Is Apollo 11 Still on the Moon?

is apollo 11 still orbiting the moon

Once Neil Armstrong and Buzz Aldrin took off from the Moon aboard an ascent stage of LM, they met with Michael Collins in the command module – although NASA engineers assumed Eagle would crash onto its lunar surface, gravitational analysis suggests otherwise – possibly creating an historical artifact!

The Eagle’s Orbit

Neil Armstrong made history when he climbed down from Eagle and set foot on the moon for the first time in 1969, leaving a footprint that became an icon. His words of “One small step for man, One giant leap for humanity” inspired generations of people to explore space while giving many an extraordinary sense of wonderment and excitement about humanity’s potential in exploring it further.

After two hours of exploration in the Sea of Tranquility, they used Eagle to return to Columbia via Lunar Orbit Rendezvous – an extensive series of maneuvers used to dock their craft using coelliptic rendezvous which is forgiving of small navigation errors. This took nearly two orbits and three hours.

At the rendezvous, Eagle was orbiting in an elliptical orbit around the moon and needed to catch up with Columbia before docking. To accomplish this feat, its propulsion system fired to shift from circular to elliptical trajectory; once in position, its powered descent initiation maneuver activated once more so it could begin touching down on lunar surface.

At the same time, Columbia was making its way down to the landing site. By using radar, Columbia’s crew could monitor both vehicles. If LM remained on target for its approach trajectory, it should pass just above the surface of the Moon in about 25% of limb crossings and at that altitude the Eagle should be detectable with radar; according to Meador four two-hour observation periods should provide sufficient coverage in search of one of space exploration’s most significant artifacts.”

But, what if something went wrong during that approach? Suppose the LM’s thrusters failed to perform as intended or its navigation systems malfunctioned? Meador performed new calculations which will be published later in Planetary and Space Science that suggest there’s still a good chance the Eagle is in a similar orbit to when it left Earth.

The Eagle’s Crash Site

Lunar surfaces can be hazardous places to land. Uneven terrain and extreme temperature variations could cause the Lunar Module’s unpowered ascent stage to crash onto the Moon and be rendered useless, an issue which NASA engineers were aware would need to be considered when designing their Apollo 11 Lunar Module in order to safely transport astronauts back to their Command Modules.

They achieved this success by adding a throttleable engine to the LM descent stage – something not available during previous NASA missions – which allowed engineers to control how much thrust was produced from each engine, helping to prevent crashes. Furthermore, the LM had unique avionics which allowed it to land safely from different directions.

Armstrong and Aldrin returned to the LM after spending two hours and 15 minutes on the lunar surface, and began their remaining mission deploying scientific experiments, collecting samples of moon rocks and soil and planting an American flag on it in an iconic photograph that symbolized human achievement on its surface.

As they approached their landing site, Armstrong and Aldrin performed another maneuver known as powered descent initiation to send the LM into an elliptical orbit around the Moon with its closest approach at 15,000 feet. Five times during powered descent initiation, its guidance computer alerted Mission Control about an overload situation; however, NASA simulations prior to mission demonstrated that landing could continue regardless of any alarms generated; so Mission Control told Armstrong and Aldrin to proceed with their planned touchdown.

At 1,500 feet, Armstrong flipped a switch to activate the contact light, switching then to manual control to steer away from West Crater’s dangerous boulder-filled ejecta field and safely touch down in the Sea of Tranquility with only 30 seconds remaining of fuel remaining in his tank.

After returning to the Command Module, astronauts jettisoned Eagle along with its lunar samples. Next, their Lunar Module’s Ascent Stage would then be destroyed through a high-speed crash into lunar soil in order to gather data on its systems durability.

The Eagle’s Debris

On July 21 after awakening from their 10-hour rest period, Apollo 11’s crew were 194,500 miles from Earth and just outside the Moon’s orbit. To accelerate toward their home planet faster and meet entry into its atmosphere more safely, they used the Reaction Control System thrusters of their Service Module’s Reaction Control System to make several midcourse maneuvers over several hours to optimize their trajectory for entry into its atmosphere.

Early in Eagle’s mission, its ascent stage was released into space, leaving it orbiting around the Moon in lunar orbit. NASA engineers anticipated it would eventually crash into its surface; however, recent analysis indicates it may still remain there for some time yet. Meador used data from GRAIL moon probe to model Eagle’s gravitational field before entering its trajectories into software known as General Mission Analysis Tool (GMAT).

GMAT simulates spacecraft orbits as uniform spheres and considers all forces acting upon it, such as gravity from Earth, the Moon, Sun, planets other than Mercury, radiation pressure from sunlight etc. Meador’s model showed that Eagle’s orbit was changing due to Earth’s strange gravity as well as sunlight-radiation pressure pressure causing radiation pressure on it from Sunlight; his expectations were for its distance to drop below 15 km (9 miles).

Armstrong and Aldrin then returned to their LM to retrieve two experiments from its SEQ bay: PSEP to measure moonquakes and LRRR to reflect laser beams sent from Earth for precise distance measurements between Earth and Moon. Once back inside their spacecraft, Aldrin sat down for another CSI burn while Armstrong began a short braking maneuver.

At 127 hours and 16 minutes Ground Elapsed Time, Collins sent out the command for a CSI burn, consisting of a 30-second firing of the LM’s DPS engine to lower its low point. Later that day with both craft lingering behind the Moon, Collins began performing station-keeping maneuvers that brought them together on an intercept course with each other.

The Eagle’s Remains

On July 20, Armstrong and Aldrin transitioned from Columbia into Eagle, their lunar landing module, via a tunnel. Once there, they performed a rigorous checklist to make sure everything was in readiness for return to Earth.

At this point, Eagle used its Reaction Control System thrusters for two minutes to slow to a minimum velocity of 3 feet per second while opening its windows so the astronauts could track landmarks as they came by on their journey toward the Sea of Tranquility on the Moon’s surface. Their prediction proved accurate: Eagle reached it exactly on time at 9:56 PM CDT – marking a huge step for mankind! – with Armstrong proclaiming, ‘That is one small step for mankind.”

As they approached the Moon’s surface, the two LMs closed their hatches to prevent back-contamination procedures and transfered lunar rock samples, film cassettes, solar wind experiment equipment and other gear from Eagle to Columbia as part of back-contamination prevention procedures. Once done, Eagle was jettisoned from Columbia using its thrusters before closing its hatch and jettisoning its rocket engine.

Once the CSI burn was complete, Eagle took roughly an hour to catch up with Columbia. Once in contact, astronauts used various maneuvers over several hours in order to bring both vehicles closer together until finally performing a short braking burn brought them close together in formation.

Apollo 11 crew performed its inaugural lunar surface extravehnal activity (EVA), setting a flag in the soil, photographing various terrain, and deploying their EASEP experiments. Their total time on the Moon’s surface lasted approximately two and a half hours after which they returned back into LM for return journey.

NASA’s GRAIL satellites used data collected during their mission to map the Moon, enabling Meador to use these results of their mapping efforts to predict where Eagle might be found. His research is still in its infancy but should it prove accurate, finding Eagle may only require looking through a telescope.

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