Are Thanos and the Black Order affected by the Sanctum at all?

Question

As we learned in Doctor Strange, earth is protected by a magical defense shield known as the Sanctum.

In Avengers: Infinity War once,

Wong was done helping Banner in New York, he said that he had to return to guard the New York Sanctum.

So we can assume that it was still operational.

However, Thanos (and his henchmen the Black Order) seem to travel to and from earth, seemingly with relative ease. What's the deal?

Can the Black Order travel to and from earth, without being affected by the Sanctum's protections?

Answer 1

Just to question the premise for a minute:

earth is protected by a magical defense shield known as the Sanctum

Is that what it is? I thought there were three Sanctums (in New York, London, and Hong Kong), physical locations from which the Sorcerer Supreme and Friends did their protection work; rather than there being a field surrounding the whole planet.

Anyhoo:

Can the Black Order travel to and from earth...?

It sure seems like they can. In Doctor Strange, Wong explains that the Sanctums and their sorcerers defend against incursions from other dimensions, rather than incursions from space. (We see the Mirror Dimension, and Dormammu's Dark Dimension, in the movie.)

Several other beings have also previously reached earth from space just fine:

• The Bifrost Bridge and other Asgardian technologies in various Thor and Avengers movies
• The Space Stone’s portals in Avengers
• Yondu’s ship in Guardians of the Galaxy
• Ego in Guardians of the Galaxy Vol. 2
• Various Kree and Skrulls (and at least one Flerken) in Captain Marvel

In Infinity War, the Bifrost even smashes straight through a window in the New York Sanctum itself to get Hulk Puny Banner a seat at the exposition conference table.