Posts Tagged ‘space travel’
This picture of our home planet truly is EPIC – literally! The full-globe image was acquired with NASA’s Earth Polychromatic Imaging Camera (aka EPIC; see what they did there) on board NOAA’s DSCOVR spacecraft, positioned nearly a million miles (1.5 million km) away at L1.
L1 is one of five Lagrange points that exist in space where the gravitational pull between Earth and the Sun are sort of canceled out, allowing spacecraft to be “parked” there. (Learn more about Lagrange points here.) Launched aboard a SpaceX Falcon 9 on Feb. 11, 2015, the Deep Space Climate Observatory (DSCOVR) arrived at L1 on June 8 and, after a series of instrument checks, captured the image of Earth’s western hemisphere above on July 6.
The EPIC instrument has the capability to capture images in ten narrowband channels from infrared to ultraviolet; the true-color picture above was made from images acquired in red, green, and blue visible-light wavelengths.
More than just a pretty picture of our blue marble, this image will be used by the EPIC team to help calibrate the instrument to remove some of the blue atmospheric haze from subsequent images. Once the camera is fully set to begin operations daily images of our planet will be made available on a dedicated web site starting in September.
Alan Stern’s speculations at the New Horizons website as to what might have happened if Voyager 1 did visit Pluto in 1986 are worth noting. Much of the science that was accomplished by New Horizons would still be achieved by the earlier probe, but technological and observational issues would have hampered things.
Across flights launched in 1977 and spanning the entirety of the 1980s, Voyagers 1 and 2 performed the historic, first detailed reconnaissance of our solar system’s four giant planets (Jupiter, Saturn, Neptune, Uranus). The essentially identical Voyagers were launched with a core mission to explore the Jupiter and Saturn systems, and each spacecraft carried a powerful and diverse scientific instrument suite. After Saturn, Voyager 2 was tasked with reconnoitering Uranus and Neptune during an extended mission.
Although Pluto’s orbital position relative to Neptune made it impossible for Voyager 2 to travel to it from Neptune, Voyager 1 actually could have reached Pluto after its Saturn flyby, had it been targeted to do so. In fact, NASA and the Voyager project actually considered this option, but eliminated it in 1980 – going instead with the very exiting but lower-risk opportunity to investigate Saturn’s large, scientifically enticing, cloud-enshrouded and liquid-bearing moon Titan.
But if Voyager 1 had been sent to Pluto, it would have arrived in the spring of 1986, just after Voyager 2’s exploration of Uranus that January. As New Horizons approaches Pluto in 2015, it’s fun to think what we might have found almost 30 years ago had Voyager 1 – rather than New Horizons – been first to Pluto.
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Voyager 1 carried a broad battery of cameras, spectrometers, plasma experiments, and even a sensitive magnetometer that it could have brought to bear on the exploration of Pluto. Because Pluto was almost exactly the same distance from the Sun in 1986 as Neptune was for the Voyager 2 flyby in 1989, it’s clear that the instruments aboard Voyager 1 would have worked well at Pluto. And because Voyager 1 is still working today, we know the spacecraft would likely have made the journey to Pluto successfully.
Although Voyager 1 would have been able to map Pluto and Charon well with its cameras, and detect Pluto’s atmosphere and study the atmosphere’s basic properties, the Voyager science team would not have known to plan observations of the small moons they would have discovered on close approach, nor would they have been able to explore Pluto nearly as thoroughly as the payload aboard New Horizons will.