Though the media has been inundated with coverage on one of Earth's closest planetary neighbors, Mars, for the last few years, thanks in no small part to the durable Mars rovers Spirit and Opportunity, it is certainly not the only local celestial body under observation. Saturn and the Cassini probe have received a bit of coverage as well. Not much has been given, however, to the big fireball that Earth and eight or nine other planets are whirling around.
There are, in fact, several satellites studying the sun and its constant flood of exotic energy and particles as you read this. One of the most well-known is SOHO, which has been sending back reams of data and images and recently showed that large solar flares actually cause powerful starquakes on the sun. Adding to the list are several probes built by Johns Hopkins University for NASA: TIMED, which studies the effects of solar radiation on Earth's upper atmosphere; ACE, which studies samples of energetic particles between the sun and Earth; the Radiation Belt Storm Probes, which study the regions of energetic particles that become trapped by Earth's magnetic field; and the STEREO probes, which capture 3D images of Sol's unique climate.
NASA has again called upon Johns Hopkins for a solar probe. The forthrightly named Solar Probe mission promises to be one of the most dangerous sun studies to date. The probe itself will fly as close as 6.6 million kilometers to the Big Ball of Hot Fire, much closer than any previous craft and well inside Mercury's orbit. The probe will pass through the sun's outer atmosphere, taking measurements and recording data to send back to mission planners and analyzers on Earth.
The 1,000 pound craft will be, somewhat expectedly, solar powered. The instruments aboard the probe will likely be protected by a nine foot diameter, six inch thick disc made of carbon foam composites. While in the sun's corona, the probe must withstand temperatures of 2,600 degrees Fahrenheit and solar energy levels greater than 500 times that of satellites orbiting Earth.
With 30 years on the idea boards at NASA, no man-made probe has needed to be able to survive such a grueling mission. Current technology has finally allowed the engineers at Johns Hopkins to design an orbiter that fits inside the NASA budget, weighing in at a mediocre $750M. Though large, the nine figure sum is still less than some of the planet-bound missions NASA has undertaken.
The probe is planned to see a 2015 launch, and after seven years of lingering in Venus's neighborhood to shrink its orbit, see its first actual solar encounter around 2022. The actual details of the Solar Probe mission will be released by NASA later this year, along with an Announcement of Opportunity concerning the scientific payload for the vehicle. According to Johns Hopkins, the Solar Probe mission planners want to accomplish many goals, including "determine the structure and dynamics of the magnetic fields at the sources of solar wind; trace the flow of energy that heats the corona and accelerates the solar wind; determine what mechanisms accelerate and transport energetic particles; and explore dusty plasma near the sun and its influence on solar wind and energetic particle formation."
Though the Solar Probe mission will not likely get the attention of recent Mars missions, the data collected by the various existing satellites and observatories as well as future missions like it will be no less valuable in helping to understand our tiny cosmic neighborhood. Unfortunately, regardless of the quality and quantity of data collected by Solar Probe, it probably won't help prevent a future ice age.