Plan B – The Phobos Co-Orbital Contingency

While the primary objective of the interplanetary architecture remains high-throughput access to the Martian surface, mission risk profiles and hardware proving phases demand a fully functional contingency pathway. Plan B shifts the initial human landing target from the deep gravity well of Mars to its outer moon, Phobos. Operating in a microgravity environment (g ≈ 0.00057 m/s²) with an escape velocity of just 11 m/s, Phobos eliminates the severe entry, descent, and landing (EDL) hazards of hypersonic atmospheric re-entry and avoids the high energetic cost of climbing out of Mars’s 5.03 km/s gravity well. This allows human crew operations on a solid body in the Mars system to be demonstrated at a fraction of the mission mass and risk.

Crucially, Plan B is far more than a simple rock collection mission. Rather than executing a brief "flags and footprints" touchdown to gather surface regolith samples, the expedition constructs a permanent, high-power communications and teleoperation grid that serves as the permanent command-and-control backbone for all future Martian operations.

To execute Plan B without introducing unstable orbital dynamics, the main mission spacecraft does not attempt to enter a tight orbit around Phobos itself. Because Phobos’s irregular mass distribution and small 16-kilometer Hill sphere render close orbits unstable, the main vehicle enters a co-orbital trajectory around Mars, trailing or leading Phobos by 100 to 500 kilometers in its exact orbital plane (9,376-kilometer radius). This position provides near-zero relative velocity to the moon while keeping the primary spacecraft clear of Phobos's active dust torus and tidal perturbations. Transfers between the main spacecraft and Phobos require negligible velocity changes (Δ v < 0.5 km/s), enabling instant abort capabilities and continuous line-of-sight communication.

Surface operations establish a dual-zone infrastructure across the moon's unique droplet geometry to optimize both deep-space connectivity and planetary relays. Zone 1, situated along the broadside rim of the giant Stickney Crater, houses high-efficiency solar arrays, optical deep-space communication links to Earth, and direct access to exposed deep-interior rock strata for high-value geological analysis. Zone 2, situated on the tidally locked sub-Mars hemisphere, houses high-bandwidth, low-latency relay nodes locked onto the Martian surface below.

Connecting these two zones across kilometers of regolith is a heavy-duty surface cable backbone deployed by a single-person Motorized EVA Vehicle ("Space Scooter"). This cable pipes high-voltage power from the Zone 1 solar arrays directly to the Zone 2 relays while routing real-time telemetry between Earth links and surface rovers. Mechanically, the structural jacket of the cable doubles as a permanent Via Ferrata fixed-rope guideline. Astronauts clipped to the line use non-impact biomimetic microspine grippers—arrays of tiny steel hooks that engage porous rock micro-cavities—to traverse safely between nodes on foot without burning RCS propellant or risking accidental detachment into space.

By combining low-risk microgravity human operations, deep geological sampling, and the deployment of a permanent planetary power and communications grid, Plan B transforms an exploratory contingency into an indispensable, long-term infrastructure asset for the entire Mars network.