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Mercury Probe Delayed by Ten Weeks, and Two Years
Gogo Dodo writes "Spaceflight Now reports that NASA's MESSENGER probe launch has been delayed by 10 weeks. Unfortunately, this means MESSENGER will not arrive at Mercury until 2011, a two year delay."
Remember, kiddies: Earth isn't the only planet that orbits the Sun!
Goo goo g'joob.
Its ironic that a mission to the fleet-footed god of messages should take so long. I guess its revenge by those ancient Roman gods.
I'm just glad that the mission was not scrubbed.
Two wrongs don't make a right, but three lefts do.
I'm kinda concerned about the budget hit, though. Maintaining an engineering infrastructure on the ground for an additional two years, even one in "standby," is going to be costly. Sure, they can loan out personell to other projects during the interim, but you're going to see two more years of attrition and then retraining costs to catch up. A boom or bust in the tech cycle will simply agravate the situation (boom=more people leaving, bust=fewer new engineers to fill vacated slots).
The delay is probably acceptable, but let's hope the added budget doesn't hurt another probe.
"Prepare for the worst - hope for the best."
Mercury goes around the sun in 87 days. Assuming that the orbits are circles (they're pretty close) it should never be more than 86 days for the planet to be in an optimal position to launch a probe. So, why would it be off by two years? What am I missing here?
Uh, maybe an in depth knowledge of how the gravity of all the planets affects trajectories?
This may answer your question. Either that or just confuse you more. ;P
What am I missing here?
a degree in astrophysics.
Because they're planning to swing around Venus to get there, and more than once.
The links already posted answer the question, but the short, simple answer is "angular momentum". Specifically, the need to dump a lot of it (and, equivelently, a lot of energy). The energy changed needed to get to Mercury is actually greater than that needed to reach Pluto. This means that it's better to use the inner planets (Earth, Venus, and/or Mercury) in gravitational slingshots (but backwards of how we usually use them) to save fuel. In theory, if you jacked up NASA's budget, you could go straight there once a synodic (not sideral: it doesn't matter how often Mercury orbits, but how long it takes to get back to the same relative arrange with Earth) period. But NASA, alas, has a finite budget for this sort of thing, so slow and cheap is the way to go.
To what extent does the "warping" of space near an object as massive as the sun affect this little spacecraft's orbital calculations? I know (but don't fully understand) that there are relativistic effects on Mercury's orbit that aren't described by pure Newtonian physics.
To what extent do the mission planners have to account for this effect? Can they even know for sure until they see what happens as they pass by Mercury those three times before orbital insertion? Or will the effect be negligible compared to the solar wind and other "normal" forces? The link above notes that Newton is only off by 43 arcseconds out of 5600, but it seems like even 0.77% could add up pretty quick.
Stressed? Me? Of course not. Stress is what a rubber band feels before it breaks, silly.
MeSSEnGeR or NOAA or ECHO or SOHO
So how long until we see names like M3553n93R or N044 or 3(H0 or 50|-|0?
If my answers frighten you, stop asking scary questions.
You're correct. It needs to loose about 62% of its angular momentum, which is a pretty significant amount of energy. This is in addition to the amount of energy needed to reach earth's escape velocity in the first place and to insert into an orbit around Mercury.