Luna–Aegis Short Hopper · Design Dossier

01 Mission Overview

The Luna–Aegis Short Hopper is a reusable single-stage VTOL lunar vehicle for crew and cargo transfer between south-polar surface sites and, in the station era, between the surface and Aegis Station in low lunar orbit. It burns ISRU-compatible LOX/LH₂ through an engine-out-capable cluster and lands powered on unprepared terrain. Its baseline mission is a 500 km surface-to-surface round trip with no refuelling at the far end; a 1,500 km one-way hop becomes available once a LUNET propellant node exists at the destination.

Rev C replaces the Rev B (Feb 2026) performance claims with the System Requirements Review Rev A baseline (Sep 2026), which is derived from a trajectory simulation validated against the Apollo 11 ascent and a linked budget model. The Rev B vehicle as published closes a 238 km single leg, not 1,500–2,000 km; the numbers below are the vehicle that closes the mission.

VTOL Single-Stage Engine-Out Capable ISRU-Compatible Fully Reusable Autonomous Capable Artemis Compatible

02 Technical Specifications

// PHYSICAL
TOTAL HEIGHT / LANDING ZONE	TBR — Rev B envelope (~6.5 m / ~4.5 m) predates the Rev C tank set
GROSS WET MASS	18,160 kg (full load, 500 km round trip)
DRY MASS	5,273 kg (Rev B allocation carried, TBR)
PROPELLANT MASS	12,088 kg (66.6% mass fraction)
PAYLOAD, SIZING CASE	800 kg — 2 crew + 500 kg cargo, carried on both legs
// PROPULSION
PROPELLANTS	LOX / LH₂ (ISRU-compatible)
ENGINE CONFIG	Gimbaled cluster, engine-out capable — three ~20 kN engines recommended (trade open)
THRUST (VAC, TOTAL)	60 kN
ISP (VACUUM)	440 s nominal (430–450 s)
T/W AT LIFTOFF (LUNAR)	2.0 at full load → increasing as propellant burns
DESIGN ΔV, ONE 500 km LEG	2,244 m/s (burns + landing allowances, incl. 10% margin)
ΔV AT FULL TANKS	4,727 m/s with the sizing payload aboard
ATTITUDE CONTROL	Engine gimbal (primary) + RCS thrusters (fine)
// PERFORMANCE
SURFACE–SURFACE, BASELINE	500 km round trip, no refuel at the remote site
SURFACE–SURFACE, GROWTH	1,500 km one-way with LUNET refuel at destination — same tanks, no hardware change
SURFACE–LLO	100 km LLO round trip, no orbital refuel, at 16,590 kg load (station era)
FLIGHT TIME, 500 km LEG	~16 min liftoff to hover gate; apex ~104 km
REUSABILITY	Min. 10 sorties between intermediate service; wear items field-replaceable; core structure life 50 sorties to retirement (requirements, TBD)
TURNAROUND TIME	24–48 hours at a LUNET node (requirement, TBD)
LANDING PRECISION	±3 m with terrain-relative navigation (TBR)
// CREW & CARGO
CREW (STANDARD)	4 astronauts
CREW (MAX / REDUCED RANGE)	6 astronauts
CARGO CAPACITY	Up to 1,000 kg (cargo config)
OPERATIONAL DURATION	72–96 hours (crewed)
// SYSTEMS
AVIONICS	Dual-redundant radiation-hardened flight computers
NAVIGATION	FOG/RLG IMU + MEMS backup, Kalman fusion, lidar/radar alt.
LANDING GUIDANCE	Terrain-relative nav; LUNET beacon alignment compatible
COMMS	S-band/UHF (short range) + high-gain directional (station uplink)
POWER	Rechargeable battery packs + passive solar backup
LIFE SUPPORT	O₂/N₂ pressurized cabin; Orion-class LSS heritage
DOCKING INTERFACE	Aft/lower hatch; soft-seal pressurized collar
FLIGHT SOFTWARE	NASA cFS stack, ten mission applications, 13-phase autonomy executive (aegis-hopper-fsw 2.0)

03 Cabin Configurations

Config A — Crew

👨‍🚀

4

Astronauts (standard) / 6 max

Full pressurized cabin with suits, airlock, and emergency portable air systems. 72–96 hr life support. Direct suitport mate with Aegis-Class Rover.

Config B — Cargo

📦

1,000

kg payload capacity

Palletized cargo mounts with latch-and-lock system. Supports ISRU tanks, EVA gear, small rovers/drones, sample return payloads. Robotic assist arm optional.

Config C — Hybrid

⚙️

2 crew

+ up to ~500 kg cargo

Mixed crew and logistics manifest. Supports medical evacuation, science payload delivery, and priority crew + equipment transfers between surface nodes.

04 Propulsion & Mass Budget

        A ballistic hop launches at 33–41° above the horizon, so lunar gravity opposes thrust for the whole burn: at Rev B's 30 kN the two burns of a
        1,500 km hop cost 24% over the impulsive ideal, not the 6% Rev B assumed, and no single 25–30 kN engine closes a standalone round trip of any
        length. The Rev C vehicle carries 60 kN of total thrust from an engine-out-capable cluster, which holds liftoff T/W at 2.0 on the heaviest leg
        and, with three engines, lands on one at a conventional 49% throttle setting. Gimbal provides pitch/yaw authority; RCS handles roll, coast trim,
        hover and docking. Propellant is LOX/LH₂ throughout, so ISRU production converts directly into reach.
      

