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a Daedalus for a new age [Q&A]


Vibha of Poornaprajna PU College asks, are there any plans to launch satellites into the Sun?

There are currently many space-based telescopes that are dedicated to observing the Sun (RHESSI, TRACE, SoHO, GOES, Hinode, STEREO [which recently managed to get, for the first time ever, simultaneous coverage of the entire surface of the Sun], and SDO). But these are all remote imaging instruments that are stationed either in low-Earth orbits or at the Lagrange points or are otherwise quite far from the Sun. The Sun is the closest star to us, surely we can go to it and collect some of the solar material?

There have been missions that traverse the solar wind and sample from the outer reaches of the solar atmosphere, like the now inoperative Ulysses, which flew over the solar poles for the first time. There are also particle monitoring satellites that are parked near the L1 point, like ACE, and WIND. But none of these get really close to the Sun, because the radiation environment a satellite would encounter would essentially blind it before it melts. There are about a hundred million X-ray photons per second per that pass by the Earth from the Sun, and at a distance a hundred times nearer, that number increases ten-thousand fold. It is hard to build instruments that can withstand such a hammering.

It is, of course, easy to build a satellite that will plunge right into the Sun. The trick is to be able to make measurements as it is doing that and send the information back to us, otherwise it is just like setting fire to money.

But there is one mission that is in the works that is designed to go where no satellite has gone before: the Solar Probe. It will likely be launched at the end of this decade, and will get to within a few million miles of the surface. It will carry instruments to collect and measure particle compositions and energetics, and measure the local magnetic fields. It will go past the sonic point in the solar wind, where the solar wind streaming out from the Sun becomes supersonic. Here’s hoping that like Daedalus it will fly high, but unlike Icarus, it won’t burn and crash.