Debris, MMOD and collision risk

Key results

• Rotation doesn't change MMOD risk. Rotation speed is trivial compared with orbital velocity, so a rotating station faces the same hazard as a regular one Paul451, 2018-08-06.
• Altitude. Lowering from 400 to 250 km cuts MMOD impacts ~90% and dose ~50% LMT, 2018-07-05. Debris is 10× lower in EVLEO LMT, 2022-11-04.
• Below 600 km sits under the Van Allen belts and the debris peak mikelepage, 2022-11-29.
• 800 km orbits last >100 years mikelepage, 2018-11-01.
• LEO vs Lagrange points. A LEO station sweeps out debris. At L4/L5 a Kessler cascade would be permanent Twark_Main, 2022-11-26.
• Area drives risk.
• In LEO, minimize area for debris risk rather than for GCR Twark_Main, 2024-07-23.
• Pressure and MMOD scale with area Paul451, 2023-06-05.
• "Mass is your friend" for passive protection and MMOD JohnFornaro, 2023-09-15.
• Active shielding favours a large r/R, partly to cut area/volume costs such as debris Twark_Main, 2023-06-17.
• Protection.
• Expandables give more MMOD protection per launch mikelepage, 2018-07-15; Kevlar MMOD protection is used on both BEAM and aluminium modules LMT, 2018-07-05.
• A Bigelow-like skin as MMOD protection for tunnels Paul451, 2022-10-11.
• Whipple shields are light compared with GCR shielding mikelepage, 2024-07-24. PE can serve as a Whipple layer Twark_Main, 2022-12-24.
• A co-orbiting power satellite in the leading position acts as a Whipple bumper Twark_Main, 2023-02-23.
• Response. Carry an MMOD patch kit in emergency cabinets mikelepage, 2024-02-28. Cellular compartments limit the effect of any one breach Twark_Main, 2023-09-25.
• Vehicle collisions. These are among the most significant risks:
• Mir–Progress 1997 Twark_Main, 2024-05-26.
• A large ship crashing into a massive rotating station would be catastrophic Coastal Ron, 2018-08-06.
• The Baltimore bridge collapse (35 ship–bridge collapses 1960–2015) motivates Coastal Ron's zero-g transfer hub Coastal Ron, 2024-03-28; lamontagne, 2024-03-28.
• Paul451 counters that transferring cargo to a shuttle reduces docking mass only ~10–20% while adding dock cycles and a whole extra station Paul451, 2024-04-03.
• Internal FOD. In large habitats, centrifugal entrainment collects debris in traps (gutter + vacuum) Twark_Main, 2023-03-06. Loose objects "pinball" in unpressurized spherical shields Coastal Ron, 2023-03-02.
• Orbital regulation. mikelepage: mandate a single LEO shell for large stations to ease debris removal and astronomy mikelepage, 2022-10-21.
• Debris removal as a side business: Exodus SDEDI (Space Debris Elimination by Dry Ice) mikelepage, 2018-06-24.

Open questions

• What MMOD protection standard applies to kilometre-scale rotating structures in LEO?
• Do long cable or truss elements significantly raise debris-strike probability?

Related pages

• Location and orbits · Emergency and lifeboats · Radiation shielding

Sources

Forum posts

• mikelepage, 2018-06-24 (reply #845, 3 likes): SDEDI. Post.
• LMT, 2018-07-05 (reply #882): 400→250 km −90% MMOD. Post.
• mikelepage, 2018-07-15 (reply #931): Expandables more MMOD. Post.
• Coastal Ron, 2018-08-06 (reply #1173): Large ship crash catastrophic. Post.
• Paul451, 2018-08-06 (reply #1185, 1 like): MMOD same hazard. Post.
• mikelepage, 2018-11-01 (reply #1251, 2 likes): 800 km >100-yr orbits. Post. Attachments: NASA Debris Orbit decay figure 1995.png.
• Paul451, 2022-10-11 (reply #1977, 2 likes): Bigelow skin as MMOD. Post.
• mikelepage, 2022-10-21 (reply #2164): Single LEO shell. Post.
• LMT, 2022-11-04 (reply #2315): Debris 10× lower EVLEO. Post. Attachments: Globus_Table6.png.
• Twark_Main, 2022-11-26 (reply #2453): LEO sweeps debris; L4/L5 permanent. Post.
• mikelepage, 2022-11-29 (reply #2495): Good window 400–600 km. Post.
• Twark_Main, 2022-12-24 (reply #2707): PE as Whipple. Post.
• Twark_Main, 2023-02-23 (reply #3392): Leading sat as bumper. Post.
• Coastal Ron, 2023-03-02 (reply #3447): Loose objects pinball. Post.
• Twark_Main, 2023-03-06 (reply #3493): FOD traps. Post.
• Paul451, 2023-06-05 (reply #3784, 3 likes): Pressure & MMOD scale with area. Post. Attachments: Modules as dumbbell.jpg.
• Twark_Main, 2023-06-17 (reply #3887): Radiation approaches summary. Post.
• JohnFornaro, 2023-09-15 (reply #3946): Mass is your friend. Post.
• Twark_Main, 2023-09-25 (reply #4022, 1 like): Cellular structure. Post.
• mikelepage, 2024-02-28 (reply #4499): MMOD patch kit. Post.
• lamontagne, 2024-03-28 (reply #4610, 5 likes): Baltimore highlight. Post.
• Coastal Ron, 2024-03-28 (reply #4613): Baltimore bridge analogy. Post.
• Paul451, 2024-04-03 (reply #4632): Shuttle reduces docking mass only ~10%. Post.
• Twark_Main, 2024-05-26 (reply #4641): Mir Progress collision. Post.
• Twark_Main, 2024-07-23 (reply #4658): Minimize area in LEO. Post.
• mikelepage, 2024-07-24 (reply #4662): Whipple vs GCR shielding. Post.

External references

• Benton & Benton (2001); Englert (2014); Kessler (1989).