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MESSENGER Enters Orbit Around Mercury

Soulskill posted more than 3 years ago | from the threading-a-distant-needle dept.

NASA 108

krswan writes "From the NASA press release: 'At 9:10 p.m. EDT, engineers in the MESSENGER Mission Operations Center at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md., received the anticipated radiometric signals confirming nominal burn shutdown and successful insertion of the MESSENGER probe into orbit around the planet Mercury.' If you don't know much about this little spacecraft, check out its website. Designed with a completely passive cooling system, it will stay at 600C on the sun side, but room temperature behind the sunshade. During its 6-year journey it used solar panels as sails, relying on the solar wind instead of thrusters to adjust its trajectory. Over the next year it will build a high-res map of Mercury, and maybe determine if there is really ice hiding within polar craters (PDF)."

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God damn it... (3)

veeoh (444683) | more than 3 years ago | (#35529046)

...this amazes me everytime. Great job.

Re:God damn it... (2)

davester666 (731373) | more than 3 years ago | (#35533508)

Wouldn't you know it, they have an off-by-one error. It was supposed to be Venus!

Most boring planet? (2)

Troll-Under-D'Bridge (1782952) | more than 3 years ago | (#35529078)

No, not really. All of the planets are interesting in their own right, including the one under your feet. However, I'd nominate Mercury as the most boring of the bunch. It has no thick atmosphere to hide what's underneath (Venus), isn't Earth-like enough to be humanity's putative second home (Mars), a mini-solar system (Jupiter, Saturn and the other gas giants), nor a former double planet (Pluto and Charon).

Re:Most boring planet? (4, Interesting)

CFBMoo1 (157453) | more than 3 years ago | (#35529162)

Mercury has a magnetic field unlike Venus or Mars. If I remember one article right it's also more dense of a planet. Maybe we'll find some nifty raw materials there that some day in the future we could harvest.

Re:Most boring planet? (1)

BJ_Covert_Action (1499847) | more than 3 years ago | (#35531946)

Yeah, I'm hoping they find Eezo there too.

Re:Most boring planet? (1)

MobileTatsu-NJG (946591) | more than 3 years ago | (#35539868)

Mercury has a magnetic field unlike Venus or Mars. If I remember one article right it's also more dense of a planet. Maybe we'll find some nifty raw materials there that some day in the future we could harvest.

Spectra-graphic analysis shows several vespene geysers.

Re:Most boring planet? (1)

Skarecrow77 (1714214) | more than 3 years ago | (#35529170)

Actually, I believe that technically Mercury is more earth-like than Mars is, in terms of composition, magnetic field, etc. It's just that it's small, hot as shit (not as bad as venus actually though, surprisingly), and lacking much in the way of an atmosphere.

That said, what it is -incredibly- similar to is Luna. If we ever finally get around to setting up a polar moon base, the technology can be almost directly ported to setting up a polar base on Mercury. The solar power generation would be fantastic there, but I can't think of much other reason to go.

Re:Most boring planet? (1)

cranil (1983560) | more than 3 years ago | (#35529372)

Actually, I believe that technically Mercury is more earth-like than Mars is, in terms of composition, magnetic field, etc. It's just that it's small, hot as shit (not as bad as venus actually though, surprisingly), and lacking much in the way of an atmosphere.

I don't find that surprising really... green house effect can be quite intense.

Re:Most boring planet? (1)

angel'o'sphere (80593) | more than 3 years ago | (#35530222)

Greenhouse effect on Merucry?
oO!

angel'o'sphere

Re:Most boring planet? (1)

linuxwolf69 (1996104) | more than 3 years ago | (#35531306)

(not as bad as venus actually though, surprisingly)

I think he was referring to the "surprising" portion of the comment... the part in parenthesis

Re:Most boring planet? (1)

angel'o'sphere (80593) | more than 3 years ago | (#35529980)

Actually, I believe that technically Mercury is more earth-like than Mars is, in terms of composition, magnetic field, etc. It's just that it's small, hot as shit (not as bad as venus actually though, surprisingly), and lacking much in the way of an atmosphere

Well, all your points make Mercury, technically speaking less earth like.
Earth + Mars has an atmosphere. Earth and Mars rotate giving both a roughly 24h day (Mercury day is roughly half of a mercury year). Mars perhaps once had life, Mercury certainly never.
Mars has a hospitable temperature range (after getting atmosphere pressure up a real hospitable one), Mercury is as hot as hell in sunlight and significantly colder at night time than Mars. The rocky composition is very similar to earth in both cases, but who cares about that? As long as the atmosphere is fine an the gravity and the temperatur I would not care if my planet was made from wood.

angel'o'sphere

Re:Most boring planet? (0)

Anonymous Coward | more than 3 years ago | (#35530694)

Mars has a hospitable temperature range [...], Mercury is as hot as hell in sunlight and significantly colder at night time than Mars.

