What is the largest antenna deployed in space?

Question

@Tristan's answer says:

The satellites are classified, so details are speculative, but it is believed that the Magnum/Orion and Mentor SIGINT satellites have parabolic antennae around 100 m in diameter.

which for an antenna hound like me is really, really intriguing. Is there any more information about that?

The answer to What's the largest area dish antenna sent beyond the Earth-Moon system? is Galileo's 4.6 meter dish.

Besides that as it may be very hard to confirm at all, what is or are the largest antennas deployed in space? They would not have to be dishes, but nonetheless I've listed two below. And masts don't count!

Some fairly large ones include Queqiao:

Source from Why is Queqiao's dish antenna so big? (Chang'e-4 relay satellite) Largest ever on/near the Moon?

And Spektr-R:

Source: @BowlOfRed's answer

Answer 1

The single largest commercial satellite reflector (18m) is on Terrestar-1.

But Japan's ETS-VIII had two reflectors, each of which was almost as big (19m x 17m).

Classified satellites are rumored to have had larger reflectors. This article claims 77 meters for a signal intelligence satellite it calls MAGNUM. This article claims 100 meters.

To my knowledge nothing official has ever been released about these satellites, so I consider this information speculative and unconfirmed.

Answer 2

KRT-10 (Kosmicheskiy (Space) RadioTelescope) on Salyut-6 in 1978 The world's first space radiotelescope (radioobservatory in orbit). The diameter of the radiotelescope dish was 10 meters.

the KRT-10 radio observatory, which incorporated a directional antenna and five radiometers. The antenna was deployed on the rear docking assembly, with the controller remaining inside the station, and was used for both astronomical and meteorological observations.

https://ru.wikipedia.org/wiki/%D0%9A%D0%A0%D0%A2-10

Answer 3

Here's one of the first launched "larger-than-what-I-would-consider-average" satellite antennas. It was launched aboard the Space Shuttle Endeavor in 1996, and looked a little something like this:

It was inflatable, and didn't last very long but it probably was the inspiration for large, deployable antennas.

The antenna correctly inflated, separating from Spartan-207, before re-entering Earth's atmosphere a few days later, on 22 May. IAE was intended to pave the way for the development of lightweight inflatable structures for space applications.

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The Wikipedia article doesn't state anything about the original size of this IAE, but there's a NASA source that states it is 15.25 meters in diameter and 28.04 meters long!

Spartan was released on May 20; the antenna was successfully deployed and it achieved the proper configuration. The inflation process was captured by the STS-77 crew on still, motion picture and video cameras. For post-mission analysis of the inflatable structure's performance, the antenna surface was illuminated by arrays of lights mounted on the Spartan satellite and the resulting patterns were acquired by Spartan's video recorders. After 90 minutes of operation, the IAE was jettisoned; the Spartan was grappled and retrieved the following day.

It burned up in the atmosphere after tests were completed and it was released from Spartan to avoid further drag on the satellite.

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Below is the original Wikipedia link: https://en.wikipedia.org/wiki/Inflatable_Antenna_Experiment

Additional learning, gratis Organic Marble:

How did this structure fit into the Shuttle and then expand to 28 meters?

Can mirrors be made from fabric?

Answer 4

The largest antenna was the entire Explorer 35 spacecraft. The four whips are often compared to a skyscraper to illustrate their size.