On January 4, 2015, the long-distance encounter between Pluto and began. On this day, the image of the target captured using the airborne LORRI imager and the Ralph telescope is only a few pixels wide. Investigators began taking images of Pluto and background star fields to assist mission navigators in designing course-correction engine maneuvers to precisely modify New Horizons' trajectory to target the approach.
New Horizons space probe
On February 12, 2015, NASA released new images of Pluto from the approach probe (taken between January 25 and 31). New Horizons was more than 203 million kilometers (126,000,000 miles) away from Pluto when it began taking photos, which show Pluto and its largest moon, Charon. The exposure was too short to see Pluto's smaller, fainter moon , . Investigators compiled a series of satellite Nix and Hydra images taken from January 27 to February 8, 2015, starting at a range of 201 million kilometers (125,000,000 miles).
Pluto and Charon shown as an overexposed object in the center. The image on the right has been processed to remove the background star field. Two other even smaller satellites, Kerberos and Styx, were seen on the photo taken on April 25. Beginning on May 11, a hazardous search was conducted to find unknown objects that could pose a danger to the spacecraft, such as rings or hithero undiscovered satellites, which could then be avoided by changing course. No rings or additional moons were discovered.
In 2005, New Horizons at the Kennedy Space Center facility.
On August 21, 2012, the team announced that they would spend mission time attempting remote observations of a Kuiper Belt object, provisionally designated VNH0004 (now designated 2011KW48), which was The object is 75 gigameters (0.50 AU) away from New Horizons.
The object is too far away to resolve surface features or perform spectral analysis, but it is capable of observations not possible on Earth, namely phase curves and finding small satellites. Plans are to observe a second object in June 2015 and a third in September after the flyby; the team hopes to observe a dozen such objects by 2018. On April 15, 2015, an image of Pluto showed the possible presence of polar caps.
SWAP - Solar Wind Around Pluto
On July 4, 2015, New Horizons experienced a software anomaly and entered safe mode, preventing the spacecraft from conducting scientific observations until engineers could resolve the problem. On July 5, NASA announced that the issue was determined to be a timing flaw in the command sequence used to prepare the spacecraft for flyby, and the spacecraft will resume scheduled science operations on July 7. Missions lost due to scientific observations due to anomalies are judged to have no impact on the primary objectives of the mission and minimal impact on other objectives. The
timing flaw involves performing two tasks simultaneously - compressing previously acquired data to free up space for more data, and making a second copy of the approach command sequence - which together overloaded the spacecraft's main computer. After detecting the overload, the spacecraft performed as designed: switching from the primary computer to the backup computer, entering safe mode, and sending a distress signal to Earth. The distress signal was received on the afternoon of July 4 and alerted engineers that they needed to contact the spacecraft to obtain more information and resolve the problem. The solution is that the problem occurred as part of approach preparations and was not expected to reoccur as no similar mission was planned for subsequent encounters.
Charon (hemisphere) opposite Pluto observed on July 11, 2015
The New Horizons spacecraft's closest approach to Pluto was at 11:49 UTC on July 14, 2015, at a distance of 12,472 kilometers (7,750 miles) from Pluto's surface. 13,658 kilometers (8,487 miles) from the center of Pluto. On July 15, 2015, UTC time 00:52:37, 22 hours after a planned radio silence due to the spacecraft being pointed, confirmation of the successful flyby and healthy spaceflight was received on Earth The telemetry data from the spacecraft is directed towards the Pluto system. Mission managers estimate there is a 1 in 10,000 chance that debris could damage the probe or its communications systems during the flyby, preventing it from sending data to Earth.Details of the first encounter were received the next day, but it took just over 15 months to download the full dataset via a 2kbps data downlink, with data analysis continuing into 2021.
Pluto's "encounter hemisphere" as seen by New Horizons on July 13, 2015
New Horizons passed within 12,500 kilometers (7,800 miles) of Pluto, with its closest approach taking place on July 14, 2015 at 11: 50UTC. New Horizons' relative speed at closest approach was 13.78 km/s (49,600 km/h; 30,800 mph), and Charon's closest approach was 28,800 km (17,900 mi). Starting 3.2 days before closest approach, long-range imaging included mapping Pluto and Charon to a resolution of 40 kilometers (25 miles). This is half the rotation period of the Pluto-Charon system , allowing all sides of both bodies to be imaged.
introduces new horizons. Atlas V rocket on the launch pad.
repeats close-range imaging twice a day to look for surface changes caused by localized snowfall or surface cryovolcanic activity. Due to Pluto's tilt, part of the northern hemisphere will always be in shadow. During the flyby, engineers expect LORRI to be able to obtain selected imagery at resolutions up to 50m per pixel (160ft/px), and MVIC is expected to obtain a four-color global daytime map of 1.6km (1 mile) if the closest distance is approximately 12,500km. resolution. LORRI and MVIC attempt to overlap their respective coverage areas to form a stereo pair. LEISA obtained hyperspectral near-infrared images at 7 km/pixel (4.3 miles/pixel) globally and 0.6 km/pixel (0.37 miles/pixel) for selected areas.
Lifting off from Cape Canaveral
Alice, meanwhile, characterized the atmosphere through the emission of atmospheric molecules (airglow) and the dimming of background stars after passing Pluto ( occultation ). During and after the closest approach, SWAP and PEPSSI sample the upper atmosphere and its influence on the solar wind. VBSDC searches for dust, infers meteoroid collision rates and any invisible rings. REX conducts active and passive radio science. Communications dishes on Earth measured the disappearance and reappearance of radio occultation signals sent by detectors as they passed behind Pluto. The results resolve Pluto's diameter (through their time) and atmosphere density and composition (through their weakening and strengthening patterns). (Alice could perform a similar occultation, using sunlight instead of the radio beacon .)
The mission, led by the Applied Physics Laboratory and Alan Stern, eventually became the first mission to Pluto
Previous The mission has the spacecraft transmit through the atmosphere to Earth (the "downlink"). Pluto's mass and mass distribution were assessed using gravitational tug on the spacecraft. As the spacecraft accelerates and decelerates, the radio signal exhibits a Doppler shift of and . Doppler shift is measured by comparison with ultrastable oscillators in communications electronics. Charon's reflected sunlight allows some imaging observations of the night. The sun's backlight provides the opportunity to highlight any rings or atmospheric haze. REX conducted radiation measurements at night.
Artist’s impression of New Horizons’ close encounter with the Pluto system
