154-501: Geocaching ( / ˈ dʒ iː oʊ k æ ʃ ɪ ŋ / , JEE -oh- KASH -ing ) is an outdoor recreational activity, in which participants use a Global Positioning System (GPS) receiver or mobile device and other navigational techniques to hide and seek containers, called geocaches or caches , at specific locations marked by coordinates all over the world. The first geocache was placed in 2000, and by 2023 there were over 3 million active caches worldwide. Geocaching can be considered
308-455: A Silica - cemented carbonate rock sample tube, two regolith sample tubes, an atmosphere sample tube, and three witness tubes. Before launch, 5 of the 43 tubes were designated "witness tubes" and filled with materials that would capture particulates in the ambient environment of Mars. Out of 43 tubes, 3 witness sample tubes will not be returned to Earth and will remain on rover as the sample canister will only have 30 tube slots. Further, 10 of
462-433: A Travel Bug (the first geocaching trackable item in space), which stayed on the station until it was brought back to earth in 2013. Due to fire restrictions on board the station, the geocache contained no official paper logbook. As of June 2024, only one confirmed geocacher (on November 17, 2013) has actually found the geocache, although others have claimed to have found it providing varying amounts of evidence. To commemorate
616-683: A United Launch Alliance Atlas V launch vehicle from Space Launch Complex 41 , at Cape Canaveral Air Force Station (CCAFS) in Florida . The rover took 29 weeks to travel to Mars and made its landing in Jezero Crater on February 18, 2021, to begin its science phase. After May 17, 2022, the rover will move uphill and examine rocks on the surface for evidence of past life on Mars . On its return downhill, it will collect sample rocks to be retrieved and examined by future expeditions. The successful landing of Perseverance in Jezero Crater
770-761: A location-based game . A typical cache is a small waterproof container containing a logbook and sometimes a pen or pencil. The geocacher signs the log with their established code name/username and dates it, in order to prove that they found the cache. After signing the log, the cache must be placed back exactly where the person found it. Larger containers such as plastic storage containers ( Tupperware or similar) or ammo boxes can also contain items for trading, such as toys or trinkets, usually of more sentimental worth than financial. Geocaching shares many aspects with benchmarking , trigpointing , orienteering , treasure hunting , letterboxing , trail blazing , and another type of location-based game called Munzee . Geocaching
924-408: A moving map display , or recorded or used by some other system, such as a vehicle guidance system. Although usually not formed explicitly in the receiver processing, the conceptual time differences of arrival (TDOAs) define the measurement geometry. Each TDOA corresponds to a hyperboloid of revolution (see Multilateration ). The line connecting the two satellites involved (and its extensions) forms
1078-553: A robotic arm , although Perseverance ' s arm is longer and stronger, measuring 2.1 m (6 ft 11 in). The arm hosts an elaborate rock-coring and sampling mechanism to store geologic samples from the Martian surface in sterile caching tubes. There is also a secondary arm hidden below the rover that helps store the chalk-sized samples. This arm is known as the Sample Handling Assembly (SHA), and
1232-458: A staff-and-serpent symbol (a Greek symbol of medicine) was placed on the rover. The project manager, Matt Wallace, said he hoped that future generations going to Mars would be able to appreciate healthcare workers during 2020. One of the external plates of Perseverance includes a simplified representation of all previous NASA Martian rovers, Sojourner , Spirit , Opportunity , Curiosity , as well as Perseverance and Ingenuity , similar to
1386-512: A wireless beacon cache . This is a Garmin -created innovative on multi-caches using wireless beacon technology. It is a physical game piece, about the size of a half dollar that can be hidden anywhere. Powered by a small battery, it is able to transmit a signal detectable on Garmin devices. The Chirp stores hints, multicache coordinates, counts visitors, and can confirm the cache is nearby. These caches caused considerable discussion and some controversy at Groundspeak, where they were ultimately given
1540-515: A GPS-located cache took place on May 3, 2000, by Dave Ulmer in Beavercreek, Oregon . The location was posted on the Usenet newsgroup sci.geo.satellite-nav at 45°17.460′N 122°24.800′W / 45.291000°N 122.413333°W / 45.291000; -122.413333 . Within three days, the cache had been found twice, first by Mike Teague. According to Dave Ulmer's message, this cache
1694-410: A Reverse cache, a locationless cache is similar to a scavenger hunt . A description is given for something to find, such as a one-room schoolhouse, and the finder locates an example of this object. The finder records the location using their GPS receiver and often takes a picture at the location showing the named object with their GPS receiver. Typically others are not allowed to log that same location as
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#17327731126261848-579: A builder application is usually used. The Wherigo site offers a builder application and a database of adventures free for download, though the builder has remained in its Alpha version since its last release in May 2008. The official player is only available for Pocket PC . A built-in player is available on Garmin Colorado and Oregon GPS models. The Wherigo Foundation was organized in December 2012. The group
2002-422: A comprehensive list of common puzzle cache ciphers. There are also some subcategories of the mystery cache, which are normally listed as a Mystery Type, which are listed below. This requires a geocacher to complete a reasonably attainable geocaching-related task before being able to log the cache as a find online. It does not restrict geocachers from finding the cache and signing the logbook at anytime. However
2156-705: A deliberate error introduced into the GPS data that military receivers could correct for. As civilian GPS usage grew, there was increasing pressure to remove this error. The SA system was temporarily disabled during the Gulf War , as a shortage of military GPS units meant that many US soldiers were using civilian GPS units sent from home. In the 1990s, Differential GPS systems from the US Coast Guard , Federal Aviation Administration , and similar agencies in other countries began to broadcast local GPS corrections, reducing
2310-450: A directive making GPS freely available for civilian use, once it was sufficiently developed, as a common good. The first Block II satellite was launched on February 14, 1989, and the 24th satellite was launched in 1994. The GPS program cost at this point, not including the cost of the user equipment but including the costs of the satellite launches, has been estimated at US$ 5 billion (equivalent to $ 10 billion in 2023). Initially,
2464-407: A find. Since 2005, all locationless caches have been archived and locked, meaning they are unable to be logged. However, with geocaching's 20th anniversary in 2020 Groundspeak decided to publish a special locationless cache for geocachers to "find" at various Mega- and Giga-Events around the world. The first locationless cache in 15 years (GC8FR0G) required finders to take a picture of themselves with
2618-517: A full complement of 24 satellites in 2027. The GPS project was launched in the United States in 1973 to overcome the limitations of previous navigation systems, combining ideas from several predecessors, including classified engineering design studies from the 1960s. The U.S. Department of Defense developed the system, which originally used 24 satellites, for use by the United States military, and became fully operational in 1993. Civilian use
2772-412: A geocache and a letterbox in the same container. Letterboxes involve a rubber stamp and logbook that are not supposed to be traded and taken instead of tradable items, but letterbox hybrids may or may not include trade items. Letterboxers carry their own stamp with them, to stamp the letterbox's logbook and inversely stamp their personal logbook with the letterbox stamp. The letterbox hybrid cache contains
2926-417: A geocache without a physical printout of the cache description. Traditionally, this means that the seeker has an electronic means of viewing the cache information in the field, such as pre-downloading the information to a PDA or other electronic device. Various applications can directly upload and read GPX files without further conversion. Newer GPS devices released by Garmin , DeLorme , and Magellan have
