onsdag 1 juli 2015
Space Station Live: Open Access to Space Station Science Data.
New Horizons ‘Speeds Up’ on Final Approach to Pluto.
With just two weeks to go before its historic July 14 flight past Pluto,
NASA’s New Horizons spacecraft tapped the accelerator late last night
and tweaked its path toward the Pluto system.
The 23-second thruster burst was the third and final planned targeting maneuver of New Horizons’ approach phase to Pluto; it was also the smallest of the nine course corrections since New Horizons launched in January 2006. It bumped the spacecraft’s velocity by just 27 centimeters per second – about one-half mile per hour – slightly adjusting its arrival time and position at a flyby close-approach target point approximately 7,750 miles (12,500 kilometers) above Pluto’s surface.
While it may appear to be a minute adjustment for a spacecraft moving 32,500 miles per hour, the impact is significant. New Horizons Mission Design Lead Yanping Guo, of the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, says without the adjustment, New Horizons would have arrived 20 seconds late and 114 miles (184 kilometers) off-target from the spot where it will measure the properties of Pluto’s atmosphere. Those measurements depend on radio signals being sent from Earth to New Horizons at precise times as the spacecraft flies through the shadows of Pluto and Pluto’s largest moon, Charon.
In fact, timing and accuracy are critical for all New Horizons flyby observations, since those commands are stored in the spacecraft’s computers and programmed to “execute” at exact times.
This latest shift was based on radio-tracking data on the spacecraft and range-to-Pluto measurements made by optical-navigation imaging of the Pluto system taken by New Horizons in recent weeks. Using commands transmitted to the spacecraft on June 28, the thrusters began firing at 11:01 p.m. EDT on June 29 and stopped 23 seconds later. Telemetry indicating the spacecraft was healthy and that the maneuver went as designed began reaching the New Horizons Mission Operations Center at APL, through NASA’s Deep Space Network at 5:30 a.m. EDT on June 30.
“We are really on the final path,” said New Horizons Project Manager Glen Fountain, of APL. “It just gets better and more exciting every day.”
“This maneuver was perfectly performed by the spacecraft and its operations team,” added mission principal investigator Alan Stern, of Southwest Research Institute, Boulder, Colorado. “Now we’re set to fly right down the middle of the optimal approach corridor.”
New Horizons is now about 10 million miles (16 million kilometers) from the Pluto system – some 2.95 billion miles (4.75 billion kilometers) from Earth.
In the New Horizons Mission Operations Center at the Johns Hopkins
University Applied Physics Laboratory in Laurel, Maryland, flight
controllers (from left) Chris Regan and Becca Sepan monitor data from
NASA’s New Horizons spacecraft on June 30, after a short
course-correction maneuver refined New Horizons sourcepath toward a flyby of
Pluto on July 14.
In the New Horizons Mission Operations Center at the Johns Hopkins
University Applied Physics Laboratory in Laurel, Maryland, Mission
Operations Manager Alice Bowman and operations team member Karl
Whittenburg watch for data confirming that the Pluto-bound NASA
spacecraft successfully executed a course correction maneuver on June
30.
Source: NASA
The 23-second thruster burst was the third and final planned targeting maneuver of New Horizons’ approach phase to Pluto; it was also the smallest of the nine course corrections since New Horizons launched in January 2006. It bumped the spacecraft’s velocity by just 27 centimeters per second – about one-half mile per hour – slightly adjusting its arrival time and position at a flyby close-approach target point approximately 7,750 miles (12,500 kilometers) above Pluto’s surface.
While it may appear to be a minute adjustment for a spacecraft moving 32,500 miles per hour, the impact is significant. New Horizons Mission Design Lead Yanping Guo, of the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, says without the adjustment, New Horizons would have arrived 20 seconds late and 114 miles (184 kilometers) off-target from the spot where it will measure the properties of Pluto’s atmosphere. Those measurements depend on radio signals being sent from Earth to New Horizons at precise times as the spacecraft flies through the shadows of Pluto and Pluto’s largest moon, Charon.
In fact, timing and accuracy are critical for all New Horizons flyby observations, since those commands are stored in the spacecraft’s computers and programmed to “execute” at exact times.
This latest shift was based on radio-tracking data on the spacecraft and range-to-Pluto measurements made by optical-navigation imaging of the Pluto system taken by New Horizons in recent weeks. Using commands transmitted to the spacecraft on June 28, the thrusters began firing at 11:01 p.m. EDT on June 29 and stopped 23 seconds later. Telemetry indicating the spacecraft was healthy and that the maneuver went as designed began reaching the New Horizons Mission Operations Center at APL, through NASA’s Deep Space Network at 5:30 a.m. EDT on June 30.
“We are really on the final path,” said New Horizons Project Manager Glen Fountain, of APL. “It just gets better and more exciting every day.”
“This maneuver was perfectly performed by the spacecraft and its operations team,” added mission principal investigator Alan Stern, of Southwest Research Institute, Boulder, Colorado. “Now we’re set to fly right down the middle of the optimal approach corridor.”
New Horizons is now about 10 million miles (16 million kilometers) from the Pluto system – some 2.95 billion miles (4.75 billion kilometers) from Earth.
Source: NASA
New Horizons Update: Methane Detected; New Images of Pluto and Charon; Sunrise/Sunset Observations.
Yes, there is methane on Pluto, and, no, it doesn’t come from cows.
The infrared spectrometer on NASA’s Pluto-bound New Horizons spacecraft
has detected frozen methane on Pluto’s surface; Earth-based astronomers
first observed the chemical compound on Pluto in 1976.
“We already knew there was methane on Pluto, but these are our first detections,” said Will Grundy, the New Horizons Surface Composition team leader with the Lowell Observatory in Flagstaff, Arizona. “Soon we will know if there are differences in the presence of methane ice from one part of Pluto to another.”
Methane (chemical formula CH4) is an odorless, colorless gas that is present underground and in the atmosphere on Earth. On Pluto, methane may be primordial, inherited from the solar nebula from which the solar system formed 4.5 billion years ago. Methane was originally detected on Pluto’s surface by a team of ground-based astronomers led by New Horizons team member Dale Cruikshank, of NASA’s Ames Research Center, Mountain View, California.
Source: NASA.
“We already knew there was methane on Pluto, but these are our first detections,” said Will Grundy, the New Horizons Surface Composition team leader with the Lowell Observatory in Flagstaff, Arizona. “Soon we will know if there are differences in the presence of methane ice from one part of Pluto to another.”
Methane (chemical formula CH4) is an odorless, colorless gas that is present underground and in the atmosphere on Earth. On Pluto, methane may be primordial, inherited from the solar nebula from which the solar system formed 4.5 billion years ago. Methane was originally detected on Pluto’s surface by a team of ground-based astronomers led by New Horizons team member Dale Cruikshank, of NASA’s Ames Research Center, Mountain View, California.
Source: NASA.
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