Test Shaft 09

"All these science spheres are made out of asbestos, by the way. Keeps out the rats. Let us know if you feel a shortness of breath, a persistent dry cough, or your heart stopping. Because that's not part of the test. That's asbestos."

- Cave Johnson

Test Shaft 09, codenamed "Zulu Bunsen," is the last in a group of nine shafts reaching approximately 1.5 km up from the deepest parts of the salt mine containing the Aperture Science Enrichment Center. Its construction is of a completely different style and level of technology than that of the modular, panel-dominated space of the modern Enrichment Center. It can be presumed that GLaDOS' monitoring and maintenance systems do not extend into this part of the facility. Chell and a potato-powered GLaDOS travel through this shaft to return to the modern Enrichment Center after Wheatley sends them down an elevator shaft in a fit of rage.

Access
During its operational period, Shaft 09 was accessed by a large main elevator leading to the surface. This elevator was taken offline and sealed long before Chell finds it in Portal 2. Judging from the lack of GLaDOS' presence it was probably sealed before the modern Enrichment Center was constructed in the 1980's-'90s.

Shaft 09 was condemned and various experiment chambers within were vitrified on June 15, 1961. The bottom and top entrances of the shaft were sealed by two gargantuan hatches. The bottom hatch can be opened by pressing two buttons on opposite sides of the entrance cavern within 3 seconds of each other. The top hatch leads to the foundation of the modern Enrichment Center and can be opened using an override button in the gel transport chamber below the hatch.

Reception and Control Complexes
The shaft contains several complexes dedicated to office space, reception for test subjects, and access control to the enrichment spheres. These complexes can be distinguished by era: the reception complex for the repulsion gel spheres was completed in the early 1950s and reflects a time when Aperture was able to attract the best and brightest to test its exotic technologies. Instructional posters and Cave Johnson's prerecorded messages suggest a time of pride and optimism for the company.

The complex for the propulsion gel spheres was completed in the early 1970s after Aperture suffered major financial and legal setbacks. Offices are decorated in brown, yellow and orange paneling typical of 1970s America. Posters caution employees to notify their supervisors if they spot inspectors from any of a long list of government safety agencies. In his messages, Johnson complains about having to hire hobos off the street at $60 per test.

The complex for the conversion gel spheres was completed in the early 1980s when Aperture had begun to replace its employees with robots, leaving the employees themselves to act as test subjects. Posters motivate human employees to accept their robotic replacements and give advice on how to deal with rogue artificial intelligences.

Enrichment Spheres
The shaft is mostly filled with a series of large geodesic asbestos and steel spheres which contain the original chambers used by Aperture Science Innovators for tests of its repulsion, propulsion, and conversion gels in conjunction with ancestors of the modern Handheld Portal Device. Each sphere may contain multiple testing rooms supported by steel pylons and connected by catwalks. Spheres also contain offices and observation rooms around their periphery. Elevators provide transport between spheres.

By the time of Portal 2, most of the testing spheres and the bottom of the shaft itself contain pools of highly corrosive toxic waste. It is unknown whether this waste was part of the cause of the shaft's condemnation or if the pools accumulated in the many years after the shaft was sealed.

Other Test Chambers
Experiments that did not require the space or modularity of the portal/gel tests were located in side chambers accessed by hatches near the '50s and '70s-era reception areas. Almost all of these chambers have been vitrified, presumably by the condemnation date of June 15, 1961, due to the danger presented by the results of the experiments. Cave Johnson's prerecorded messages near these doors describe such absurd side effects as human blood turning into gasoline or "peanut water," excrement turning into coal, and test subjects gaining superpowers. Of particular interest is an unsealed door leading to the dry dock of the Borealis, an icebreaker ship lost during a teleportation experiment.

Pumping Stations
The shaft also contains several pumping stations codenamed Alpha, Beta, and Gamma which pump the three gels up the shaft and into various testing chambers. These stations were taken offline when the shaft was abandoned, but are reactivated by Chell during the events of Portal 2. The stations are in surprisingly good repair given the amount of time passed since they were last maintained. The catwalks have decayed, but the pipe system has survived with only a few broken valves and leaking flanges.

The gel pipe network was designed to feed into the modern Enrichment Center, and Chell restores this connection when she opens the hatch at the top of Shaft 09.

History
See Timeline of the Half-Life universe from 1944 to 1986.

Trivia

 * A poster outside of the first repulsion gel chamber warns test subjects that they must have an Aperture Science Portable Quantum Tunneling Device equipped in order to solve the tests. The poster features a cartoon silhouette of a man wearing a large backpack-like device with a flexible arm. This suggests that Aperture had functioning ancestors of the ASHPD as early as 1953.
 * A display case in the repulsion gel reception area contains awards and a newspaper front page that help describe Cave Johnson's prowess as a shower curtain salesman, the creation of Aperture Science Innovators and the Enrichment Center, and the beginnings of the company's long rivalry with Black Mesa.
 * Dates in the display case, Cave Johnson's recorded messages, and construction dates written on various structures in the shaft significantly alter the Aperture timeline from what was established in text archives from ApertureScience.com. These changes have been added to the timeline.
 * Portal 2's narrative gives no explicit reason why Test Shaft 09 was condemned or why most of the structures in the shaft are dated after the 1961 condemnation.