Herschel and Planck Launch Tomorrow

The Herschel and Planck space observatories will lift off tomorrow (May 14th) from the European Space Agency's (ESA) Kourou spaceport, in the French Guiana, South America. The two craft will be delivered to orbit by the same Ariane 5 carrier vehicle, which has recorded a large percentage of successful deliveries over the years. Officials from the agency are convinced that the deployment will run smoothly, in spite of the complex stages involved in the process. After the telescopes are delivered into Earth orbit, they will begin their 1.5-million-kilometer travels to the second Lagrangian point, where they will remain relatively in the same position as compared to the Earth, Sun and Moon.

Inside the Ariane 5 rocket, Herschel will be seated on top of Planck, and the two will be separated by a small shield. Some four minutes into the flight, the fairings (protective covers) that surround the telescopes will be jettisoned, and the devices readied for ejection. Herschel will be the first to exit the upper stage of the delivery vehicle, about 26 minutes after the launch, according to the timeline supplied by the European Space Agency. Some three minutes later, the shield that will have separated the two observatories will also be jettisoned, and then Planck, shortly after.

The instruments will follow different paths to reach their orbits, with Planck having the most difficult time ahead. It will have to make a number of orbital corrections, in order to be able to take the correct “road” to space. Herschel's job will be equally as complex, though admittedly a bit more “straightforward.” Both will arrive at their destinations in two to three months, and it will then take a few extra months until they are calibrated and ready for scientific use. “They are at a pivotal point. From now on astronomy is going to be done from deep space,” the ESA Director of Science, David Southwood, said of Herschel and Planck, quoted by Nature News.

The orbits chosen for the two observatories are very different as compared to those of regular satellites, or of others. The Lagrangian points, all five of them, are locations surrounding each planet, in which an object seems to be standing still, and thus remain in the same relative position to everything around it. This orbit was necessary because of the sensitivity of the observatories' instruments, which must be kept away from residual light, emitted back in space by the Earth and the Moon. It also has to be kept away from direct light, so that the Sun doesn't “blind” its mirrors.

Herschel will survey its targets in the far-infrared and sub-millimeter wavelengths. The 7.5-meter-high observatory is in charge with determining exactly how galaxies form, and how they evolve to become the supermassive formations some of them get to be. The smaller Planck has an equally difficult mission, in that its objective is to survey the Cosmic Microwave Background (CMB). This type of radiations can only be detected with radio observers, but it can yield significant knowledge of how the Universe itself came to be, as well as of why it looks like it currently does.