Solar Orbiter Mission (ESA) - The near-Sun phase  approach the Sun as close as 48 solar radii (~0.22 AU). At these distances, the angular speed of a spacecraft near its perihelion approximately matches the rotation rate of the Sun, enabling instruments to track a given point on the Sun surface for several days. - Out-of-ecliptic phase (extended mission)  higher solar latitudes (up to 35º in the extended phase), making possible detailed studies of the Sun’s polar caps. Venus Gravity Assist Manoeuvre (GAM) to reduce the perihelion distance. Later Venus GAMs increase the orbital inclination to more than 30 degree with respect to the solar equator. e/www/object/index.cfm?fobjectid=37625http://sci.esa.int/science- e/www/object/index.cfm?fobjectid=37625 To be launched 2015 Objectives: Will produce images of the Sun at an unprecedented resolution and perform closest ever in-situ measurements and get to high latitudes Orbit: It incorporates both a near-Sun and a high-latitude phase.

The Second Solar Orbiter workshop: goals Inform the wider community of the SolO opportunity and to investigate synergies to enhance the opportunity, including ground-based support and modelling. Discuss Solar Orbiter operations strategies and scenarios, and outline how the goals of Orbiter will be achieved. Strengthen the political and scientific support for the mission, demonstrating the wide international interest in the mission. Improve the definition of the payload scientifically and technologically. Identify ways of mission optimization and international cooperation.

Visible-Light Imager and Magnetograph (VIM)  Full Magnetic Vector, Continuum and Velocity Images.  Spectral line: Fe I 6173A  2048x2048 detector  Two telescopes:  High Resolution Telescope  Full Disk Telescope: FOV of 2.6 degrees and a pixel size of 730Km at 0.22 AU (GONG ~ 1.5Mm)  At high latitudes  Short observation periods of days

Solar Sentinels (NASA)  Inner Heliospheric Sentinels--four identical probes stationed inside the orbits of Venus and Mercury. These spacecraft would sample freshly accelerated solar energetic particles close to the Sun. The four Inner Heliospheric Sentinels will face unique thermal and power challenges as they orbit the Sun, some well inside Mercury's orbit.  Near-Earth Sentinel—a single probe orbiting Earth. This Sentinel would carry a coronagraph, a special telescope for observing the Sun's faint corona where CMEs get their start.  Farside Sentinel—a single probe to watch the farside of the sun. Together with other spacecraft, this sentinel would provide a complete picture of the Sun-- not just the half we see from Earth.

Some Advantages: –Reduce the cost –Increase the probability of both missions to actually happen. –Increase scientific opportunities Remote sensing capability of SoLO will enhance IHS science Combined ESA/NASA ground stations improve SoLO data rate and cadence. Some Disadvantages: –Reduce the proximity to the Sun for SoLO, and max inclination –Suggestion of reduce from 4 to 3 IHS –Redundancy of some instruments (?) –Weight load. Solar Orbiter / Solar Sentinels

Solar Orbiter – the orbit