Posted on by Fraser Cain

Why Don’t We Send Probes “Up” In The Solar System?

Why Don't We Send Probes "Up" In The Solar System?

Wouldn’t it be easier to see what’s outside the solar system if we just send out probes straight up?

Dammit, science people! Why are you always firing probes “outwards”? Then they have to go past all this stuff, like planets and asteroids and crap to escape the solar system. Don’t you realize that if we want to see what’s outside the solar system we just need to shoot them straight up?

Then we don’t have to go past all that junk, and we can finally see what’s between us and the next star system over! Is it thick goo? Is it thin goo? Is it the aether?!

What the heck is wrong with you! It’s so easy. Just go up! Why are we always going out?

Whenever we talk Solar System, we’re always using flat objects for reference. Plates, flying disks, pancakes and pizzas, as it’s arranged in a flat disk known as the plane of the ecliptic.

Formed from a blob of hydrogen gas and dust in the solar nebula. Gravity pulled everything together, and the conservation of angular momentum set the whole thing spinning, faster and faster. The spinning pulled the whole Solar System into the disk we see today, with our star at the center and the planets embedded in the surrounding disk. As a result, the Sun, Moon, planets and their moons all move through a relatively small region in the sky.

This definitely makes things easier to send spacecraft from world to world. NASA’s Voyager 2 was able to visit Jupiter, Saturn, Uranus and Neptune because they were all lined up like dominoes.

When Willie Sutton was asked why he robbed banks, he answered, “that’s where the money is,” and we explore along the plane of the ecliptic because that’s where the science is. Everything in our Solar System is arranged along this flat area, so it makes sense to look along this region.

But wait! As you know, the Solar System isn’t actually flat. Some objects rise a little above or below the plane of the ecliptic. This is known as a planet’s orbital inclination.

Orbit of Mercury
Orbit of Mercury

Of all the planets, Mercury has the greatest with 7-percent. It’s even crazier for the the dwarf planets, Pluto is 17-percent off the plane of the ecliptic, and Eris is 44-percent.

One of the reasons Eris went undiscovered for so long is because it orbits so far outside the planet of the ecliptic. It wasn’t until Mike Brown and his team from Caltech looked far enough outside the usual hiding spaces that they found these additional dwarf planets.

There really isn’t much outside the flat plane of the ecliptic, it’s also much more difficult to get spacecraft to travel above or below. When spacecraft launch, they already have tremendous velocity just from the rotation of the Earth and the speed of the Earth orbiting the Sun.

I realize this is just more “outwardist” propaganda for you. So why no “up”? If you did want to go that way, you need a powerful rocket capable of creating velocity in this direction, or that direction.

If you wanted to escape the Earth’s gravity and explore the Solar System in the regular old way, you’d need to add about 10 km/s in velocity to your spacecraft. But for straight up, you’d need about 30 km/s, meaning more fuel, and compromises to your payload.

It still sounds like I’m making excuses. Here’s the deal, you might be amazed to learn that spacecraft actually have been sent “up”.

Artist impression of the Ulysses spacecraft. Credit: NASA/ESA
Artist impression of the Ulysses spacecraft. Credit: NASA/ESA

The European Space Agency’s Ulysses spacecraft, launched in 1990 had the goal of looking down on the Sun from above. It wasn’t possible to do this just with a rocket, but engineers were able to use a gravitational assist from Jupiter to kick Ulysses into an orbital inclination of 80-degrees, and for the first time, we were able to see the Sun from above and below.

A new European mission is in the works called the Solar Orbiter, and it’ll get into an orbital inclination of 90-degrees to be able to see the Sun’s poles directly for the first time. If all goes well, it’ll launch in 2018.

So, why don’t we go up? Actually, we do. We’re going “up” again very soon. It’s good to go up. It’s always good to get outside of our regular stomping grounds and see our Solar System from new angles and perspectives.

If you could send a probe anywhere in our Solar System, where would you choose?

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Posted on by Nancy Atkinson

Watch Live Webcast of Ulysses Spacecraft Switch-off

Artist impression of the Ulysses spacecraft. Credit: NASA/ESA

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UPDATE: Use this link to watch the webcast (the other one isn’t working very well!)

