SEI Swan Song: International Lunar Resources Exploration Concept (1993)

In the top image, the Soviet Union's two-stage Energia heavy-lift rocket and Buran reusable shuttle orbiter ride a transporter to a launch pad at Baikonur Cosmodrome in Kazakhstan. A sturdy armature designed to hoist the combination upright on the pad obscures Energia's lower half. In the bottom image, 59-meter-tall Energia stands on a launch pad bearing Polyus, an experimental military payload developed in response to the U.S. Strategic Defense Initiative. After the Soviet Union crumbled and Russia became a potential international supplier of rockets and spacecraft, hopeful NASA advance planners tentatively tapped Energia to launch hardware for piloted Moon and Mars missions. Image credit: NPO Energia.

By the close of 1992, the handwriting had been on the wall for the Space Exploration Initiative (SEI) for more than two years. President George H. W. Bush had launched his Moon and Mars exploration initiative on the 20th anniversary of the Apollo 11 lunar landing (20 July 1989), but it had almost immediately run headlong into a minefield of fiscal and political difficulties. The change of Presidential Administration in January 1993 was the final nail in SEI's coffin. Nevertheless, exploration planners across NASA continued to work toward SEI goals into early 1994.

In the same period, the Soviet Union was falling apart. Even as Bush called on NASA to return astronauts to the Moon and launch them onward to Mars, Soviet domination in eastern Europe collapsed, then the Soviet Union itself began to disintegrate. A bungled coup d'etat in August 1991 undercut the authority of Soviet President Mikhail Gorbachev and led to the official demise of the Soviet Union on 26 December 1991. The largest state on Earth divided into more than a dozen countries, with the Russian Federation under President Boris Yeltsin emerging as the most significant.

The end of the U.S.-Soviet Cold War created dangers and opportunities. Some feared that, impelled by economic chaos in the former Soviet Union, scientists and engineers would sell their skills and knowledge abroad, leading to unprecedented global nuclear proliferation.

Others noted that high-level Soviet space officials had begun to peddle their space hardware at important aerospace meetings in the late 1980s. They saw an opportunity to, among other things, save the U.S./European/Japanese/Canadian Freedom Space Station from cancellation. Yeltsin and Bush agreed to wide-ranging space cooperation in June 1992, partly in the hope that NASA money might help to forestall an exodus of Russian aerospace talent.

In February 1993, Kent Joosten, an engineer in the Exploration Program Office (ExPO) at NASA's Johnson Space Center (JSC) in Houston, Texas, proposed a plan for lunar exploration which, he hoped, would take into account the emerging realities of post-Cold War space exploration. His International Lunar Resources Exploration Concept (ILREC) would, he wrote, reduce "development and recurring costs of human exploration beyond low-Earth orbit" and "enable lunar surface exploration capabilities significantly exceeding those of Apollo." It would do these things by exploiting the abundant oxygen in the lunar regolith (that is, surface material) as oxidizer for burning liquid hydrogen fuel brought from Earth, shipping most cargo to the Moon separate from crews, employing Earth-based and Moon-based teleoperations, and cooperating with the Russian Federation.

Joosten's concept was a variant of the Lunar Surface Rendezvous (LSR) mission mode. The Jet Propulsion Laboratory (JPL) in Pasadena, California, put forward LSR in 1961 as a candidate mode for achieving President John F. Kennedy's goal of a man on the Moon by the end of the 1970s. In 1962, after NASA selected Lunar Orbit Rendezvous (LOR) as its Apollo lunar mission mode, the LSR scheme faded into obscurity. Joosten's concept was not inspired by the early 1960s scenario; instead, his work drew upon contemporary In-Situ Resource Utilization (ISRU) and Mars surface rendezvous techniques proposed for use in NASA's Mars Design Reference Mission 1.0 and Martin Marietta's Mars Direct scenario.

