Raptor 2 testing at full throttle on the SpaceX McGregor test stands

by Chris Bergin

Numerous Raptor 2 engines are now being put through their paces at SpaceX’s test center in McGregor, involving static fire testing at the five test bays, ahead of the evolved engine being shipped to Starbase to be involved in future launches.

While Booster 4 and Ship 20 remain at the launch site, Boosters 7 and 8 and future Ships are continuing their build-up processing at the Production Site.

Forward Path:

Following milestone testing with the Chopsticks on the Launch Tower’s Mechazilla system, the prospect of the arms being used for the next stacking operation has grown.

Aft covers have been installed on Booster 4 while Ship 20 was attached to SpaceX’s LR11000 crane – and then lifted off Suborbital Pad B onto the transport stand atop the self-propelled modular transporter (SPMT) on Saturday. On Sunday, Ship 20 was rolled to the Launch Tower.

This operation has been interrupted by poor weather in the region – specifically high winds. Incidentally, it is known that the Chopsticks can deal with wind loads more capably than crane operations.

While Elon Musk’s last update to the test series noted Booster 4 and Ship 20 were still set to be the duo to undertake the orbital velocity flight test, it is increasingly likely that the final decision won’t be made until additional ground testing has concluded.

Although Ship 20 has completed testing through a full-set, six-engine firing of its three sea-level Raptors and trio of RVacs, Booster 4 has yet to move past a cryoproofing test.

Booster 4 and Ship 20 via Mary (@bocachicagal) for NSF.

A series of Static Fire tests have been expected for the Booster. However, to complete a firing where up to all 29 engines are ignited, the Super Heavy will have to be placed back onto the Orbital Launch Mount (OLM). It will then receive Liquid Oxygen and Liquid Methane from the OLS Tank Farm – with the latter’s status a continued public discussion per its readiness.

A further test related to the Tank Farm was conducted last week via Test Tank GSE-4. GSE – Ground Support Equipment – includes the giant tanks that hold the propellant ahead of fueling the vehicle.

While Test Tanks are usually pressed to failure to gain data on structural margins, no information has been forthcoming on how GSE-4 performed before it reached its failure point.

Regardless of how the forward plan pans out, there is the potential that test stack operations of Booster 4 and Ship 20 could take place via the aid of the Chopsticks, allowing for a full stacking test of the Mechazilla system and fit checks with the Booster and Ship QDs (Quick Disconnects).

Any additional testing would also provide value should SpaceX opt to switch the flight test to a future Booster and Ship combination.

While Booster 5 has been placed alongside SN15 and Ship 16 in what is fast becoming a Starbase “Rocket Garden,” and Booster 6 ended up being a Test Tank, Booster 7 is currently being stacked in the High Bay and could quickly be completed in time to take Booster 4’s place.

Sections of Booster 8 are now being staged at the Production Site as well, which places future Super Heavy vehicles into the realm of the Thrust Pucks that can cater for 33 Raptor engines. Elon Musk confirmed this evolution some time ago, yet more recently added that Ship will move from six to nine engines.

While Ship 21 has departed the Mid Bay and is now parked outside, work to build up the sections for Ship 24 is already underway.

Other future advances for the prototype Starships have also been on show, such as the “Smooth” nosecone and the latest version of the payload cargo door.

Although SpaceX is highly-focused on reaching orbital velocity, the company will want to quickly begin operational cargo flights in the short term, starting with the launch of large flocks of Starlink satellites. These will require payload door modifications to the nosecone.

Raptor Push:

Elon Musk recently placed his focus on improving the production cadence of the Raptor engine.

With assembly currently taking place at the Hawthorne factory in California before testing at McGregor, efforts were already underway to centralize production and testing of Raptor 2 at the McGregor test site.

The latest view of the McGregor Raptor 2 factory, via Gary Blair for NSF/L2

A large factory has risen out of the ground in the space of months, with outfitting already taking place. It’s possible the first “McGregor-born” Raptor 2s could be rolling out of the local factory in short order.

Those units will avoid a road trip from California and will only have to travel a short distance to one of the five test bays dedicated to the Raptor engine.

McGregor has two test bays at the original dedicated horizontal test stand and a brand new dual-bay next door with the allowance for vertical testing. That new stand was built shortly after the Tripod Stand – previously used for Falcon 9 Booster tests – was converted to hosting Raptor engines.

The five bays for Raptor Testing via Gary Blair for NSF L2

“Each Raptor 1 engine above produces 185 metric tons of force. Raptor 2 just started production & will do 230+ tons or over half a million pounds of force,” noted Elon on Twitter, citing the increased performance of the new iteration of Raptor.

The engine is also more streamlined, which can now be confirmed via photos taken of Raptor 2s on the McGregor test stands via NSF’s Gary Blair during his latest flybys for L2 McGregor.

Raptor 2’s on the Test Stands at McGregor via Gary Blair for NSF L2

While Elon Musk has not yet tweeted how Raptor testing has proceeded over recent weeks, the number of tests and variation on items such as throttling has been documented by NSF’s Reagan Beck.

The following milestones will involve the first Raptor 2s to arrive at Starbase, followed by the confirmation of production beginning inside the McGregor Raptor 2 factory.

For live updates, follow NASASpaceFlight’s Twitter account and the NSF Starship Forum Sections. L2’s Starship sections include fast turnaround full sets of hi-res photos and much more.

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