Blue Origin’s first Blue Moon Mark 1 lunar lander, Endurance, has completed environmental testing at NASA’s Johnson Space Center in Houston, the agency announced May 4. The milestone clears one of the final ground hurdles before the uncrewed cargo lander attempts a south polar lunar landing later this year.
The chamber work was conducted under a reimbursable Space Act Agreement, with Blue Origin funding the campaign as a commercial demonstration intended to mature Human Landing System capabilities for NASA’s Artemis program. The thermal vacuum facilities allow engineers to reproduce the vacuum and temperature swings the spacecraft will experience in flight, letting teams verify structural and thermal performance before launch.
Endurance is designed to demonstrate precision landing, cryogenic propulsion and autonomous guidance, navigation and control. It will also carry two NASA payloads under the Commercial Lunar Payload Services initiative: the Stereo Cameras for Lunar Plume-Surface Studies (SCALPSS), an array of high-resolution cameras that will document the interaction between engine plume and regolith during descent, and the Laser Retroreflective Array, a passive optical aid that helps orbiting spacecraft fix their position with reflected laser light.
Perhaps more importantly, the Mk1 lander is a technology test-bed for the Mk II edition, which is planned for crewed landings on the lunar surface.
This Is Not Your Grandfather’s Apollo LM
| Category | Apollo Lunar Module | Blue Moon MK1 | Blue Moon MK2 |
|---|---|---|---|
| Program / Era | Apollo program; six crewed landings, 1969–1972 | Artemis-era CLPS pathfinder; first flight planned 2026 | Artemis HLS Sustaining Lunar Development; uncrewed demo NET 2027, crewed Artemis V NET March 2030 |
| Builder | Grumman Aircraft Engineering Corp. | Blue Origin | Blue Origin (lead), with Lockheed Martin, Draper, Boeing, Astrobotic, Honeybee Robotics |
| Crew | Two astronauts (Commander, Lunar Module Pilot) | Uncrewed cargo lander | Up to four astronauts; cargo variant also planned |
| Configuration | Two-stage: descent stage + ascent stage | Single-stage, expendable | Single-stage, fully reusable (on-orbit refueling) |
| Height | ~7.04 m, legs deployed | ~8.05 m | ~15 m (50 ft, reported) |
| Wet Mass | ~14,700–16,400 kg (mission-dependent; J-mission max) | Under 21,350 kg | Reported above 45,000 kg fueled |
| Propellants | Aerozine 50 / N₂O₄ — hypergolic, storable | LH₂ / LOX — cryogenic, ISRU-compatible | LH₂ / LOX — cryogenic, with active boil-off mitigation for long-duration storage |
| Main Engine(s) | TRW LM Descent Engine (LMDE) + Rocketdyne LM Ascent Engine | Single Blue Origin BE-7 (dual expander cycle) | Three Blue Origin BE-7 engines |
| Thrust & Throttling | Descent: 45.04 kN max, throttleable (with a forbidden mid-range band); Ascent: ~15.6 kN, fixed | 44 kN max, deep-throttle to 8.9 kN, multi-restart | Three-engine cluster of throttleable, restartable BE-7s; cluster-level performance figures not publicly disclosed |
| Launch Vehicle | Saturn V (stowed in Spacecraft-LM Adapter atop S-IVB) | New Glenn, 7-meter fairing | New Glenn, 7-meter fairing; refueled in lunar orbit by Lockheed Martin Cislunar Transporter (tug + tanker) |
| Mission Architecture | Direct TLI by S-IVB; CSM transposition & LM extraction; ~3-day coast; lunar-orbit rendezvous with CSM | LEO → elliptical Earth orbit → TLI burn; 5–7 day coast; autonomous landing | Pre-positioned via Cislunar Transporter; crew ferried by SLS/Orion to Gateway in NRHO; transfer to lander, descent, return to NRHO |
| Surface Payload | Two crew plus ALSEP, LRV (J-missions), tools; samples returned via ascent stage | Up to 3 metric tons of cargo, one-way | Up to four crew; cargo variant up to 20 t reusable / 30 t one-way |
| Guidance & Piloting | Apollo Guidance Computer + manual hover; commander flew final approach | Fully autonomous precision landing; onboard terrain interpretation | Autonomous precision landing with crewed override capability; Draper-supplied GN&C |
| Surface Duration | Up to ~75 hours (Apollo 17, J-class) | Designed to support cargo ops as a static surface asset | Up to 30 days crewed |
| Return Capability | Yes — ascent stage returned crew to lunar orbit for CSM rendezvous | None — lander remains on the surface | Yes — ascent and return to NRHO; reusable across multiple missions |
| Status | Six successful crewed landings; Aquarius served as Apollo 13 lifeboat | First article “Endurance” completed thermal-vacuum testing at NASA JSC, May 2026; second MK1 in production at Lunar Plant 1, Florida | $3.4 billion Sustaining Lunar Development HLS contract awarded May 2023; uncrewed demonstration NET 2027; first crewed landing on Artemis V, NET March 2030 |
| Sources: NASA Apollo program documentation; Blue Origin; NASA Johnson Space Center (May 2026); Gunter’s Space Page; NASA Artemis program. MK2 dimensions and mass are reported figures pending updated official disclosure. | |||
Mk1, designated MK1-SN001, stands roughly eight meters tall and masses about 21,350 kilograms, larger than the Apollo lunar module, and is built to deliver approximately 3,000 kilograms to the lunar surface. That’s about the same as the original LM weight-wise, but keep in mind, this is the test version. The Blue Moon Mk2 will be able to deliver up to 20,000 kilograms to the Moon’s surface in a reusable configuration, or 30,000 kilograms on a one-way mission.
The Mk1 flight will land near Shackleton Crater in the moon’s south polar region, an area thought to harbor water ice in permanently shadowed pockets that have not seen sunlight for more than a billion years.
Endurance is powered by Blue Origin’s throttleable BE-7 engine, which produces up to 44,000 newtons of thrust on liquid oxygen and liquid hydrogen. Blue Origin CEO Dave Limp recently shared video of a 1,030-second BE-7 hot fire in Texas. The burn simulates the Apogee Raise Maneuver required to push the lander toward the moon, plus margin.
The lander returned to Florida from Houston for additional preflight work. Blue Origin has run modal testing, using sensors to measure how the vehicle responds to launch loads, and plans to qualify the launch vehicle separation system and communications system before a wet dress rehearsal with cryogenic propellant. The mission is currently tracking to no earlier than the third quarter of 2026, with a New Glenn launch from Cape Canaveral’s Launch Complex 36.
Author: Charles Boyer
NASA kid from Cocoa Beach, FL, born of Project Apollo parents and family. I’m a writer and photographer sharing the story of spaceflight from the Eastern Range here in Florida.
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