Why Apollo 18, 19 & 20 Never Flew: The Moon Missions That Died on Paper

“Wait…there were supposed to be ten Moon landings?”
If that question just popped into your head, you’re not alone. Most Americans remember Neil, Buzz, and, if they’re real space buffs, Gene Cernan’s final footsteps in 1972. Few realize NASA originally booked three more voyages, labelled Apollo 18, 19, and 20.

Those flights promised deeper science, risk‑taking landing sites, and the first geologist to step onto another world. Yet they never left the drawing board. This post unpacks why the last three Apollo missions were cancelled, what they would have accomplished, and how the decision still echoes through today’s Artemis program. Buckle up for a tour through budgets, politics, and lost lunar dreams.

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1. 1969: Riding High on Six Successes

1.1 The post‑Apollo master plan

When Apollo 11 touched down in July 1969, NASA had nine Saturn V rockets left in the warehouse—enough to deliver a total of ten crewed landings (Apollos 11 – 20). The roadmap called for:

• Two “H‑class” missions (Apollos 12–14) to hone pinpoint landings.
  
• Five “J‑class” missions (Apollos 15–20) with upgraded Lunar Modules, three‑day stays, and a battery‑powered rover.
  
• Launches every four months, wrapping up by late 1974.
  

In short, Apollo was just hitting its scientific stride when the plug got pulled.

1.2 The changing national mood

While astronauts planted flags, voters worried about Vietnam, inflation, and inner‑city unrest. NASA’s once‑soaring budget had already fallen from a 1966 peak of 4.4 % of federal spending to well under 1 % by 1970. Congressional hawks began treating Moon landings as expensive reruns with diminishing political returns.

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2. The Slow Squeeze: Budgets, Politics and Public Risk Perception

2.1 Sticker shock in the Oval Office

President Richard Nixon’s Office of Management and Budget demanded NASA trim costs. Administrator Thomas Paine floated three options; each slashed at least one Moon mission to free a Saturn V for an Earth‑orbiting space station (what became Skylab).

Fiscal Reality Check	FY 1966	FY 1970	Δ
NASA top‑line (in 2025 $)	~$46 B	~$24 B	–48 %
Share of federal budget	4.4 %	~0.9 %	–80 %

Table 1 – NASA’s shrinking slice of the pie.

2.2 Apollo 13’s close call

April 1970’s oxygen‑tank explosion proved the Moon was still a dangerous frontier. Lawmakers asked: “Why risk more lives for bragging rights we’ve already won?” Paine used the accident to justify locking in a “minimum viable program” and cutting missions en masse rather than one‑by‑one.

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3. Apollo 20: The First Domino Falls (January 1970)

• Decision: Reassign its Saturn V (SA‑513) to launch Skylab as a “dry workshop.”
  
• Official rationale: Maintain momentum toward a permanent space station.
  
• Hidden driver: Money—Skylab on a Saturn 1B would have required risky on‑orbit tank conversion and still cost more.
  

NASA announced the cancellation on January 4, 1970. The agency promised lunar flights would resume after Skylab, but that was optimistic at best.

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4. The Final Blow: Cancelling Apollo 18 & 19 (September 2, 1970)

Facing a $64 million shortfall in FY 1971 appropriations, Paine axed two more landings. A somber press conference made it official: Apollo would end with mission 17 in December 1972.

Key ingredients behind the decision:

• Budget pressure from Vietnam and social programs
  
• Public indifference after “been‑there‑done‑that” sentiment peaked
  
• Fear of a fatal accident that could tarnish Apollo’s legacy
  

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5. Missions That Might Have Been

5.1 Planned landing sites & science goals

Mission	Intended Launch	Candidate Landing Site	Primary Science Targets
Apollo 18	Aug 1973	Copernicus or Schröter’s Valley (Aristarchus Plateau)	Massive sinuous rille, volcanic glass deposits, TLP monitoring
Apollo 19	Feb 1974	Hyginus Rille or Hadley Rille extension	Mare/highland boundary samples, deep lava layers
Apollo 20	July 1974 (pre‑cancellation)	Tycho Rim or Marius Hills domes	Young impact melt, basaltic domes, far‑side comms test

Table 2 – Proposed objectives for the cancelled landings (compiled from NASA site‑selection memos).

5.2 Who would have flown?

Using Deke Slayton’s three-mission crew‑rotation rule, historians generally agree on these “ghost crews”:

• Apollo 18: Richard Gordon (CDR), Vance Brand (CMP), Harrison “Jack” Schmitt (LMP)
  
• Apollo 19: Fred Haise, William Pogue, Gerald Carr
  
• Apollo 20: Charles “Pete” Conrad, Paul Weitz, Jack Lousma
  

Fun fact: Schmitt lobbied hard for a far‑side landing that would have placed satellites in lunar orbit for continuous comms—an idea decades ahead of its time.

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6. Follow‑the‑Hardware: Where Everything Went

Asset	Original Purpose	Ultimate Fate
Saturn V SA‑513	Apollo 20 launch vehicle	Launched Skylab on 14 May 1973
Saturn V SA‑514	Apollo 18	Displayed horizontally at Kennedy Space Center Visitor Complex
Saturn V SA‑515	Apollo 19	Vertical display at NASA Johnson Space Center Rocket Park
LM‑13	Apollo 18 Lunar Module	On exhibit at Cradle of Aviation Museum, NY
LRV‑4	Apollo 18 rover	Never completed; parts cannibalized
Crew members	Moon walkers	Reassigned to Skylab, Shuttle test flights, Apollo‑Soyuz

Table 3 – “Lost & Found”: Hardware and crew destinies.

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7. Downstream Ripples: How the Cancellations Shaped Spaceflight

7.1 Skylab gets its ride

Without SA‑513, America’s first space station would have been delayed or downsized. The dry‑workshop Skylab proved long‑duration human spaceflight, solar observations, and micro‑gravity science—vital stepping‑stones to ISS.

7.2 Birth of the Shuttle

The budget freed by dropping lunar landings helped sell the Space Shuttle as a “low‑cost” next step. Ironically, cost overruns later dwarfed Apollo’s price tag.

7.3 Science, we never got

Geologists still pine for Copernicus crater’s pristine rays and Tycho’s young ejecta. Modern remote‑sensing data hint that those sites hold answers about lunar volcanism—and maybe resources future Artemis crews will tap.

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8. Lessons for Today’s Artemis Program

1. Budget reality always wins. Artemis managers must guard against cost creep or risk Apollo‑style cuts.
   
2. Public engagement matters. Each mission needs a story—Mars prep, resources, STEM inspiration—to keep voters invested.
   
3. Science vs. spectacle. Cancelled Apollo’s show that once “firsts” are done, deeper science must carry the torch; Artemis science definition teams are right to push for drills, seismometers, and sample return.
   

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9. Key Takeaways

• Money and politics, not technology, killed Apollo 18‑20.
  
• The hardware existed; the will did not.
  
• Cancelling the final Moon shots enabled Skylab and, indirectly, the Shuttle, but cost us priceless geology.
  
• The story is a cautionary tale as NASA aims to return to the Moon with Artemis III in 2026 and build a sustainable lunar blueprint thereafter.
  

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Conclusion & Next Steps

Apollo’s cancelled trio reminds us that space history is written as much in board rooms as in blastoffs. Want to dive deeper?

• Explore more Apollo insights on my site: Apollo11Space.com
  
• Watch mission animations, archival audio, and my weekly “Moon Monday” live streams on YouTube: Subscribe here
  

If you found this breakdown useful, share it with a fellow space enthusiast, because the best missions are the ones we still talk about, even when they never launched. 🚀

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