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49

I wrote the article you are referencing. @Hobbes has it exactly correct. It is a lightweight vehicle that can launch on even a small rocket, and takes advantage of gravity assists and favorable celestial mechanics to catch Triton at just the right time for encounter with the plumes illuminated. It will image the entirety of Triton in sunlight on approach, ...


43

The mission was to fly by the outer planets. Once it got to Neptune that mission was complete. From Wikipedia: Because this was the last planet of the Solar System that Voyager 2 could visit, the Chief Project Scientist, his staff members, and the flight controllers decided to also perform a close fly-by of Triton, the larger of Neptune's two originally ...


38

Orbiters are expensive, and the further away its target is, the more expensive it gets. you want a high transit speed, to get there in a reasonable time then you need to brake to get into orbit, this takes lots of fuel (more fuel due to the high transit speed) because of the long mission duration, personnel cost is high for the outer planets, solar panels ...


35

They wanted a close flyby of Triton. Triton's orbit is at a large angle to the ecliptic plane, and Triton was below Neptune at the time of Voyager's flyby, so they needed a course change that pointed "down" from Neptune. From the Voyager Neptune travel guide (large PDF), page 118-119 of the PDF (page number 107-108 indicated on the page): However, ...


25

The initial plan was to visit all of the outer planets: The Planetary Grand Tour was to send several pairs of probes to fly by all the outer planets (and Pluto) along various trajectories, including Jupiter-Saturn-Pluto and Jupiter-Uranus-Neptune. Limited funding ended the Grand Tour program, but elements were incorporated into the Voyager Program, which ...


25

Buoyancy is a big problem. To stay aloft, the average density of the balloon envelope, lifting gas and gondola must be <= the density of the surrounding atmosphere. The pressure inside a balloon must be equal to or slightly greater than the surrounding atmosphere, otherwise the balloon will collapse. If you look at the ideal gas law you'll see that see ...


14

It's a fast flyby in the $500M cost class (a Discovery mission). So not really comparable to Beresheet. A rare, low Δv trajectory (Fig. 1) enables an MMRTG-powered spacecraft fitting under the Discovery cost cap. The mission would have to be launched in 2026, for a Neptune encounter in 2038. New Horizons has effectively demonstrated the scientific ...


11

Using my Hohmann spreadsheet you can get an idea of approximate delta V and trip times. The spreadsheet assumes circular, coplanar orbits. So it's ballpark, not exact estimates. LEO to Mars capture: 4.3 km/s, .71 years LEO to Uranus capture: 8.5 km/s, 16 years LEO to Neptune capture: 8.6 km/s, 30.6 years For a capture orbit I assume a 300 km altitude ...


10

That sounds like a terrible idea. The article says that: Lastly, Both planets contain high concentrations of methane. Like graphite, it too can actually transform into various forms of complex hydrocarbons given enough heat and pressure. Consider this: Pressure is high enough to make diamonds, so any mining equipment would need to sustain even ...


7

Using the Trajectory Browser, I was able to figure out the following trajectories that are available. The dates are Jan-18-2018, Feb-22-2019, Feb-23-2031, and Mar-29-2032. So basically there are two good launch windows roughly every 13 years To show out the path a bit more, I've included more than just the optimal paths. Unfortunately the tool doesn't ...


7

I'll try to get you started anyway. From the frame of reference of the assisting body, the trajectory of the probe is hyperbolic, with the same $v_\infty$ going out as coming in, but in a different direction. The trajectory is simply bent. The bend angle is: $$\delta=2\sin^{-1}\left(1\over e\right)$$ where $e$ is the eccentricity of the hyperbola. You ...


6

Venus' atmosphere is mostly CO2 which has a higher molar weight than N2 or O2 so a balloon filled with our atmosphere would be buoyant. Balloons filled with H2 or He even more so. But Uranus' atmosphere is mostly hydrogen and helium. Balloons that float would be harder. For a more thorough explanation of this problem, see pericynthion's excellent answer. ...


4

First of all, Neptune is a gas giant. Meaning there is no place for the spacecraft to land safely. And on top of that Neptune is about 2.26 Billion miles from Earth (When lined up towards the sun). Okay, but lets say the almighty diamond rush starts and they take off. The last time something visited Neptune was NASAs New Horizon which took 8 years of ...


4

I posted this image in the question where are the solid motors of Pioneer and voyager spacecraft? Jupiter gravity assit It helps explain when a spacecraft speeds up for a gravity assist and when it does not.Use this image along with Neptune/Triton flyby posted above.Objects that flyby in front of a planet orbital motion or polar regions slow down. The ...


4

My first concern was the magnetosphere, but Venus seems to have little or no intrinsic magnetic field, and Uranus's is somewhat stronger than Earth's, but not ridiculously so. The temperature and pressure of Venus' atmosphere at 50-65km altitude are pretty manageable, not unlike conditions that can be found near Earth's surface. Uranus's atmosphere seems ...


4

My 1965 Sourcebook On The Space Sciences indicates that they are resolvable: The polar flattening of [Uranus] is clear from its telescopic image and the ellipticity determined from the motion of the nearest satellite is 1/18. The result derived from direct measurement of the equatorial and polar diameters is about 1/12, but since the maximum angular ...


3

I believe it's so hard to find a good picture because there wasn't one. The best telescope in the world in the 1980s was Hale telescope at Palomar Observatory. It was a 5m telescope, but subject to atmospheric effects. Uranus has a resolution of about 18 urads from Earth, or about 3.7 arc seconds. Pre-adaptive optics, the best one could hope for in terms ...


2

This wikipedia article suggests that the conditions for diamond formation might (the same article mentions considerable doubts) be found 7000-10000 km below the cloud tops of Uranus and Neptune at temperatures of thousands of degrees and pressures of close to a million atmospheres. Since the interior of these planets is fluid, any diamonds formed would ...


2

Time to burst some bubbles. In all likelihood the diamond inside giant planets is merely industrial quality, so we would be seeking a commodity that's actually cheap. The United States Geological Survey reports that industrial diamond brings in only a few dimes per carat, not the thousands of dollars per carat brought in by the gem-quality stuff. From ...


1

Is it possible to combine both approaches to perform flybys to the outer planets and escape the solar system?? Launch it first as if it was a Venus mission which heavily relies on oberth trickery, then use Venus and Earth gravity assists to reach Jupiter, and from there beyond Basically yes. If your main concern is to get to the outer solar system or onto a ...


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