The Apollo LOR mode was designed to permit the U.S. to reach the Moon quickly and relatively cheaply, not to support a sustained lunar presence. It split lunar mission functions between two piloted spacecraft, each of which comprised two modules. Modules were discarded after they fulfilled their functions.

Joosten's ILREC piloted moonship would be roughly intermediate in size between the Apollo Lunar Module (LM) (left) and the Apollo Command and Service Module (CSM) (right). This NASA artwork from 1966 is a partial cutaway showing two blue-clad astronauts moving from the CSM to the LM in preparation for undocking and landing on the Moon. A third astronaut, who will remain in lunar orbit, awaits LM undocking strapped into his CSM couch.

At the start of an Apollo lunar mission, a Saturn V rocket launched a Command and Service Module (CSM) mothership and a Lunar Module (LM) Moon lander. The mighty rocket's S-IVB third stage boosted the CSM and LM into a parking orbit about the Earth; then, about 90 minutes later, reignited to push itself, the CSM, and the LM out of Earth orbit toward the Moon. This maneuver, called Trans-Lunar Injection (TLI), marked the real start of the lunar voyage.

After TLI, the CSM separated from the spent S-IVB, turned end-for-end, docked with the LM, and extracted it from the S-IVB. The S-IVB then vented propellants to change its course so that it would not interfere with CSM/LM navigation. Beginning with Apollo 13, the S-IVB was intentionally crashed on the Moon to trigger seismometers left behind by previous Apollo expeditions.

As they neared the Moon, the Apollo crew fired the CSM engine to slow down so that the Moon's gravity could capture the joined Apollo spacecraft into lunar orbit. The LM then separated from the CSM bearing two of the astronauts and descended to the lunar surface using the engine in its Descent Stage.

After a maximum of three days on the Moon, the Apollo lunar crew lifted off in the LM Ascent Stage using the Descent Stage as a launch pad. The astronaut in the CSM performed a rendezvous and docking with the Ascent Stage in lunar orbit to recover the moonwalkers — hence the name Lunar Orbit Rendezvous — then the crew discarded the LM Ascent Stage and fired the CSM engine to depart lunar orbit for Earth. Nearing Earth, they cast off the CSM's drum-shaped Service Module and reentered Earth's atmosphere in its conical Command Module (CM).

According to Joosten, a spacecraft that flew from Earth to the lunar surface, arrived on the Moon with empty oxidizer tanks, and reloaded them for the trip home with liquid oxygen mined and refined from lunar regolith, could have about half the TLI mass of an equivalent LOR spacecraft. The Apollo 11 CSM, LM, and spent S-IVB stage had a combined mass at TLI of about 63 metric tons; the ILREC spacecraft and its spent TLI stage would have a mass of about 34 metric tons. This substantial mass reduction would permit use of a launch vehicle smaller than the Apollo Saturn V, potentially slashing lunar mission cost.

Lunar regolith is on average about 45% oxygen by weight. According to Joosten, literally dozens of lunar oxygen (LUNOX) extraction methods are known. He listed 14 as examples, including one, Hydrogen Ilmenite Reduction, for which the U.S. Patent Office had issued a patent to the U.S.-Japanese Carbotek/Shimizu consortium.

Joosten assumed that an automated LUNOX extraction process involving "solid-state high-temperature electrolysis" could produce 24 metric tons of LUNOX in cryogenic liquid form per year. He estimated that the process would need between 40 and 80 kilowatts of continuous electricity, and suggested that a nuclear reactor would be the best power-supply option. Such a reactor would have ample reserve power for charging electrically powered teleoperated mining vehicles and could supply crew electricity needs when astronauts were present.

Joosten acknowledged that ILREC emphasized technologies "in somewhat different areas than most exploration scenarios." Among these were teleoperated surface vehicles and surface mining and processing. On the other hand, the technological areas it emphasized had a "high degree of terrestrial relevance," a fact which, he argued, might prove to be a selling point for the new piloted lunar program.

