Friday, 27 November 2015

19.08.2103 - Solar Flyby

By NASA Goddard Space Flight Center from Greenbelt, MD, USA [CC BY 2.0 (], via Wikimedia Commons

Distance: 124,166,232 km from Earth | Content Flag: Public

This close to the Sun, the sheer power of its luminance dazzles our optical sensors at the visible part of the spectrum. In ultraviolet and at other wavelengths, we can see the detail of the Sun’s power. Jets of energised plasma arc into space, spanning millions of kilometres before they fall back into the boiling globe.

Across its surface we can see dark spots. These sunspots are markers for magnetic storms within the Sun’s atmosphere. Like the surface, the magnetic fields around the Sun are a storm of fluctuating energies, reaching out deep into space.

UNSA will soon be launching a new series of Helios probes into solar orbits at varying distances to provide constant observation of the Sun. Ground-based observatories have monitored our star since the Sun Dragon encounter and some variances in its composition and activity have been recorded.
Passing close to the Sun allows us to capture more information to assist the research teams back on Earth trying to determine what effect the Sun Dragon might have had when it wrapped itself around the Sun for a month, before splitting into two. Anything that might have intensified or created solar storms could pose a hazard to the reconstruction programmes on Earth. Although, as the power and communications systems are now built with protection against a return visit from the alien lifeform, any solar disruption should be minimised. Still, it would be better to know of any danger in advance.

We also don’t know what we’ll encounter when we arrive at Tau Ceti, so the Venti probe has been designed to investigate any part of the star system. That might well include a close approach to the star. As Tau Ceti is similar to our Sun, this is an ideal test for our instruments and protection from the solar wind when it is at its most fierce.

At this range it’s more like a solar gale and the energised particles could damage components of the probe. The electronics are particularly vulnerable, especially closely packed electronics like microchips. The Venti probe carries more computing power than any spacecraft ever built and that has to be protected. As well as the main shielding and the solar sail, key areas of the probe are protected by layers of ultra-dense material to block or deflect energised particles.

We won’t gain much from a gravity assist manoeuvre around the Sun because it is stationary compared to the movement of the planets. To use the technical jargon, the planets’ frames of reference are subordinate to the Sun’s, so no energy is lost or gained by switching into it. However, as we swing around the Sun and start the outward leg of the mission, the solar sail will come into its own.

The sail is 9 square kilometres across and is covered with a layer of grapheme facing in the direction of the solar wind. The pressure of the solar wind pushes against the sail and accelerates us into space. The grapheme has a property that creates extra thrust as the particles from the solar wind hit it. Even with this added acceleration the effective thrust is minute, so it would take a long time to reach the speeds we need to. It does have the advantage of not needing fuel and that keeps the mass of the probe to a minimum.

So far all of the systems are operating within their expected parameters, so as we prepare for the next step in the mission, this is Seb signing off.

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