Forty years ago, on February 3, 1984, NASA made history when two astronauts embarked on the first untethered spacewalk. This groundbreaking moment in spaceflight history is still remembered today through pulse-pounding photos that capture the thrill and danger of venturing into the void of space without the safety of a tether.
For decades, astronauts have bravely ventured outside their spacecraft to perform spacewalks, but the majority of these missions involved a safety tether connecting them to their orbital home. However, in 1984, NASA decided to experiment with a new approach to spacewalks. The Space Shuttle Challenger, on its fourth mission, carried a crew consisting of commander Vance Brand, pilot Robert Gibson, and mission specialists Robert Stewart, Ronald McNair, and Bruce McCandless II.
Stewart and McCandless were seen wearing NASA’s Extravehicular Mobility Units (EMUs), or spacesuits as they are commonly known. These suits would play a crucial role in the upcoming untethered spacewalks. On February 7, 1984, the Manned Maneuvering Unit (MMU) made its debut. Unlike previous spacewalks that relied on tethers, the MMU allowed astronauts to venture beyond the cargo bay and conduct tasks away from the spacecraft.
One of the most iconic images from this historic mission was captured by Robert Gibson. It shows Bruce McCandless free-flying in space, propelled by tiny jets and completely untethered. McCandless humorously remarked, “It may have been one small step for Neil, but it’s a heck of a big leap for me.” The image became one of NASA’s most requested and celebrated photographs, symbolizing the incredible achievement of human exploration in space.
The MMU was powered by two dozen gaseous nitrogen thrusters stored in tanks on the astronaut’s backpack. Hand controllers allowed the spacewalkers to adjust thrust and direction, enabling precise navigation during extravehicular activities. While the technology demonstration was successful, many within NASA expressed concerns about the use of a self-propelled and untethered backpack in space.
During the first untethered spacewalk, McCandless ventured a maximum distance of 322 feet away from the Space Shuttle. It’s hard to believe that both McCandless and the Shuttle were traveling at speeds reaching 17,500 miles per hour. The risks of spacewalks, whether tethered or not, were evident, as a collision with micrometeorites or space debris could prove fatal.
McCandless also captured a stunning view of Challenger from his perspective, showcasing the spacecraft against the backdrop of space. Tragically, Challenger was destroyed during a launch in January 1986, resulting in the loss of all seven crew members aboard.
During the STS-41B mission, McCandless and Stewart performed two concurrent spacewalks, practicing procedures intended for capturing and repairing malfunctioning satellites. The duo spent a total of 12 hours and 12 minutes outside the spacecraft. The MMUs used during the mission were marked with serial numbers 2 and 3.
In one photo, McCandless appears to be walking along Challenger’s payload bay, but he was actually being maneuvered above the cargo bay using the Manipulator Foot Restraint (MFR) and Remote Manipulator System (RMS), also known as the “cherry picker.” The RMS, commonly referred to as the Canadarm, allowed for precise and controlled movement in space, essential for tasks such as satellite repairs and space station construction.
Another stunning photo from the mission shows McCandless standing on the cherry picker, highlighting the capabilities of the MMU. However, despite their usefulness, MMUs were only used twice more in 1984 before NASA discontinued their use due to safety concerns. The agency found safer alternatives for astronauts to perform work outside the Shuttle.
Challenger safely returned to Earth on February 11, marking the first landing of a Shuttle at its launch site, the Kennedy Space Center in Florida. The mission lasted nearly eight days and was a resounding success.
While untethered spacewalks are no longer a common practice, NASA did perform one in September 1994 to test a backpack known as Simplified Aid for EVA Rescue (SAFER), designed for emergency situations when astronauts become untethered during EVAs.
The photos from the STS-41B mission continue to captivate and inspire, reminding us of the incredible achievements and risks undertaken by astronauts in the pursuit of space exploration. These pulse-pounding images serve as a testament to the bravery and ingenuity of those who venture into the unknown, pushing the boundaries of human exploration.