Automated exploration missions would precede the new piloted lunar program. These might take the form of Lunar Scout orbiters and Artemis Common Lunar Landers, both JSC-proposed projects. The automated missions would have some "science linkages," Joosten explained, but would serve mainly to locate landing sites with abundant oxygen-rich regolith, perform ISRU experiments under real lunar conditions using real lunar materials, and map candidate landing sites to enable mission planners to certify them as safe for landings and rover traverses.

The NASA JSC engineer envisioned a three-phase piloted lunar program, though he provided details only for Phases 1 and 2. In Phase 1, three cargo landers would deliver equipment to the target landing site ahead of the first piloted mission. Flight 1 of Phase 1 would deliver the nuclear reactor on a teleoperated cart and the automated liquid oxygen production facility (the latter would remain attached to its lander); flight 2 would deliver teleoperated diggers, regolith haulers, oxygen tankers, and carts for auxiliary fuel-cell power and consumables resupply; and flight 3 would deliver a pressurized Moon bus exploration rover and science equipment for the astronauts who would reach the Moon on flight 4.

Following launch on an Energia rocket, translunar injection, and an Earth-moon voyage lasting up to about a week, a U.S.-built cargo lander bearing a self-deploying LUNOX regolith processing payload descends toward the lunar surface on a direct-descent trajectory. The lander is arranged horizontally, not vertically, to reduce the risk of tipping and, as important, to provide the astronauts who will follow it to the Moon with easy access to its cargo. Image credit: NASA.

After touchdown, the LUNOX regolith processing payload pivots into vertical operational position and deploys ramps so that teleoperated regolith hauler rovers (two are shown on the left side of the image) can reach its screen-covered input hopper. Meanwhile, a teleoperated tanker rover (right) collects and stores LUNOX in preparation for the arrival of a piloted ILREC spacecraft. Image credit: NASA.

An Energia-launched cargo lander slowly lowers a U.S.-built pressurized Moon bus lunar rover to the surface ahead of the arrival of the first two-person ILREC crew. Image credit: NASA.

The one-way automated cargo landers, each rectangular in shape and capable of delivering 11 metric tons of payload to the Moon's surface, would be assembled and packed in the U.S. and shipped to Russia in C-5 Galaxy or Antonov-124/225 transport planes, then launched on Energia rockets from Baikonur Cosmodrome, a Russian enclave in independent Kazakhstan. The Soviet Union's Energia heavy-lift rocket and Buran reusable shuttle were developed beginning in 1976 in response to the planned U.S. Space Shuttle. Energia replaced the Soviet answer to the U.S. Saturn V rocket, the N-1, which was cancelled in 1974 after four failed test flights. 

In contrast to the N-1, Energia flew successfully both times it was launched. Energia payloads were required to perform a short burn after they separated from the rocket so that they could achieve a stable orbit about the Earth. Polyus, launched 15 May 1987, did not orient itself properly ahead of the burn and did not reach orbit, while the unpiloted Buran completed a single orbit as planned and landed on a Baikonur runway on 15 November 1988. 

Based on data Russia provided to NASA, launch teams at Baikonur could prepare two Energia rockets for launch simultaneously. Three Energia launch pads were available — two originally built for the Soviet N-1 Moon rocket and an all-new pad. Energia could launch a 5.5-meter-diameter canister containing a U.S.-built cargo lander attached to a Russian "Block 14C40" upper stage. Following an Earth-orbit insertion burn, the upper stage would perform a TLI burn, boosting the cargo lander toward the Moon.

Shuttle-derived heavy-lift boosters would launch Joosten's piloted landers from the twin Kennedy Space Center (KSC) Complex 39 pads. The pads, monolithic Vehicle Assembly Building, and other KSC facilities, most of which were originally constructed in the 1960s for the Apollo Moon program, were modified in the 1970s to serve the Space Shuttle. They would require new modifications to support the ILREC program; Joosten assured his readers, however, that no wholly new facilities would need to be constructed at the Florida spaceport.