You've got it backwards. By the intermediate value theorem, Mercury has room-temperature spots, while all of Mars is below room temperature. So Mercury is the one with a hospitable temperature range, not Mars.

Re:Most boring planet? (1)

MichaelSmith (789609) | more than 3 years ago | (#35536862)

while all of Mars is below room temperature

No. Daytime atmospheric temperatures on Mars get to 20C or so, which is pretty warm. Still the cold ground would be freezing you.

Its worth emphasising: When talking about places other than Earth there is no "temperature". You can't say "how hot is is?". You can only say "how hot is the air?", "how hot is the ground?", "how hot is the solar wind?", etc

Re:Most boring planet? (0)

Anonymous Coward | more than 3 years ago | (#35540170)

As a creationist I've been trying all my life to justify why the Earth is special in the universe. Looks like you just nailed it for me: the Earth is the only place where we can say "how hot is it?" and the question doesn't make sense for other places! This is so elegant and such a simple test. tHANK YOU!!

Re:Most boring planet? (1)

FatdogHaiku (978357) | more than 3 years ago | (#35531546)

The solar power generation would be fantastic there, but I can't think of much other reason to go.

Well, if you look at the composition of the planets they generally seem to have lighter elements as you move away from the sun. Rocks close in, gas farther out. So the densest elements should be found on Mercury. In fact, in a temperate zone it would be possible (not likely) to have a lake of mercury with islands of rock or iron floating on it... It truth I would expect any mercury to long since have vaporized and been blown away on solar winds, but there might be molten metal lakes on the hot side.

In any case I would expect a high concentration of metal at the surface of the planet.So you build a rail gun and send big chunks of metal into space for use as building materials. You could use the sun to slingshot it just about anywhere.... In fact that might be a nice thing to have if we see an asteroid coming at us.

Re:Most boring planet? (1)

olsmeister (1488789) | more than 3 years ago | (#35529352)

Mercury has an extremely large iron core [universetoday.com] for its size, much larger by volume than Earth's. I'd say that's interesting.

Re:Most boring town? (1)

rwa2 (4391) | more than 3 years ago | (#35529384)

Heh, I grew up in Laurel, MD. Finally, something to put us on the map other than "Where Arthur Bremer shot George Wallace".

Re:Most boring town? (0)

Anonymous Coward | more than 3 years ago | (#35529764)

Uh, you forgot Laurel Park. I actually like going there to watch races every once in a while, but the atmosphere of that place really is that of broken dreams.

Re:Most boring town? (0)

Anonymous Coward | more than 3 years ago | (#35531904)

Too bad the lab isn't actually in Laurel. It's closer to Columbia, MD, although it has a Laurel mailing address.

Re:Most boring town? (0)

Anonymous Coward | more than 3 years ago | (#35532982)

Oh, come on now, you have Toucan Taco! (formerly Tippy's)

Re:Most boring town? (1)

TheSync (5291) | more than 3 years ago | (#35535544)

Not to mention that the hijackers of flight 77, including Mohamed Atta, al-Midhar, Nawaq Alhamzi, and Hani Hanjour, stayed at the Valencia Motel and Pin Del Motel in Laurel.

Re:Most boring planet? (1)

Hartree (191324) | more than 3 years ago | (#35529414)

It'll be interesting to see what the surface chemistry is like on a place that has such a high temperature solar wind blasted face and massive temperature gradients along the terminator. They loaded Messenger up with spectrometers for atmosphere (tenuous, I know) and surface element and chemistry analysis.

The magnetometer and orbit monitoring of the spacecraft are going to give a lot of info on what the core of the planet is like.

I love this kind of thing. Beats the daylights out of most of the other news around the world in the past week.

Re:Most boring planet? (3, Interesting)

pinkushun (1467193) | more than 3 years ago | (#35529494)

Then again:

- Mercury's density implies that a metal-rich core occupies at least 60% of the planet's mass, a figure twice as great as for Earth.
- only 45% of the surface of Mercury had been photographed by a spacecraft.
- Mercury has a global internal magnetic field, as does Earth, but Mars and Venus do not.
- At Mercury's poles, some crater interiors have permanently shadowed areas that contain highly reflective material at radar wavelengths.
- the period of time from which the position of the Sun in the sky at a given, fixed Mercury longitude returns to that same position is 176 Earth days.
- 3:2 resonance - 3 planet rotations during 2 orbits around the sun

Given the mysterious material hiding in the cold craters turns out to be water ice, the abundant solar energy on Mercury could be used to separate this into Hydrogen and Water. Both great resources to stay put with operations on the little rock.

http://messenger.jhuapl.edu/why_mercury/index.html [jhuapl.edu]

Re:Most boring planet? (1)

blair1q (305137) | more than 3 years ago | (#35533974)

the period of time from which the position of the Sun in the sky at a given, fixed Mercury longitude returns to that same position is 176 Earth days.

