NASA To Sedna? The ‘Pluto-Killing’ World That Orbits Our Sun Every 11,408 Years Is Almost In Range Say Scientists

What’s three times further out than the planet Neptune, takes 40 Earth-days to rotate and 11,400 years to orbit the Sun?

Welcome to Sedna, the farthest object in the Solar System from the Sun when it was discovered in 2003. According to a new paper there’s a unique opportunity to send a mission to this strange and distant trans-Neptunian object—and we should launch it in 2029 or 2034.

If we don’t take advantage of the opportunity then it will be impossible to reach for another 11,000+ years.

What and where is Sedna?

Known variously as a dwarf planet, a Trans-Neptunian Object (TNO) and as an “object of the scattered disk,” (90377) Sedna is an icy body way beyond the orbits of the giant planets in the outer Solar System.

Close to Sedna is 2012 VP113, also called “Biden.” President Biden was Vice-President when it was discovered. It’a called a “sednoid,” and it’s not the only one. The existence of Sedna and the “sednoids” is, some think, possible evidence for the so-called “Ninth Planet.”

Why do we have to visit Sedna soon?

It’s now or never. Sedna has a highly eccentric and elongated orbit and is currently moving to its perihelion—the closest it gets to the Sun during its massive 11,400 years orbit. It will reach that point in 2073-74. Sadly, even then it will only reach to about 74 au from the Sun. Let’s get that in perspective:

• An au is the distance from the Earth to the Sun and is the unit of measurement used to talk about distances in the Solar System.
• Neptune, the eight planet, is 30 au from the Sun, on average.

So Sedna is very far away even at its closest—and at its farthest it’s a whopping 937 au distant.

In short, the upcoming perihelion of Sedna is a rare opportunity to study a proper deep space object that spends much of its time in the outer reaches of our Solar System—and possibly even the Oort Cloud. The Oort Cloud is thought to be a vast sphere around the Solar System that’s home to small icy bodies and would-be comets.

However, it’s going to take a while to get to Sedna.

When would we have to launch?

As detailed this week in Analysis of Mission Opportunities to Sedna in 2029-2034—a preprint paper also submitted to Advances in Space Research —a spacecraft would need to begin its journey between 2029 and 2034.

According to a team of scientists led by Vladislav Zubko from the Space Research Institute of the Russian Academy of Sciences it would be possible to send a direct flight to Sedna from Earth once each year, but the problem is speed. Any spacecraft needs to be going as fast as possible to reach Sedna during a human lifetime while going slow enough as its approaches to go into orbit.

The authors concluded that a direct flight would be practically unrealistic, as would a flight that went into orbit, so a flyby is the only option. A flight that launches in 2029 via gravity assists from Venus, Earth and Jupiter could be done in 20 years, though probably more like 30 years. The advantage of the latter would be a slower flyby and the chance top gather more scientific data—much like the New Horizons spacecraft’s flyby of Pluto in 2015 after a 10 year journey.

After the Sedna flyby the spacecraft could also perform flybys of main-belt asteroids (20) Massalia (if it leaves in 2029) or (16) Psyche (if it leaves in 2034).

What is Sedna like?

Sedna is an exciting object for deep space exploration because:

• It shines red, which may indicate that it has a layer of organic hydrocarbon compounds called tholins—thought to be possibly the building blocks from which life started in the early Solar System.
• The surface of Sedna is covered in ice.
• There may be an ocean beneath its surface of Sedna.
• It has a thin atmosphere±though perhaps only when it’s close to perihelion, as it is now.

When was Sedna discovered?

When Sedna was discovered by American astronomer Michael Brown in 2003 it was the most distant object ever found in the Solar System. It was the first of a series of distant objects discovered, with the likes of Pluto-sized Haumea, Makemake and Eris eventually tempting the International Astronomy Union to remove full planet status from Pluto. The alternative would have been to call about 20 different objects planets.

The controversy about Pluto’s demotion—and the bizarre way it was done, by voting—is why the term “worlds” has caught on when talking about anything other than the (now) eight planets.

But forget about nomenclature—Sedna is a unique world and we have a once-in-11,000 years opportunity to visit it.

Wishing you clear skies and wide eyes.