The second Watchtower was an orbital command center for the Justice League. It was built to replace the original Watchtower that was sacrificed to save the Earth during the Thanagarian invasion. Several other, smaller annexes were in orbit close by.
Two years after the Thanagarian invasion, the Justice League decided to not only rebuild but also considerably expand its roster. With the League's growing membership, a new base of operations was needed, thus the Watchtower II was built. Whether or not this new Watchtower was built by Batman in similar secrecy as its predecessor from Wayne Enterprises stockholders, is unknown. The second Watchtower was significantly larger and had a far greater logistical presence.
During the Dark Heart incident, J'onn introduced to the United States government the Watchtower's Binary Fusion Generator, a nuclear weapon aboard the base, much to the surprise of the government. The cannon was used to delay the advance of the Heart's forces by digging a deep trench while the military took over evacuations. Given the gravity of the incident, the government begrudgingly allowed the use of said weapon, but left them suspicious of the Justice League. General Wade Eiling and Amanda Waller, both members of Project Cadmus, asserted that the existence of such a weapon could potentially make the Justice League a global threat. Knowing this, Lex Luthor cannily used the Generator as a "flashpoint" to discredit the League, taking remote control of it and using it to fire down on Cadmus headquarters, causing massive devastation in the surrounding area. Though there were no fatalities, tempers ran high. After Luthor was exposed and apprehended, Superman announced that the cannon had been permanently dismantled. Some, including Eiling, remained skeptical.
The Watchtower was originally slated to be decommissioned (therefore the disbandment of the Justice League altogether as well) after the Cadmus incidents, but instead was used in tandem with the League's new ground-based headquarters, the Metro Tower.
Following Darkseid's resurrection, the Watchtower witnessed firsthand the god's massive army, prompting Shayera to call for emergency transport, allowing the Justice League's entire roster of superheroes to teleport directly to where the invasion forces were concentrated.
The new Watchtower is built to accommodate the expanded Justice League. Unlike the old Watchtower, its successor has several annexes orbiting nearby. In addition to new superheroes enlisting to the Justice League, an extensive support staff was required for the base's daily operations.
Promenade and control deck
Located at the main base, the control deck serves as the Watchtower's main seat of operations. Since the League's expansion, J'onn filled the role of mission coordinator, keeping watch on a global scale and handing out assignments based on the availability, as well as the capabilities of its superhero roster. While known for his intellect and wisdom thus being a perfect candidate for the job of coordinator, J'onn insisted to have the role, as he had no existing loved ones on Earth to leave behind. As such, he was not known to personally engage in missions since the establishment of the new base. The control room is also known to have a direct communications link to the President of the United States.
Below the control room is the promenade fitted with a teleportation deck that could send out at most seven people at a time. In cases of omega-level (i.e. global) threats, emergency teleportation could be used to quickly deploy heroes who are not aboard the Watchtower.
The new Watchtower is equipped with a wide hangar facility of at least nine launch pads to support the fleet of new Javelins, as well as holding bays for large craft, typically used for humanitarian efforts. The Javelin launch pads have an emergency drop-off option in cases that require urgent attendance. Batman invoked this function when a missile with a Kryptonite warhead was fired at the island of San Baquero, where he used a Javelin to steer the missile off-course.
After the League was expanded, the Conference Room is a place where the founding members go to talk about important events or to plan out situations. In rare times, the conference room also serves as a courtroom of-sorts. The only known case this has happened was when the founding members concluded that Doomsday could not be imprisoned anywhere on Earth safely, thus prompting Superman to use his Phantom Zone projector to banish the brute to the penal dimension indefinitely.
A vast collection of items confiscated from missions are kept in a high-security storage facility, away from unscrupulous hands. Some of the items stored here are:
- The Annihilator (stolen by Task Force X, and later destroyed by Wonder Woman and Shayera)
- A Gorilla City hover bike
- Grodd's mind control helmet
- The Weather Wizard's wand
- Pieces of Lex Luthor's giant robot
- Pieces of Toyman's giant robot
- Lex Luthor's battlesuit
- Several Thanagarian melee weapons
- Lex Luthor's energy disruptor
Given the Watchtowers size and complexity, a sizable staff and hero complement; facilities such as an infirmary, a laboratory, a cafeteria, gym and sleeping quarters are available.
Several heroes many of whom were aliens, non-human in general took up long term or permanent residence aboard the station. Standard quarters consisted of a bed large enough to accommodate two adults with attached end table, column lighting, a computer terminal and desk and clothing/equipment locker, though they can be customized per the discretion of the occupant. For example, Wonder Woman's quarters has an ancient Greek motif, while The Question's is characteristically cluttered and riddled with interconnecting conspiracy webs. Nearby shower areas are also nearby. Quarters are opened through passcodes unique to each League member, though founding members reserve the right to override any security and enter the room using their identification codes for whatever purpose it may serve. One such case was when Wonder Woman tried to steal Shayera's mace before going to a mission to Tartarus. Batman, Superman and Wonder Woman's identification codes are 001, 002 and 003 respectively. In addition, J'onn and Flashs' codes are 004 and 006, as shown in the episodes Flashpoint and I Am Legion. Based on context clues, it can be assumed that Green Lantern is 005, and Hawkgirl is 007, due to her having rejoined the League following the reconstruction of the Watchtower.
The Watchtower possessed a commissary, a huge seating and eating area where members and presumably staff alike dined and relaxed pre/post mission.
Binary Fusion Generator
Perhaps the most powerful weapon aboard the new Watchtower was the Binary Fusion Generator. Put into commission as a countermeasure for threats similar in proportion as the Thanagarian invasion, J'onn describes the cannon as "a gun with the punch of a small nuclear weapon". While the Binary Fusion Generator was exceptionally powerful and usually fired with pinpoint accuracy, operating it would require much of the Watchtower's available energy, temporarily disabling its sensor devices and primary functions for an hour, except life support, communication links and artificial gravity.
The Generator could fire a beam of energy at Earth with pinpoint accuracy, though not fast enough to shoot down a missile in flight. The major disadvantage of using it was that it drained all of the Watchtower's available energy for an hour, disabling its sensor devices and all available functions, except minimal life support and communications (meaning it would take the League an hour to even be able to assess the effectiveness of the blast).