It's okay, you can say "Mercury's day is 176 Earth days long." I mean, unless you want to replace "Earth day" with the same long-winded macro you used for "Mercury day"....

Re:Most boring planet? (1)

butalearner (1235200) | more than 3 years ago | (#35535500)

the period of time from which the position of the Sun in the sky at a given, fixed Mercury longitude returns to that same position is 176 Earth days.

It's okay, you can say "Mercury's day is 176 Earth days long." I mean, unless you want to replace "Earth day" with the same long-winded macro you used for "Mercury day"....

To be fair Earth's solar day and sidereal day are four minutes apart, so we Earthlings might easily think "one rotation" is synonymous to a day. Not true, but close enough. But it's not even close on Mercury, where a solar day is exactly three sidereal days. Depending where you are on the surface, a single solar day might have more than one sunrise.

Another interesting property of Mercury is that it has a very miniscule axial tilt (<0.1 degrees), which means at the poles, the sun -- appearing three times larger than on Earth -- will always be halfway above the horizon and the temperature would stay relatively constant. Constant temperatures, possible water ice, Mars-level gravity...all interesting things. If we ever become the space-faring species we should be, we may very well have a place there.

Re:Most boring planet? (1)

blair1q (305137) | more than 3 years ago | (#35535924)

Depending where you are on the surface, a single solar day might have more than one sunrise.

Errrrr....how's that supposed to work?

It's rotating about its axis every 55 days. It's rotating about the sun every 88 days. Which means the sun is always going the same direction in the Mercurial sky. Backwards.

The sun rises on Mercury once every two mercury years or 3.5 mercury sidereal days or 176 earth days or 176.5 earth sidereal days. But only once, except maybe in very tiny spots owing to that very tiny axial tilt, so is that what you meant?

Re:Most boring planet? (1)

MichaelSmith (789609) | more than 3 years ago | (#35537062)

I believe Mercury has an eccentric orbit, probably forced by resonance with Venus and Earth. So the sun goes around the sky at a rate with varies significantly and the rate caused by the orbit can cross over the rate caused by rotation, leading to a "retrograde summer".

Re:Most boring planet? (0)

Anonymous Coward | more than 3 years ago | (#35534168)

- only 45% of the surface of Mercury had been photographed by a spacecraft.

That was only true until the first or second flyby by messenger. After those passes, mercury's surface had mostly been imaged.

Re:Most boring planet? (1)

MichaelSmith (789609) | more than 3 years ago | (#35536928)

Hydrogen and Water

Hydrogen and Oxygen.

I think Mercury should be the first target for a manned mission to another planet. It is easy to get to with solar sails. A surface to orbit shuttle could make its own fuel on the surface. Not having an an atmosphere makes temperature regulation a lot easier.

Re:Most boring planet? (1)

wumpus188 (657540) | more than 3 years ago | (#35538512)

Not having an atmosphere will actually make temperature regulation much harder - without convection to cool suite off there will be a problem with excessive heat, esp. on Mercury.

Re:Most boring planet? (1)

MichaelSmith (789609) | more than 3 years ago | (#35538982)

Photons are easy to deflect. You just need a think sheet of metal, plastic or glass. Its light and simple. Pressure suits used on the moon were white but I think suits for use on Mercury would need a reflective shield separated from the pressure garment by a small vacuum gap. That will keep most of the photons off the suit. Boots could possibly be designed with studs to minimise contact area. Exposed equipment would get hot so tools should be kept in the shade as much as possible before use. Initially I think landings would be at one of the poles and close to water. If there isn't water on Mercury I doubt humans will go there for a long time.

Re:Most boring planet? (2)

MrQuacker (1938262) | more than 3 years ago | (#35531542)

Yeah, but when we cover the whole thing in solar panels and beam the power back to Earth, we will have an amazing source of clean and free energy.

Not to mention all the goodies that will have accumulated on and under the surface. So close to the sun it should be covered in layers of Helium-3 and other exotics.

Re:Most boring planet? (1)

blair1q (305137) | more than 3 years ago | (#35534010)

Yeah, but when we cover the whole thing in solar panels and beam the power back to Earth, we will have an amazing source of clean and free energy.

For about 2 months out of every 3.

To get the power when it's on the other side of the sun you'll need to put up relay satellites. And you might as well just put the big solar array on them. You'll only have to put them on one side, then.

Re:Most boring planet? (1)

MrQuacker (1938262) | more than 3 years ago | (#35537218)

If you think of the solar system as an X - Y plane, with Earth and Mercury both on the same Y plane, then you need only one satellite high on the X plane. By being up high like that, both planets can be on opposite sides of the sun, yet still in line-of-sight of the satellite. And it doesnt even have to be anything fancy, just a giant mirror with positioning and rotating capabilities, so it just bounces the beam from Mercury to Earth orbit.

