[X] My Assistant

[djellison]

Rob Manning and I swopped emails last night - and we think it might make sense to pool all the questions people have about MSL (and specifically MSL's EDL ) into one thread - and then answer as many as make sense either via a Q'n'A in the style of the previous ones I've done with Steve and Jim - or via Rob's typing fingers.

It'll be a few weeks till we sort this out - but submit-away until then

Doug

[Thu]

I have some questions:

1. What is the ratio of final mass delivered (the rover) and entry mass at Martian atmosphere for the two methods: SkyCrane and airbag delivery method on Mars?
I'm expecting SkyCrane to have better efficiency than using airbag but could anybody give me some specific numbers for comparison?

2. I remember reading somewhere that MSL will be equipped with a flashlight that will allow it to move or perform some science observations at night. Is this true and what's the advantages for observing in the dark on Mars?

3. Another question, maybe a stupid one: Did engineers find out what went wrong with Spirit's right front wheel and come up with an upgrade for MSL's wheels? Or should we let it happens because who knows a dragging wheel may lead to an unexpected discovery

4. Thinking of the 3rd question, I come up with this last one: if something bad forces MSL to move backward just as Spirit is doing now, I think it'll be more difficult for MSL's computer to navigate because her camera mast is not at the center as her sister's. How do you think about this?

Thanks,

[mcaplinger]

2. I remember reading somewhere that MSL will be equipped with a flashlight that will allow it to move or perform some science observations at night. Is this true and what's the advantages for observing in the dark on Mars?

http://www.msss.com/msl/mahli/MAHLI_description.html

"MAHLI has a suite of white light LEDs and a suite of ultraviolet LEDs to provide illumination of the targets it is imaging. The white light LEDs permit the instrument to operate at night and allows the science team to avoid problems of shadowing during daytime imaging. The ultraviolet LEDs provide an opportunity to look for minerals that fluoresce."

[Pertinax]

http://www.msss.com/msl/mahli/MAHLI_description.html

"MAHLI has a suite of white light LEDs ..."

I would presume that this would also be useful in further constraining 'true color' as we will be able to view an object under both under daylight conditions and under a fully understood source of illumination.

BTW, what is the spectrum of the white light LED' in MAHLI?


-- Pertinax

[mcaplinger]

I would presume that this would also be useful in further constraining 'true color' as we will be able to view an object under both under daylight conditions and under a fully understood source of illumination.

To an extent, but the LEDs are not intended to be calibrated light sources and there is likely to be some color shift as a function of current and temperature. White LEDs typically have a narrow peak in the blue where the LED actually emits, and then a broader peak centered in the yellow where the phosphor emits; see http://en.wikipedia.org/wiki/LED