Comet-Chaser Rosetta Ready For Launch

Karl Kennedy writes "Europe's Rosetta space mission, which aims to chase and then land on a comet, is standing by for lift-off in French Guiana. Once up in space, Rosetta will be placed in orbit around Earth before departing for the outer Solar System. In 2014, Rosetta will reach the comet and deliver a lander to its surface. The probe will perform three close fly-bys of the Earth and one of Mars in "slingshot" manoeuvres that will use the planets' gravity to help the probe build up speed."

Finally

[Justin Ames]

The language barrier between earth and comets will be bridged by the Rosetta probe. Now, instead of harsher measures, we can talk a comet out of hitting us...

Re:Finally

[Cecil]

Comet says, "Oh, I see! This delivery of water was supposed to refresh the supply of water a few hundred thousand years for your neighbor, Mars. Oh, you say he's dead now? That's terrible! There must've been some mix-up when I went into orbit. I'm very sorry to bother you folks. I'll be on my way, then."

Seriously though, it really will be an impressive feat if they are able to land this probe on something so small, eccentric and fast-moving. I wish them the best of luck.

Been done before, or close

[Tau Zero]

The NEAR spacecraft landed on the asteroid Eros [space.com] over 3 years ago. Eros is rather eccentric, spinning, and small by our usual standards.

Re:Been done before, or close

[cobbaut]

Eros is an asteroid, not a comet.
Asteroids circle the sun more or less like planets,
comets go much further, come back a lot faster and sometimes get much closer to the sun.
NEAR was a great mission, but much simpler than Rosetta.

Re:Been done before, or close

[hubie]

However, don't forget that NEAR was not designed for landing, so it didn't have landing gear, contact sensors, etc.

Both the asteroid and the comet are both going around in elliptical orbits, where the comet orbit has a larger eccentricity, but getting to each one is basically the same. Getting to the comet will have a more complicated trajectory, but the orbital guys have that problem pretty well licked. If you can do ISEE-3/ICE [nasa.gov] you can do just about anything.

Re:Finally

[El]

Now, instead of harsher measures, we can talk a comet out of hitting us... Or threaten it with regime change if it doesn't change it's course...

Re:Finally

[Daniel Dvorkin]

No, it's a European probe. Probably a good thing, too.

Godspeed, little probe.

[TwistedGreen]

The engineering effort for something like this must be amazing. To launch this thing from Earth and have it eventually land on a moving comet... so much could go wrong.

But I hope for the best, and I hope that the scientists involved discover what they're looking for. Onward and upward, in the name of discovery. Missions like these are what will truly benefit our understanding, a little bit at a time.

Orbit a comet?

[lgbarker]

The article states that the probe "will enter orbit around the comet".
A comet has enough gravity to orbit? I would have expected that the probe would have to match the comet's speed & course - more like docking.
This is an impressive long-term mission.

Re:Orbit a comet?

[Baron_Yam]

Any two objects can orbit. Distance, speed, and outside gravitional effect must be taken into consideration, and one assumes the comet outmasses the probe (otherwise the comet would likely be described as orbiting the probe!), but there is no reason the probe couldn't enter into an orbit of the comet.

Artificial Intelligence

[El]

During Rosetta's rendezvous with the comet, commands from Earth will take about 50 minutes to reach the spacecraft. So the probe has been designed with a degree of autonomy, allowing it to think for itself. Couldn't this come back to haunt us, or have I been watching too much Sci-Fi? You know, if it could really think for itself, Rosetta would be telling us "You want me to do WHAT?!? Are you out of your mind?!?"

Re:Artificial Intelligence

[cruff]

Reminds me of "Dark Star" and the smart bomb. The crew had to convince one of the bombs that it had deployed in error and should not explode while still attached to the ship.

Re:Artificial Intelligence

[Heywood Giablomi]

Yeah...the Phoenix Asteroids... (surfs down to planet on metal hull fragment)

No, no

[Walkiry]

You're missing the important point of how humans define intelligence. Why is a dog intelligent? Because you can teach him to follow orders, and the more orders (or more complex) orders he can follow, the smarter it is considered.

Makes you wonder doesn't it ;)

Re:Artificial Intelligence

[gustgr]

Maybe you have been watching TOO MUCH "2001 A Space Odyssey", but I belive HAL 90... Rosetta will not be so smart as they say. Mayber their conception of "think" is different from everyone's else.

I hope it has lots of cameras on it

[glen604]

If it's flying around the solar system for 10 years until it meets it's comet destiny, it should make a pretty interesting interim astronomy platform. Then if it somehow crashes into the comet or dies en route it won't be a wasted mission.

10 years is an awfully long time- lots of stuff could go wrong

Orbit animation here...