Joosten considered both Shuttle-C and in-line Shuttle-derived launchers. The Shuttle-C design had a cargo module with attached Space Shuttle Main Engines (SSMEs) mounted on the side of a Shuttle External Tank (ET) in place of the delta-winged Shuttle Orbiter. The in-line design, a conceptual ancestor of the Space Launch System, would place the cargo module on top of a modified ET and three SSMEs underneath. The tank would have attached to its sides twin Advanced Solid Rocket Motors more powerful than their Space Shuttle counterparts. Joosten appears to have favored the Shuttle-C design.

The image above is slightly confusing: it displays a piloted ILREC lander and, below that, a conical TLI stage with three engines, but does not make clear that, except for the white, black, and gray conical crew capsule at the top, both lander and stage would be hidden from view under a streamlined white launch shroud. Missing from this illustration is the solid-propellant launch-escape system tower mounted on the crew capsule's nose. Image credit: NASA.

A piloted ILREC lander descends toward a landing near the regolith processing lander and the teleoperated tanker rover. The aft compartment, located between the two rear landing gear, holds up to two tons of cargo. Image credit: NASA.

Shortly after touchdown, the teleoperated tanker rover moves into position beside the ILREC crew lander and extends an umbilical so that it can refill the lander's empty liquid oxygen tanks with LUNOX for the trip home to Earth. Note the position of the crew hatch and two of the lander's four engines. Image credit: NASA.

The Shuttle-derived heavy-lift rocket would launch the piloted lander, bearing an international crew and about two tons of cargo, into Earth orbit. About 4.5 hours after liftoff, following a systems checkout period, the TLI stage would place the piloted lander on a direct trajectory to the Moon. The stage would then be cast off.

Joosten's crew lander design outwardly resembled the fictional "Eagle" transport spacecraft from the 1970s Gerry Anderson TV series Space: 1999. The crew compartment, a conical capsule modeled on the Apollo Command Module (but lacking a nose-mounted docking unit), would be mounted on the front of a horizontally oriented three-legged lander. The three landing legs would fold against the lander's belly beneath a streamlined shroud during ascent through Earth's lower atmosphere.

On the Moon, the crew hatch would face downward, providing ready access to the surface via a ladder on the lander's single forward leg; on the launch pad, the hatch would permit horizontal access to the capsule interior much as did the Apollo CM hatch. The crew compartment windows would be inset into the hull and oriented to enable the pilot to view the landing site during descent. The crew spacecraft would land on and launch from the Moon using the same set of four belly-mounted throttleable rocket engines.

During descent to the lunar surface, the engines would burn Earth oxygen and hydrogen. Soon after lunar touchdown, the lander would be reloaded with liquid oxygen from the automated lunar oxygen plant.

During return to Earth, Joosten's spacecraft would burn Earth hydrogen and lunar oxygen. The entire crew lander would lift off from the Moon; only descent stages that delivered automated payloads would remain on the Moon to clutter up the site. After a brief period in lunar parking orbit, the ILREC lander would ignite its four engines again to place itself on course for Earth.

Nearing Earth, the crew capsule would separate from the lander section and orient itself for reentry by turning its Apollo-style bowl-shaped heat shield toward the atmosphere. The lander section, meanwhile, would steer toward a reentry point well away from populated areas. The crew capsule would deploy a steerable parasail-type parachute. Joosten recommended that NASA recover the capsule on land — perhaps at Kennedy Space Center — to avoid the greater cost of an Apollo-style CM splashdown and water recovery. Most of the lander section would burn up during reentry.

The first piloted ILREC lander, with a U.S.-Russian crew of two on board, would spend two weeks on the Moon. The crew would inspect the automated mining and oxygen production systems and explore using the Moon bus rover. In Phase 1, the Moon bus would be capable of traveling away from the crew lander landing site for two or three days at a time.