Re:Most boring planet? (1)

blair1q (305137) | more than 3 years ago | (#35533842)

But you can use it as a soldering iron.

First pictures of new flyby (-1, Troll)

slashdotfan1 (2020366) | more than 3 years ago | (#35529086)

Here you can see them [blog.com] Really amazing and unusual.

Re:First pictures of new flyby (0)

Anonymous Coward | more than 3 years ago | (#35529122)

all i can see is a gaping security hole!

btw, capcha: annals

Re:First pictures of new flyby (1)

MyLongNickName (822545) | more than 3 years ago | (#35529168)

So you like pictures of gaping anuses? I can definitely see why some folks find this fascinating. Can you please go into more detail on why this is the case?

Re:First pictures of new flyby (1)

E IS mC(Square) (721736) | more than 3 years ago | (#35529252)

What? We found a giant wormhole on Mercury???!!!11!!

Re:First pictures of new flyby (1)

Hartree (191324) | more than 3 years ago | (#35529294)

You looked closely enough to see if he had worms?

Eeeeew...

Re:First pictures of new flyby (1)

Stooshie (993666) | more than 3 years ago | (#35530422)

We are discussing Mercury, not Uranus. Please keep up!

This is what space exploration should look like (5, Insightful)

lwsimon (724555) | more than 3 years ago | (#35529090)

This is what we should be doing - high-tech, compact probes doing important work all over the solar system.

Guys in suits in space is cool, but we need to learn, understand, and develop commercial applications first. The rest will come in time.

Re:This is what space exploration should look like (0)

Anonymous Coward | more than 3 years ago | (#35529260)

If it's not ultimately for the purpose of sending a human somewhere else, it's wasting time.

Re:This is what space exploration should look like (2)

lwsimon (724555) | more than 3 years ago | (#35529854)

So, in your estimation, an orbital solar collector with microwave power transmission back to the ground is a waste of time, unless it has a human operator?

Re:This is what space exploration should look like (1)

C_amiga_fan (1960858) | more than 3 years ago | (#35529348)

Also develop warp drive, so our robotic probes can explore *other* solar systems.

PHOTOS FROM MESSENGER:
2008 http://apod.nasa.gov/apod/ap080116.html [nasa.gov]
2010 http://apod.nasa.gov/apod/ap100901.html [nasa.gov]
2011 http://apod.nasa.gov/apod/ap110223.html [nasa.gov]

Re:This is what space exploration should look like (1)

Walterk (124748) | more than 3 years ago | (#35529736)

I think we should send more people [google.co.uk] to space. Suits optional.

Re:This is what space exploration should look like (1)

decipher_saint (72686) | more than 3 years ago | (#35529860)

Actually I think it's very important we send guys in suits into space, there is so much left to learn.

Re:This is what space exploration should look like (4, Interesting)

camperdave (969942) | more than 3 years ago | (#35529866)

Which program do you think has inspired more children to enter the sciences Apollo or Voyager? Which do you think has had a bigger cultural and economic impact, manned spaceflight or planetary probes?

Re:This is what space exploration should look like (1)

cpu6502 (1960974) | more than 3 years ago | (#35529994)

>>>Apollo or Voyager?

It was Voyager for me. Reading the latest updates of V'ger's progress plus the gorgeous photos of Saturn, Uranus, Neptune..... definitely ignited by imagination. The shuttle program never interested me.

And of course there was that cool movie starring V'ger. "The Motion Picture" I think it was called.

Re:This is what space exploration should look like (1)

blair1q (305137) | more than 3 years ago | (#35534042)

So the people in the spaceship that re-discovered V'ger didn't have anything to do with it...

Re:This is what space exploration should look like (1)

TheTurtlesMoves (1442727) | more than 3 years ago | (#35530208)

For me it was Voyager. I clearly remember waiting for the national geographic with the images...

Re:This is what space exploration should look like (1)

somersault (912633) | more than 3 years ago | (#35530224)

I wouldn't really want to go into orbit with current levels of technology, but I would be interested in taking part in a project to launch, communicate with and research via a probe..

Re:This is what space exploration should look like (1)

c6gunner (950153) | more than 3 years ago | (#35540210)

I wouldn't really want to go into orbit with current levels of technology

That's you. Personally, I'd gladly go into orbit wearing a pressure-suit and strapped to a rocket-powered office-chair, if that was the only means available. I doubt I'm all that rare in that respect, either ...

