The first successful American "astronaut" is on display at the Smithsonian in the Apollo to the Moon exhibition. It’s not Alan Shepard, but Able, a rhesus monkey.

Able and a squirrel monkey named Baker were the first American animals to enter space and return safely. On May 28, 1959 at Cape Canaveral, Able was placed in the nose cone of Jupiter AM-18 secured by a contour cradle made of fiberglass with sponge rubber lining specifically built for her body. Included in the cradle were multiple electrodes used to collect information on Able’s reaction to noise, acceleration, deceleration, vibration, rotation, and weightlessness. The cradle was then placed in a capsule with a life support system that included oxygen, moisture and CO2 absorbers, and electrical heating and cooling systems to keep the monkey alive. Baker was placed her in own separate capsule in the nose cone.

Able and Baker’s mission lasted for approximately 16 minutes, nine of which they experienced weightlessness. The two monkeys traveled to an altitude of over 300 miles and 1,700 ground miles south of the launching point. After recovery by the naval ship USS Kiowa, the primate space travelers were reported as unhurt and in good spirits.

After recovery, the two monkeys were flown to Washington, DC for a press conference, where they were treated like celebrities. They even appeared on the cover of LIFE magazine on June 15, 1959. Able was awarded a medal and Certificate of Merit from the American Society for the Prevention of Cruelty to Animals.

Able was not the first choice for this mission. Another rhesus monkey had been extensively trained for the flight, but was replaced with Able only two weeks before the launch. The first candidate was born in India, and President Eisenhower determined that this might offend the Indian people who view rhesus monkeys as sacred animals. Therefore, American-born Able from Independence, Kansas was the new choice.

Unfortunately, Able died on the operating table at Armored Medical Research Laboratory (AMRL) in Fort Knox  just four days after her space flight. She was having an Electroencephalography (EED) electrode removed, a routine procedure. An EED measures electrical activity of the brain. The incision site was a shallow half inch, but anesthesia was used to save Able from discomfort. While under the anesthesia, her heart abruptly stopped. Extensive measures were taken to save her, to no avail. On March 22, 1960, Able’s body was transferred to the National Air and Space Museum and the National Museum of Natural History preserved her.

Able’s space partner Baker, or Miss Baker as she has been known since her flight, lived out her days first at the Naval Aerospace Medical Center in Pensacola, Florida and then at the U.S. Space and Rocket Center in Huntsville, Alabama. On November 29, 1984, Miss Baker died of kidney failure at Auburn University, making her the oldest living squirrel monkey in captivity. Miss Baker’s grave can be seen at the U.S. Space & Rocket Center frequently with a banana or two on top.

Thanks to Able and Miss Baker, NASA and the U.S. military were assured that humans could survive in space. These two monkeys paved the way to human exploration in space.