3080-406: A geocache. It consists of a container with a log sheet, and is located at the posted coordinates. Cache containers come in many different sizes. These caches are intended to be found at night, usually by use of a UV torch. These caches include at least one stage in addition to the physical final container with a log sheet. The posted coordinates for a multi-cache are the first stage. At each stage,
3234-469: A geocacher is not allowed to log a find on the geocaching website unless they qualify for the challenge specified in the cache description. Examples include finding a number of caches that meet a category, completing a number of cache finds within a period of time, or finding a cache for every calendar day. Since 2017, Groundspeak has required new challenges to have a geochecker in which users can put their name into an algorithm to see if they qualify without
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#17327731126263388-654: A geographic area based on criteria such as ZIP code or coordinates , downloading the results as an email attachment on a schedule. In recent years, Android and iPhone users can download apps such as GeoBeagle that allow them to use their 3G and GPS-enabled devices to actively search for and download new caches. A variety of geocaching applications are available for geocache data management, file-type translation, and personalization. Geocaching software can assign special icons or search (filter) for caches based on certain criteria (e.g. distance from an assigned point, difficulty, date last found). Paperless geocaching means hunting
3542-417: A greater diameter, 52.5 cm (20.7 in), than Curiosity 's 50 cm (20 in) wheels. The aluminum wheels are covered with cleats for traction and curved titanium spokes for springy support. The heat shield for the rover was made out of phenolic-impregnated carbon ablator (PICA), to allow it to withstand up to 2,400 °F (1,320 °C) of heat. Like Curiosity , the rover includes
3696-650: A hemisphere-shape canopy, and each strip consisted of four pieces. Dr. Clark thus had 320 pieces with which to encode the message. He also included the GPS coordinates for the Jet Propulsion Laboratory's headquarters in Pasadena, California (34°11’58” N 118°10’31” W). Clark said that only six people knew about the message before landing. The code was deciphered a few hours after the image was presented by Perseverance ' s team. "Dare mighty things"
3850-473: A landing ellipse devoid of hazards. The landing occurred in the late afternoon, with the first images taken at 15:53:58 on the mission clock (local mean solar time). The landing took place shortly after Mars passed through its northern vernal equinox ( Ls = 5.2°), at the start of the astronomical spring, the equivalent of the end of March on Earth. The parachute descent of the Perseverance rover
4004-429: A liaison. The U.S. Department of Defense is required by law to "maintain a Standard Positioning Service (as defined in the federal radio navigation plan and the standard positioning service signal specification) that will be available on a continuous, worldwide basis" and "develop measures to prevent hostile use of GPS and its augmentations without unduly disrupting or degrading civilian uses". USA-203 from Block IIR-M
4158-595: A long distance from home, or to travel to a certain country, or to travel faster and farther than other hitchhikers in a race. Less common trends are site-specific information pages about the historic significance of the site, types of trees, birds in the area or other such information. Higher-value items are occasionally included in geocaches as a reward for the First to Find (called "FTF"), or in locations which are harder to reach. Dangerous or illegal items, including weapons and drugs, are not allowed and are specifically against
4312-563: A manageable level to permit accurate navigation. During Labor Day weekend in 1973, a meeting of about twelve military officers at the Pentagon discussed the creation of a Defense Navigation Satellite System (DNSS) . It was at this meeting that the real synthesis that became GPS was created. Later that year, the DNSS program was named Navstar. Navstar is often erroneously considered an acronym for "NAVigation System using Timing And Ranging" but
4466-412: A mass of 45 kg (99 lb) and uses 4.8 kg (11 lb) of plutonium-238 oxide as its power source. The radioactive decay of plutonium-238, which has a half-life of 87.7 years, gives off heat which is converted to electricity —approximately 110 watts at launch. This will decrease over time as its power source decays. The MMRTG charges two lithium-ion rechargeable batteries which power
4620-461: A minimum, four satellites must be in view of the receiver for it to compute four unknown quantities (three position coordinates and the deviation of its own clock from satellite time). Each GPS satellite continually broadcasts a signal ( carrier wave with modulation ) that includes: Conceptually, the receiver measures the TOAs (according to its own clock) of four satellite signals. From the TOAs and
4774-523: A new "attribute". These types of geocaches can also be listed as a traditional, multi-cache, or letterbox. It is up to the cache owner to designated the cache type for wireless beacon caches. This is an official geocache located inside the Groundspeak headquarters office in Seattle, Washington . It is technically classified as a separate cache type under mystery caches, with its own unique icon both on
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4928-413: A picture which can be developed and uploaded to a geocaching web site listed below. Also common are objects that are moved from cache to cache called "hitchhikers", such as Travel Bugs or geocoins, whose travels may be logged and followed online. Cachers who initially place a Travel Bug or Geocoin(s) often assign specific goals for their trackable items. Examples of goals are to be placed in a certain cache
5082-560: A place that requires people to pay a fee to visit such as airports or theme parks may get the Adventure permanently removed from the Adventure Lab app. There are several kinds of events geocaches. While encouraged, events do not require visitors to sign their name a logbook to prove they attended an event. Attendees of event caches can log that they 'attended', which will increment their number of found caches. Event caches can be of
5236-456: A player can type into the RWIG cartridge. Instead of following a story or interacting with characters, and RWIG gives you the distance to the final cache, but not direction. It requires geocachers to get closer to the final geocache by process of elimination. Once you are within 25 metres, the final coordinates are given to provide a more accurate location for the geocache. This is a combination of
5390-465: A puzzle or bring a special tool to reveal the next waypoint or final coordinates. Most often, the final container is not at the posted coordinates which is noted in the cache description. Some puzzles can be easy and involve basic math operations or they can be quite difficult, with some of the more challenging ones requiring a firm understanding of computer programming . Geocaching Toolbox, a website dedicated to create and solve puzzle geocaches, provides
5544-431: A receiver start-up situation. Most receivers have a track algorithm , sometimes called a tracker , that combines sets of satellite measurements collected at different times—in effect, taking advantage of the fact that successive receiver positions are usually close to each other. After a set of measurements are processed, the tracker predicts the receiver location corresponding to the next set of satellite measurements. When
5698-671: A report in July 2013 that the mission should "select and store a compelling suite of samples in a returnable cache." The Perseverance rover has four main science objectives that support the Mars Exploration Program 's science goals: In the first science campaign Perseverance performs an arching drive southward from its landing site to the Séítah unit to perform a "toe dip" into the unit to collect remote-sensing measurements of geologic targets. After that it will return to
5852-555: A rover mission. By the summer of 2012, a program that had been launching a mission to Mars every two years suddenly found itself with no missions approved after 2013. In 2011, the Planetary Science Decadal Survey , a report from the National Academies of Sciences, Engineering, and Medicine containing an influential set of recommendations made by the planetary science community, stated that
6006-402: A trial version with limited functionality. The site promotes mobile applications, and lists over two dozen applications (both mobile and browser/desktop based) that are using their proprietary but royalty-free public application programming interface ( API ). Developers at c:geo have criticised Groundspeak for being incompatible with open-source development. Additionally, "c:geo - opensource"
