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Fraser
2004-Sep-17, 11:04 PM
SUMMARY: After its crash landing, NASA scientists weren't too hopeful that they'd turn up much science in the wreckage of Genesis' sample capsule, but the results so far have been a pleasant surprise. Even though the capsule smashed into the ground at nearly 320 km (200 miles) per hour, the samples aren't smashed up too badly, and scientists are able to extract fairly large pieces for further analysis. Genesis' purpose was to gather particles from the Sun's solar wind, which would be returned to Earth and then distributed to scientists around the world.

What do you think about this story? Post your comments below.

antoniseb
2004-Sep-17, 11:25 PM
It's great to hear that they'll be able to recover a lot of science from this crash. I wonder if we shgould design future sample return craft to simply crash, and never even try to use a parachute. Maybe design the sample return craft to be a glider shaped piece of aerogel or something.

om@umr.edu
2004-Sep-17, 11:34 PM
Sounds great!

I look forward to seeing the results, especially for elements from the Sun that could not be measured in lunar fines and breccias.

Who will be doing what analyses? When can expect to see the results?

With kind regards,

Oliver
http://www.umr.edu/~om

antoniseb
2004-Sep-18, 12:16 AM
Originally posted by om@umr.edu@Sep 17 2004, 11:34 PM
especially for elements from the Sun that could not be measured in lunar fines and breccias.
As I recall, you yourself pointed out to the forum that one advantage that the Genesis mission had over the lunar samples was that we know the duration that the samples were collected over, and that Genesis is giving us a snapshot, whereas the lunar samples are a long time-lapse picture. Both are valuable, and they are different from each other.

om@umr.edu
2004-Sep-18, 03:52 PM
Originally posted by antoniseb@Sep 18 2004, 12:16 AM
As I recall, you yourself pointed out to the forum that one advantage that the Genesis mission had over the lunar samples was that we know the duration that the samples were collected over, and that Genesis is giving us a snapshot, whereas the lunar samples are a long time-lapse picture. Both are valuable, and they are different from each other.
Yes, Anton, the degree of mass separation in the Sun depends on:

1.) The energy with which material leaves the solar surface, and on

2.) Solar magnetic fields that accelerate material away from the Sun.

The Genesis mission only collected material coming from the Sun for 27 months, during a period of high magnetic activity (high sunspot numbers).

You are right, lunar samples collected material coming from the Sun for billions of years.

Measurements show that Light (L) isotopes of He, Ne, Ar, Kr, and Xe implanted in the surfaces of fine-grained lunar material are enriched by a mass-dependent power law relative Heavy (H) isotopes.

This power law defines a common mass-fractionation factor, f, over the entire mass range of stable noble gas isotopes, 3-4, 20-22, 36-38, 78-86, and 124-136 atomic mass units (amu).

Fractionation, f = (H/L)^4.56

Here are the results from analyses of lunar samples:
http://web.umr.edu/~om/images/Excess_light_isotopes_in_SW.jpg

The greatest advantage of the Genesis mission would be in filling in the holes in this graph by providing a quantitative measure of the mass-fractionation factor, f, over the mass range not covered by noble gas isotopes.

For example, Genesis measurements on solar-wind

Oxygen isotopes cover the mass range of 16-18 amu .
Magnesium isotopes cover the mass range of 24-26 amu .
Silicon isotopes cover the mass range of 28-30 amu .
Sulfur isotopes cover the mass range of 32-36 amu .
Iron isotopes cover the mass range of 54-58 amu .

With kind regards,

Oliver
http://www.umr.edu/~om

PS - Caution: Solar-flare atoms have higher energy and will be implanted deeper in the Genesis wafers than solar-wind atoms. Removing surface contamination will likely remove more solar-wind atoms than solar-flare atoms. This may reduce somewhat the value of the mass-fractionation factor, f.