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ES-15 ICARUS Mission

ES-15 ICARUS (European Spacecraft model 15, Intra-Corona Activities Research - Understanding Sun) is a ion-powered probe with sophisticated thermal protection design. Its mission is to perform dangerously close solar fly-by and gather precious data from space near the Sun and its outer corona.

Detailed descriptions of the ICARUS spacecraft can be found on its own page HERE. This page is mainly about the mission.

Pure stock, no mods or DLCs. 82 parts, root part is the QBE core on the spacecraft.

In spite of the maybe-exciting solar fly-by that may make you proud, it's totally possible to find such a mission frustrating and/or boring.

Some unusual spaceflight techniques would be required. In the most important phases, it needs frequent manual intervention with limited or no time-wrap possibility. Total mission time would be more than 2 years in-game. Consider these before conducting the mission.

One thing is clear: completing such a demanding mission does feel good.

AG1=vertical control point (default, lock surface radial-out over the Sun in this mode)
AG2=horizontal control point (fire ion engines at AP in this mode)
AG4=toggle solar panels and antennas
AG8=conduct experiments
AG0=ion engines ON/OFF

Launch
- Liftoff, conduct gravity turn and reach 45deg pitch @ 10km, lock prograde, jettison burnt-out SRBs.
- Push AP to 75km, shut down engine, coast till it escapes atmosphere, stage to jettison fairings, press AG4 to extend solar panels and antennas.
- Circularize. After first stage burn-out, it would require a very short kick with the upper stage.
- Now there should be ~4200m/s dV from the upper stage chemical rocket.
- Alternatively, transport the spacecraft+upper stage with a fully reusable SSTO spaceplane like shown in one of the screenshots.

Bi-elliptical Transfer
- Explanation on KSPwiki: HERE[wiki.kerbalspaceprogram.com]
- Escape from 75x75km LKO and push AP to near Dres orbit. This requires ~1470m/s dV if traveling in the same direction with Kerbin when escaping, gravity slingshot not in consideration.
- "1 year and 100 days later"
- Near AP: use all remaining rocket fuel to de-orbit (sun-dive). This should lower solar PE to ~1,000,000km, exactly the boarder value between being "high" and "low" over the Sun.
- Decouple upper stage, hit AG2 to switch to horizontal control point.
- Use ion engines to further de-orbit and push PE into space low over the Sun. It's tested for a safe fly-by with a PE of 180,000km, be extra careful under 200,000km. If you only want the low orbit science, >600,000km PE would be totally safe.
- It requires 2-3 charges for the ion engines to achieve lowest safe orbit altitude, however recharge takes merely seconds under maximum time wrap. Timing is not important: given how high the AP is, the spacecraft stays near AP for a pretty long time.
- Time-wrap to Moho orbit, prepare for the fly-by.

Solar Fly-by
- Hit AG1 to switch to vertical control point, lock radial-out (surface) to keep heat shield pointing at the sun, protecting the spacecraft.
- Extend top radiator.
- Use max. 100x time-wrap, otherwise the heat accumulation will go out of control and lead to the spacecraft exploding. Therefore, the fly-by would require a while to complete.
- Once the spacecraft main body begins to overheat, quit time-wrap, let it align itself to radial-out and enter time-wrap again. Repeat.
- Be extra careful under 200,000km. Use less time-wrap and quicksave a lot.
- Before quickloading, it's recommended to use Alt+F12 menu to briefly enable "ignore max temperature" cheat, otherwise the spacecraft would likely explode upon loading. This is caused by sudden exposure to extreme heat source with no time for the radiators to react. Disable the cheat when it gets stable.
- Near PE, you can choose to fire ion engines to lower AP value. Rotate the spacecraft to let the engines face orbital retrograde while still having the spacecraft lock surface radial-out. They now work continuously with ridiculous power input so close to the Sun.

Wish you enjoy the sunshine!