6160-411: A virtual cache generally requires one to email the cache hider with information such as a date or a name on a plaque, or to post a picture of oneself at the site with a GPS receiver in hand. As of 2005, new virtual caches are no longer allowed by Groundspeak as it is considered a legacy cache. On August 24, 2017, Groundspeak announced "Virtual Rewards", allowing 4000 new virtual caches to be placed during
6314-531: A walking tour of a city or park. An example would be Route 66 or the Lincoln Highway , which are a nationwide series of Adventure Lab sets of 10 that stretch the entire route across the United States . Adventure labs were first introduced in 2014 as a way to test market ideas through Groundspeak. Initially, geocachers would find a key word at a designated site where they could then enter it onto
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6468-513: A website to claim "credit". Soon after, they were made available to "find" at select Mega-Events. In 2020, Groundspeak released the "Adventure Lab" app, separate from the geocaching app. The app made it possible to enter a geo-fence when, once inside, a question will appear that can be answered either in the form of a written answer or a multiple choice answer. This question can be answered at anytime once activated, however, some Adventure Labs must be completed sequentially implying that one must answer
6622-719: Is a GPS location-aware software platform initially released in January 2008. Authors can develop self-enclosed story files (called "cartridges") that are read by the Wherigo player software, installed on either a GPS unit or smartphone. The player and story take advantage of the location information provided by the GPS to trigger in-game events, such as using a virtual object or interacting with characters. Completing an adventure can require reaching different locations and solving puzzles. Cartridges are coded in Lua . Lua may be used directly, but
6776-650: Is a satellite-based radio navigation system owned by the United States Space Force and operated by Mission Delta 31 . It is one of the global navigation satellite systems (GNSS) that provide geolocation and time information to a GPS receiver anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites. It does not require the user to transmit any data, and operates independently of any telephone or Internet reception, though these technologies can enhance
6930-439: Is a free opensource full function application for Android phones that is very popular. This app includes similar features to the official Geocaching mobile application, such as: View caches on a live map ( Google Maps or OpenStreetMap), navigation using a compass, map, or other applications, logging finds online and offline, etc. Global Positioning System The Global Positioning System ( GPS ), originally Navstar GPS ,
7084-543: Is a quote attributed to U.S. president Theodore Roosevelt and is the unofficial motto of the Jet Propulsion Laboratory. It adorns many of the JPL center's walls. In December 2021, the NASA team announced a program to students who have persevered with academic challenges. Those nominated will be rewarded with a personal message beamed back from Mars by the Perseverance rover. March 5, 2024: NASA released images of transits of
7238-440: Is composed of all Wherigo application developers who, up until that time, had been acting and developing separately. Their goal is to provide a consistent Wherigo experience across platforms, connect Wherigo applications via an API , and add modern features to the Wherigo platform. While Groundspeak is aware of this project, the company has yet to take a position. An RWIG provides three lines of code composed of 9 digits each that
7392-399: Is no longer allowed because it restricts geocachers to find specific geocaches. Instead, Groundspeak has encouraged new challenges to be more creative. Acceptable challenges include finding caches in 10 states, finding 100 traditional geocaches, or finding 1000 geocaches with the "wheelchair accessible" attribute. A bonus cache requires the finder to have found an amount of caches, usually by
7546-527: Is owned and operated by the United States government as a national resource. The Department of Defense is the steward of GPS. The Interagency GPS Executive Board (IGEB) oversaw GPS policy matters from 1996 to 2004. After that, the National Space-Based Positioning, Navigation and Timing Executive Committee was established by presidential directive in 2004 to advise and coordinate federal departments and agencies on matters concerning
7700-664: Is planned to climb onto the Jezero Crater rim. In its progressive commissioning and tests, Perseverance made its first test drive on Mars on March 4, 2021. NASA released photographs of the rover's first wheel tracks on the Martian soil. In support of the NASA-ESA Mars Sample Return , rock, regolith ( Martian soil ), and atmosphere samples are being cached by Perseverance . As of October 2023, 27 out of 43 sample tubes have been filled, including 8 igneous rock samples, 12 sedimentary rock sample tubes,
7854-747: Is published not by a local reviewer, but by a volunteer regional reviewer associated with the Geological Society of America . The geocacher usually has to perform a task which teaches an education lesson about the geology of the cache area. Visitors must answer geological questions to complete the cache which can be as simple as describing the color and thickness of layers in an outcrop or can be as complicated as taking measurements of stream velocities or fault offsets. Earthcaches covers geologic topics such as: rock formation , mineralogy , earthquakes , fluvial processes , erosion , volcanology , and planetary science (among others). Otherwise known as
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#17327731126268008-623: Is responsible for moving the soil samples to various stations within the Adaptive Caching Assembly (ACA) on the underside of the rover. These stations include volume assessment (measuring the length of sample), imaging, seal dispensing, and hermetic seal station, among others. Owing to the small space in which the SHA must operate, as well as load requirements during sealing activities, the Sample Caching System "is
8162-507: Is similar to the game letterboxing (originating in 1854), which uses clues and references to landmarks embedded in stories. Geocaching was conceived shortly after the removal of Selective Availability from the Global Positioning System on May 2, 2000 ( Blue Switch Day ), because the improved accuracy of the system allowed for a small container to be specifically placed and located. The first documented placement of
8316-425: Is the second most logged geocache in history. The second published locationless cache since 2005 (GC8NEAT) required visitors to take a photo of them picking up trash and cleaning up their local area. geocachers were able to log this cache from 6 February 2021 through 31 December 2022. It has been logged over 33,500 times and holds the title for the most "found" geocache. On 17 August 2022, Geocaching.com made available
8470-808: Is unhealthy For a more complete list, see List of GPS satellites On February 10, 1993, the National Aeronautic Association selected the GPS Team as winners of the 1992 Robert J. Collier Trophy , the US's most prestigious aviation award. This team combines researchers from the Naval Research Laboratory, the U.S. Air Force, the Aerospace Corporation , Rockwell International Corporation, and IBM Federal Systems Company. The citation honors them "for
8624-503: The Doppler effect , they could pinpoint where the satellite was along its orbit. The Director of the APL gave them access to their UNIVAC I computer to perform the heavy calculations required. Early the next year, Frank McClure, the deputy director of the APL, asked Guier and Weiffenbach to investigate the inverse problem: pinpointing the user's location, given the satellite's. (At the time,
8778-465: The GPS stash hunt or gpsstashing. This was changed shortly after the original hide when it was suggested in the gpsstash eGroup that "stash" could have negative connotations and the term geocaching was adopted. Over time, a variety of different hide-and-seek-type activities have been created or abandoned, so that "Geocaching" may now refer to hiding and seeking containers, or locations or information without containers. An independent accounting of
8932-584: The VxWorks operating system , is written in C and is able to access 4 gigabytes of NAND non-volatile memory on a separate card. Perseverance relies on three antennas for telemetry , all of which are relayed through craft currently in orbit around Mars. The primary UHF antenna can send data from the rover at a maximum rate of two megabits per second. Two slower X-band antennas provide communications redundancy. NASA considered nearly 60 proposals for rover instrumentation. On July 31, 2014, NASA announced
