This week marks the 15th anniversary of the signing of the Comprehensive Nuclear-Test-Ban Treaty, which when ratified will finally close the door on the archaic practice of nuclear weapons testing.

In 1985, I orbited the Earth on the space shuttle Discovery amid the tensions of the Cold War. That experience, during a time when the nuclear arsenals of the United States and Russia were continuing to grow, offered me a unique perspective on the pace of technological advancement, the nature of global security and the fragility of our shared home.

Nothing else threatens to so quickly and permanently extinguish that home than nuclear weapons.

After I left Congress, the U.S. Senate voted whether to ratify the Comprehensive Nuclear-Test-Ban Treaty (CTBT). During the debate, Sen. Orrin Hatch, who voted against the treaty, presciently remarked that "there may be a day when my colleagues and I can be convinced that science-based technology can ensure the reliability and safety of our arsenal to a level that matches what we learn through testing. That would be a time to responsibly consider a Comprehensive Test Ban Treaty."

That day has arrived. Now is the responsible time for the United States to ratify the Comprehensive Nuclear-Test-Ban Treaty.

We must move beyond Cold War-era thinking: Explosive nuclear weapons testing jeopardizes our nation's security instead of ensuring it. Banning nuclear weapons testing will make it tougher for nuclear-armed states to develop more advanced warhead designs.

Once it is in effect, the CTBT provides for critical on-site inspections of nations suspected of testing. The treaty also creates an international norm that would cause a nation that defies the ban to become isolated, lose prestige and be subject to prompt international sanctions. Ratification of the CTBT is the United States' best opportunity to constrain the nuclear ambitions of our foes, while preserving our own strategic interests.

One-time CTBT skeptics, such as former National Security Advisor Brent Scowcroft and former Secretary of State Henry Kissinger, are now ardent proponents of the treaty. These men, both former cold warriors like myself, recognize that continuing to allow the Cold War to guide our nuclear strategy is not only naive, but actually could compromise the very national security which we've dedicated our lives to preserving.

In 2002, the National Academy of the Sciences conducted a study of the treaty's technical issues. This report concluded that the U.S. "has the technical capabilities to maintain confidence in the safety and reliability of its existing nuclear-weapon stockpile under [a test ban]." The report also declared that a program of nuclear test explosions was unnecessary to address any problems that may hamper the reliability of our nation's nuclear stockpile.

The National Academy is about to release an updated study, which will find that technological advancements have further strengthened arguments in favor of ratification.

The U.S. will have limited need to develop new weapons for decades. New studies demonstrate that plutonium parts in warheads are not affected by aging for at least 85 years, much longer than previously thought.

The number of worldwide monitoring stations capable of looking for evidence of nuclear testing has increased exponentially over the last 12 years (from 20 to 280 operational facilities). These facilities are located in more than 80 countries around the world and can detect underground nuclear explosions as small as 0.1 kilotons. In 2006, when North Korea tested a weapon, the explosion was detected at more than 20 sites within two hours. North Korea's second test, in 2009, was detected by 61 stations. The monitoring facilities have proved their utility beyond testing as well, by tracking the radioactive plumes emanating from the Fukushima nuclear plant.

As a former U.S. senator, as well as a U.S. Navy and U.S. Air Force pilot, I have always supported a strong national defense. As a man who gazed upon Earth from space and understands the threat nuclear weapons pose to all terrestrial life, I recognize that ratifying the CTBT is a critical step toward improving United States national security and buttressing global efforts to reduce and eventually eliminate the nuclear weapons threat.

Jake Garn is a former U.S. senator from Utah, serving from 1974-1993.