Tuesday, July 27, 2010

Exploring Mercury with The Messenger Spacecraft

Wow, what a great experience last night. It was so refreshing to be in the presence of highly intelligent, competent, enthusiastic people pursuing science for it's own sake, attempting to discover the secrets of the universe by reaching beyond our own planet and into the inner edge of our solar system. Sean Solomon is a role model for all human beings.

Here are a few things I learned...

- A while ago, NASA approved nine big ticket projects collectively known as the Discovery Program, one of which was the Rovers on Mars. One of which was the space craft called "Messenger" which is tasked with achieving orbit around Mercury and gathering data.

- the last space ship sent to explore Mercury was many years ago. It was a straight shot from Earth towards Mercury. Late in the project a European mathematician explained how it would be possible for them to actually loop around Mercury so they could get two whole passes at the planet before it fell into the sun (or smashed on the planet's surface... wasn't clear what it's fate was). This flight took about 6 or 8 months of travel.

- To achieve a true orbit around Mercury, Messenger needs to be launched at a high speed (just to get off the earth, then to not get sucked into the sun, etc). Then it has to decelerate at 100Km/s... not mile per hour or meters per second, but Km per second... that's a daunting amount of deceleration. It can't be done practically with thrusters. So they chose to use a more elegant solution. The ship first circled the Earth, twice, decelerating on each pass. Then it circled Venus, twice, decelerating again each pass. Then it circled Mercury once, decelerating yet again... and started to send us data on Mercury at that time. In approximately 6 months time, the Mercury Orbit Insertion will be attempted, and if all goes well, it will remain in orbit around Mercury for several years until they run out of propellant needed to make the fine adjustments. At that time, the sun's gravity will influence the orbit and it will crash on the surface of Mercury.

- This circuitous journey is taking 6 years of travel time.

- The mission is funded for one year after the insertion date, and they hope to be extended for some time after that if the data collection is going well.

- Right now they expect to get as close as 200 Km away from the surface of the planet. They hope, towards the end, to attempt to get even closer.

- The ship had to be designed to deal with the extreme heat. Thanks to a ceramic curtain on one side, the craft will exceed 700 degrees Fahrenheit on one side facing the sun and will remain at room temperature on the other side facing Mercury. That's where the electronics and data gathering equipment (the payload) reside.

- This payload consists of about 12 devices including a high resolution camera, a magnetometer, several spectrometers, and a few things I won't remember... but sound really really cool.

- From the one spin around the planet, we have already gathered an immense amount of data including high res images (as in, this is what you would really see with your eyes if you were there), maps of the small magnetic field, composition of the atmosphere (not technically called an atmosphere as it is not dense enough... the atoms contained don't interact and are unaware of each other's presence... similar to the outer edge of Earth's atmosphere), maps of elements from the solar wind as it passes around Mercury, mineral distribution on the surface, maps of volatile compounds being emitted from the planet, evidence of volcanic activity as seen by huge impact craters that seem to be filling themselves in over time (billions of years) and even pouring over their edges, various topographical features indicating tectonic activity...

- We are going to learn a hell of a lot about planets in general, and Mercury in particular over the next couple of years.

- When you gather amazing people from many different disciplines in science, you can do mind-bendingly amazing things.

- This is a great time to be alive.

1 comment:

Anonymous said...

where's the picture of yuor shirt?