Several Phase 1 piloted missions to the site would be possible; alternately, NASA and Russia could skip immediately to Phase 2 — establishment of a temporary lunar outpost — after only a single Phase 1 piloted flight. In ILREC Phase 2, three more cargo flights would deliver to the same site a second Moon bus rover, a rover support module with an attached airlock derived from Space Station hardware designs, consumables in a cart-mounted pressurizable Space Station-derived module, and science equipment.

An Energia-launched cargo lander would deliver the U.S.-built airlock/rover support node to the outpost site and lower it to the lunar surface. Astronauts in the pressurized Moon bus rovers would drive it to a flat area using teleoperations techniques, then would use robot arms on their rovers to lower stilt-like supports. These would level and raise the airlock/node. After the airlock/node's wheels became raised off the ground, they would be removed, clearing the way for the twin rovers to "dock" with the node's two round side ports (one port is visible below the observation cupola just right of center). Image credit: NASA.

Phase 2 ILREC temporary lunar outpost. Two pressurized rovers are docked tail-first to the support node, as is a pressurized consumables cart (at the end of the node opposite the airlock). Hanging regolith-filled bags on the node provide added protection from ionizing radiation. Wheels removed from the airlock/node are stacked to the left of the surface access gangway; they serve as spares for the pressurized Moon bus rovers. A buried electrical cable (visible as a curved line in the lunar dirt running from center to lower right) leads toward a nuclear reactor (out of view). Image credit: NASA.

Phase 2 outpost with components identified. The lower image is turned 90 degrees relative to the top image. Image credit: NASA.

A piloted flight would then deliver a four-person crew for a six-week lunar surface stay. The crew would divide up into pairs, with each pair living in and operating a Moon bus rover. The support module/airlock would include docking ports so that the two Moon buses and the consumables module cart could link to it, forming a small outpost.

The Moon buses would tow auxiliary power carts in Phase 2 to enable longer traverses across the lunar surface. The Moon bus/cart combinations might travel in pairs along parallel routes or one Moon bus might remain at the outpost while the other Moon bus and its power cart ventured far afield. In the event that a Moon bus rover failed beyond walking distance from the outpost and could not be repaired, the other Moon bus could rescue its crew.

ILREC Phase 3 was poorly defined: it might see larger lunar crews venturing further afield, or NASA might change direction and use technology developed for the lunar program to put humans on Mars (perhaps still in partnership with Russia). Joosten identified the piloted Moon lander crew capsule, Shuttle-derived heavy-lift rocket, pressurized Moon bus rovers, and Energia as candidate Mars mission hardware. Both Energia and the Shuttle-derived rocket might be upgraded for piloted Mars missions; they might even be merged to create a single international heavy-lift rocket more powerful than either Energia or the Shuttle derivative.

Joosten envisioned that in Phases 1 and 2 Russia would pay for Energia and the Block 14C40 TLI stage, while NASA would pay for the Shuttle-derived rocket and its TLI stage, the crew and cargo landers, Moon bus rovers and teleoperated carts, and lunar oxygen production systems. In exchange for Russia's participation, its cosmonauts would walk on the Moon in the early years of the 21st century. If U.S.-Russia space cooperation were for any reason curtailed, NASA could continue the Moon program by using Shuttle-derived launchers to launch Moon-bound cargo — provided, of course, that U.S. policy makers determined that an all-U.S. Moon program was worth the added cost.

Sources

Mir Hardware Heritage, NASA Reference Publication 1357, NASA Johnson Space Center Reference Series No. 3, David S. F. Portree, March 1995, pp. 168-170.

"International Lunar Resources Exploration Concept," Kent Joosten, Low Cost Lunar Access Conference Proceedings, 1993, pp. 25-61; paper presented at the AIAA Low Cost Lunar Access conference, Arlington, Virginia, 7 May 1993.

International Lunar Resources Exploration Concept, Presentation Materials, Kent Joosten, Exploration Programs Office, NASA Johnson Space Center, February 1993.

Press Kit: Apollo 11 Lunar Landing Mission, NASA, 6 July 1969.

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