Re:This is what space exploration should look like (0)

Anonymous Coward | more than 3 years ago | (#35530690)

Definitely Voyager for me. The 'robotic' study of the distant planets was absolutely awe-inspiring and got me interested in the sciences. That and the nifty CGI back in the day. While Astronauts are cool in their own right and provided that human element, it was Voyager -- and other spacecraft exploring the solar system that hooked me.

Re:This is what space exploration should look like (0)

Anonymous Coward | more than 3 years ago | (#35531080)

Which do you think has had a bigger cultural and economic impact, manned spaceflight or planetary probes?

The latter, obviously. It enables the former.

Re:This is what space exploration should look like (3, Insightful)

Nyeerrmm (940927) | more than 3 years ago | (#35531310)

As always with this debate, people are trying to debate the means without agreeing on the ends they are trying to achieve.

If you're talking pure science, then manned programs are a waste of time (I may be biased though, I'm a JPLer).

If you want inspiration I think its a toss-up -- the younger generation just has the shuttle which isn't that inspiring. Really, its hard to say. Same with spin-offs, economic impact, and everything else.

However, if you want to see humanity expand beyond our home planet, then the reason to send people to space is to learn how to do it, and to do it better, cheaper, and more safely. As long as you have them out there, science seems a good thing to do. Of course, something economically justifiable and self-sustaining like resource extraction will need to be there to get it beyond anything that are the mere tech demos we have today.

Re:This is what space exploration should look like (1)

lwsimon (724555) | more than 3 years ago | (#35532990)

Oh, I agree - but the only way to get the self-sustaining stuff is to go out and see what's there - and the only way to do that right now is via unmanned exploration.

We need knowledge more than anything. At some point, there will be profit to be had from sending actual humans into space. That's when things will change forever, and we will no longer be a species bound to one rock.

Re:This is what space exploration should look like (1)

MarkRose (820682) | more than 3 years ago | (#35533856)

I'm 28, and for me, it was Voyager. Putting a man on the moon is cool (and expensive!), but seeing and learning more of the solar system makes Voyager more inspiring to me.

Re:This is what space exploration should look like (1)

dryeo (100693) | more than 3 years ago | (#35539684)

Though I never entered the sciences, if I had it would have been Voyager. I remember reading about the idea of a grand tour of the solar system and how (relatively) soon the planets would be in an alignment that made it possible and it would be a long time before the celestial configuration allowing the grand tour to happen would roll around again.
That idea was more inspiring then going to the moon and it was fantastic when Voyager actually did the grand tour.

Re:This is what space exploration should look like (1)

MobileTatsu-NJG (946591) | more than 3 years ago | (#35539884)

Which program do you think has inspired more children to enter the sciences Apollo or Voyager?

TNG. :)

Re:This is what space exploration should look like (1)

Skywolfblue (1944674) | more than 3 years ago | (#35540874)

Pfft. Kirk > TNG

How many children want to grow up to be a bald guy? Noooo sireee.

Swaggering around the galaxy womanizing and barbrawlin is the iconic future of space travel! :P

Re:This is what space exploration should look like (0)

Anonymous Coward | more than 3 years ago | (#35530964)

This sounds like last weekend: "high-tech, compact probes doing important work all over".

#screamingwife

Fuck yea, Science! (1)

nstlgc (945418) | more than 3 years ago | (#35529094)

I love you so much.

Untrue (4, Informative)

MyLongNickName (822545) | more than 3 years ago | (#35529098)

". During its 6-year journey it used solar panels as sails, relying on the solar wind instead of thrusters to adjust its trajectory"

I do not think this is true;

"These views of MESSENGER show the orientation at the start of trajectory correction maneuver 43 (TCM-43). Because TCM-43 will use the large bi-propellant thruster to place the spacecraft into orbit about Mercury, TCM-43 is also called Mercury orbit insertion (MOI). "

"MESSENGER’s dual-mode propulsion system includes a 660-newton (150-pound) bipropellant thruster for large maneuvers and 16 hydrazine-propellant thrusters for smaller trajectory adjustments and attitude control. The Large Velocity Adjust (LVA) thruster requires a combination of hydrazine fuel and an oxidizer, nitrogen tetroxide. Fuel and oxidizer are stored in custom-designed, lightweight titanium tanks integrated into the spacecraft’s composite frame. Helium pressurizes the system and pushes the fuel and oxidizer through to the engines."

And I know I read about this mission using chemical propulsion several times during the mission to make course adjustment.

Re:Untrue (1)

rossdee (243626) | more than 3 years ago | (#35529172)

Besides if you were going from the Earth to Mercury, trying to catch the solar wind is not going to help you much.

Re:Untrue (5, Interesting)

Buggz (1187173) | more than 3 years ago | (#35529202)

Not for boost, but for steering aka adjusting trajectory - sure! Like when you're rowing, just dipping an oar into the water will cause your boat to turn.

