Starship-Super Heavy flies its third test!

SpaceX launched its Starship-Super Heavy vehicle today for its third flight test! The two vehicles used in the flight were Ship 28 and Booster 10, with both making more progress than the previous two vehicles.

Liftoff occurred at 13:25 pm Univerversal Coordinated Time with all thirty-three Raptors engines firing. The ascent of the flight went as planned with Ship 28 successfully hot-staging from Booster 10 for the second time ever for SpaceX.

Booster 10 became the first Super Heavy to successfully relight its ten engines and performed the full 'boost back' burn as planned. The booster successfully made it through descent, not needing to relight its engines again for re-entry, but began to spin shortly before the planned landing burn. Booster 10 did attempt to start up for landing but only managed to light three engines before hitting the ocean at 1111 kilometers per hour, or 691 miles per hour.

While Booster 10 was flying back towards the launch site, Ship 28 was heading towards space. The ship made it successfully to second-stage engine cutoff and proceeded to coast for a little over forty minutes. During the coast, the vehicle successfully tested the opening of its payload bay door, although it did fail to close. A planned in-space startup of a Raptor engine was planned but did not occur, the reason why is not known outside of SpaceX. Ship 28 is also believed to have attempted to transfer fuel from its header tanks into the main tanks, with mission control callouts for the start and end of the test.

Ship 28 unfortunately met a fiery end above the Indian Ocean and was lost on re-entry. During the webcast SpaceX claimed the re-entry was controlled however the vehicle was spinning upon the start of atmospheric re-entry, Ship 28 had been tumbling since second-stage engine cutoff.

The launch mount and ground support equipment at the launch site are believed to have minimal or no damage. SpaceX teams will perform an investigation and cleanup of the launch site when the entire site is deemed safe.

With the loss of both vehicles, SpaceX will need to complete a mishap investigation with the Federal Aviation Administration before being able to launch the fourth test flight. Due to the progress made on this flight, it is believed the mishap investigation may take less time.

How does it compare to flight two?

Back on the 18th of November 2023, Starship-Super Heavy made its second flight, SpaceX considered the flight a success despite ending with the loss of both vehicles, similar to this flight.

Last flight the Super Heavy booster, Booster 9, lit all thirty-three of its engines with all of them lasting up until hot staging. Booster 9 was lost during its 'boost back' burn due to a filter blockage where liquid oxygen is supplied to the engines, which led to a loss of inlet pressure in engine oxidizer turbopumps that eventually resulted in one engine failing in a way that resulted in the rapid unscheduled disassembly of Booster 9.

Ship 25, the Starship vehicle of flight two, was lost after continuing to power the second-stage flight for six minutes after hot-staging. Ship 25 was believed to have been lost due to a leak in the aft section of the vehicle that started when the vehicle's liquid oxygen dump had started. This is believed to have led to fires and loss of communications which caused the onboard computers to command a shutdown of the engines, and followed shortly after by the flight termination system commanding destruction of the vehicle.

SpaceX believes that flight three allowed them to gather more data on how the Starship-Super Heavy vehicle flies, as well as gathering the first pieces of data for re-entry and booster landing.

What changes were on Ship 28 & Booster 10?

All information in this section was spotted and gathered by the teams of the Ringwatchers and a more in-depth list can be found here.

Ship 28

Ship 28 is believed to have had its vent and control thrusters moved on the vehicle, with the nose vents having diverters installed. The liquid oxygen tank vent 'cowbell' diverters were also removed. Starship is believed to have tested three new liquid oxygen vents located in the engine section of the vehicle.

More thermal protection tiles were spotted on Ship 28, notably under the aero covers of the forward flaps. The tiles were also spotted as being more uniform than the past two ships. The four flaps also have small static wicks added to prevent a buildup of a dangerous static charge.

It's also believed that more internal stringers, used to reinforce the tank walls, were added to Ship 28, along with larger flap mounts for the aft flaps. The most visible change to Ship 28 was four Starlink terminals to enable a more stable connection to the vehicle.

