In the latest twist in the legend of SpaceX’s customized Starship launch pad propellant storage tank, the company seems to have retroactively decided to build a small prototype that is only used for testing.
Known as the “test tank,” the relatively small steel structure was quickly assembled from parts of an old ground support equipment (GSE) tank that was scrapped in July in the past week or so. SpaceX completed the first Starship-derived propellant storage tank in April 2021, and quickly rolled this tank (GSE1) and the second (GSE2) from the construction site to the orbital launch pad in just a few weeks. Less than a month later, SpaceX also completed the GSE 3 tank, although things seemed to immediately fall into chaos after that.
Only three months later, GSE3 was finally transported to — and installed — on the concrete support of the interstellar spacecraft’s first orbital launch site, and only after several structural modifications and GSE tanks #5 and #6 After the footsteps. What’s less known is why SpaceX’s custom GSE tank production stalled shortly after it started, why none of the five Starship-sized tanks installed on track pads were fully installed or subjected to any type of testing, or why it seemed that construction was needed. Modified afterwards. However, it is safe to say that SpaceX’s new GSE “test tank” is now at the center of the mystery.
Fortunately, the rapid emergence of SpaceX’s first GSE test tank has at least made people familiar with the short but chaotic history of the Starship orbital launch pad propellant tank. Test tanks are nothing new, and since Test Tank 1 first went to SpaceX’s suborbital launch (and test) facility in January 2020, it has been an integral part of Starship’s development. In the following 20 months, SpaceX has built and tested seven small test tanks, several of which did not survive.
Regardless of intentional damage, each test tank clearly helps SpaceX validate new manufacturing techniques, different materials, and different skin thicknesses, and is generally faster and less costly than the data collection allowed by full-scale prototypes. For example, recently, SpaceX seems to have successfully tested a super-heavy booster test tank, placing the prototype in cryogenic liquid nitrogen, and using hydraulic cylinders to simulate the thrust of nine Raptor engines on an unproven disc thrust structure.
Now, SpaceX has almost recovered from the trance and remembered the practicality of the test tank. The company has assembled a small GSE prototype, presumably to verify that its custom propellant storage tank can handle a series of very different from interplanetary spacecraft. Condition they come from. In this case, the GSE tank was actually built from the scrapped part of GSE tank #4. In fact, after the tank was scrapped for unknown reasons last month, the upper part (the front dome part) was completely cut off by GSE4.
In the past few months, despite unexpected interruptions in the production and installation of GSE tanks, SpaceX staff slowly but steadily welded steel rings (stiffeners) to the exterior of GSE1, GSE2, and GSE3. When GSE5 and GSE6 finally made their way to the tarmac, they had installed those stiffeners when they left, which meant that anything that tripped SpaceX could be structural. The GSE4 test tank also includes external reinforcement along each circumferential weld (ring stack or dome connection).
While SpaceX is (or hasn’t) built its own GSE storage tanks in a few months, the contractor who usually assembles water towers and storage tanks in situ built eight huge 12m (~40 ft) wide storage tanks themselves. Regarded as “cryogenic shells”, as their name implies, these tanks are designed to completely surround SpaceX’s GSE tanks. SpaceX will use these shells to insulate its thin single-walled steel propellant tanks to keep its cryogenic contents as low as possible for as long as possible. However, how they will be isolated is unclear.
Based on the seemingly retrospective decision to strengthen the exterior of these GSE tanks, the recent general consensus is that SpaceX wants to vacuum at least in the gap between the shell and the tank. SpaceX may also take the opposite approach and pressurize the gap (as much as possible) with an insulating gas such as nitrogen. The additional confusion comes from the fact that Starship tanks are technically designed to support real spacecraft (operating in almost complete vacuum) without the need for external reinforcements.
In addition, it is clear that SpaceX has not yet constructed a customized ultra-small cryogenic shell or concrete mounting pad for its GSE4 test tank, which means that it is actually only useful for testing some of the loads that GSE tanks will encounter in their sleeves. In addition, given that SpaceX has completed six of the seven GSE tanks of the orbital pad and all of their seven cryotubes, any major issues discovered during GSE4 testing can easily lead to months of rework and delays. However, if you are lucky, GSE4 will clear the way for SpaceX to complete the pipeline, casing and activate Starship’s first orbital launch site oil depot through the upcoming test activities.
Post time: Sep-18-2021