Last week, the European Space Agency announced a final date — November 11 — for when it will release its Rosetta lander, a tiny pod called Philae, down to the surface of the comet. Like a cosmic hobo carrying a stick and bindle, it will travel laden with only the essentials. Thanks to Universe Today, ESA, and NASA, we know what it's bringing.
The tools and instruments that will accompany Philae down to the surface of comet 67P/Churyumov–Gerasimenko are crucial. It's our first chance to truly analyse a comet, and these mechanisms will be responsible for it. Universe Today's Tim Reyes points out that Philae weighs only 100 kilos, so all of the instruments it's bringing are absolutely essential, and have been whittled down to be as light and tiny as possible.
Again, Philae is light and it doesn't have a whole lot of battery power to work with. So it will bring with it a series of photovoltaic panels, 21 square feet in all, to power all of its busy days spent digging, listening, and analysing the comet.
Sensors to Listen to the Comet
As part of a package that includes sensors to measure things like permittivity, Philae will also send acoustic waves across the comet using a transmitter. Then, with receivers embedded in its legs, it will measure how they bounce off and through the comet. According to Reyes, they'll also record audio of the "creaks" and "groans" on the surface.
Image: Institute for Planetary Science.
A Transmitter To Send Radio Through the Comet's Core
ESA's team is interested in what's inside the comet, so they'll use a simple method to get some basic measurements: Radio. While Rosetta orbits around the side of the comet opposite of the lander, it will put out radio waves which Philae will receive and return. Essentially, they're performing tomography, which involves imaging the interior of the comet by sending waves through it and listening to how they distort and move.
A Hammering Arm to Bury Sensors In the Surface
Here's a fascinating one: a mechanical arm will "hammer" up roughly 30cm into the comet's surface with an accelerometer and a thermometer at its tip, which will measure not only the thermal makeup, but how deep the hammer can punch before it's stopped. Other sensors will measure the temperature of the comet as it gets closer to the blazing-hot sun.
Rosetta and Philae are on a mission to analyse — or "taste," as the ESA says – the dust and ice on the comet. So Philae will use a drill to collect and then transport surface samples to a series of ovens where they'll be studied by the other devices on the lander. Since the little lander doesn't have much power to work with, the ESA says the drill consumes only a hundredth of the power your average drill does. Here's where it's located, shown on a replica of Philae:
A system called CIVA-P (which weighs less than 100 grams!) will shoot colour and infrared images of the landing site, while another imaging system called ROLIS will shoot images of the process of landing, along with close-ups of the comet's surface.
A Spectrometer to Measure Chemical Makeup
This device can measure the chemical makeup of samples on comet 67P/Churyumov–Gerasimenko's surface — how much hydrogen or helium exists up (down?) there, for example — by exposing samples to radiation. That radiation creates energy by interacting with the samples, which the spectrometer can measure.
Lead image: Wikimedia.