Fifty Years Ago: Apollo 10 … ‘to Sort Out the Unknowns’

About one month before their mission, Apollo 10 astronauts Thomas P. Stafford, Eugene A. Cernan and John W. Young held a press conference at NASA’s Kennedy Space Center. The trio described their upcoming flight as essentially a dress rehearsal for the Moon landing, with Stafford stating that Apollo 10 will “sort out all the unknowns and actually pave the whole way for the lunar landing mission.” 

Apollo Spacecraft Program Manager George M. Low explained that the plan for Apollo 10 was to do “everything that we did on Apollo 9—only in lunar orbit.”

Officials also announced that the Apollo 10 Command Module may carry a color TV system in addition to the standard black-and-white cameras. The color camera, equipped with a zoom lens, would provide live TV broadcasts from the spacecraft during critical mission operations and give viewers at home a glimpse of life aboard an Apollo spacecraft during a lunar mission. Views of the Earth, as well as the lunar landscape, were also expected.

Left: From left to right, Apollo 10 astronauts Thomas Stafford, John Young and Eugene Cernan participate in crew press conference at Kennedy. Right: Stafford, Young and Cernan pose with their mission patch. Image Credits: NASA

Stafford, Cernan and Young announced the call signs they gave their spacecraft to aid in communications with the ground, with the Command and Service Module (CSM) dubbed “Charlie Brown” and the Lunar Module (LM) “Snoopy” after characters in the Peanuts© comic strip by Charles M. Schulz.

They went on to describe what was to come with their eight-day mission, beginning with a very busy first day. After launching from Launch Pad 39B, the crew would make two revolutions around Earth while still attached to the Saturn V’s S-IVB third stage. The S-IVB would then reignite, propelling them toward the Moon. Shortly after that, they would undock Charlie Brown from the S-IVB, turn it around and dock with Snoopy, which would be tucked away in the top of the rocket stage for a maneuver called transposition and docking. After jettisoning the S-IVB, the crew would coast toward the Moon for about three days … up until the Service Propulsion System (SPS) fired to drop them into orbit around the Moon.

Later, Stafford and Cernan would enter the LM and undock, leaving Young alone in the CSM. Using the LM’s Descent Propulsion System engine to lower their altitude, Stafford and Cernan would descend to about 50,000 feet above the lunar surface and photograph the primary landing site for Apollo 11 in the Sea of Tranquility. Snoopy would travel up to 350 miles from Charlie Brown during these maneuvers.

As the descent stage is jettisoned, the Ascent Propulsion System engine would then fire in a simulated litfoff from the Moon, and Stafford and Cernan would complete a rendezvous and docking with Young in the CSM. After jettisoning the LM’s ascent stage and completing 11 more orbits around the Moon, Apollo 10 would fire up the SPS engine for the return trip to Earth—ending with a maginificent splashdown in the Pacific Ocean. Except for an actual descent to and touchdown on the surface, Apollo 10 would follow all the steps of the actual Moon-landing mission.

Engineers at Kennedy completed the Flight Readiness Test between April 7 and 10, which would ensure that all the vehicle systems were in a state of flight readiness and functioned well with ground-support equipment. Successful completion of the Flight Readiness Test paved the way for the Countdown Demonstration Test in early May—a dress rehearsal of the actual countdown for the launch.

Stafford, Cernan and Young took part in an emergency egress drill at Launch Pad 39B, including inspecting the slide wire escape mechanism and the blast room, a concrete reinforced structure under the launch pad to be used in case of a catastrophic emergency during fueling of the rocket or the countdown.

Left: Apollo 10 astronauts (front to back) Young, Stafford and Cernan inspect the slide wire escape mechanism at the top of Launch Pad 39B. Right: Apollo 10 astronauts (left to right) Young, Stafford and Cernan are briefed on escape protocols inside the blast room beneath the launch pad. Image Credits: NASA

Left: Young in the Command Module flight simulator. Right: Cernan (left) and Stafford in the Lunar Module flight simulator. Image Credits: NASA

The Apollo 10 crew participated in simulations of various phases of their mission using LM and CSM flight simulators at Kennedy. Flight controllers in mission control at the Manned Spacecraft Center in Houston, now Johnson Space Center, participated in many of these simulations with the crew. 

Left: The Apollo 10 backup crew (left to right) L. Gordon Cooper, Edgar Mitchell and Donn Eisele prepare for water egress training. Right: The Apollo 10 backup crew in the life raft. Image Credits: NASA

Apollo 10 backup crew members L. Gordon Cooper, Edgar D. Mitchell and Donn F. Eisele completed water egress training in the Gulf of Mexico on April 4. Using a boilerplate Apollo Command Module and tended by the motorized vessel Retriever, the astronauts practiced emerging from the capsule as if after splashdown. With the assistance from divers, the crew waited for a helicopter to retrieve them as they floated on life rafts in the ocean.

Celebrate Apollo 10 on April 25

Relive the thrills of all things Apollo on April 25. Doors to the Teague Auditorium will open at 9 a.m. as Annette Hasbrook with the Orion Program moderates an Apollo 10 Lessons and Legacies panel discussion featuring Apollo astronaut Gen. Thomas Stafford; Apollo Propulsion Engineer Bernie Rosenbaum; astronaut Randy Bresnik; and Lara Kearney, deputy Gateway Program manager. Come early and snag a great seat!

Silver Snoopy awardees, please wear your Silver Snoopy pins to the panel so that you can be recognized.

In the Teague Auditorium lobby following the panel, there will be Gateway and Orion exhibits, an exhibit on the connections between the Silver Snoopy Program, the Apollo 10 Lunar Module "Snoopy" and the "Snoopy in Space" cartoons created by Charles M. Schulz during Apollo. Also, enjoy Space Snoopy—live, human-sized and poised for photo ops. Snacks and beverages will be provided by Starport.

Later that evening on April 25, Space Center Houston will host a Thought Leader Series with Stafford. Get your free ticket to that event, which starts at 7 p.m., here.

John Uri, Johnson Space Center