60 kN

Total Vac Thrust

440 s

Isp (nominal)

2,244 m/s

Design ΔV per 500 km leg

2.0×

T/W at full load

        MASS BUDGET — 18,160 kg WET (500 km ROUND TRIP, FULL LOAD)
      

PROPELLANT (LOX/LH₂)

12,088 kg · 66.6%

STRUCTURE / TANKS

2,110 kg · 11.6% (TBR)

CABIN / LSS

1,055 kg · 5.8%

PROPULSION SYSTEM

790 kg · 4.4% (TBR, cluster)

LANDING GEAR

527 kg · 2.9%

AVIONICS / GN&C

422 kg · 2.3%

MASS MARGIN (7%)

369 kg · 2.0%

PAYLOAD (2 CREW + 500 kg)

800 kg · 4.4%

GROSS WET MASS

18,160 kg

        Dry mass is the Rev B allocation carried unchanged; the tank set now holds 4.4× the Rev B propellant and the structure, tank and cluster allocations are to be re-sized by partners. Every figure on this page is generated from the SRR Rev A linked budget workbook and trajectory tool.
      

        SIZING — WET MASS vs RANGE, SINGLE LEG AND ROUND TRIP
      

Gross wet mass versus surface range for single-leg and round-trip hops at 30, 45, 60 and 90 kN

        Round trips are flown leg by leg: the outbound leg lands carrying the return load. A 1,500 km standalone round trip needs a 33 t vehicle at 60 kN and does not lift off at 30 or 45 kN, which is why the baseline is 500 km round trip and 1,500 km one-way is a growth case that depends on a LUNET node.
      

Design delta-v versus range for the Rev B vehicle, showing it closes a 238 km single leg

05 Landing, Autonomy & Interfaces

LANDING SYSTEM

Four fixed legs, thermal-shielded with adaptive dust-tolerant footpads
Terrain-relative navigation via lidar + radar altimeter
FOG or RLG IMU with MEMS backup; Kalman sensor fusion
LUNET beacon alignment for node-assisted precision landing
Nominal precision: ±3 m; abort-to-pad, abort-to-surface and abort-to-orbit modes defined; engine-out on descent is designed out by the cluster
Operable in permanently shadowed regions (PSRs)

INTERFACES & INTEGRATION

Soft-docking collar: compatible with Aegis Station, surface habs, Aegis-Class Rover suitport
Pressurized telescoping tunnel with dust seals — no EVA required for crew transfer
Cryogenic refueling via LUNET-compatible cartridge port
Palletized cargo latch-and-lock; optional robotic assist arm
Field diagnostics via rover interface or LUNET node
Modular avionics and structural interfaces for rapid field swap

REUSE & SERVICING

        There is no hangar or depot on the Moon before the station exists, so reuse is built around a LUNET node, EVA crew and the rover arm. Everything that wears is a field-replaceable unit: engines, legs and footpads, RCS pods, collar and hatch seals, sensor heads, battery and avionics boxes. The one thing that is not, the tank and structure core, sets the vehicle's retirement. What limits life, in order: engine starts, cryogenic fill and pressure cycles on the tanks, landings on unprepared terrain with plume ejecta on every touchdown, and dust on everything that moves or seals. Cycle counters live on the vehicle in the flight software and trigger service; per-leg load cells trigger a hard-landing inspection.
      

// SERVICE TIERS (SRR §2.8, REQUIREMENTS TBD)
1 — LINE SERVICE	Every sortie, inside the 48 h turnaround, at the home node. Telemetry and cycle-counter review, leak check on refuel, camera inspection of gear and underside, sensor-window cleaning, consumables and RCS reload. No planned hands-on work.
2 — INTERMEDIATE	On counters or on condition, not more often than every 10 sorties. EVA crew or rover arm, no pressurised facility. Engine inspection or swap, footpad and damper replacement, seal replacement, sensor recalibration, insulation inspection.
3 — RETIREMENT	Tanks, structure and pressure vessel at their certified life, 50 sorties (200 burns, 300 starts, 100 landings), to be reviewed against dust and ejecta erosion data. Credible on cycles: reusable boosters already exceed 20 flights. Pre-station the vehicle is retired in place; station-era return to an orbital facility is a growth option, not a dependency.

06 Role in the Lunar Stack

Artemis puts boots on the surface. CLPS puts instruments on the ground. ISRU demonstration missions prove you can make propellant. What's missing is the vehicle that ties all of it together — a reusable, refuelable shuttle that can move crew and cargo between any two points on the Moon and back to orbit, on a schedule, without a new launch from Earth every time.

The Short Hopper is designed to fill that gap. It turns surface sites into connected nodes rather than isolated flags-and-footprints destinations. It converts ISRU propellant into operational reach. And it gives a lunar orbital station — Aegis or otherwise — a reason to exist as a logistics hub rather than an end unto itself.

A vehicle like this doesn't get built by one company. It requires the kind of sustained investment and technical depth that comes from NASA program involvement and major aerospace partners working toward a shared architecture. What Aegis Station Infrastructure brings is a System Requirements Review baseline that says what closes and what does not: reference missions with simulated trajectories, a linked budget that reproduces the simulation, requirements with sources, trade studies with numbers, a risk register, and a flight-software stack already flying the mission profile in simulation. The open decisions — baseline range, one vehicle or two, engine count — are stated as open. That is the part we bring to the table.

For partnership and technical inquiries: contact@aegisstation.com