For the first time in more than six months, SpaceX has stacked two next-generation Starship rocket stages, creating the largest and most powerful fully assembled launch vehicle ever.
It’s not the first time. SpaceX has conducted three more Starship demos: once in August 2021 and again in February and March 2022. But earlier this year, SpaceX (or at least CEO Elon Musk) decided to drop the upper stage of the Starship and Super Heavy booster prototypes that supported all three previous tests and, at one point, were considered candidates for the rocket’s first orbital launch attempt. Booster 4 and Ship 20 are sent to the retirement yard by June 2022.
By that time, SpaceX had already begun testing new favorites for the Starship’s orbital launch for the first time: the Super Heavy Booster 7 (B7) and Starship 24 (S24). Nearly six months into that busy period of testing, both models recently reached the point where SpaceX was confident enough in their progress to combine the two in the most challenging phase of spacecraft testing to date.
After an aborted dawn attempt on October 11, SpaceX technicians discovered some mysterious kinks in critical infrastructure on Starship’s (almost) first orbital launch pad in Boca Chica, Texas. As part of a chariot-by-horse gamble by CEO Elon Musk that saw SpaceX completely remove all modern superheavy and spacecraft models in hopefull That it will one day be able to pick up building-sized missile stages from the air, the company has built a 145-meter (~475-foot) launch tower and outfitted it with three giant robotic arms. Two of these arms are identical and attached to each other, forming a kind of claw that could one day come close around flying rockets to prevent the need for landing legs. A simpler third arm swings in and out to connect the Starship’s upper stage to launch pad power, fuel, and gas supplies.
“Chopsticks,” as they’re known, have another, more important goal: assembling the spacecraft’s rockets on the launch pad. Thanks to their strong connection to a tower with a foundation sunken deep in the wetlands of Boca Chica and a design that ignores a hanging hook or jig for giant arms, they are less sensitive to wind than the massive crane otherwise required to stack the starship on top of the super-heavy. Sitting a stone’s throw from the Gulf of Mexico, storms and high winds are not entirely uncommon.
Near sunset on October 11, SpaceX had better luck on its third attempt and was able to slide the booms into place under the 24th. It weighs 100 tons or more (about 220,000 pounds) and is nine meters (about 30 feet) wide and ~50 long m (~165 ft), the spacecraft was slowly raised about 80 m (~250 ft) off the ground, translated to Booster 7, and lowered atop the 69 m high (~225 ft) first stage. After about two more hours of automated tweaking of their positions, the two spacecraft stages were finally secured together. With the arms still attached to Ship 24, SpaceX workers were able to get close to the rocket and prepare to attach the umbilical cord of the swinging arm to the Starship.
Since they began qualifying testing in April and May 2022, the Booster 7 and Ship 24 have both completed several coolant proof tests, eight “first spins” for some or all of their Raptor engines, and several static fires for those same engines. The latest developments, Ship 24 lit all 6 RaptorsBut the apparently successful test on Sept. 8 was followed by more than a month of apparent fixes. Booster 7 finally completed a steady fire lit Scored seven out of 33 Raptor engines Providing an idea of how much SpaceX still has to go to finish the Super Heavy test.
According to CEO Elon Musk, Booster 7 and Ship 24 will attempt Starship’s first full wet dress rehearsal (WDR) once all is well. Prototypes will be simultaneously loaded with approximately 5,000 tons (~11 million pounds) of liquid oxygen and methane fuel and then powered through a countdown to launch. Spacing just before ignition and takeoff, WDR is meant to be more or less identical to attempted launch.
If the rehearsal goes as planned, SpaceX will simultaneously attempt to ignite all 33 Raptor engines installed on the Super Heavy B7, making it certainly the most powerful liquid rocket ever tested. Even if all 33 engines did not reach more than 60% of their maximum thrust of 230 tons (~510,000 lbf), it would likely break the Soviet N-1 missile’s record of 4,500 tons of thrust (~10M lbf) at The surface of the sea. It will also be the most simultaneously ignited rocket engine in a single vehicle. SpaceX will push the envelope with several measures, and success is far from guaranteed.
It’s unclear if SpaceX will immediately attempt a full rehearsal or a 33-engine static shootout. Based on the test history of Ship 24 and Booster 7, it would be a departure from the norm if the company didn’t slowly progress to both major milestones with smaller tests in the meantime. At least, assuming the WDR test completes without much problem, SpaceX will likely attempt at least one or more static fires with fewer than 33 engines before attempting the first full test.
If both phases (full WDR launch and 33 static drives) are completed without much problem, there is a possibility that SpaceX will move directly to preparations for Starship’s first orbital launch attempt without disassembling the missile. In the most likely scenario that some Issues arise and some Repairs needed, the track will be more tortuous but still should end with an orbital launch attempt late this year or early next.
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