Location and orbits

Key results

• Consensus for near-term stations: equatorial LEO (ELEO), ~400–600 km at 0–20° inclination. Reasons:
• Radiation: Earth's shadow and field, and avoiding the SAA at <5° inclination.
• Access and cost: only LEO is reachable without refuelling.
• Debris sweep, low latency, escape at any time mikelepage, 2022-11-29; mikelepage, 2018-11-01; Habitant, 2026-09-15; Twark_Main, 2023-01-17.
• Globus's ELEO work "makes lunar shielding obsolete" Twark_Main, 2023-01-17.
• Altitude trades.
• ~600 km compromise between drag, the Van Allen belts and launch Roy_H, 2014-03-17.
• 800 km gives >100-year orbits mikelepage, 2018-11-01.
• EVLEO at ~250 km (LMT) cuts MMOD ~90% and dose ~50% but needs drag cancellation LMT, 2018-07-05; LMT, 2022-11-04; LMT, 2019-02-27.
• Formation flying in LEO needs matched drag mikelepage, 2024-03-01.
• LEO as transfer point (Twark_Main): Oberth departures, aerobraking arrivals, rehabilitation Twark_Main, 2023-01-17. LEO rest stops beat EML-1 Twark_Main, 2022-12-18.
• EML-1 is worse: more ΔV, time and ticket cost; harsher radiation; eternal sunlight is available more cheaply in SSO LEO Twark_Main, 2022-12-18. Paul451 agrees: no tourist, research or industrial station at EML-1 Paul451, 2022-12-19.
• JohnFornaro chooses EML-1 for his ring; Twark_Main calls his reasons (1 g, zero radiation, EML-1) "chosen favourites" Twark_Main, 2022-12-08. JohnFornaro: "delta-t matters more than delta-v" JohnFornaro, 2023-01-16.
• L4/L5. Quasi-stable, 5–20 m/s/yr of stationkeeping (photon pressure) mikelepage, 2022-11-29; Twark_Main, 2022-11-26. But a Kessler cascade there would be permanent Twark_Main, 2022-11-26, and radiation makes them "unrealistic" (Globus) LMT, 2024-03-16.
• lamontagne's L5 economic model from lunar materials: the pressure vessel costs more than the shielding lamontagne, 2024-03-20.
• LEO vs EML by use (lamontagne): LEO is better for biology and tourism (views, access, less shielding, precursor experience); EML for industry lamontagne, 2022-10-06.
• Beyond Earth orbit.
• Coastal Ron expects rotating stations far from Earth: a Mars-g refuge for asteroid-belt miners orbiting the sun Coastal Ron, 2022-11-29; Coastal Ron, 2023-01-17.
• "No business case for living in LEO" (Coastal Ron) Coastal Ron, 2026-09-18.
• Solar orbit makes propellant resupply costly Twark_Main, 2025-09-19.
• Mars orbit and moons.
• LMT's Deimostation, tethered 14 km to Deimos LMT, 2023-01-14. Deimos L1 instead of L5 LMT, 2024-03-20.
• lamontagne's Mars-orbit ring4 lamontagne, 2023-04-18.
• Moving a 40,000 t station from LEO to Deimos L1 (6.5 km/s) takes ~3.6 Mt of Earth-launched methalox, ~220 kt with ISRU, or ~2.1 kt with fusion LMT, 2024-03-16.
• Relocate a LEO station to Mars/Phobos for a second life floss, 2025-09-07.
• Cyclers. Mars cyclers as economy transport Twark_Main, 2022-12-23. rakaydos's single-Starship cycler rakaydos, 2024-03-21.
• Sun-synchronous orbit is about ground-track timing, not sunlight, and has high radiation at 500 km Paul451, 2022-12-19; mikelepage, 2019-09-04.
• Regulation. A mandated single LEO shell for large stations mikelepage, 2022-10-21.

Open questions

• Is ELEO's low-radiation advantage enough to make it the location for long-term residence, not just near-term stations?
• Is there any business case for rotating stations beyond LEO before large-scale ISRU?

Related pages

• Radiation environment · Reboost · Debris · ISRU

Sources

Forum posts

• Roy_H, 2014-03-17 (reply #192): ~600 km compromise. Post.
• LMT, 2018-07-05 (reply #882): 250 km benefits. Post.
• mikelepage, 2018-11-01 (reply #1251, 2 likes): ELEO ~600 km: 20-yr life, <40 mSv/yr. Post. Attachments: NASA Debris Orbit decay figure 1995.png.
• LMT, 2019-02-27 (reply #1313): EVLEO with ISEP. Post.
• mikelepage, 2019-09-04 (reply #1664, 3 likes): SSO high radiation. Post.
• lamontagne, 2022-10-06 (reply #1874): LEO for biology/tourism. Post.
• mikelepage, 2022-10-21 (reply #2164): Single LEO shell. Post.
• LMT, 2022-11-04 (reply #2315): EVLEO 10 cm water. Post. Attachments: Globus_Table6.png.
• Twark_Main, 2022-11-26 (reply #2453): 5–7 m/s/yr. Post.
• mikelepage, 2022-11-29 (reply #2495): Good window 400–600 km, 0–20° (4 likes). Post.
• Coastal Ron, 2022-11-29 (reply #2496): Stations far from Earth. Post.
• Twark_Main, 2022-12-08 (reply #2581): Chosen favourites. Post.
• Twark_Main, 2022-12-18 (reply #2665, 1 like): EML-1 critique. Post.
• Paul451, 2022-12-19 (reply #2673): No station at EML-1. Post.
• Twark_Main, 2022-12-23 (reply #2697): Cycler economy transport. Post.
• LMT, 2023-01-14 (reply #2894): Deimostation. Post. Attachments: Omaha_Trail_2021.png.
• JohnFornaro, 2023-01-16 (reply #2924): Δt > Δv. Post.
• Coastal Ron, 2023-01-17 (reply #2941): Asteroid belt. Post.
• Twark_Main, 2023-01-17 (reply #2947): LEO is the transfer point. Post.
• lamontagne, 2023-04-18 (reply #3615): Mars-orbit ring4. Post.
• mikelepage, 2024-03-01 (reply #4522): Matched drag. Post.
• LMT, 2024-03-16 (reply #4562): Relocation propellant. Post. Attachments: Hammer-station-camera-28-b.jpg.
• LMT, 2024-03-16 (reply #4566): L5 unrealistic. Post. Attachments: The High Frontier - An Easier Way.png.
• lamontagne, 2024-03-20 (reply #4594, 1 like): L5 cost model (1 like). Post. Attachments: costs.PNG, JBIS-v72-no09-September-October-2019_dk64ll.pdf.
• LMT, 2024-03-20 (reply #4595): Deimos L1. Post.
• rakaydos, 2024-03-21 (reply #4603, 2 likes): Single-Starship cycler (2 likes). Post.
• floss, 2025-09-07 (reply #4935): Second life relocation. Post.
• Twark_Main, 2025-09-19 (reply #4987): Solar orbit costly resupply. Post.
• Habitant, 2026-09-15 (reply #5111): ELEO reasons. Post.
• Coastal Ron, 2026-09-18 (reply #5132): No LEO business case. Post.

External references

• Globus, A. et al., dose vs altitude and inclination tables; "Space Settlement: An Easier Way".