Air date: 1990-01-09

Runtime: 55 min

NOVA reports on the 100-year-old legacy of pollution from mining that poisons the once-pristine waters of the Rocky Mountain states. Acid Rain and economic development also contribute to stress on the West's scarce water supply.

Air date: 1990-01-23

Runtime: 55 min

Using some of the largest machines ever built on earth, American and European physicists race to discover one of the most fundamental and most elusive objects in nature—the top quark.

Air date: 1990-02-06

Runtime: 55 min

Sixty-five years after attempts to ban them, chemical weapons pose more of a threat than ever. NOVA looks at the problem of controlling substances that are easily produced and cruelly effective.

Air date: 1990-02-13

Runtime: 55 min

NOVA examines an alarming nuclear waste problem at the Hanfrod Nuclear Reservation in eastern Washington state, where 45 years of mismanagement in the nuclear weapons industry will cost billions to correct.

Air date: 1990-02-27

Runtime: 55 min

Covering last year's Exxon Valdez oil spill from an unexplored angle, NOVA focuses on how technology failed in preventing, containing and cleaning up the Alaskan disaster.

Air date: 1990-03-20

Runtime: 55 min

China in the 13th century was the richest, most powerful, most technologically advanced civilization on earth. NOVA looks at how China achieved what it did, and what in Chinese politics, culture and economy kept it from doing more. Part one of a four part series.

Air date: 1990-03-27

Runtime: 55 min

NOVA examines the extraordinary transformation that propelled Europe outward into the world from the 15th to 18th centuries, while China remained the insular middle kingdom. Part two of a four part series.

Air date: 1990-04-03

Runtime: 55 min

Ever wonder how junk mail finds you? NOVA investigates the hidden world of direct marketing, pointing out how advertisers know a lot more about us than we think.

Air date: 1990-04-10

Runtime: 55 min

NOVA covers China's long road to economic and technological equality with the West, punctuated by frequent setbacks such as the 1989 massacre of pro-democractic demonstrations in Beijing. Part four of a four part series.

Air date: 1990-10-02

Runtime: 55 min

This documentary covers the surprising tale of an average systems administrator who stumbled upon a KGB spy operation. Clifford Stoll carried out one of the first successful digital forensics investigations by tracking down Markus Hess, a KGB hacker, after noticing a discrepancy in the logs of a University of California computer.

Air date: 1990-10-09

Runtime: 55 min

NOVA visits Neptune, the planet that took Voyager 12 years to reach. Mysteries abound in and around this big, blue world at the outer limits of the solar system. Actor Patrick Stewart hosts.

Air date: 1990-10-16

Runtime: 55 min

NOVA chronicles the Voyager space mission—from Earth to the ends of the solar system. Jupiter, Saturn, Uranus and dozens of moons star in this epic voyage of exploration. Actor Patrick Stewart hosts.

Air date: 1990-10-23

Runtime: 55 min

Sixty-five years after attempts to ban them, chemical weapons pose more of a threat than ever. NOVA looks at the problem of controlling substances that are easily produced and cruelly effective.

Air date: 1990-10-30

Runtime: 55 min

NOVA examines the troubled past and promising future of blimps, zeppelins, cyclocranes and other species of airships. There's life in the old gasbags yet.

Air date: 1990-11-06

Runtime: 55 min

NOVA looks at the high-stakes quest to predict earthquakes. Despite past disappointments, geologists still hope to divine the clues that precede nature's ultimate upheavals.

Air date: 1990-11-13

Runtime: 55 min

Robotic weapons that seek out and destroy ships, planes, and other targets are the wave of the future. NOVA questions whether their proliferation may spell an end to superpower invincibility.

Air date: 1990-11-20

Runtime: 55 min

Is the ivory ban in the elephant's best interest? NOVA looks at the controversial strategies to save the world's largest land animal from extinction.

Air date: 1990-11-27

Runtime: 55 min

Ever wonder how junk mail finds you? NOVA investigates the hidden world of direct marketing, pointing out how advertisers know a lot more about us than we think.

Air date: 1990-12-04

Runtime: 55 min

NOVA profiles the llama, alpaca, vicuna and guanaco of South America. At one time nearly extinct, these four members of the camel family are exceptionally well adapted to life in the beautiful high Andes.

Air date: 1990-12-18

Runtime: 55 min

NOVA tracks a mysterious disease that suddenly and fatally attacks the children of a small Brazilian town. Researchers from the Centers for Disease Control in Atlanta are called in to crack the case.