Launch and Eve transfer

Mission designers chose the launch window by analyzing Kerbin-Eve porkchop plots (using alexmoon's great Launch Window Planner). The selected transfer would take the Eve Express spacecraft on a 49-day trip to Eve using about 1070 m/s.

Launch to Kerbin orbit and spacecraft separation went without incidents.

Because of the particulars of the planetary positions at the time of launch, the selected transfer deviated from a normal Hohmann transfer, intercepting Eve way after Kerbol periapsis.

Still, this trajectory was the most efficient for at least 100 days before and after the selected launch date.

The transfer burn was uneventful.

This put the spacecraft on a 49-day trajectory with a predicted Eve closest encounter distance of about 52400 km. This would be improved tremendously before arrival.

Eve Express was now bound for Kerbin's larger neighbor.

After a lengthy trip, the spacecraft sensors finally spotted Eve ahead.

The midcourse correction arrived one day before Eve intercept, a bit later than expected. The correction would use more fuel than is usual to complete a transfer in order to adjust the Eve periapsis as close as possible to the planet. This, of course, required a sizeable delta-v expenditure, which was still within budget.

The correction burn was executed and lowered the current Eve periapsis from 52400 km to 141 km — almost within Eve's atmosphere. The higher-precision final correction would have to wait until being much closer to Eve.

On Eve's sphere of influence switch, the Eve Express spacecraft was moving in a fast hyperbolic trajecory.

The final trajectory correction was now planned. Target periapsis: 65.5 km. The actual periapsis had to be very precise since aerobraking can be sensitive to small differences in periapsis altitude. The orbital inclination was also adjusted so the periapsis was nearly equatorial.

After the main 3-second burn and several brief precision corrections, a trajectory with a periapsis of 65.504 km was established.

All was set for orbital insertion through aerobraking.

Continue to Aerobraking ...


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