Credit:SpaceX
Starship, one of the most powerful rockets ever made, has executed three flight tests, getting with each of them closer to its goal to take humans to Mars.
Watching this rocket soar through the sky, powerful but at the same time sublime, was an exhilarating experience, even when watching it through the computer at home. SpaceX made considerable progress with each attempt, and the wait in between was incredibly short. Starship's first flight took place on April 20, 2023, followed by another on November 18, 2023, and another four months later on March 14, 2024.
Weeks before the first launch, Elon Musk, the founder, CEO, and CTO of SpaceX, announced that the first flight of this fully integrated Starship and Super Heavy rocket would be an exciting launch, and he delivered. Although the rocket has to demonstrate it can achieve many objectives, the main goal of the First Flight Test was to clear the launch pad.
Credit:SpaceX
The rocket successfully liftoff at 8:33 AM CT from Starbase in Boca Chica, TX, but experienced multiple engines out, reducing power and resulting in altitude loss. It started to tumble, so the flight system commanded termination on the booster and Starship, just a few minutes after take-off, when it was ~39 km over the Gulf of Mexico. [1].
Credit:SpaceX
Credit: Reuters
Regardless of the loss of the vehicle, the flight itself was a success. It allowed SpaceX to gather information that would help improve future flights. "With a test like this, success comes from what we learn, and we learned a tremendous amount about the vehicle and ground systems today," said SpaceX.
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On this flight, they also learned how the launch pad worked. Although not all the 33 first-stage Raptor engines ignited during the first liftoff and delivered the full 16.5 million pounds of thrust, without a structure to deflect the exhaust's plume away from the pad, Starship blasted out a big crater beneath the pad and sent chunks of concrete and other debris high into the Texas sky[2]. This was not a mistake but a deliberate decision made by SpaceX, which decided not to dig a flame trench but rather build a massive water-cooled steel plate to go under the launch mount. Although the steel plate was not ready for debut for the first launch, SpaceX still decided to go ahead, figuring out that the underlying Fondag (a special heat-resistant type of concrete) of the orbital mount could survive one liftoff[3].
Credit: SpaceX
The Second Flight Test went even further, providing invaluable data to continue with Starships' rapid development. In this test, all 33 Raptor engines on the Super Heavy Booster started up successfully and, for the first time, completed a full-duration burn during ascent. Also in this flight, the booster successfully powered down all but three Super Heavy Raptor engines and the second stage successfully ignited the six Raptor engines before separating -the first time this hot-stage separation technique was done successfully with a vehicle of this size and the test flight's primary goal. Following separation, the Super Heavy booster successfully completed its flip maneuver and initiated the boostback burn. Thirty seconds later, at an altitude of ~90 km over the Gulf of Mexico, it experienced an exciting end of its journey, what SpaceX calls RUD - rapid unscheduled disassembly- or a "blew up," in layman's terms. Later, SpaceX determined that the RUD resulted from a filter blockage of a liquid oxygen line that supplied the engines.
Credit: SpaceX
The second stage, also known as Starship, continued climbing to an altitude of ~150 km at 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 the second stage burn, before engine cutoff, there was a planned venting of liquid oxygen (brought in excess to simulate the needs of future payloads). While performing the activity, a valve leak caused fires that ended up shutting down the six Raptor engines and prevented Starship from reaching the expected altitude. This resulted in a mission roll violation which was detected by the autonomous flight safety system and triggered a safe command for flight termination or RUD. This time, the test flight lasted more than eight minutes[4].
Credit: SpaceX
During takeoff, SpaceX also tested the launch pad water-cooled flame deflector and other upgrades. These performed as expected, requiring minimal post-launch work on the pad and making it ready almost immediately for upcoming vehicle tests.
Credit: SpaceX
The Third Test Flight accomplished several major milestones and first-time events, gathering important telemetry that included information about the heat shield during reentry and how the vehicle performed.
The liftoff was at 8:25 AM CT, and 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, followed by a successful flip maneuver and full boost back burn of the Super Heavy booster that sent it towards its splashdown point in the Gulf of Mexico. It also successfully lit a few engines for its first-ever landing burn before the vehicle experienced a RUD. The booster’s flight concluded at approximately 462 meters of altitude and just under seven minutes into the mission.
In the meantime, six Raptor engines powered the Starship to its expected orbit, becoming the first Starship to complete its full-duration ascent burn. Just as the engines cut off after reaching the desired orbit, the cameras on board provided a view of the aft of the vehicle alongside the wedge view of the earth. This orbit was on a steep trajectory to ultimately bring down the vehicle into the Indian Ocean.
For about 30 min of its flight, Starship only transmitted telemetry via the TDRS satellite system, and we had no view of the vehicle. The telemetry was essential to communicate the start and successful completion of several of the flight'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 vehicle roll rates during coast. This test intended to demonstrate this capability but was not part of the deorbit burn.
Credit:SpaceX
After about 46 min of its flight, Starship went on to experience its first-ever entry from space, providing valuable data on heating and vehicle control during hypersonic reentry. For about two and a half minutes, Starlink's terminals operating on Starship made it possible to have views of the hot plasma field building up around the vehicle. As stated by the SpaceX team, the Starlink and TDRS data were crucial to the success of the test. The data provided is needed to improve on future flights[5].
Credit:SpaceX
This time, the conclusion of the flight test came during reentry, with the last telemetry signals received at approximately 49 minutes into the flight. Because SpaceX did not intend to recover any of the hardware, the accomplished milestones made this test a complete success.
As we speak, SpaceX is getting ready for the next test flight. With boosters and Starships already built, the next launch test can happen any time now. This rapid iterative development approach is the basis for all of SpaceX’s major innovative advancements, including Falcon, Dragon, and Starlink. Starship - SpaceX's fully reusable transportation system capable of carrying crew and cargo to Earth orbit, the Moon, and ultimately travel to Mars- will soon be available for spectacular space flights that up to now were only possible in movies.
References:
[3] Elon Musk post in Twitter - https://twitter.com/elonmusk/status/1649523985837686784