A Real Sun Probe, Take the Solar Plunge Options

[Guest_Sunspot_*]

Cool


We can never have too many solar missions

[punkboi]

A new article on Solar Probe Plus... 5 science instruments have been selected for the mission

http://science.nasa.gov/science-news/scien...2010/02sep_spp/

So will NASA or The Planetary Society have a "Send Your Name to the Sun" campaign before the launch in 2018?

[stevesliva]

Actually only four instruments mentioned, but radio science isn't mentioned, so that might as well be a 5th.

[scalbers]

What is the highest level of albedo that's been achieved with metals on Earth? If a shield had 100% reflectivity (impossible I know but theoretically), would that solve all heating problems, or does the albedo vary for different types of electromagnetic radiation?

At least in visible light silver is pretty high (somewhere above 90%). Dielectric coatings can use interference to make reflectivity even higher. More info here on reflectivity of coatings:

http://www.optosigma.com/miva/merchant.mv?...ection+Coatings

What is being used on the shield in the solar probe design?

[stevesliva]

What is being used on the shield in the solar probe design?

I was determined to find the answer to this seemingly simple question.

Judging from the document, they're hedging their bets for prototype build and testing, but it will likely be 15cm of carbon-carbon with a coating of aluminum oxide or pyrolytic boron nitride.

Page 58/146 marked as 3-42 of this:
http://solarprobe.gsfc.nasa.gov/SolarProbe+ME.pdf

As part of the TPS Risk Mitigation effort, two potential ceramic coatings were found that met the requirements of the Solar Probe+ mission. Ceramic materials that are visibly white generally provide the optical characteristics compatible with the proposed shield passive thermal management strategy. These characteristics are low solar absorptivity and high IR emissivity. Thermodynamic stability and chemical compatibility with C-C are additional differentiators that further narrow the list of candidate ceramics. At the end of the study, both aluminum oxide (Al2O3), commonly called alumina, and pyrolytic boron nitride (PBN) were found to notionally satisfy these basic characteristics.

Plenty more in there.

[stevesliva]

If it actually gets funded, it should also give us a nice Jupiter bonus.

In reading about the thermal shield, I've just noticed the new mission has a perihelion that is farther than the original plan, and incidentally an aphelion at 1 AU. So no Jupiter flyby. They dumped the RTGs that would've provided power out there as well.

A good point mentioned in the report is that by lowering the perihelion gradually with aphelion TCMs, they have time to learn to manage the spacecraft before getting closer. Jupiter would no doubt have sent it right in.

[illexsquid]

Actually only four instruments mentioned, but radio science isn't mentioned, so that might as well be a 5th.

The linked article mentions five instruments; the ISIS investigation uses two instruments, EPI-hi and EPI-lo, presumably to measure particles at different energies. It also discusses five investigations that have been funded, the fifth one being a project scientist that won't fly with the spacecraft. Obviously.

[Guest_Sunspot_*]

More on one of the instruments

http://www.spaceref.com/news/viewpr.html?p...rce=twitter.com

Wide-field Imager Selected for Solar Probe Plus Mission

[mps]

Solar Orbiter is selected as ESA's first M-class mission:
Europe to lead daring Sun mission

[Paolo]

selected again, you mean. I don't want to get into politics, but Solar Orbiter has been on and off several times at ESA and was first selected as a medium mission in the early 2000s...

[stevesliva]

Solar Probe Plus mentioned in this interesting solar wind article:
http://science.nasa.gov/science-news/scien...8mar_solarwind/

Also mentioned is WIND, still trucking after almost 19 years...