Emergency supply

I've been considering Hohmann transfer between inner planet A and outer B. Over the past week I've been considering especially emergencies; this is ready for its own post.

To begin with, a->b Hohmanns run with the ecliptic just like b->a Hohmanns; b->a with the head-start (four weeks, Venus / Earth). The two don't meet. Anti-Hohmann against the orbits of the ecliptic would meet Hohmann but that is a great waste of fuel.

If we have ten regular Hohmann cyclers, I expect one of the eight in-betweeners will meet our starving colonists, or get close enough to toss over some help. In the event needs are not met, for target planet to supply inbound Hohmann requires some advance planning, as Brigham Young supplied the handcarts.

I assume heavy cargo, so I'm bringing propellant. Uranium fission should work to supply missions from rockey planets (e.g. Da Erf) past a couple months - provisions, not people. From Venus we haven't the fissile elements (nor much hydrogen) but we do have the energy, from the Sun. And the propellant: this planet has a glut of CHONS type gas, minus the H. If from an inner planet A to an outer one B, some boost might be given by solar-sails. For the other direction consider a focusing mirror at SBL1. That might push a sail downward: along the ecliptic (speeding b->a) or against it (slowing a->b).

Interior planet A is in position to bounce cargo more-or-less opposite from the Sun, which then falls back by Newton to meet incoming Hohmann. Venus is energy-rich enough it may find easier to help thus: redirected solar power, satellites in prograde (=ecliptic retrograde) orbit.

Starting at Conjunction, I wonder also if outbound a->b can boost some supplies to the a-bound craft ahead of it. [ANSWER 11/29: yeah: outbound +a_E to b-_A.] Energy is still a likely nonproblem between Venus and Earth, and outgoing Hohmann may well exist to sell spare propellant to the relatively gas-poor inner planets. Venus, with its 13 revolutions to 5 synods plus another 5 in the other direction, should toss more propellant to whatever Hohmann is going out.