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Friday, March 1, 2024

Spider: a lunar rehearsal in Earth orbit

© Mark Ollig

On Sept. 12, 1962, President John F. Kennedy spoke at Rice University in Houston, TX, where he set the goal of landing a man on the moon and bringing him back safely to Earth before the decade’s end.

While in Houston, President Kennedy visited what is now known as the Johnson Space Center.

During his visit, he was shown a mock-up of the lunar excursion module for use on the moon.
Although initially designated the lunar excursion module and known by the acronym LEM, it was later shortened to lunar module, with the acronym LM.

At 11 a.m. EST, March 3, 1969, three astronauts aboard the Apollo 9 spacecraft lifted off aboard a Saturn V rocket from Launch Pad 39A at NASA’s Kennedy Space Center (KSC) on Merritt Island, FL.

The F-1 engines on the Saturn V rocket were the most powerful single-chamber liquid-fueled engines developed at the time.

These engines generated 7.5 million pounds of thrust, propelling the Apollo 9 spacecraft into Earth orbit.

Astronauts on board were Commander James A. McDivitt (1929 to 2022), command module pilot David R. Scott (1932 to present), and lunar module pilot Russell L. Schweickart (1935 to present).

Following liftoff, the flight was managed by Mission Control at the Johnson Space Center under Flight Director Eugene Kranz.

Apollo 9’s primary objective was to test all aspects of the lunar module in space, ensuring it was ready for lunar operations.

During their orbit around the Earth, two astronauts aboard the lunar module (LM) nicknamed “Spider” conducted tests and practiced rendezvous and docking maneuvers with the command-service module (CSM) called “Gumdrop.”

The lunar module was nicknamed “Spider” due to its spidery leg-like shape, while the command-service module was called “Gumdrop” because of its candy-like appearance when it arrived at KSC wrapped in blue cellophane.

The Apollo command-service module was designed to support the crew during the mission and provide life support and operational functions.

The detachable command module (CM) spacecraft ensured their safe return to Earth.

During liftoff, the lunar module was positioned beneath the CSM with its legs folded inside the spacecraft-to-lunar module adapter (SLA) compartment attached inside the third stage of the Saturn V rocket.

The astronauts conducted a series of five engine burns on the CSM’s service propulsion system (SPS) to simulate various scenarios, including LM rescues.

The docking and rendezvous maneuvers of the CSM and LM began with extracting the lunar module from its “garage” inside the SLA.

These exercises were necessary for testing the docking mechanism’s reliability, specifically when firing the SPS engine.
McDivitt and Schweickart then pressurized the tunnel connecting Gumdrop and Spider by removing the hatch of the CSM and attaching the umbilical connectors, providing power, communications, and life support for the LM.

During the Apollo 9 mission, Scott performed an extravehicular spacewalk.

Floating through the open hatch of the CM, he took photographs, collected thermal samples from the spacecraft’s exterior, and verified the operation of equipment and various procedures for the upcoming Apollo 11 moon landing.

Schweickart and McDivitt conducted practice maneuvers of the LM descent and ascent engines firing on orbital change patterns, simulating lunar-orbit rendezvous, and backup abort procedures.

Schweickart would perform a spacewalk outside the LM wearing the portable life support system (PLSS) backpack.

The PLSS maintained suit pressure, provided breathable oxygen, filtered out contaminants, circulated and maintained comfortable environmental temperatures, maintained oxygen levels, enabled communications, and monitored his overall health parameters.

Schweickart confirmed that all the systems in the PLSS backpack functioned accurately.

He could effectively work outside the lunar module and complete tasks in the weightless environment future astronauts would experience on the moon.

A seven-pound Westinghouse camera designed for the moon landing was successfully tested; the pictures taken were described as “spectacularly clear.”

Inside the LM ascent stage (crew cabin), McDivitt and Schweickart separated from the attached lunar module descent stage (lower platform), which burned up during re-entry into the Earth’s atmosphere nine days later.

After firing the LM ascent stage engine, McDivitt and Schweickart navigated the spacecraft to a lower orbit to line up for a rendezvous with the CM, which Scott piloted.

They successfully rendezvoused and docked both their spacecraft.

After McDivitt and Schweickart re-entered the CM, the empty LM ascent stage was detached and floated away.

On March 13, 1969, the Apollo 9 command module separated from the service module, re-entered Earth’s atmosphere, and splashed down in the Atlantic Ocean at 12:00:54 p.m. EST, concluding a mission that lasted 241 hours.

The LM ascent stage remained in Earth’s orbit until Oct. 23, 1981, when it disintegrated upon re-entering the planet’s atmosphere.

Today, the California San Diego Air and Space Museum displays the Apollo 9 command module “Gumdrop.”

Apollo 9’s success led to Apollo 10, the dress rehearsal for the lunar landing, and finally, the historic Apollo 11 lunar landing, nearly seven years after Kennedy’s speech at Rice University.

My model of the Apollo 9 lunar module docked with the
command-service module with added labels

My model of the docked Apollo-Lunar Module and Command-Service Module