Re:Untrue (3, Informative)

MyLongNickName (822545) | more than 3 years ago | (#35529290)

I think I see the source of the confusing

The author of this submission did a wikipedia search and found two things:

1) Wikipedia reports that this mission will MEASURE solar wind.
2) Wikipedia's solar wind article states "Both the Mariner 10 mission, which flew by the planets Mercury and Venus, and the MESSENGER mission to Mercury demonstrated the use of solar pressure as a method of attitude control in order to conserve attitude-control propellant."

The article submitter then took that grain of usage and made it the sole method of propulsion. Bad article submitter.

Re:Untrue (0)

Anonymous Coward | more than 3 years ago | (#35530710)

Mod this up, attitude correction != trajectory correction. The former requires little energy, the latter quite a lot.

Re:Untrue (1)

Stooshie (993666) | more than 3 years ago | (#35530470)

Depends what side of the sun the two are on.

Re:Untrue (2)

angel'o'sphere (80593) | more than 3 years ago | (#35530778)

Oh, it could.
Immagine the sails tilted in a way that they slow the craft down.
Every trajectory in the solar system is basically an orbit around the sun.
You can use solar sails to increase your velocity to widen that orbit to reach outer planets or you can use a solar sail to reduce velocity to make your orbit smaller to reach inner planets.
angel'o'sphere

Re:Untrue (1)

dryeo (100693) | more than 3 years ago | (#35539720)

Depends on the route you take. IIRC Messenger used gravity assists from Venus and the Earth to get to Mercury (Mercury is harder to get to then Jupiter) so a solar assist would help on the Venus to Earth leg of the trip.
Solar assist might also help in slowing down when arriving as well.

Re:Untrue (4, Informative)

Digicrat (973598) | more than 3 years ago | (#35529284)

Inaccurately worded, but true none-the-less.

The solar wind isn't used in place of traditional thrusters, but as a complement to them, allowing the spacecraft to save precious fuel.

Google yields a good explanation of this from an old article at http://www.spacedaily.com/reports/MESSENGER_Sails_On_Sun_Fire_For_Second_Flyby_Of_Mercury_999.html [spacedaily.com] discussing the cancellation of several TCMs due to the successful usage of solar sailing.

Re:Untrue (1)

MyLongNickName (822545) | more than 3 years ago | (#35529346)

'Inaccurately worded, but true none-the-less."

wait. what?

If it is inaccurately worded, it is not true. I think I know what you mean and I go into detail on where it is inaccurate in another post in this thread. But the wording indicates that there is no traditional thruster. When I read this, I immediately had to check the project web page, because I have followed this mission and missed this peice of revolutionary news :)

So, I think we agree on what is really going on. And I appreciate the additional source of news. I just don't want others thinking that this mission is propellant free. Solar sails might be very valuable, but they don't provide enough force to do the type of adjustments necessary for this mission.

Re:Untrue (1)

camperdave (969942) | more than 3 years ago | (#35529680)

Perhaps ambiguously worded might be a better way of putting it. "During its 6-year journey it used solar panels as sails, relying on the solar wind instead of thrusters to adjust its trajectory" could mean "At some point in its 6-year journey..." or "For the duration of its 6-year journey...".

Re:Untrue (1)

harperska (1376103) | more than 3 years ago | (#35529696)

He's right. It is inaccurate, yet true. The spacecraft did use solar wind rather than thrusters to adjust it's trajectory for some maneuvers. It also used thrusters rather than solar wind to adjust trajectory for others. So the wording that would have made it both accurate and true would be "During its 6-year journey it used solar panels as sails, often relying on the solar wind instead of thrusters to adjust its trajectory"

It is possible that the submitter did understand the mechanics of the mission, and intended the 'often' to be implied. Then again, he may simply have been mistaken.

Re:Untrue (1)

c6gunner (950153) | more than 3 years ago | (#35540194)

If it is inaccurately worded, it is not true

"The Earth is round" - inaccurate, but true.

Re:Untrue (3, Informative)

camperdave (969942) | more than 3 years ago | (#35529516)

Just because it had chemical thrusters, doesn't mean that it didn't use solar panels as sails and the solar wind to adjust its trajectory at some point during its 6-year journey. The sentence "During its 6-year journey it used solar panels as sails, relying on the solar wind instead of thrusters to adjust its trajectory" only says that it happened, not that it was the sole method used. (Granted, the sentence is somewhat ambiguous.)

Re:Untrue (0)

Anonymous Coward | more than 3 years ago | (#35529534)

I'd argue that this is lis like saying "During the four years I went to college I relied on my own income not my parents" when the accurate statement is "One semester i paid my own tuition, the rest my parents paid for".

Re:Untrue (0)

Anonymous Coward | more than 3 years ago | (#35529922)

Like he said, it's ambiguous. Doesn't make it untrue.

