SpaceX advances Starship program with successful stacking of Booster 19 after recent challenges

Following the recent setback of Booster 18 during a pressure assessment, SpaceX has made significant strides in its Starship Program by successfully stacking Booster 19, which sets a new operational record for the initiative. Over the weekend, the company transported Booster 19 to its Masseys facility for cryogenic proof testing, marking an important step towards preparing for Flight 12.

Booster 19 was assembled within a span of just 26 days and has been under preparations for cryogenic proof testing since December 26, having spent additional time in Mega Bay 1 to ensure the integrity of its construction, particularly after the issues encountered with Booster 18. In the early hours of February 1, the booster was moved to Masseys, where it underwent a pneumatic pressure test on February 2. During this assessment, teams pressurized the propellant tanks and Composite Overwrapped Pressure Vessels (COPVs) to check for potential leaks and verify the functionality of valves and avionics, without adding any fuel. Following this, a small section was removed for inspection near the location where Booster 18 had experienced a fault, though it remains unclear whether this was a precautionary measure or indicative of a problem.

After reinstalling the section, SpaceX performed a brief cryogenic proof test on Booster 19, likely to clear out the aft section and prepare for more extensive testing. The next phase will involve a series of cryogenic proof tests, some of which may include structural assessments of the thrust structure using hydraulic rams on the cryo stand. Historically, SpaceX has tended to conduct only two cryogenic tests per booster; however, the new design of the aft section allows for multiple tests prior to rollback.

Once the testing sequence is complete, Booster 19 will return to Mega Bay 1 for the installation of 33 Raptor 3 engines, marking the inaugural application of this engine variant. The timeline for this installation is currently uncertain, but enhanced engine shielding should expedite the process compared to previous boosters. Following the completion of engine installations, Booster 19 is set to be transferred to Pad 2 for an extensive array of testing, including propellant loading and several static fire tests, before it undergoes preflight checks alongside Ship 39.

Ship 39, the first vessel of Block 3, has been entirely assembled since November 15, 2025, and has had various components added, including aft flaps and several tile experiments. It remains in Mega Bay 2, awaiting the availability of a ship cryo stand and the installation of a new quick disconnect plate at Masseys. There are plans for potential early deployment to Masseys using the static fire stand, as preparations continue for a new truss structure designed for future ship captures.

Once testing of Ship 39 is complete, it will be rolled back for Raptor 3 engine installation before undergoing static fire testing and a full wet dress rehearsal. This rehearsal will simulate the countdown procedure, allowing crews to fully load the ship and booster, while also testing the capabilities of the new tank farm.

On the infrastructure front, Pad 2 appears to have all necessary structural components installed, with ongoing efforts to connect cryogenic, electrical, and high-pressure systems. Recent tests on the deluge system and detonation suppression system have been successful, paving the way for final preparations. Once systems are connected, there will be tests to ensure the readiness of the pad before a planned 33-engine static fire test involving Booster 19.

Amid these developments, three test tanks at Masseys are integral to the preparation for Flight 12. Test Tank B18.1 has completed several cryogenic tests and is nearing the conclusion of its testing phase. Test Tank B18.3 is also expected to wrap up testing soon, while Tank S39.1 is currently in its second round of cryogenic assessments.

Despite ambitious expectations set by SpaceX CEO Elon Musk for a flight within six weeks, the timeline is contingent upon the completion of several critical testing milestones for Booster 19, Ship 39, and Pad 2.