SpaceX fully installs Super Heavy Booster “Aerocovers”

For the first time, SpaceX has installed more or less a full set of “aerodynamic covers” on a prototype super-heavy booster.

Designed to protect the booster from itself and the Earth’s atmosphere during ground testing, launch, ascent and re-entry, Super Heavy’s structures consist of thin steel hulls mounted on metal frames. The most obvious aerocovers fit over six racks mounted outboard on the Super Heavy’s rear, giving the engine a sort of supply belt of hydraulics, pressure vessels, avionics and heat exchangers. Unsurprisingly, these racks are adorned with electronics, composites, and thousands of feet of wiring and delicate tubing — none of which is particularly suited to being within a few dozen feet of the fury of the 29-33 Raptor engines or close by sitting on the leading edge of a hypersonic reentry vehicle.

Aside from the steel they’re mounted on, it’s likely that every system in Super Heavy’s “built utility” would malfunction or be utterly destroyed if directly exposed to a hypersonic tremor for even seconds. Entry. . Unlike Falcon boosters, which almost always use reentry burns to slow down and create some sort of heat shield with their own exhaust, SpaceX Super Heavy is theoretically engineered to survive the full force of reentry without additional burns to cushion the blow.

To survive the fall and Always landing in good enough condition to allow for near-same-day reuse, which is SpaceX’s goal, every ounce of vulnerable equipment installed outside of Super Heavy will likely need to be carefully protected. In theory, that’s the purpose of the aerocovers that SpaceX just fully installed — let alone tested — on Super Heavy B4.

December 11, 2021.
January 14, 2022.

Prior to the final installation of Booster 4 on the in-orbit launch pad, SpaceX installed covers on a pair of hydraulic racks and heat exchangers, but left the four racks with overfilled composite pressure vessels (COPVs) and an exposed utility port. After B4 was removed from the launch pad for the third time on December 30, both covers were uninstalled. However, on January 14, 2022, SpaceX quickly installed all six covers for the first time. and began sealing the exposed corners of each blanket. On Jan. 17, SpaceX even installed aerodynamic surfaces around Booster 4’s protruding umbilical port, smoothing out any hypothetical airflow around the device.

Prior to the main installation of the aerocovers, SpaceX also added at least half a dozen small boxes, apparently designed to protect a series of thin metal probes that pass through Super Heavy’s tanks and skin and connect to the dash boxes. In addition, although less noticeable, crews also worked to complete Super Heavy B4’s Raptor heat shield with a large number of similar sheet steel covers and plates. Without official photos from SpaceX or another lift on the launch pad, it’s impossible to know if Booster 4’s Raptor heat shield is fully enclosed, but the shielding that wraps around its perimeter appears to be complete.

The Super Heavy B4’s Raptor heat shield is partially visible in these views. (SpaceX)

As it stands, Super Heavy B4 is probably only a few games away from actual completion and is as good as ever for static fire testing. Most likely, these Raptor aerocovers and heat shields are essential for Super Heavy B4 to run more than one test at a time without requiring major repairs immediately. Unlike Starship, which primarily tested three engines at a time and did few six-engine static fires, Super Heavy B4 could potentially test all 29 Raptor engines at once.

Even if almost 30 engines are involved nominal Pre-combustion testing will likely create a massive fireball that could engulf Super Heavy’s rear end (if not the entire booster) in flames. During static fire tests, Raptors will typically produce a smaller, shorter (but still significant) fireball while stationary, creating another potential source of damage to sensitive hardware located anywhere on or within the Booster 4’s thrust envelope. As such, Super Heavy Aerocovers can be as important to surviving static fires as they are to surviving takeoffs and landings.

It’s unclear if or when Super Heavy B4 will return to the orbital launch pad for a wetsuit rehearsal and static fire tests. SpaceX has ambiguous test windows scheduled on January 18, 19, and 20 from 10 a.m. to 10 p.m.

SpaceX fully installs Super Heavy Booster “Aerocovers”