Re:Untrue (1)

Kilrah_il (1692978) | more than 3 years ago | (#35533146)

Or "During my four years in collage I once paid for my own lunch, the rest my parents paid for". Even accurater (I know...)

Re:Untrue (1)

blair1q (305137) | more than 3 years ago | (#35534236)

It has a finite surface area, therefore it feels the solar wind.

Accounting for that force when predicting its trajectory, maybe even aligning the spacecraft to make it additive to thrust rather than subtractive wherever possible, doesn't make it "how they maneuvered".

Much, and possibly most, of the vehicle's maneuvering was done by gravity assist [jhuapl.edu] during several flybys of Earth and Venus and Mercury [jhuapl.edu] . I just wish the website showed a graphic of the whole thing.

Re:Untrue (1)

pinkushun (1467193) | more than 3 years ago | (#35529570)

Press release doesn't mention that, perhaps just the OP's words? Anyway there's a good QA on how much fuel the solar sails saved. [jhuapl.edu]

Not solar sails or thrusters but gravity assists! (3, Insightful)

wisebabo (638845) | more than 3 years ago | (#35529876)

Because I'm lazy I'll repost part of previous reply:

(In answer to a question, "Why did it take MESSENGER 6 years to get to Mercury?")

Because it did a lot of gravity assist maneuvers. It is (energy wise) very difficult to get to put a probe in mercury's orbit, first you have to do a lot of braking to put it into an elliptical orbit to reach mercury's orbit then another lot of braking to make it match mercury's orbit then more braking to put it into (some sort) of elliptical orbit AROUND mercury then (optional) more braking to "circularize" your orbit around mercury!

I think energetically speaking it's about as difficult to send a probe to Mercury as it is to Jupiter even though Jupiter is much farther away. So in order to not have to use a huge (expensive booster), the probe does a bunch of gravity assists by sling-shotting near Venus, Mercury and maybe even the earth. This saves a LOT of fuel but adds a LOT of time (otherwise as you probably guessed it would've gotten there years earlier).

Re:Not solar sails or thrusters but gravity assist (3, Insightful)

Megahard (1053072) | more than 3 years ago | (#35530216)

Imagine you're on the lip of a large crater. Near the bottom is a little mound with its own tiny crater. Your objective is to roll a ball down the large crater and land it in the tiny crater. Of course if your ball is moving too fast when it hits the tiny crater it will skip right over. That's the challenge of putting a probe in orbit around Mercury.

Re:Not solar sails or thrusters but gravity assist (2, Informative)

Anonymous Coward | more than 3 years ago | (#35533968)

It's worse than that - you're not at the lip of a crater, but pinned to the wall of a large centrifuge. Now try rolling the ball into the tiny crater.

Re:Untrue (1)

angel'o'sphere (80593) | more than 3 years ago | (#35530736)

". During its 6-year journey it used solar panels as sails, relying on the solar wind instead of thrusters to adjust its trajectory"
I can't believe that either.
A solar panel is not a solar sail and using the solar wind is even more obscure.
However if someone finds some links regarding this claim I would be very interested.
angel'o'sphere

Also... (1)

sootman (158191) | more than 3 years ago | (#35529204)

... nice APOD [nasa.gov] today.

Really proud of the U.S.A. (4, Interesting)

wisebabo (638845) | more than 3 years ago | (#35529748)

I know the US has done a lot of bad things and made some pretty bad mistakes but I just wanted to celebrate one of its (many) good achievements. Only the US has sent (or is sending) a probe to every major object in the solar system (yes that includes you Pluto). Only the US has launched four "Great Observatories" (Hubble, Chandra, Compton, Spitzer). Only the US has... well the list goes on and on even in just the field of unmanned space exploration.

Of course the Cosmos is not solely an American prerogative. So here's a question; why haven't other wealthy federations/countries (EU, Japan) been hitting in their weight class? Is it because only the US (and to a lesser extent) the USSR had the close linkage between the military development of ballistic missile technology and space exploration as a means of bolstering national pride? Or, is it because the US is a nation full of dreamers and visionaries who pursue ideals (and ideologies) that may not appeal as much to the pragmatic and efficient Europeans (I'm mostly thinking of Germany) and Japanese? Is the reason why 70% Americans profess to strongly believe in God the same reason why they are (relatively) so willing to spend billions on space exploration? Do the same impulses that drive many (stupid) Americans to deny Evolution and Global Warming paradoxically cause them to fund the most productive scientific community on earth?

And maybe that will answer this follow up question: will rising China follow (and perhaps surpass) the US in space exploration? If it is a matter of military development and national pride then perhaps yes. If it is something more cultural though...?

