1 : Encounter
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Press Release September 18, 2001Veteran Spacecraft Attempts to Earn Extra Credit at CometLike a slugger trying to pile up extra home runs after breaking the world record, a venerable NASA spacecraft already famed for bringing science fiction's ion-engine technology to life is preparing to fly daringly close to a comet on Saturday, Sept. 22.Deep Space 1, which has already completed a highly successful mission testing a number of advanced spacecraft technologies, will attempt to pass inside the mostly unknown environment just 2,000 kilometers (about 1,200 miles) from the nucleus of comet Borrelly at 2230 Universal time (3:30 p.m. PDT) on Sept. 22.\"It has been a tremendously rewarding effort for the small Deep Space 1 team to keep this aged and wounded bird aloft,\" said Dr. Marc Rayman, project manager of Deep Space 1 at NASA's Jet Propulsion Laboratory, Pasadena, Calif. \"Its mission to test new technologies is already highly successful and any science we get at the comet will be a terrific bonus.\"By the time of the flyby Deep Space 1 will have completed three times its intended lifetime in space and its primary mission to test ion propulsion and 11 other high-risk, advanced technologies in September 1999. NASA extended the mission, taking advantage of the ion propulsion and other systems to target a chancy but exciting encounter with Borrelly.The spacecraft may tell us more about comets and their place in the solar system. The robotic explorer will attempt to investigate the comet's environment when it tries to fly through the cloud of gas and dust surrounding the comet's nucleus, known as the coma.The risks involved in gathering science data are very high, so results of this latest venture are unpredictable. The spacecraft will be traveling through a cloud of gas, dust and comet pieces to collect its data. Since Deep Space 1 wasn't built to go to a comet, it does not carry a protective shield. \"We expect to be hit by debris from the comet, and at 16.5 kilometers per second (about 36,900 mph), even a tiny particle might prove fatal,\" said Rayman. \"But this is an adventure too exciting to pass up.\"If all goes well, scientists will use the comet chaser's measurements to find out the nature of Borrelly's surface and to measure and identify the gases coming from the comet. The spacecraft will also attempt to measure the interaction of solar wind with the comet, a process that leads to formation of the beautiful tail.Borrelly makes a good target for study now, as it is just 1.34 astronomical units (about 200 million kilometers or 125 million miles) from the Sun -- the closest it will get for another seven years. The Sun's heat will make the gases escaping from the nucleus flow faster and more thickly, so they will be easier to study. The icy nucleus and the spacecraft will flash past each other at 16.5 kilometers per second (more than 36,900 miles per hour).The flight team is also hoping that Deep Space 1 will have enough gas to get to the comet. The long-lived spacecraft keeps itself pointed correctly by firing small thrusters fueled by hydrazine gas. When the hydrazine runs out, Deep Space 1 will be unable to keep itself pointed correctly, and the spacecraft will die. The flight team has an estimate of how much gas is left, but a few hours' worth of gas could make all the difference in the comet encounter.As it approaches the center of the coma, the spacecraft will face its greatest challenge: to obtain pictures and infrared measurements of the nucleus. Deep Space 1 can't tell exactly where the nucleus is or what it will look like. The craft will have to locate the nucleus on its own and try to point the camera toward it as it streaks by.In late 1999, Deep Space 1 lost its star tracker, which helps determine the spacecraft's orientation. Faced with what could have been a mission-terminating injury, the controllers performed a spectacular ultra-long-distance rescue. They reconfigured the spacecraft to use the photographic camera to orient itself by the stars around it.The camera cannot align the spacecraft and snap photos of Borrelly at the same time. Instead, Deep Space 1 will have to rely on its fiber-optic gyroscopes to help maintain its orientation. But the gyros are not accurate enough by themselves, so engineers designed complex new software to help the camera stay pointed at the comet's nucleus during the critical few minutes that the probe will be close enough to try to get a view of it.More information can be found online at Space 1 was launched in October 1998 as part of NASA's New Millennium Program, which is managed by JPL for NASA's Office of Space Science, Washington. The California Institute of Technology in Pasadena manages JPL for NASA.
Get up close to our animals, visit behind-the-scenes areas not accessible to the public, receive a guided tour from zoo staff and see what goes into the amazing care our animals receive daily. Behind the Scenes Tours can accommodate up to 16 guests and includes three encounters. The list of available encounters can be found below the pricing information.
