearances and secured launch licenses after environmental reviews.

- SpaceX scrubbed the first test launch of the giant Starship rocket due to a fueling issue.
- SpaceX's Starship test flight was delayed until Thursday after a valve problem requiring a rescheduled wet dress rehearsal.
- The second attempt on April 20, 2023 consisting of the Starship S24 and Super Heavy B7, launched from SpaceX's Starbase in Boca Chica, Texas.
- Seventy-eight seconds into the launch, the rocket lost thrust vector control of its central engines, causing it to lose altitude and enter a spin preventing stage separation.

-The mission lasted approximately 3 minutes and 57 seconds.
-The autonomous flight termination system (AFTS) was activated, but the vehicle disintegrated 40 seconds later, nearly 4 minutes into the flight.

-Starship reached a maximum altitude of about 39 kilometers (24 miles).

Conclusion

- The launch was seen as a significant step in Starship's developmental progress, receiving congratulatory messages from various public officials and figures.
- Elon Musk pointed out that the requalification of the flight termination system would be the main delay for the next launch.
- The launch pad was built without flame diverters, water deluge systems, or sound suppression systems, resulting in comprehensive damage to the concrete and surrounding infrastructure.
- SpaceX planned to rebuild the launch pad with water-cooled steel plates after the launch.
- Residents and researchers were concerned about the impact on local communities’ health and wildlife, reporting various issues such as particulate matter falling from the sky and wildlife damage.
- A wildfire started and burned state parkland to the south of the launch pad, while debris scattered across the SpaceX property and Boca Chica State Park.
- The FAA required SpaceX to conduct an investigation on the mishap, grounding Starship during the investigation and monitoring the cleanup.
- In September 2023, SpaceX conducted a mishap investigation under FAA oversight following a launch mishap.
- The mishap investigation concluded on September 8, 2023 and SpaceX was required to implement a total of sixty-three corrective actions, including hardware redesigns, launch pad robustness improvements, and additional safety reviews and testing. These corrective actions were aimed at addressing safety concerns and preventing recurrence of similar mishaps.

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Integrated Flight Test 2 (IFT-2)

SpaceX filed a request for FCC approval for a second flight between June 15 and December 15, using Booster 9 and Ship 25. SpaceX performed the second integrated near-orbital flight of its Starship rocket on November 18, 2023.

Mission Objectives

The mission's primary objectives were for Starship to enter trans-atmospheric orbit, re-enter the atmosphere above the Pacific Ocean, and make a splashdown near Kauai, Hawaii.

Primary objectives were similar to OFT 1:

-Collecting data from the integrated vehicle stack, which consisted of the Starship 25 with the Super Heavy booster 9 (SH with S).
- Achieving liftoff, clearing the launch tower and entering a suborbital flight trajectory.
- Testing the re-entry capabilities, particularly the performance of the heat shield tiles during re-entry into Earth's atmosphere and performing a controlled landing and splashdown in the Pacific Ocean near Hawaii. The Super Heavy booster was intended to perform a similar landing in the Gulf of Mexico, about 20 miles off the Texas coast.

Launch Details

-Significant work was done on the launch mount to repair the damage it sustained during the test and prevent future issues after the first test flight ended in the destruction of the Starship vehicle as well as Stage O (Ground System)
-Various changes were implemented by SpaceX compared to the previous flight, including an expansion of the Super Heavy's fire suppression system and re-qualifying their autonomous flight safety system.

- SpaceX also rebuilt the damaged launch pad and installed a water-cooled steel plate. It acts as flame deflector by ejecting water upwards through perforations in the steel plate.

- The first launch attempt of the second integrated flight test occurred on November 18 at 13:03 UTC.

-The rocket successfully lifted off under the power of all 33 Raptor engines on the Super Heavy booster encountering maximum aerodynamic stress (MaxQ) with no anomalies reported.

-Booster exploded during boostback burn.

The Starship second stage continued to fly for over 8 minutes after successfully making through stage separation.

-It reached an altitude of 149 km, above common boundaries of space (Karman line) and a velocity of ~24,000 km/h, becoming the first Starship to reach outer space and nearly completing its full-duration burn.

-Telemetry was lost on the second stage of the Starship after over eight minutes of flight, prior to engine cutoff.

-Soon after that, Flight Termination System was triggered which destroyed the second stage, concluding IFT 2.