9086-504: The navigation equations gives the position of the receiver along with the difference between the time kept by the receiver's on-board clock and the true time-of-day, thereby eliminating the need for a more precise and possibly impractical receiver based clock. Applications for GPS such as time transfer , traffic signal timing, and synchronization of cell phone base stations , make use of this cheap and highly accurate timing. Some GPS applications use this time for display, or, other than for
9240-583: The 2001 remake of Planet of the Apes . There were 14 APE geocaches placed around the world and each one contained a prop from the film. As of 2023, only 2 APE caches are still active with one near Seattle, Washington ('Tunnel of Light', GC1169) and the other in Brazil ('Southern Bowl', GCC67). Of those two, the Brazil APE cache is the only surviving original APE cache because GC1169 was muggled in 2016. However,
9394-569: The 43 tubes are left as backups at the Three Forks Sample Depot. In July 2024, NASA’s Perseverance rover discovered “leopard spots” on a reddish rock nicknamed " Cheyava Falls " in Mars’ Jezero Crater , that has some indications it may have hosted microbial life billions of years ago, but further research is needed. NASA plans to invest roughly US$ 2.75 billion in the project over 11 years, including US$ 2.2 billion for
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#17327731126269548-541: The Crater Floor Fractured Rough to collect the first core sample there. Passing by the Octavia E. Butler landing site concludes the first science campaign. The second campaign will include several months of travel towards the "Three Forks" where Perseverance can access geologic locations at the base of the ancient delta of Neretva river, as well as ascend the delta by driving up a valley wall to
9702-524: The Earth's center) and the offset of the receiver clock relative to the GPS time are computed simultaneously, using the navigation equations to process the TOFs. The receiver's Earth-centered solution location is usually converted to latitude , longitude and height relative to an ellipsoidal Earth model. The height may then be further converted to height relative to the geoid , which is essentially mean sea level. These coordinates may be displayed, such as on
9856-664: The GPS and related systems. The executive committee is chaired jointly by the Deputy Secretaries of Defense and Transportation. Its membership includes equivalent-level officials from the Departments of State, Commerce, and Homeland Security, the Joint Chiefs of Staff and NASA . Components of the executive office of the president participate as observers to the executive committee, and the FCC chairman participates as
10010-668: The GPS service, including new signals for civil use and increased accuracy and integrity for all users, all the while maintaining compatibility with existing GPS equipment. Modernization of the satellite system has been an ongoing initiative by the U.S. Department of Defense through a series of satellite acquisitions to meet the growing needs of the military, civilians, and the commercial market. As of early 2015, high-quality Standard Positioning Service (SPS) GPS receivers provided horizontal accuracy of better than 3.5 meters (11 ft), although many factors such as receiver and antenna quality and atmospheric issues can affect this accuracy. GPS
10164-740: The Global Positioning System (GPS) its 60th Anniversary Award, nominated by IAF member, the American Institute for Aeronautics and Astronautics (AIAA). The IAF Honors and Awards Committee recognized the uniqueness of the GPS program and the exemplary role it has played in building international collaboration for the benefit of humanity. On December 6, 2018, Gladys West was inducted into the Air Force Space and Missile Pioneers Hall of Fame in recognition of her work on an extremely accurate geodetic Earth model, which
10318-637: The Martian surface, and testing oxygen production from the Martian atmosphere to prepare for future crewed missions . Despite the high-profile success of the Curiosity rover landing in August 2012, NASA's Mars Exploration Program was in a state of uncertainty in the early 2010s. Budget cuts forced NASA to pull out of a planned collaboration with the European Space Agency which included
10472-480: The Navy TRANSIT system were too slow for the high speeds of Air Force operation. The Naval Research Laboratory (NRL) continued making advances with their Timation (Time Navigation) satellites, first launched in 1967, second launched in 1969, with the third in 1974 carrying the first atomic clock into orbit and the fourth launched in 1977. Another important predecessor to GPS came from a different branch of
10626-582: The Navy was developing the submarine-launched Polaris missile, which required them to know the submarine's location.) This led them and APL to develop the TRANSIT system. In 1959, ARPA (renamed DARPA in 1972) also played a role in TRANSIT. TRANSIT was first successfully tested in 1960. It used a constellation of five satellites and could provide a navigational fix approximately once per hour. In 1967,
10780-786: The Original Stash Tribute Plaque, now sits at the site. Geocaching company Groundspeak allows extraterrestrial caches, e.g. the Moon or Mars , although presently, the website provides only earthbound coordinates. The first published extraterrestrial geocache was GC1BE91, which was placed on the International Space Station by Richard Garriott in 2008. It used the Baikonur launch area in Kazakhstan as its position. The original cache contained
10934-604: The SLBM situation. In 1960, the Air Force proposed a radio-navigation system called MOSAIC (MObile System for Accurate ICBM Control) that was essentially a 3-D LORAN System. A follow-on study, Project 57, was performed in 1963 and it was "in this study that the GPS concept was born". That same year, the concept was pursued as Project 621B, which had "many of the attributes that you now see in GPS" and promised increased accuracy for U.S. Air Force bombers as well as ICBMs. Updates from
11088-701: The Sun contain the phrase "Explore As One" written in Morse code . The plate was then mounted on the rover on March 26, 2020. Part of Perseverance ' s cargo is a geocaching trackable item viewable with the SHERLOC's WATSON camera. In 2016, NASA SHERLOC co-investigator Dr. Marc Fries — with help from his son Wyatt — was inspired by Geocaching's 2008 placement of a cache on the International Space Station to set out and try something similar with
11242-524: The TOTs, the receiver forms four time of flight (TOF) values, which are (given the speed of light) approximately equivalent to receiver-satellite ranges plus time difference between the receiver and GPS satellites multiplied by speed of light, which are called pseudo-ranges. The receiver then computes its three-dimensional position and clock deviation from the four TOFs. In practice the receiver position (in three dimensional Cartesian coordinates with origin at
11396-607: The U.S. Navy developed the Timation satellite, which proved the feasibility of placing accurate clocks in space, a technology required for GPS. In the 1970s, the ground-based OMEGA navigation system, based on phase comparison of signal transmission from pairs of stations, became the first worldwide radio navigation system. Limitations of these systems drove the need for a more universal navigation solution with greater accuracy. Although there were wide needs for accurate navigation in military and civilian sectors, almost none of those
11550-442: The U.S. Secretary of Defense, William Perry , in view of the widespread growth of differential GPS services by private industry to improve civilian accuracy. Moreover, the U.S. military was developing technologies to deny GPS service to potential adversaries on a regional basis. Selective Availability was removed from the GPS architecture beginning with GPS-III. Since its deployment, the U.S. has implemented several improvements to
11704-416: The US government announced that the next generation of GPS satellites would not include the feature at all. Advances in technology and new demands on the existing system have now led to efforts to modernize the GPS and implement the next generation of GPS Block III satellites and Next Generation Operational Control System (OCX) which was authorized by the U.S. Congress in 2000. When Selective Availability
11858-512: The United States military. In 1964, the United States Army orbited its first Sequential Collation of Range ( SECOR ) satellite used for geodetic surveying. The SECOR system included three ground-based transmitters at known locations that would send signals to the satellite transponder in orbit. A fourth ground-based station, at an undetermined position, could then use those signals to fix its location precisely. The last SECOR satellite