One of the more important changes to the Ship was Electric Thrust Vector Control for the three sea-level Raptor engines. Ship 28 was the first to fly the Electric Thrust Vector Control, which allowed the hydraulic power unit to be removed from the vehicle.

Booster 10

Booster 10 had few changes compared to Booster 9, which flew on flight two. The booster is known to feature a new common dome design allowing for a small mass savings. Booster 10 also had redesigned Starlink terminals which are also believed to enable a more stable connection to the booster.

What is Starship-Super Heavy?

Starship-Super Heavy is SpaceX's in-development fully reusable super heavy-lift launch vehicle and the largest rocket currently flying. SpaceX is currently aiming to have the launch vehicle deliver one-hundred and fifty tons to low Earth orbit while reused or two-hundred and fifty tons when expended, although there are rumors from SpaceX of an expendable payload capacity of three-hundred tons.

On the launch pad, Starship-Super Heavy is one-hundred and twenty-one meters tall and weighs 5,000,000 kilograms fully fuelled. The diameter of both vehicles is nine meters, excluding aerodynamic control surfaces.

What is Starship?

Starship is the second-stage of the Starship-Super Heavy launch vehicle and is planned to be capable of multiple missions into orbit, after a short refurbishment. The vehicle is fifty meters tall and nine meters in diameter, excluding its four aerodynamic control surfaces. Fully fuelled Starship is believed to weigh 1,300,000 kilograms with an approximate weight of 100,000 kilograms unfuelled.

The Starship second-stage is powered by three sea-level Raptor engines along with three vacuum-optimized Raptor engines. These sea-level engines are believed to generate 230 tons of thrust each with the vacuum-optimized engines generating 258 tons of thrust each for a total combined 1,500 tons of thrust for Starship. The vacuum-optimized Raptors are unable to gimbal requiring the sea-level Raptors for control of the second-stage on ascent and landing.

The total burn time for the Starship second-stage remains unknown outside of SpaceX but is known to burn liquid methane and liquid oxygen in its engines.

In order to survive re-entry for reuse, Starship has several thousand thermal protection tiles on one side of the vehicle and on all four of its aerodynamic control surfaces. The four control surfaces help guide the vehicle during re-entry and prior to landing inside the atmosphere at a pre-determined location. Starship also has a series of small thrusters to control the vehicle in space before re-entry.

SpaceX is believed to be working on a few variants of Starship for use as a Moon lander, tanker, space station, Mars lander, and as a crewed spacecraft.

What is Super Heavy?

Super Heavy, also called 'the Super Heavy booster', is the first-stage of SpaceX's Starship-Super Heavy launch vehicle. The giant Super Heavy first-stage is planned to be capable of multiple flights per day with minimal refurbishments and inspections. The vehicle is seventy-one meters tall and nine meters in diameter, excluding its four grid fins and chines. Fully fuelled Super Heavy is believed to weigh 3,600,000 kilograms with an approximate mass of 200,000 kilograms unfuelled.

The Super Heavy first-stage is powered by thirty-three sea-level Raptor engines generating a combined thrust of 7,590 tons, with each engine generating 230 tons of thrust. The outer twenty Raptor engines are unable to gimbal with the inner thirteen being able to for control of the first-stage.

The total burn time of Super Heavy remains unknown outside of SpaceX but is known to burn liquid methane and liquid oxygen in its engines.

To enable the reuse of Super Heavy, the vehicle has four large grid fins placed in the interstage to assist in guiding and controlling during descent. Super Heavy also has four chines running along the lower third of it to generate lift and assist in stabilization.

Shortly after completing the ascent, Super Heavy relights ten engines, as three were running during staging, and performs a 'boost back' burn in order to return to the launch site. After the 'boost back' burn is completed the engines shut down with Super Heavy being guided by a series of small thrusters and its grid fins. Once Super Heavy is at the correct altitude above is landing location three engines start backup for the landing burn. SpaceX currently plans to have Super Heavy land in the ocean with launch site landing attempts happening with later flights.

Super Heavy also features a hot-staging ring atop of it to allow for a faster and simpler staging process, according to SpaceX. The hot-staging ring has dozens of gaps on the sides to allow for the Raptor engine exhaust of Starship to escape.