-NOAA weather radar detected a debris cloud a few hundred miles north of the Virgin Islands at the predicted re-entry point.

Conclusion

-SpaceX considered the mission a success, and Elon Musk stated that the water deluge would not require any refurbishment for IFT-3.

-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.'

-SpaceX and Cameron County reopened the road to the launch site a few hours after the launch, noted as a faster reopening than the first flight attempt, which remained closed for two days.

-The FCC issued final denial of a $885M Starlink subsidy due to all attempted Starship launches being regarded as failures.

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Integrated Flight Test 3 (IFT-3)

Starship returned to integrated flight testing with its third launch from Starbase in Texas. On March 14, 2024, Starship successfully lifted off at 8:25 a.m. CT from Starbase in Texas and went on to accomplish several major milestones and firsts, breaking and creating world records. The third launch of SpaceX's Starship provided some significant advancements and a few setbacks

Mission Objectives

The following mission objectives were designed to push the envelope of what's possible with the Starship and to gather valuable data for future missions:

-The mission was planned for 65 minutes.
- Starship aimed to reach an altitude of 150 miles.

-Reaching Orbital Velocity: For the first time, the Starship was intended to reach orbital speed during its flight.

-Thrust Vector Control (TVC): The flight included upgrades like electronic TVC for improved control during flight.
-Hot Staging: This technique involves igniting the next stage's engine before the previous stage is jettisoned, which was successfully demonstrated.
- Flight Termination System (FTS): An upgraded FTS was tested to ensure safety and compliance with range safety requirements.
- Payload Door Operations: Testing the opening and closing mechanism of Starship's payload door was a crucial objective. This is an important milestone as it will allow SpaceX to use starship to launch and deploy starlink v2 satellites in near future.
- Propellant Transfer Demonstration: During the upper stage's coast phase, a propellant transfer demonstration was planned.
- Raptor Engine Re-light: This test aimed to be the first-ever re-light of a Raptor engine while in space to demonstrate its capability of performing in-space manoeuvres like orbital insertion as well as de-orbit burn.
- Controlled Reentry: A controlled reentry of Starship above Indian ocean instead of near Hawaii was another significant goal of the mission. The first stage, Super Heavy, was expected to splash down in the Gulf of Mexico seven minutes after liftoff.

Launch Details

-On March 14, 2024, Starship successfully lifted off at 8:25 a.m. CT from Starbase in Texas and went on to accomplish several major milestones and firsts:

-For the second time, all 33 Raptor engines on the Super Heavy Booster started up successfully and completed a full-duration burn during ascent.

-Starship executed its second successful hot-stage separation, powering down all but three of Super Heavy’s Raptor engines and successfully igniting the six second stage Raptor engines before separating the vehicles.

-Following separation, the Super Heavy booster successfully completed its flip manoeuvre and completed a full boostback burn to send it towards its splashdown point in the Gulf of Mexico.

-Super Heavy successfully lit several engines for its first ever landing burn before the vehicle experienced a RUD (that’s SpaceX-speak for “rapid unscheduled disassembly”). The booster’s flight concluded at approximately 462 meters in altitude and just under seven minutes into the mission.

-Starship's six second stage Raptor engines all started successfully and powered the vehicle to its expected orbit, becoming the first Starship to complete its full-duration ascent burn.

-While coasting, Starship accomplished several of the flight test’s additional objectives, including the opening and closing of its payload door (aka the pez dispenser,) and initiating a propellant transfer demonstration. Starship did not attempt its planned on-orbit relight of a single Raptor engine due to uncontrolled vehicle roll rate during coasting.

-Starship went on to experience its first ever entry from space, providing valuable data on heating and vehicle control during hypersonic reentry. First ever live views of entry were made possible by Starlink terminals operating on Starship.

-The flight test’s conclusion came during entry, with the last telemetry signals received via Starlink from Starship at approximately 49 minutes into the mission.

Conclusion

Despite the loss of the vehicle during reentry, Flight Test #3 provided SpaceX with valuable data and insights into the Starship's capabilities and performance. The successful demonstration of several key technologies, such as propellant transfer and hot staging, marks progress in the development of the Starship system. These advancements are critical for SpaceX's long-term goals of lunar and Mars missions. The test also highlighted areas for improvement, which will inform future design and operational strategies. Overall, Flight Test #3 was a pivotal step in the iterative testing process that drives innovation at SpaceX.

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