12012-428: The ability to read GPX files directly, thus eliminating the need for a PDA . Other methods include viewing real-time information on a portable computer with internet access or with an Internet-enabled smart phone. The latest advancement of this practice involves installing dedicated applications on a smart phone with a built-in GPS receiver. Seekers can search for and download caches in their immediate vicinity directly to
12166-403: The application and use the on-board GPS receiver to find the cache. A more controversial version of paperless Caching involves mass-downloading only the coordinates and cache names (or waypoint IDs) for hundreds of caches into older receivers. This is a common practice of some cachers and has been used successfully for years. In many cases, however, the cache description and hint are never read by
12320-439: The area, is a likely place to discover evidence of perchlorate-reducing microbes, if such bacteria are living or were formerly living on Mars. A few days after landing, Perseverance released the first audio recorded on the surface of Mars, capturing the sound of Martian wind . During its travels on Mars, NASA scientists had observed around Sol 341 (February 4, 2022) that a small rock had dropped into one of its wheels while
12474-451: The axis of the hyperboloid. The receiver is located at the point where three hyperboloids intersect. It is sometimes incorrectly said that the user location is at the intersection of three spheres. While simpler to visualize, this is the case only if the receiver has a clock synchronized with the satellite clocks (i.e., the receiver measures true ranges to the satellites rather than range differences). There are marked performance benefits to
12628-746: The basic position calculations, do not use it at all. Mars Perseverance Rover Perseverance , is a car -sized Mars rover designed to explore the Jezero crater on Mars as part of NASA 's Mars 2020 mission. It was manufactured by the Jet Propulsion Laboratory and launched on July 30, 2020, at 11:50 UTC . Confirmation that the rover successfully landed on Mars was received on February 18, 2021, at 20:55 UTC. As of 27 November 2024, Perseverance has been active on Mars for 1341 sols (1,378 Earth days , or 3 years, 9 months and 9 days) since its landing. Following
12782-648: The clocks on GPS satellites, as observed by those on Earth, run 38 microseconds faster per day than those on the Earth. The design of GPS corrects for this difference; because without doing so, GPS calculated positions would accumulate errors of up to 10 kilometers per day (6 mi/d). When the Soviet Union launched its first artificial satellite ( Sputnik 1 ) in 1957, two American physicists, William Guier and George Weiffenbach, at Johns Hopkins University 's Applied Physics Laboratory (APL) monitored its radio transmissions. Within hours they realized that, because of
12936-434: The creation of 1 set of 5 waypoints, with each of the 5 waypoints counting towards a cache find. If selected, Adventure Labs can be created using the Adventure Lab builder. Adventure Labs, unlike all other geocaches, are not subject to review and are published at will by the creator. However, Adventure Labs can at anytime be archived by Groundspeak if they are in violation of terms of use. For example, placing an Adventure Lab in
13090-690: The development and building of the hardware, US$ 243 million for launch services, and US$ 291 million for 2.5 years of mission operations. Adjusted for inflation, Perseverance is NASA's sixth-most expensive robotic planetary mission, though it is cheaper than its predecessor, Curiosity . Perseverance benefited from spare hardware and "build-to print" designs from the Curiosity mission, which helped reduce development costs and saved "probably tens of millions, if not 100 million dollars" according to Mars 2020 Deputy Chief Engineer Keith Comeaux. NASA's "Send Your Name to Mars" campaign invited people from around
13244-496: The distance from the satellite to the ground station. With the distance information collected from multiple ground stations, the location coordinates of any satellite at any time can be calculated with great precision. Each GPS satellite carries an accurate record of its own position and time, and broadcasts that data continuously. Based on data received from multiple GPS satellites , an end user's GPS receiver can calculate its own four-dimensional position in spacetime ; However, at
13398-451: The distance traveled between two position measurements drops below or near the random error of position measurement. GPS units can use measurements of the Doppler shift of the signals received to compute velocity accurately. More advanced navigation systems use additional sensors like a compass or an inertial navigation system to complement GPS. GPS requires four or more satellites to be visible for accurate navigation. The solution of
13552-440: The early history documents several controversial actions taken by Jeremy Irish and Grounded, Inc., a predecessor to Groundspeak, to increase "commercialization and monopolistic control over the hobby". More recently, other similar hobbies such as Munzee have attracted some geocachers by rapidly adopting smart-phone technology, which has caused "some resistance from geocaching organizers about placing caches along with Munzees". For
13706-407: The effect of both SA degradation and atmospheric effects (that military receivers also corrected for). The U.S. military had also developed methods to perform local GPS jamming, meaning that the ability to globally degrade the system was no longer necessary. As a result, United States President Bill Clinton signed a bill ordering that Selective Availability be disabled on May 1, 2000; and, in 2007 ,
13860-401: The finder. Aside from the logbook, common cache contents are unusual coins or currency , small toys, ornamental buttons, CDs, or books. Although not required, many geocachers decide to leave behind signature items, such as personal geocoins , pins, or craft items, to mark their presence at the cache location. Disposable cameras are popular as they allow for anyone who found the cache to take
14014-418: The following types: GPX files containing information such as a cache description and information about recent visitors to the cache are available from various listing sites. Geocachers may upload geocache data (also known as waypoints ) from various websites in various formats, most commonly in file-type GPX , which uses XML . Some websites allow geocachers to search (build queries) for multiple caches within
14168-451: The following year. Each year, eligible geocachers can opt-in to a drawing and some selected with the opportunity to submit a virtual cache for publication. From 2005 to 2017, the geocaching website no longer listed new caches without a physical container, including virtual and webcam caches (with the exception of earthcaches and events); however, older caches of these types have been grandfathered . Similar to virtual geocaches, an Earth cache
14322-551: The future. JPL built a copy of the Perseverance ; a twin rover used for testing and problem solving, OPTIMISM (Operational Perseverance Twin for Integration of Mechanisms and Instruments Sent to Mars), a vehicle system test bed (VSTB). It is housed at the JPL Mars Yard and is used to test operational procedures and to aid in problem solving should any issues arise with Perseverance . The Perseverance rover lifted off successfully on July 30, 2020, at 11:50:00 UTC aboard
14476-444: The geocacher gathers information that leads them to the next stage or to the final container. Multi-caches can consist of physical stages (i.e. the first stage contains coordinates for the next stage and so forth) or virtual stages (i.e. the first stage is a historical marker where geocachers have to answer questions to calculate the coordinates to the final physical container). Also called a 'puzzle cache', players might need to solve
14630-415: The geocaching app and on one's profile statistics tab. Since publication in 2004, it has over 20,000 finds as of June 2024. A multi-stage cache hunt that uses a Wherigo "cartridge" to guide players to find a physical cache sometime during cartridge play, usually at the end. However, not all Wherigo cartridges incorporate geocaches into gameplay. Wherigo caches are unique to the geocaching.com website. Wherigo
14784-562: The geocaching mascot, Signal the Frog, at Mega- and Giga-Events during 2020. The cache was made available to log starting 1 January 2020. However, because of the COVID-19 pandemic , nearly all planned Mega- and Giga-events were cancelled for the year, including the planned 20th anniversary celebration event in Seattle, Washington . Therefore, Groundspeak decided to extend the deadline to log this geocache through 1 January 2023. With 22,500 finds it
