THIS DAY IN SPACE

Monkeys Able and Baker Survive Spaceflight
On May 28, 1959, the United States achieved a critical milestone in space biology by launching and safely recovering two monkeys—Able, a rhesus macaque, and Baker, a squirrel monkey—aboard a Jupiter missile. The mission, conducted by NASA and the U.S. Army, was designed to test the effects of space travel on living organisms in preparation for human spaceflight. The monkeys were launched from Cape Canaveral and experienced approximately 9 minutes of weightlessness during a suborbital flight that reached an altitude of 360 miles. They were enclosed in specially designed capsules to monitor vital signs, physical movements, and neural responses under zero gravity and high-G environments. After the flight, both monkeys were recovered in good health, making this the first time primates were successfully returned alive after space travel. The success of this mission provided valuable data on biological stress factors in space and was a key stepping stone toward sending humans beyond Earth’s atmosphere. Able sadly died a few days later due to a surgical complication, but Baker lived several more years and became a celebrated figure in space science outreach.

Phoenix Lander Sees Evidence of Water Ice on Mars
On May 28, 2008, NASA's Phoenix Mars Lander transmitted one of its most significant early discoveries—bright material uncovered by the robotic arm during trenching appeared to be water ice. This finding, captured in images shortly after landing in the Martian arctic plains, supported long-held theories that water existed just beneath the planet’s surface in frozen form. Initially, the bright material was speculated to be salt or another mineral, but subsequent images taken days later showed the material sublimating, a key indication of water ice exposed to the thin Martian atmosphere. This discovery confirmed that Mars had stores of water just below its surface—critical for understanding the planet’s climate history and its potential to support microbial life. The Phoenix mission was equipped with various instruments including a robotic arm, a wet chemistry lab, and a thermal and evolved gas analyzer (TEGA) to conduct soil analysis. Its success revitalized interest in Martian polar exploration and laid the groundwork for future missions that would pursue the potential for life and human colonization. The Phoenix Lander operated for five months—well beyond its planned three-month lifespan—before losing contact due to the harsh Martian winter.