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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 amazes me everytime. Great job.
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).
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.
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". 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.
See my journal for slashdot ID's by year. Mine created in 2005. http://slashdot.org/journal/289875/slashdot-ids-by-year
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.
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).
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.
I eat only the real part of complex carbohydrates.
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.