14938-468: The geocaching trackable code was carefully printed on a one-inch, polycarbonate glass disk serving as part of the rover's calibration target. It will serve as an optical target for the WATSON imager and a spectroscopic standard for the SHERLOC instrument. The disk is made of a prototype astronaut helmet visor material that will be tested for its potential use in crewed missions to Mars. Designs were approved by
15092-407: The highest-quality signal was reserved for military use, and the signal available for civilian use was intentionally degraded, in a policy known as Selective Availability . This changed on May 1, 2000, with U.S. President Bill Clinton signing a policy directive to turn off Selective Availability to provide the same accuracy to civilians that was afforded to the military. The directive was proposed by
15246-453: The important materials for this. Typically, letterbox hybrid caches are not found at the given coordinates which only act as a starting location. Instead, a series of clues are given as to where to find the cache such as "take a left past the bridge" or "about 25 paces past the big oak tree". Also known as Ape caches , these are a special type of traditional cache that were hidden in conjunction with 20th Century Fox and Groundspeak to promote
15400-441: The logbook and online, but then must return the cache to the same coordinates so that other geocachers may find it. Geocachers are free to take objects (except the logbook, pencil, or stamp) from the cache in exchange for leaving something of similar or higher value. Typical cache "treasures", also known in the geocaching world as SWAG (a backronym of "stuff we all get"), are not high in monetary value but may hold personal value to
15554-568: The loss of a rotor blade (imaged, by Perseverance , lying on the sand roughly 15 m (49 ft) distant from the upright body of Ingenuity ), causing NASA to retire it. Associate Administrator of NASA 's Science Mission Directorate, Thomas Zurbuchen selected the name Perseverance following a nationwide K-12 student "name the rover" contest that attracted more than 28,000 proposals. A seventh-grade student, Alexander Mather from Lake Braddock Secondary School in Burke, Virginia , submitted
15708-459: The mission leads at NASA's Jet Propulsion Laboratory (JPL), NASA Public Affairs, and NASA HQ, in addition to Groundspeak Geocaching HQ. Perseverance launched during the COVID-19 pandemic , which began to affect the mission planning in March 2020. To show appreciation for healthcare workers who helped during the pandemic, an 8 cm × 13 cm (3.1 in × 5.1 in) plate with
15862-430: The most complicated, most sophisticated mechanism that we have ever built, tested and readied for spaceflight." The combination of larger instruments, new sampling and caching system, and modified wheels makes Perseverance heavier, weighing 1,025 kg (2,260 lb) compared to Curiosity at 899 kg (1,982 lb)—a 14% increase. The rover's multi-mission radioisotope thermoelectric generator ( MMRTG ) has
16016-543: The most significant development for safe and efficient navigation and surveillance of air and spacecraft since the introduction of radio navigation 50 years ago". Two GPS developers received the National Academy of Engineering Charles Stark Draper Prize for 2003: GPS developer Roger L. Easton received the National Medal of Technology on February 13, 2006. Francis X. Kane (Col. USAF, ret.)
16170-491: The need of physically checking all of one's previous finds. These geocheckers can be requested using the ProjectGC forums where volunteers can write and create scripts for specific challenges. Groundspeak also has been more strict into what types of challenges are published. For example, prior to 2017 it was possible to create a challenge cache to find 10 caches that have a food item in the title. Under current guidelines, this
16324-440: The new measurements are collected, the receiver uses a weighting scheme to combine the new measurements with the tracker prediction. In general, a tracker can (a) improve receiver position and time accuracy, (b) reject bad measurements, and (c) estimate receiver speed and direction. The disadvantage of a tracker is that changes in speed or direction can be computed only with a delay, and that derived direction becomes inaccurate when
16478-458: The northwest. The Perseverance design evolved from its predecessor, the Curiosity rover . The two rovers share a similar body plan, landing system, cruise stage, and power system, but the design was improved in several ways for Perseverance . Engineers designed the rover wheels to be more robust than Curiosity 's wheels, which had sustained some damage . Perseverance has thicker, more durable aluminum wheels, with reduced width and
16632-487: The nuclear triad, also had requirements for a more accurate and reliable navigation system. The U.S. Navy and U.S. Air Force were developing their own technologies in parallel to solve what was essentially the same problem. To increase the survivability of ICBMs, there was a proposal to use mobile launch platforms (comparable to the Soviet SS-24 and SS-25 ) and so the need to fix the launch position had similarity to
16786-488: The occasion, Groundspeak allowed specialized geocaching events to be published across the world, allowing attendees to obtain a virtual souvenir on their profile. The second geocaching trackable in space is TB5EFXK which is attached to the SHERLOC calibration target on board the Mars Perseverance Rover , which landed on Mars on 18 February 2021. Geocachers were given the opportunity to virtually discover
16940-477: The original container was later found by a Groundspeak led survey in April of that year. What remains of "Tunnel of Light" is an "official" replacement of the original ammo can that was left in 2001. This cache type does not contain a physical logbook. They are normally hidden at a rather interesting or unique location, usually with a described object such as an art sculpture or a scenic lookout. Validation for finding
17094-524: The precision needed for GPS. The design of GPS is based partly on similar ground-based radio-navigation systems, such as LORAN and the Decca Navigator System , developed in the early 1940s. In 1955, Friedwardt Winterberg proposed a test of general relativity —detecting time slowing in a strong gravitational field using accurate atomic clocks placed in orbit inside artificial satellites. Special and general relativity predicted that
17248-431: The question to move on to the next waypoint. Many Adventure Labs caches have a physical bonus cache associated with them that are listed as a "mystery cache". Coordinates to the bonus cache, if applicable, can be seen in the journal entries once a user has correctly answered the question at a waypoint. Geocachers can create their own Adventure Lab, but must first opt-in to receive an "Adventure Lab credit" which allows for
17402-652: The reason for the ultra-secrecy at that time. The nuclear triad consisted of the United States Navy's submarine-launched ballistic missiles (SLBMs) along with United States Air Force (USAF) strategic bombers and intercontinental ballistic missiles (ICBMs). Considered vital to the nuclear deterrence posture, accurate determination of the SLBM launch position was a force multiplier . Precise navigation would enable United States ballistic missile submarines to get an accurate fix of their positions before they launched their SLBMs. The USAF, with two thirds of
17556-408: The reference atomic clocks at the ground control stations; any drift of the clocks aboard the satellites from the reference time maintained on the ground stations is corrected regularly. Since the speed of radio waves ( speed of light ) is constant and independent of the satellite speed, the time delay between when the satellite transmits a signal and the ground station receives it is proportional to
17710-420: The rover mission. After floating the idea around mission management, it eventually reached NASA scientist Francis McCubbin, who would join the SHERLOC instrument team as a collaborator to move the project forward. The Geocaching inclusion was scaled-down to a trackable item that players could search for from NASA camera views and then log on to the site. In a manner similar to the "Send Your Name to Mars" campaign,
17864-462: The rover picked up another pet rock named "Dwayne". It is planned for Perseverance to visit the bottom and upper parts of the 3.4 to 3.8 billion-year-old Neretva Vallis delta, the smooth and etched parts of the Jezero Crater floor deposits interpreted as volcanic ash or aeolian airfall deposits, emplaced before the formation of the delta; the ancient shoreline covered with Transverse Aeolian Ridges (dunes) and mass wasting deposits, and finally, it