On a related note: there was a recent article in (I think) the NYTimes about how, the Chinese Central Committe (the assemblage that runs China) got together recently. Since many of the members of this elite group were laden with the latest iPad and iPhones, a major topic of discussion was; why hadn't China produced anyone like Steve Jobs and would it ever? Say what you will about Mr. jobs, he has created and revolutionized several industries from scratch (personal computing, "windows" based computing, computer animated movies (Pixar), digital distribution of media, portable digital media devices, cellphones, tablet computers). Basically the article concluded that unless China were to become more democratic, less authoritarian and less hierarchal, they would have little chance of allowing a (paraphrased) Beatles fanatic, fruitarian, hippy dropout who spent a year in India before returning to start a self-proclaimed revolution, from becoming a success.

Or is there another reason why the US has been blessed (cursed*?) by people like Jobs? (Education? Drugs? Fluorine in the water supply?)

*"cursed" might be what some of his employees would say. He, like others whom I would call visionary (like James Cameron), have not been known to provide the most caring and supportive of work environments.

Re:Really proud of the U.S.A. (1)

Anonymous Coward | more than 3 years ago | (#35530596)

It's the fluorine in the water supply, workings its way into our precious bodily fluids.

Re:Really proud of the U.S.A. (1)

Electricity Likes Me (1098643) | more than 3 years ago | (#35530974)

The EU does launch probes, but I'd say the big reason is simply that space is expensive and is mostly "blue sky" research. We do it because the applications down the track range from efficient power, to understanding the origin of life and our environment, determining the likelihood of other life and maybe determining the fate of the human race.

All important endeavors, all generating huge amounts of side-data, spin-off projects and interesting research at the extremes of materials, chemical, physical and biological science which has (repeatedly) improved life on Earth. But all expensive and not-immediately commercial, and all being done largely by scientists with a strong interest in keeping costs down and collaborating to achieve the most they can.

So thanks to winning the space race and it's economy, the US gets credit for most of the "firsts". But it would be folly to ignore the diversity of nationalities and research bits and pieces which lead to those.

Re:Really proud of the U.S.A. (2)

angel'o'sphere (80593) | more than 3 years ago | (#35531022)

Hubble is a joined ESA/Nasa program.
There are numerous ESA programs you perhaps are not aware of: VEnus Express, Rosetta, Mars Express, Double Star Cluster, Cassini-Huygens and and and ... http://sci.esa.int/science-e/www/area/index.cfm?fareaid=71 [esa.int]

I don't really get what your point is, but besides computer technology (mainly processors) and aero space industries the USA is on the decline since 30 or more years. OTOH the USA have those sparks of Elite Universities, some bright guys (like Jobs) and one of the greatest interior markets ...

angel'o'sphere

Re:Really proud of the U.S.A. (0)

Anonymous Coward | more than 3 years ago | (#35531048)

http://saturn.jpl.nasa.gov/index.cfm

EOF

Re:Really proud of the U.S.A. (1)

Anonymous Coward | more than 3 years ago | (#35531458)

Well, beside the fact the Europe has been launching one or two space projects (http://en.wikipedia.org/wiki/List_of_projects_of_the_European_Space_Agency) part of the problem probably is that it takes a huge lot of politicking to get independent nations to work together on any ginormously expensive project. It is probably somewhat easier if it only involves a single country.

Also, Europe recently spent most of its spare science change on another little project that you might have heard of (http://en.wikipedia.org/wiki/Large_Hadron_Collider#Cost). Maybe there just wasn't much left to also explore space at the same time.

Re:Really proud of the U.S.A. (1)

blair1q (305137) | more than 3 years ago | (#35534260)

Because the USA understands competition, and gets involved in other nations' big space projects if it can, wherupon they generally become the USA's big space projects.

Re:Really proud of the U.S.A. (1)

airdweller (1816958) | more than 3 years ago | (#35537004)

"Say what you will about Mr. jobs, he has created and revolutionized several industries from scratch (personal computing, "windows" based computing, computer animated movies (Pixar), digital distribution of media, portable digital media devices, cellphones, tablet computers)."
I don't think you know the meaning of the word 'revolutionize' :)

How tine flies. (0)

Anonymous Coward | more than 3 years ago | (#35530724)

I was at the launch. I remember thinking: "2011? That's so far away!" Definitely feeling old...

obligatory (0)

Anonymous Coward | more than 3 years ago | (#35533026)

i didnt read TFComments but is there an unobtanium joke in there?

Ah, the silence (0)

Anonymous Coward | more than 3 years ago | (#35533044)

Designed with a completely passive cooling system

Finally a probe that can satisfy my HTPC needs in the living room..

Oops misunderstood the title... (1)

Anonymous Coward | more than 3 years ago | (#35533956)

I thought Microsoft packed the source code and executables of MSN Messenger into a capsule and blasted it off into space. :)

I thought it was just a tagline... (1)

garompeta (1068578) | more than 3 years ago | (#35534798)

"Where do you want to go today?"
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