Interactive Orbital Mechanics

The Artemis Program

Four missions. Four fundamentally different orbital profiles. Explore the real physics of humanity's return to the Moon — from uncrewed test flight to the first lunar landing in over 50 years.

Near-Rectilinear Halo Orbit
Drag to rotate · Scroll to zoom
Mission 1 · Uncrewed · 2022

Artemis I — Proving the System

The first integrated test of the Space Launch System and Orion capsule. No crew. The mission validated every system that will carry humans — life support, heat shield, navigation, propulsion — from Earth to the Moon and back. Launched November 16, 2022 and returned December 11, 2022 after 25.5 days in space.

Launch Date
Nov 16
2022
Mission Duration
25.5
days
NRHO Perilune
~3,000
km from Moon surface
NRHO Apolune
~70,000
km from Moon surface
NRHO Orbits
~1.5
loops
Max Lunar Distance
432,210
km — farthest spacecraft record for crew-rated capsule

Orbital Sequence

  • LEO insertion at 322 km altitude
  • Trans-Lunar Injection (TLI) burn: +3.2 km/s Δv
  • 4-day outbound coast to Moon
  • Lunar flyby + Distant Retrograde Orbit insertion
  • Near-Rectilinear Halo Orbit (~1.5 revolutions, 9-day period)
  • Trans-Earth Injection (TEI) burn
  • 4-day return coast to Earth
  • 26,000 km/h re-entry, 0.5g skip entry at 40,000°F
  • Pacific Ocean splashdown, December 11 2022

NRHO stands for Near-Rectilinear Halo Orbit. Yes, someone got paid to name that. It works remarkably well.

Mission 2 · Crewed Flyby · 2026

Artemis II — Humans Around the Moon

The first crewed flight of Orion, launched April 1, 2026 — the first time humans have traveled beyond LEO since Apollo 17 in December 1972. This is a free-return trajectory: the spacecraft swings around the Moon using pure orbital mechanics, with no Lunar Orbit Insertion burn. If anything fails, physics brings the crew home automatically.

Launch Date
Apr 1
2026
Crew
4
astronauts
Lunar Closest Approach
~8,900
km from lunar surface
No Lunar Orbit
free-return only
Mission Duration
~10
days
First Crewed Beyond LEO
~54
years since Apollo 17 (1972)
Splashdown
Pacific
Ocean, ~10 days after launch

Complete Mission Profile — Launch to Splashdown

  • Launch + TLI burn: SLS sends Orion onto trans-lunar trajectory from LEO
  • Outbound coast (~4 days): Orion coasts to the Moon, rising above the Earth-Moon plane
  • Lunar flyby: Closest approach ~8,900 km — Moon's gravity bends trajectory back toward Earth
  • Return coast (~4 days): Asymmetric arc — NOT a mirror of outbound, shaped by lunar gravity assist. Sweeps wider below the Earth-Moon plane
  • Entry interface: Orion enters atmosphere at ~122 km altitude, heat shield absorbs reentry energy
  • Splashdown: Pacific Ocean recovery, ~10 days total mission duration
Mission 3 · Replanned · ~2027

Artemis III — The Pivot

Originally planned as the first crewed lunar landing since Apollo 17, Artemis III was replanned as a LEO rendezvous and docking test. The reason: SpaceX's Human Landing System (HLS Starship) development fell significantly behind schedule, and its certification requirements meant a direct 2025–26 lunar landing was no longer achievable safely on the original timeline. Rather than delay the entire program, NASA restructured: Artemis III now validates Orion-to-HLS Starship docking procedures in low Earth orbit.

Original Plan
Lunar
South Pole Landing
Revised Plan
LEO
Docking Test
Orbit Altitude
~400
km LEO
No Lunar Trajectory
stays in Earth orbit
Target Year
~2027
TBD
Key Test
Orion
+ HLS Starship rendezvous

What Artemis III Now Tests in LEO

  • Orion autonomously approaches and docks with HLS Starship
  • Crew transfers between Orion and Starship in zero-g
  • HLS life support, airlock, and EVA systems validated
  • Proximity operations and rendezvous algorithms flight-tested with crew
  • No lunar trajectory — all procedures happen in LEO at ~400 km altitude
  • Success gates access to Artemis IV lunar landing
Mission 4 · Crewed Landing · 2028

Artemis IV — Boots on Regolith

The first crewed lunar landing since Apollo 17 on December 11, 1972 — over 55 years between footsteps on the Moon. Artemis IV is the full mission: TLI to NRHO, transfer to HLS Starship, descent to the lunar south pole, surface EVAs, ascent, NRHO rendezvous, and trans-Earth injection. The target: the permanently shadowed craters near Shackleton Crater where water ice deposits have been confirmed by LCROSS and LRO data.

Target Year
2028
planned
Landing Site
South
Pole (Shackleton Crater region)
NRHO Perilune
~3,000
km
NRHO Apolune
~70,000
km
Last Lunar Landing
Dec 1972
Apollo 17 — Gene Cernan
HLS Vehicle
Starship
SpaceX Human Landing System

Full Mission Sequence

  • SLS launches Orion + crew from KSC Pad 39B
  • Trans-Lunar Injection: ~3.2 km/s burn, 4-day outbound coast
  • NRHO insertion: near-rectilinear halo orbit around Moon
  • HLS Starship arrives at NRHO (pre-positioned by separate launch)
  • Orion-to-Starship crew transfer, descent to lunar south pole
  • Surface EVAs: sampling regolith, testing water ice extraction
  • Ascent from surface, Starship-to-NRHO rendezvous
  • Crew transfers back to Orion
  • Trans-Earth Injection, 4-day coast, Pacific splashdown
Mission References
NASA Artemis I Mission Overview — nasa.gov/artemis-1. Duration: 25.5 days; NRHO perilune 3,000 km × apolune 70,000 km; splashdown Dec 11 2022.
NASA Artemis II Mission Overview — nasa.gov/artemis-2. Crewed free-return trajectory; closest lunar approach ~8,900 km; launched April 1 2026.
Zimovan, E.M., et al. "Near Rectilinear Halo Orbits and Their Application in Cis-Lunar Space." AAS 17-826. American Astronautical Society, 2017. — Physics basis for NRHO orbital parameters.
NASA HLS Solicitation & Artemis III Timeline Revision — NASA announced Artemis III mission profile change from lunar landing to LEO Orion-HLS docking test due to Starship HLS certification schedule. GAO Report GAO-24-106491 (2024).
Artemis IV Lunar South Pole Target — Lunar Reconnaissance Orbiter and LCROSS data confirm water ice deposits in permanently shadowed regions near Shackleton Crater (87°S). NASA LCROSS Science Team, Science, 2010.
Space Launch System Performance — SLS Block 1: 95 tonnes to LEO, 27 tonnes TLI. NASA SLS Performance Fact Sheet, 2022.
Share 🔗 𝕏