MESSENGER Enters Orbit Around Mercury

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)."

This is what space exploration should look like

[lwsimon]

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.

Not solar sails or thrusters but gravity assists!

[wisebabo]

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

[Megahard]

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:This is what space exploration should look like

[Nyeerrmm]

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.