Come and create lasting memories while visiting with our furry and unique red pandas. In this encounter, you will go behind the scenes with an Asia zookeeper and learn the exciting truths of this rare endangered animal.
On the way into the first encounter, Parker Solar Probe conducted a Venus Flyby on 2018 October 3rd, in which measurements were taken of the Venusian bowshock. These flybys provide much needed information into the near-Venus space environment and allow for exciting research outside of the primary mission of Parker Solar Probe.
The first perihelion of Parker Solar Probe reached a solar distance of 0.17 au (35.6 RS), breaking the record as the closest human-made object to the Sun. Findings from the first two encounters were reported in four Nature articles (1, 2, 3, 4) and as a set of over 50 articles in a special issue of The Astrophysical Journal Supplement series (ApJS).
The second Parker Solar Probe encounter also reached a solar distance of 0.17 au (35.6 RS) and provided additional insight into the structure of the solar wind in the inner heliosphere. Findings from the first two encounters were reported in four Nature articles (1, 2, 3, 4) and as a set of over 50 articles in a special issue of ApJS.
The orbit of Parker Solar Probe (Parker) during the 4th encounter with the Sun presented a unique opportunity for a multi-mission and multi-observatory collaboration as the 4th perihelion occurred nearly at the Sun-Earth line. This unprecedented configuration allowed ground-based solar observatories to measure the solar surface that Parker was magnetically connected to while Parker simultaneously measured the near-Sun environment at the closest distance to the Sun recorded to date (27.8 RS). Additionally, near-Earth missions (e.g., ACE, ARTEMIS, and MMS) could then measure this solar wind once it reached 1 au to study the evolution of solar wind structures as they propagate radially outward from the Sun. Probes within the magnetosphere of Earth, and observatories focused on the ionosphere, could then study how these structures affect the near-Earth environment. To take advantage of this great opportunity for large-scale coordinated science, the Parker Project Science team and the Whole Heliosphere and Planetary Interactions (WHPI) group organized a campaign that has brought together observatories and missions from across the world. This page is meant to contain information and links relevant to the Parker Solar Probe Encounter 4 campaign. For more information, please contact Robert C. Allen (Robert.Allen@jhuapl.edu), the Parker Project Science team coordinator for this effort.
Movie showing the footpoint locations from ballistic mapping of Parker (yellow), STEREO-A (red), and Earth (blue) for 300 and 600 km/s solar wind during encounter 4 (Courtesy of Sam Badman; SDO/AIA 193A synoptic map produced by David Stansby).
The fifth encounter of Parker Solar Probe provides measurements of the inner heliosphere down to 0.13 au (27.8 RS), the same distance as Encounter 4. The orbit configuration of Parker and Earth will allow for footpoint observations at the limb starting near the time of the Parker perihelion.
Ballistic propagation predictions, provided by Sam Badman, give an early prediction of when the Parker footpoint may cross into view from Earth. Below is a movie showing the (left) helioprojective viewpoint and (right) Carrington coordinates of Parker during encounter 5. The orange dashed line represents the limb from the point of view of Earth. Ballistic footpoints for solar wind speeds of 200 (blue), 400 (orange), and 600 (red) km/s speeds are shown in both plots (unless they are not visible from Earth in the left panel). The Carrington meridian is shown with the blue curve in the left panel and is dashed when on the opposite side of the Sun as Earth. These estimates predict that the ballistic footpoint of Parker will cross over the East limb on June 7th (0600 UTC for 200 km/s, 1200 UTC for 400 km/s, and 1800 UTC for 600 km/s). This is remarkably close to the perihelion (June 7th, 0800 UTC).
Using data from the movie above, the panels in the image below show the course of predicted Parker footpoint locations during Encounter 5. The blue circles in the left panel mark, with the dates labeled, when the Parker footpoints are in view of the Earth for a solar wind speed of 400 km/s. This is shown in the helioprojective frame. The predicted footpoints in the right panel are shown in Carrington coordinates over the full encounter. For this solar wind speed, these ballistic estimates predict that the Parker footpoints will be visible from the Earth by June 8th. Please note that these ballistic footpoints just show the orbital position of Parker mapped down to solar surface using a Parker Spiral to correct the longitude and includes no modeling of the corona. Therefore these do not indicate probable sources on the photosphere but do give a good idea of when the footpoints are on disk and approximately which solar meridian they will lie on. 59ce067264
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