Into the Fire

[astroron]

NASA, is planning to send a Space craft as close to the sun as it can go:eyepop:
http://www.bbc.co.uk/news/science-environment-11181567
should be an interesting journey:)

[renormalised]

Now that will be a very, very interesting mission:)

[CraigS]

How are they going to get information back to Earth ?

Man, the heat and radiation is one thing, but the Electromagnetic interference/distortion effects on the spacecraft and then the RF signals carrying the data ??..
Also, how are they going to extract the signal from a background landscape like that ?

What if there's a CME or a big flare ?

Must be some super-dooper technology coming up for this one !!

Thanks for a great post, Ron .. very interesting !

Cheers & Rgds.

[astroron]

Thanks Craig,I had similar thoughts when I first read the article:question:

[RobF]

Wow - how amazing is that close up of the sunspot! :eyepop:

[CraigS]

I'm reading up on the Engineering Design issues behind this puppy .. lots to read. It appears as though they don't transmit the science data in real time. They buffer it and send it at times when the orbit is conducive.

They have carefully selected the operating band to avoid what they call 'scintillation' effects caused by the Sun. Also the antenna design of the plasma experiments are really tricky. Apparently the antennae have to be in contact with the plasma to do the readings ... keeping the antennae away from the spacecraft & in the correct orientations reduces the current effects induced in the spacecraft, on the readings.

Fascinating stuff !
Gotta go ... Dad's day ... Happy Father's Day to all you Dads out there !!
More later.

Cheers
PS: "Science data collected during the solar encounters will be stored on the redundant SSRs for subsequent downlink via the HGA once the
spacecraft is beyond 0.59 AU. No real-time science data downlink is planned inside 0.25 AU."

[CraigS]

Seems like they are going to exploit the elliptical orbit to collect & store the science data during the perihelion and download during the aphelion:

"From an operational perspective, Solar Probe1 orbits are divided into aphelion and perihelion segments. While some science data will be taken at a low rate throughout an orbit, most of the science data will be acquired during the solar encounters around perihelion. Encounter data will be stored on the redundant SSRs and played back, along with any cruise data acquired since the last ground contact, when the spacecraft is outside 0.59 AU, in the aphelion segment of the orbit."
...
"the Earth–Probe distance varies from 0.3 AU to 1.9 AU"
...
Attitude control:
"Solar Probe1 will be subjected to several environmental effects that must be taken into account in developing the design of the Guidance & Control subsystem. First, as the spacecraft approaches perihelion, sunlight reflected off of dust particles will be seen by a star tracker that is viewing the sky through the corona. Coronal lighting reduces the signal-to-noise ratio for a tracker using a CCD, thereby reducing the number of detectable stars and degrading the performance of the star tracker. As noted above, this effect will be mitigated by using multiple trackers and carefully selecting those that will perform well in the elevated background noise of the near-Sun environment."
...
Solar radiation pressure will be very high and change rapidly during solar encounters. Because the center of photon pressure is ahead of the center of mass, the solar pressure torque is destabilizing and is an important factor in the dynamics of the spacecraft near perihelion.
...
Dust problems:
"Dust impacts can also affect spacecraft attitude, especially near perihelion. Dust particles hitting the spacecraft will impart an instantaneous momentum impulse that the reaction wheels must remove. If the momentum impulse is too large for the wheels to handle, the thrusters will have be fired to keep the spacecraft oriented so that the sensitive spacecraft systems remain safely within the protective shadow of the TPS."

This list goes on. This is just a small sample of the 'challenges'.
Bottom line is that this thing will have to be be an engineering masterpiece!!

Cheers

[renormalised]

Only 0.3AU!!!...pfft....why not go the whole hog and send it in for a close look....5-10 solar radii!!!!!:):P

Make the heat shield out of tungsten carbide and synthetic corundum...that'll also solve the dust and other problems too:):P

[CraigS]

They've justified this thing on the basis of improving models for the purpose of protecting human habitats eventually on the Moon and Mars:
...
"An extraordinarily intense event occurred on January 20, 2005, with a very hard proton energy spectrum extending up to 400 MeV. An astronaut, exposed during this event on the surface of the Moon and protected only by a space suit, would have received an estimated radiation dose of ~50 cSv, which would have been enough to cause radiation sickness"
...
"Models that can provide real-time forecasting of Solar Energetic Particle (SEP) spectra and fluxes are currently being developed and refined (e.g., the Space Weather Modeling Framework at the University of Michigan). At present, however, the accuracy of such models is limited by their dependence upon assumptions about the physical conditions in the corona and inner heliosphere, between 2 and 20 Rs, where gradual SEP events originate. Solar Probe+ will explore this critical region for the first time (Figure 1-1).

Your mate Alven is mentioned in the Figure, Carl !
:P:)
Cheers

[renormalised]

No mate of mine!!!!:):P