[X] My Assistant

[MarcF]

Jet Propulsion Laboratory scientists proposed a new low cost mission to Triton, to check for the presence of an internal ocean inside the moon.

https://www.nytimes.com/2019/03/19/science/...sa-trident.html

"Unlike multibillion dollar proposals for spacecraft that the agency has usually sent to the outer solar system, this spacecraft, named Trident, aims to be far less expensive, the mission’s scientists and engineers said, or the price of a small mission to the moon."

To get to Triton, the spacecraft would fly in a fast, straight trajectory after an orbital assist from Jupiter, similar to the flyby that was used by the New Horizons spacecraft to visit Pluto in 2015. It would rely on a payload of scientific instruments to conduct ocean detection and atmospheric and ionospheric science. The spacecraft would photograph the entirety of Triton, which is the largest object in the solar system that has not yet been fully imaged.
Timing is also critical because of the moon’s changing seasons as Neptune makes its orbit around the sun.

“In order to view the plumes that Voyager saw in 1989, we have to encounter Triton before 2040,” said Dr. Mitchell. Otherwise, because of the positions of the objects in their orbits, Triton will not be illuminated again for over eighty years.

Link to original abstract:
http://adsabs.harvard.edu/abs/2018DPS....5011415P

Fingers crossed !
Regards,
Marc.

[scalbers]

Apparently the equinox (for most complete viewing) is right about 2040.

[JRehling]

Triton has a weird (and, of course, very long) "season" but, yes, the sub solar latitude will be nearly equatorial around 2040. It also was just a bit south of equatorial in 1989, so the season will be similar to the Voyager 2 flyby. For the entire time between those, the sub solar latitude has been considerably south and the north polar region has not seen daylight in decades.

As a convenient comparison, the length of a Tritonian day is about the same as on Pluto so one might expect similar coverage of a near-encounter and far-encounter hemisphere to that which New Horizons yielded at Pluto. We could have better luck with neptune-shine images of Triton's sub-Neptunian hemisphere since Neptune is brighter than Charon.

[Julius]

Triton has a weird (and, of course, very long) "season" but, yes, the sub solar latitude will be nearly equatorial around 2040. It also was just a bit south of equatorial in 1989, so the season will be similar to the Voyager 2 flyby. For the entire time between those, the sub solar latitude has been considerably south and the north polar region has not seen daylight in decades.

As a convenient comparison, the length of a Tritonian day is about the same as on Pluto so one might expect similar coverage of a near-encounter and far-encounter hemisphere to that which New Horizons yielded at Pluto. We could have better luck with neptune-shine images of Triton's sub-Neptunian hemisphere since Neptune is brighter than Charon.

So by 2040 as Trident flies through the Neptune system, it will be end of summer in the southern hemisphere, do we expect most of the south polar ice deposit seen at the time of Voyager disappear and instead an icy polar cap developing over the northern hemisphere??