[snake_dad]

IMHO this is ESA's biggest challenge thusfar. 10 years is a very long time to wait for results of your mission... This flash animation [esa.int] shows Rosetta's long journey. This mission is even more awe inspiring than Stardust or Deep Impact.

Re:Orbit animation here...

[MindStalker]

Ok maybe I'm just being stupid, but in the year 2008 the comet and earth are fairly close to one another. I know with our current tech we probably wouldn't be able to succesfully land on it, but wouldn't it be sad if in 2008 we had the ability to launch a craft to beat the Rosetta to its goal.

Re:Orbit animation here...

[snake_dad]

True... But there is a reason that Rosetta intercepts the comet on the outermost point of it's orbit. Because the comet is so far away from the sun it is not yet ejecting gas and particles, that happens when the comet nears the sun and heats up. That's when the famous tail(s) of comets start to appear. The really interesting part of this mission is that we'll see this process of heating up from very close up, from start to finish (if Rosetta lives that long).

Re:Orbit animation here...

[johnjay]

Thanks for the link. I didn't understand the magnitude of complexity necessary to get the satellite's path and comet's orbit to match up.

Let's hope that, after all that delicate manuvering, the rendevous works as planned.

It's interesting that the comet's orbit doesn't extend past Jupiter. That's not what I learned about comets growing up.

Re:Orbit animation here...

[snake_dad]

What you learned about comets while growing up is mostly right. Most comets originate from outside the planets' orbits, either from the Kuiper Belt (in the Pluto region of the solar system) or from the Oort Cloud (waaaaay out there). Sometimes an object from those areas will be nudged into an orbit that brings it closer to the sun. Interaction with the Sun's or planets' gravity may force some comets in smaller orbits (like this one). IANA astronomer, maybe someone else can explain it better...

Slingshots and speed

[Quill_28]

Am I know physicist, but how does 'slingshotting' help a object gain speed?

Wouldn't it just change the direction not the speed of the object?

I think I should be quoting vectors, velocity, and some energy law but I think you understand the question.

Re:Slingshots and speed

[philbert26]

It works because the planet you slingshot around is moving. NASA [nasa.gov] has a page talking about it in quite some detail.

Energy and momentum are conserved. A slingshot slows down the planet by a tiny bit (just like you move the Earth when you jump in the air). The speed at which you leave the planet isn't any faster relative to the planet, but since the planet itself is moving, your speed relative to what you're aiming at can be increased.

Launch is postponed

[rpiquepa]

It's just been announced. Because of high winds above Kourou, the launch of Ariane 5 carrying Rosetta is being postponed until (at least) tomorrow.

speed?

[hutkey]

i hope this happens as planned, my best wishes are with the people who have spent years developing this amazing transporter. isn't the speed of the comet pretty high(very high, infact, Hale Bopp speed = 200 000 km pr hour in the inner core of solar system) how does Rosetta will be able to handle the tremendous speed. and the urface temparature o the comet when she starts orbitting

Re:speed?

[snake_dad]

I don't know the numbers, and am too busy at work to look them up (:-)), but the comet's speed is indeed very high with respect to the Sun. That is why Rosetta does 3 Earth flyby's, and one Mars flyby. Each slingshot adds speed to Rosetta until it matches the comet's speed. Rosetta's speed will be very slow wrt the comet, they want to stay in orbit around it.

The surface temperature? I couldn't find any meaningful information in a quick google, but since the comet stays outside Earth's orbit it receives less energy from the Sun than Earth does. So I wouldn't imagine the comet as a red hot glowing piece of molten rock that might melt the spacecraft.

Re:speed?

[hutkey]

thank you for clearing some facts,
i know about the sling-shot, my qusetion is
"is the material used to build up the spacecraft, sustainable at high speed?" when the comeet stars to come near the sun, it's temparature starts to rise, that's where the sustainabilt to the temparature cmes into picture. can anybody elaborate?

Hmmm...

[Bob Vila's Hammer]

News on any front about a new mission to investigate another interesting part of our solar system is good these days - even if it will take place ten years from now.

I wonder what kind of space faring adventures we'll be seeing in the mean time and during this ambitious project when it finally achieves its goal? I hope, like I hope for the success of this great mission, that all is well and still inspired. Go ESA!

Launch has been delayed

[Frans Faase]

Launch has been delayed to strong winds at high altitudes.

Re:Launch has been delayed

[snake_dad]

And again [spaceflightnow.com], at least until next week. This time because of insulating foam coming loose.

No luck with launch vehicle

[flowerp]

It has just been announced that there is a chunk of foam insulation missing on the Ariane booster, such that they will have to haul the booster back into the assembly building to fix it. Appears like the earliest possible launch will be next week (March!).