New Horizons has phoned home. Just before 9 PM Tuesday, the spacecraft radioed back engineering data that said, essentially, “mission accomplished.” Which is to say, the “collecting data” part of the mission has been done. It remains to get all that data back to Earth.
New Horizons blasted past Pluto at a speed of over 30,000 mph and kept on going. It’s headed for the Kuiper Belt where, it is hoped, the spacecraft will make more observations. During the Pluto encounter, the spacecraft took photos and pointed science instruments at Pluto and its satellites. So far, only a few images have been sent back, as sending images is a very slow process. The spacecraft is almost 3 billion miles from earth and that number is, of course, continually growing. The spacecraft’s radio transmitter has just 12 watts of power. By comparison, a nightlight bulb typically consumes 4 to 7 watts of power. Imagine trying to detect two glowing nightlights at a distance of 3 billion miles.
By the time the signal reaches Earth, it is so faint that a giant radio dish is necessary to detect it. Even so, New Horizons must “speak slowly” to be heard, so the data rate is only about 1,000 bits per second. (A 1980s digital fax machine could send 14 times as much data each second.) Because of the slow data rate, a single image will require over three hours to send. Even if highly compressed, an image will still require 20 minutes to send. The spacecraft will be busy sending images and data for the next 16 months. Then, as it hurtles through the darkness of empty space, it will likely be told to hibernate until it gets close to its next encounter.
The New Horizons mission is on Twitter and also has a Facebook page. The NASA website has a New Horizons section.
No comments:
Post a Comment