18018-481: The rover was studying the Máaz rock formation. The rock was visible from one of the hazard avoidance cameras, and was determined not to be harmful to the rover's mission. The rock has since stayed on Perseverance ' s wheel for around 427 sols (439 days) as the rover traveled over 6 miles (9.7 km) on the martian surface. NASA deemed that Perseverance had adopted a pet rock for its journey. Later, by May 2024,
18172-627: The rover's activities, and must be recharged periodically. Unlike solar panels , the MMRTG provides engineers with significant flexibility in operating the rover's instruments even at night, during dust storms , and through winter. The rover's computer uses the BAE Systems RAD750 radiation-hardened single board computer based on a ruggedized PowerPC G3 microprocessor (PowerPC 750) . The computer contains 128 megabytes of volatile DRAM , and runs at 133 MHz. The flight software runs on
18326-849: The rover's arrival, NASA named the landing site Octavia E. Butler Landing . Perseverance has a similar design to its predecessor rover, Curiosity , although it was moderately upgraded. It carries seven primary payload instruments, nineteen cameras, and two microphones. The rover also carried the mini-helicopter Ingenuity to Mars, an experimental technology testbed that made the first powered aircraft flight on another planet on April 19, 2021. On January 18, 2024 (UTC), it made its 72nd and final flight , suffering damage on landing to its rotor blades, possibly all four, causing NASA to retire it. The rover's goals include identifying ancient Martian environments capable of supporting life, seeking out evidence of former microbial life existing in those environments, collecting rock and soil samples to store on
18480-512: The rules of most geocache listing sites. Food is also disallowed, even if sealed, as it is considered unhygienic and can attract animals. If a geocache has been vandalized or stolen by a person who is not familiar with geocaching, it is said to have been "muggled". The term plays off the fact that those not familiar with geocaching are called " muggles ", a word borrowed from the Harry Potter series of books which were rising in popularity at
18634-496: The same hider, before finding the bonus cache. The cache can be any type, however a bonus cache cannot be required for a second bonus cache. These were found at a listed set of coordinates. The finder hides the cache in a different location, and updates the listing, essentially becoming the hider, and the next finder continues the cycle. This cache has been discontinued at geocaching.com and those that have been grandfathered in are solely declining and are being archived. Also known as
18788-544: The same time geocaching started. Geocaches vary in size, difficulty, and location. Simple caches that are placed near a roadside are often called "drive-bys", "park 'n grabs" (PNGs), or "cache and dash". Geocaches may also be complex, involving lengthy searches, significant travel, or use of specialist equipment such as SCUBA diving , kayaking , or abseiling . Different geocaching websites list different variations per their own policies. Container sizes range from nano , particularly magnetic nanos , which can be smaller than
18942-517: The seeker before hunting the cache. This means they are unaware of potential restrictions such as limited hunt times, park open/close times, off-limit areas, and suggested parking locations. The website geocaching.com now sells mobile applications which allow users to view caches through a variety of different devices. Currently, the Android , iOS , and Windows Phone mobile platforms have applications in their respective stores. The apps also allow for
19096-463: The seven instruments that would make up the payload for the rover: There are additional cameras and two audio microphones (the first working microphones on Mars), that will be used for engineering support during landing, driving, and collecting samples. For a full look at Perseverance ' s components see Learn About the Rover . The Ingenuity helicopter, powered by solar-charged batteries,
19250-458: The southeast, with the RTG on the back of the vehicle pointing northwest. The descent stage (" sky crane "), parachute and heat shield all came to rest within 1.5 km of the rover (see satellite image). Having come within sixteen feet (~5 meters) of its target, the landing was more accurate than any previous Mars landing; a feat enabled by the experience gained from Curiosity ' s landing and
19404-520: The spirit and insight to explore the Moon, Mars, and beyond. But, if rovers are to be the qualities of us as a race, we missed the most important thing. Perseverance. We as humans evolved as creatures who could learn to adapt to any situation, no matter how harsh. We are a species of explorers, and we will meet many setbacks on the way to Mars. However, we can persevere. We, not as a nation but as humans, will not give up. The human race will always persevere into
19558-557: The success of the Curiosity rover and in response to the recommendations of the decadal survey, NASA announced its intent to launch a new Mars rover mission by 2020 at the American Geophysical Union conference in December 2012. Though initially hesitant to commit to an ambitious sample-caching capability (and subsequent follow-on missions), a NASA-convened science definition team for the Mars 2020 project released
19712-416: The third locationless cache to be logged since 2005 (GC9FAVE). Instead of finding Signal or picking up trash, this cache encouraged geocachers from around the world to share their favorite geocaching story. This geocache was archived and locked on 1 January 2024. A type of virtual cache whose coordinates provide the location to a public webcam . The finder is required to capture an image of themselves through
19866-805: The tip of a finger and have only enough room to store the log sheet, to 20-liter (5 gallon) buckets or even larger containers, such as entire trucks. The most common cache containers in rural areas are lunch-box-sized plastic storage containers or surplus military ammunition cans. Ammo cans are considered the gold standard of containers because they are very sturdy, waterproof, animal- and fire-resistant, and relatively cheap, and have plenty of room for trade items. Smaller containers are more common in urban areas because they can be more easily hidden. Over time many variations of geocaches have developed. Different platforms often have their own rules on which types are allowed or how they are classified. The following cache types are supported by geocaching.com. The simplest form of
20020-427: The top priority of NASA's planetary exploration program in the decade between 2013 and 2022 should be to begin a NASA-ESA Mars Sample Return campaign, a four-mission project to cache, retrieve, launch, and safely return samples of the Martian surface to Earth. The report stated that NASA should invest in a sample-caching rover as the first step in this effort, with the goal of keeping costs under US$ 2.5 billion. After
20174-419: The trackable after the WATSON camera sent back its first photographs of the calibration target that contained the tracking code number. The code is printed on a prototype helmet visor material that will be used to test how well it can withstand the Martian environment. This will help scientists in creating a viable Martian spacesuit for future crewed missions to Mars . The activity was originally referred to as
20328-489: The traditional geocache, a geocacher will place a waterproof container containing a log book, often also a pen and/or pencil and trade items or trackables , then record the cache's coordinates . These coordinates, along with other details of the location, are posted on a listing site (see list of some sites below). Other geocachers obtain the coordinates from that listing site and seek out the cache using their handheld GPS receivers. The finding geocachers record their exploits in
20482-404: The trend of automobile window decals used to show a family's makeup. The orange-and-white parachute used to land the rover on Mars contained a coded message that was deciphered by Twitter users. NASA's systems engineer Ian Clark used binary code to hide the message "dare mighty things" in the parachute color pattern. The 70-foot-wide (21 m) parachute consisted of 80 strips of fabric that form
20636-581: The use of new steering technology. One such new technology is Terrain Relative Navigation (TRN), a technique in which the rover compares images of the surface taken during its descent with reference maps, allowing it to make last minute adjustments to its course. The rover also uses the images to select a safe landing site at the last minute, allowing it to land in relatively unhazardous terrain. This enables it to land much closer to its science objectives than previous missions, which all had to use
