If KSP is to be believed, this is shockingly difficult to do
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Earth's orbital velcity is ~30km/s. So by extension, anything that comes from Earth will at least have that speed. So the probe needs to find 30km/s delta v in order to actually get close to the sun.
I would say it's your velocity that keeps you in orbit. Without the velocity, you fall into the star. Without the star's gravity, you keep going away in a straight line. Any object we launch starts off with Earth's velocity.
Long ago, playing Elite if I remember correctly, you could fly close to a star and scoop up a load of hydrogen for later resale. I'd be interested to see a graph of gas density vs tendency to melt spacecraft compared to distance from the core for a typical star.
1. Orbit yourself around low earth
2. When entering the transfer window (opposite side of the sun-facing earth, i.e. above midnight longitude) booooost
3. For orbit, aim for tangent with your target. For sun discovery, aim for sun center. Choose but don’t change.
The game is in 2D and you got nice auto-calculated transfert windows and trajectories. Is it one of those game simplification that makes it easy or there’s more difficulties?
And I'm not aware of any KSP mod that helps you plan slingshots. And even if there was a slingshot maneuver requires a lot of precision because your ejection angle is highly sensitive to exactly how close you came.
The Parker probe was sent outward to Jupiter and used it to slingshot away much of it's energy. (We normally think of using a planetary encounter to gain energy but it works both ways. Ejection velocity from a slingshot at Jupiter can be anywhere from hitting the sun to solar escape. It's just most probes are heading out, not in.)
I don't understand why we aren't doing solar + ion drive everywhere (except obviously launch), and instead we settle for slow multi-year multi-grav-boosts trajectories. Current ion drives (by NASA and on Starlink) have 2500-3500 Isp. Which means that even 100+ km/s is easy doable with just 2 stages.
[1]https://en.wikipedia.org/wiki/Parker_Solar_Probe?wprov=sfti1... [2]https://svs.gsfc.nasa.gov/3966/
The Parker Solar Probe mass is 555kg. An achievable amount of ion thrust is around 0.5N. Thus, running that thruster would accelerate the craft at 0.0009m/s2.
Getting such a craft to 30km/s of delta-v would therefore take about 33.3 million seconds of thruster time, or about 13 months.
I don't know what the duty cycle is on ion thrusters. Maybe they aren't robust enough to fire for over a year straight?
To be precise for 555kg probe you'd need additional 600-800kg of propellant mass and thus run the thruster(s) at about 1.5N thrust using 40-60KW - 250m2 of solar panels - everything is available at the current state of tech.
https://en.wikipedia.org/wiki/Ion_thruster
"A test of the NASA Solar Technology Application Readiness (NSTAR) electrostatic ion thruster resulted in 30,472 hours (roughly 3.5 years) of continuous thrust at maximum power. Post-test examination indicated the engine was not approaching failure.[75][3][4] NSTAR operated for years on Dawn."
If you're willing to go for the full n-body package, Principia [0] has a pretty nice flight planner that is quite usable for planning more complicated missions.
KSP Trajectory Optimization Tool [1] is a non-mod alternative with some additional capabilities beyond flight planning as well. I think this one is designed for stock gravity so it should be usable in an otherwise vanilla install.
You can, and I believe this probe will. The Sun’s atmosphere is just much nastier than our own, which means your aerobraking destroys your spacecraft quicker.
There was a bug (or was it?) in the very PC version where by if you had fuel scoops installed, set your view to looking out the rear of the ship, flew toward a star, and ignored all the warnings on your dashboard, you could fly right through the star. If you were being chased at the time you had the additional satisfaction of watching your pursuers' ships explode as they tried to follow you in.
In real life they used a set of Venus gravity assists instead. This has allowed them to slowly get closer while observing over time instead of a long wait and then one big bang close up before being shot ridiculously far back out.
In that case I have a theory. The extra propellant mass, extra solar panel mass, etc, are all more mass against a small amount of thrust. Every bit of additional mass extends that 1-year timeline, and all the extra stuff is extra things that might go wrong.
So instead of a 7 year mission being reduced to 18 months, we have a 7 year mission reduced to maybe 4 years, but then there's possibly a higher chance of failure.
Balancing three years against failure risk, I could see that falling on one side for some missions, and the other side for others. I'm not surprised that they pick the extra time for some missions. I am surprised that they don't pick the faster option more frequently.