It’s the spacecraft that just won’t quit. We ran a story about a year ago that the Ulysses spacecraft was dying of natural causes (running out of power to keep the spacecraft warm and functional) and its mission would likely end by July 1, 2008. The thing is, the spacecraft just kept hanging on…and hanging on….and hanging on. But now, after 18.6 years in space and defying several earlier expectations of its demise, Ulysses will finally be switched off. You can watch a live webcast of the final communication with the spacecraft, which will occur on June 30, 2009, starting at 15:35 GMT and go until 20:20 GMT.

“Ulysses has taught us far more than we ever expected about the Sun and the way it interacts with the space surrounding it,” said Richard Marsden, ESA’s Ulysses Project Scientist and Mission Manager.

Ulysses was the first spacecraft to survey the environment in space above and below the poles of the Sun in the four dimensions of space and time. Among many other ground-breaking results, the mission showed that the Sun’s magnetic field is carried into the Solar System in a more complicated manner than previously believed. Particles expelled by the Sun from low latitudes can climb up to high latitudes and vice versa, even unexpectedly finding their way down to planets.

And as a eulogy to the Ulysses spacecraft, here’s the last lines from the poem “Ulysses” by English poet Alfred, Lord Tennyson:

“Death closes all; but something ere the end,
Some work of noble note, may yet be done…
‘Tis not too late to seek a newer world…
To sail beyond the sunset.”

Link for webcast.

Posted on by Nancy Atkinson

Ulysses Spacecraft Dying of Natural Causes

ulysses_hat-trick_l.thumbnail.jpg

“One equal temper of heroic heart
Made weak by time and fate, but strong in will
To strive, to seek, to find, and not to yield.”
—from the poem “Ulysses” by Alfred, Lord Tennyson

The Ulysses spacecraft has been heroically studying our sun for more than 17 years, almost four times its expected lifetime. But now, the mission might be finally succumbing to the harsh environment of space. Mission managers say the spacecraft will likely “die” in the next month or two.

“Little remains; but every hour is saved
From that eternal silence, something more,
A bringer of new things;
To Follow knowledge like a sinking star,
Beyond the utmost bound of human thought.”
(more from “Ulysses”)

Ulysses is a joint mission between ESA and NASA that was launched in 1990 during space shuttle mission STS-41. Ulysses was the first mission to study the environment of space above and below the poles of the Sun. The spacecraft has returned a huge amount of data that has changed the way scientists view the Sun and its effect on the space surrounding it.

Ulysses. Image credit: ESA
Ulysses is in a six-year orbit around the Sun. Its long orbital path carries it out to Jupiter’s orbit and back again. The further it ventures from the Sun, the colder the spacecraft becomes. If it drops to 2ºC, the spacecraft’s hydrazine fuel will freeze.

This has not been a problem in the past because Ulysses carries heaters to maintain a workable on-board temperature. The spacecraft is powered by the decay of a radioactive isotope and over the 17-plus years, the power it has been supplying has been steadily dropping. Now, the spacecraft no longer has enough power to run all of its communications, heating and scientific equipment simultaneously.

“We expect certain parts of the spacecraft to reach 2ºC pretty soon,”says Richard Marsden, ESA’s Ulysses Project Scientist and Mission Manager. This will block the fuel pipes, making the spacecraft impossible to maneuver.

The ESA-NASA project team had tried to solve this problem by temporarily shutting of the main spacecraft transmitter, which would provide 60 watts of extra power that could be channeled back to the heater and science instruments. Unfortunately, the transmitter failed to turn back on.

“The decision to switch the transmitter off was not taken lightly. It was the only way to continue the science mission,”says Marsden, who is a 30-year veteran of the project, having worked on it for 12 years before the spacecraft was launched.

After many attempts, the Ulysses project team now consider it highly unlikely that the X-band transmitter will be recovered. They believe the fault can be traced to the power supply, meaning that the extra energy they hoped to gain cannot be routed to the heater and science instruments after all.

So, the spacecraft’s fuel lines are gradually freezing. This spells the end of this highly successful mission.

“Ulysses is a terrific old workhorse. It has produced great science and lasted much longer than we ever thought it would,” says Marsden. “This was going to happen in the next year or two, it has just taken place a little sooner than we hoped.”

The team plan to continue operating the spacecraft in its reduced capacity for as long as they can over the next few weeks. “We will squeeze the very last drops of science out of it,” says Marsden.

“Death closes all; but something ere the end,
Some work of noble note, may yet be done…
‘Tis not too late to seek a newer world…
To sail beyond the sunset.”
—more from “Ulysses” by Tennyson

Original News Source: ESA Press Release