20790-404: The usefulness of the GPS positioning information. It provides critical positioning capabilities to military, civil, and commercial users around the world. Although the United States government created, controls, and maintains the GPS system, it is freely accessible to anyone with a GPS receiver. The GPS project was started by the U.S. Department of Defense in 1973. The first prototype spacecraft
20944-403: The user carrying a clock synchronized with the satellites. Foremost is that only three satellites are needed to compute a position solution. If it were an essential part of the GPS concept that all users needed to carry a synchronized clock, a smaller number of satellites could be deployed, but the cost and complexity of the user equipment would increase. The description above is representative of
21098-403: The webcam for verification of the find. New webcam caches are no longer allowed by Groundspeak as it is a legacy cache. Webcam caches are a category at Waymarking.com. A type of virtual cache that typically consists of a set of 5 waypoints, with each waypoint counting as a "cache find". The waypoints usually have an overall theme such showcasing the history of a small town and are often created as
21252-507: The winning entry at the Jet Propulsion Laboratory . In addition to the honor of naming the rover, Mather and his family were invited to NASA's Kennedy Space Center to watch the rover's July 2020 launch from Cape Canaveral Air Force Station (CCAFS) in Florida . Mather wrote in his winning essay: Curiosity . InSight . Spirit . Opportunity . If you think about it, all of these names of past Mars rovers are qualities we possess as humans. We are always curious, and seek opportunity. We have
21406-422: The world to submit their names to travel aboard the agency's next rover to Mars. 10,932,295 names were submitted. The names were etched by an electron beam onto three fingernail-sized silicon chips, along with the essays of the 155 finalists in NASA's "Name the Rover" contest. The three chips share space on an anodized plate with a laser engraved graphic representing Earth, Mars, and the Sun. The rays emanating from
21560-408: Was a black plastic bucket that was partially buried and contained various items, such as software, videos, books, money, a can of beans , and a slingshot . The geocache and most of its contents were eventually destroyed by a lawn mower , but the can of beans was the only item salvaged and was later turned into a trackable item known as the "Original Can of Beans". Another geocache and plaque, called
21714-579: Was allowed from the 1980s. Roger L. Easton of the Naval Research Laboratory , Ivan A. Getting of The Aerospace Corporation , and Bradford Parkinson of the Applied Physics Laboratory are credited with inventing it. The work of Gladys West on the creation of the mathematical geodetic Earth model is credited as instrumental in the development of computational techniques for detecting satellite positions with
21868-436: Was announced at 20:55 UTC on February 18, 2021, the signal from Mars taking 11 minutes to arrive at Earth. The rover touched down at 18°26′41″N 77°27′03″E / 18.4446°N 77.4509°E / 18.4446; 77.4509 , roughly 1 km (0.62 mi) southeast of the center of its 7.7 km × 6.6 km (4.8 mi × 4.1 mi) wide landing ellipse. It came down pointed almost directly to
22022-420: Was concerned with the curving of the paths of radio waves ( atmospheric refraction ) traversing the ionosphere from NavSTAR satellites. After Korean Air Lines Flight 007 , a Boeing 747 carrying 269 people, was shot down by a Soviet interceptor aircraft after straying in prohibited airspace because of navigational errors, in the vicinity of Sakhalin and Moneron Islands , President Ronald Reagan issued
22176-490: Was destroyed in a launch failure). The effect of the ionosphere on radio transmission was investigated in a geophysics laboratory of Air Force Cambridge Research Laboratory , renamed to Air Force Geophysical Research Lab (AFGRL) in 1974. AFGRL developed the Klobuchar model for computing ionospheric corrections to GPS location. Of note is work done by Australian space scientist Elizabeth Essex-Cohen at AFGRL in 1974. She
22330-703: Was discontinued, GPS was accurate to about 5 meters (16 ft). GPS receivers that use the L5 band have much higher accuracy of 30 centimeters (12 in), while those for high-end applications such as engineering and land surveying are accurate to within 2 cm ( 3 ⁄ 4 in) and can even provide sub-millimeter accuracy with long-term measurements. Consumer devices such as smartphones can be accurate to 4.9 m (16 ft) or better when used with assistive services like Wi-Fi positioning . As of July 2023 , 18 GPS satellites broadcast L5 signals, which are considered pre-operational prior to being broadcast by
22484-625: Was inducted into the U.S. Air Force Space and Missile Pioneers Hall of Fame at Lackland A.F.B., San Antonio, Texas, March 2, 2010, for his role in space technology development and the engineering design concept of GPS conducted as part of Project 621B. In 1998, GPS technology was inducted into the Space Foundation Space Technology Hall of Fame . On October 4, 2011, the International Astronautical Federation (IAF) awarded
22638-626: Was launched in 1969. With these parallel developments in the 1960s, it was realized that a superior system could be developed by synthesizing the best technologies from 621B, Transit, Timation, and SECOR in a multi-service program. Satellite orbital position errors, induced by variations in the gravity field and radar refraction among others, had to be resolved. A team led by Harold L. Jury of Pan Am Aerospace Division in Florida from 1970 to 1973, used real-time data assimilation and recursive estimation to do so, reducing systematic and residual errors to
22792-453: Was launched in 1978 and the full constellation of 24 satellites became operational in 1993. After Korean Air Lines Flight 007 was shot down when it mistakenly entered Soviet airspace, President Ronald Reagan announced that the GPS system would be made available for civilian use as of September 16, 1983; however, initially this civilian use was limited to an average accuracy of 100 meters (330 ft) by use of Selective Availability (SA),
22946-549: Was never considered as such by the GPS Joint Program Office (TRW may have once advocated for a different navigational system that used that acronym). With the individual satellites being associated with the name Navstar (as with the predecessors Transit and Timation), a more fully encompassing name was used to identify the constellation of Navstar satellites, Navstar-GPS . Ten " Block I " prototype satellites were launched between 1978 and 1985 (an additional unit
23100-588: Was photographed by the HiRISE high-resolution camera on the Mars Reconnaissance Orbiter (MRO). Jezero Crater is a paleolake basin. It was selected as the landing site for this mission in part because paleolake basins tend to contain perchlorates . Astrobiologist Dr. Kennda Lynch's work in analog environments on Earth suggests that the composition of the crater, including the bottomset deposits accumulated from three different sources in
23254-530: Was seen as justification for the billions of dollars it would cost in research, development, deployment, and operation of a constellation of navigation satellites. During the Cold War arms race , the nuclear threat to the existence of the United States was the one need that did justify this cost in the view of the United States Congress. This deterrent effect is why GPS was funded. It is also
23408-419: Was sent to Mars in the same bundle with Perseverance . With a mass of 1.8 kg (4.0 lb), the helicopter demonstrated the reality of flight in the rarefied Martian atmosphere and the potential usefulness of aerial scouting for rover missions. It carried two cameras but no scientific instruments and communicated with Earth via a base station onboard Perseverance . Its pre-launch experimental test plan
23562-495: Was three flights in 45 days, but it far exceeded expectations and made 72 flights in nearly three years. After its first few flights, it made incrementally more ambitious ones, several of which were recorded by Perseverance ' s cameras. The first flight was April 19, 2021, at 07:15 UTC, with confirmation from data reception at 10:15 UTC. It was the first powered flight by any aircraft on another planet. On January 18, 2024 (UTC), it made its 72nd and final flight , suffering
23716-529: Was ultimately used to determine the orbit of the GPS constellation. On February 12, 2019, four founding members of the project were awarded the Queen Elizabeth Prize for Engineering with the chair of the awarding board stating: "Engineering is the foundation of civilisation; ...They've re-written, in a major way, the infrastructure of our world." The GPS satellites carry very stable atomic clocks that are synchronized with one another and with
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