Messenger Flies by Mercury

Riding with Robots writes "Today, more than three decades after the last spacecraft visited Mercury, Messenger buzzed just 200 kilometers above the planet's surface. During the encounter, the robotic spacecraft conducted a range of scientific observations, including imaging swaths of Mercury's surface that have never been seen up close before. A few of the first pictures are now available, with many more to come in the next few days."

Re:Photos are FAKE

[palegray.net]

You must have read this highly informative site [ufos-aliens.co.uk] and applied your intensive research efforts directly to the debunking of this obviously fake planetary fly-by. My hat is off to you; job well done buddy...

Dang it all, even I can't keep from laughing at that page.

Re:Oops...

[dryeo]

Actually July and August were just renamed. July was Quintilis before being renamed in honour of Julius and August was Sextilis. The year used to start in March (Spring) so the month numbers were correct at one time.

Re:Again?

[MorpheousMarty]

Perhaps you could clarify something for me. After you break earth's orbit, why would it take any extra energy to get to the sun? (This is assuming of course that the garbage is pointed at the sun and timed so it wouldn't get close enough to Venus and Mercury to divert it's course. Why would getting away from the sun be easier than going towards it?

And a solution to send garbage safely would be to aim it a bit high or low (perpendicular to orbit of Earth). The slingshot would almost never send it back towards the orbit. As a space geek I'm just curious.

Re:Again?

[Tom Rothamel]

That's why they did three slingshot maneuvers to get there. The navigation team at JPL has really outdone themselves with this flight, and are to be commended.

Interestingly enough, the navigation of this flight was outsourced to Kintex [kinetx.com]. The mission itself is managed by APL... AFAIK, JPL wasn't particularly involved.

Re:Again?

[CheshireCatCO]

The answer is easiest to see in terms of angular momentum. (Orbits are really all about angular momentum, more so than energy.) If you break free of Earth's immediate gravity, you're still in pretty much the same orbit as the Earth going around the Sun. You have to dump a lot of that angular momentum to reach Mercury or the Sun, and that takes quite a bit of work. Remember, escape speed from the Earth's surface is around 11 km/sec, but the Earth's orbital speed is around 30 km/sec. You have to dump about 7 km/sec to go into a sufficiently elliptical orbit to reach Mercury and then you need to dump another 20-something km/sec to circularize the orbit. You have to dump almost all your orbital velocity it to reach the Sun at all (even on an elliptical orbit that reaches the Earth, I figure you need to drop down to 3 km/sec at Earth's orbit to reach the surface of the Sun). On the other hand, escaping completely from a circular orbit requires less than 45% more speed, so escaping the solar system completely requires less delta-v than going to Mercury. (It takes about 15 km/sec to reach Pluto's orbit, making yours ultimately circular.)

Extremely Close

[PhotoGuy]

200km! Wow, that's incredibly close to Mercury. For comparison's sake, geosynchronous orbit (where all our TV and most communication satellites live) are at 36,371 km from earth, 181 times as far as this probe went to mercury. Even the highest resolution earth imaging satellites we have orbit at around 500km.

While you can't scoop up the dirt, being that close for visuals has to be nearly as good as landing there...