A satellite bigger than the International Space Station (ISS) could not be disguised as space debris. Considering ISS was assembled and constructed in space, this makes it the biggest human fabricated object in Earth orbit. If anything bigger than that was launched and place in Earth orbit, it would be even bigger than ISS. This means it would attract considerable attention and subject to careful surveillance.
The United States Strategic Command already maintains surveillance on known orbital objects including space junk. Space junk is cataloged and accurately tracked.
Space debris, Space junk, Space waste, Space trash, or Space litter is
the collection of defunct human-made objects in earth orbit, such as
old satellites, spent rocket stages, and fragments from
disintegration, erosion, and collisions – including those caused by
the space debris itself. As of December 2016, five satellite
collisions have resulted in generating space waste.
As of 5 July 2016, the United States Strategic Command tracked a total
of 17,852 artificial objects in orbit above the Earth, including
1,419 operational satellites. However, these are just objects large
enough to be tracked. As of July 2013, more than 170 million debris
smaller than 1 cm (0.4 in), about 670,000 debris 1–10 cm, and around
29,000 larger debris were estimated to be in orbit. Collisions with
debris have become a hazard to spacecraft; they cause damage akin to
sandblasting, especially to solar panels and optics like telescopes or
star trackers that cannot be covered with a ballistic Whipple shield
(unless it is transparent)
Even with ground-based tracking orbital traffic is monitored in great detail and with high precision.
Radar and optical detectors such as lidar are the main tools for
tracking space debris. Although objects under 10 cm (4 in) have
reduced orbital stability, debris as small as 1 cm can be
tracked, however determining orbits to allow re-acquisition is
difficult. Most debris remain unobserved. The NASA Orbital Debris
Observatory tracked space debris with a 3 m (10 ft) liquid mirror
transit telescope. FM Radio waves can detect debris, after
reflecting off them onto a receiver. Optical tracking may be a
useful early-warning system on spacecraft.
The U.S. Strategic Command keeps a catalog of known orbital objects,
using ground-based radar and telescopes, and a space-based telescope
(originally to distinguish from hostile missiles). The 2009 edition
listed about 19,000 objects. Other data come from the ESA Space
Debris Telescope, TIRA, the Goldstone, Haystack, and EISCAT
radars and the Cobra Dane phased array radar, to be used in
debris-environment models like the ESA Meteoroid and Space Debris
Terrestrial Environment Reference (MASTER).
All of this clearly indicated that any piece of purported space junk bigger than the ISS would be tracked, cataloged and subject to minute analysis concerning its function and purpose.
The fascist nation in preparing to drop "rods from god" on unsuspecting enemy nations couldn't be done in secret. Just launching the orbital kinetic weapon satellite would be warning enough. There is a high probability that many other nations would mobilize their antisatellite weapons in preparation to destroying it at the slightest provocation. A tungsten rod from orbit exceeds the usual bounds for slightest provocation. Expect this orbital weapon to be subject to multiple attacks from the majority of other nations with space-capacity.