{"id":12275,"date":"2020-08-13T22:46:45","date_gmt":"2020-08-13T14:46:45","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/nasa-asteroid-explorer-aces-final-rehearsal-before-sampling-run\/"},"modified":"2020-08-13T22:46:45","modified_gmt":"2020-08-13T14:46:45","slug":"nasa-asteroid-explorer-aces-final-rehearsal-before-sampling-run","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/nasa-asteroid-explorer-aces-final-rehearsal-before-sampling-run\/","title":{"rendered":"NASA asteroid explorer aces final rehearsal before sampling run"},"content":{"rendered":"<p><iframe loading=\"lazy\" src=\"https:\/\/www.youtube.com\/embed\/Ak1qjV3YbWY\" width=\"678\" height=\"381\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><span data-mce-type=\"bookmark\" style=\"display: inline-block; width: 0px; overflow: hidden; line-height: 0;\" class=\"mce_SELRES_start\">\ufeff<\/span><\/iframe><\/p>\n<p>NASA\u2019s OSIRIS-REx spacecraft moved within about 131 feet, or 40 meters, of asteroid Bennu this week in the $1 billion mission\u2019s final practice run before a touch-and-go landing on the asteroid in October to collect samples for return to Earth.<\/p>\n<p>During the sampling rehearsal Tuesday, engineers monitoring the spacecraft\u2019s maneuvers from Earth confirmed that navigation algorithms, software for autonomous operations, science instruments, and numerous mechanical systems all functioned as expected.<\/p>\n<p>On Tuesday, the OSIRIS-REx spacecraft fired thrusters to leave a \u201csafe-home orbit\u201d roughly 0.6 miles (1 kilometer) from asteroid Bennu, then descended to a point around 410 feet (125 meters) above the asteroid\u2019s surface. The spacecraft then fired thrusters to perform a so-called \u201ccheckpoint\u201d burn to begin a free fall toward the asteroid.<\/p>\n<p>Eight minutes later, OSIRIS-REx pulsed its control jets again for a \u201cmatchpoint\u201d burn to match the spacecraft\u2019s movement with the asteroid\u2019s rotation. That allows the spacecraft to make its final descent to the surface over the targeted sampling location.<\/p>\n<p>The spacecraft continued descending toward the asteroid for three minutes after the matchpoint burn, reaching a point 131 feet from Bennu before firing thrusters again for a back-away maneuver.<\/p>\n<p>The position OSIRIS-REx reached during Tuesday\u2019s rehearsal marked the closest the spacecraft has come to asteroid Bennu, following a similar sampling exercise in April that practiced the mission\u2019s descent maneuvers up to a point 213 feet, or 65 meters, from the asteroid.<\/p>\n<p>After launching from Earth in 2016 and arriving at its asteroid target in 2018, NASA\u2019s&nbsp;Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer, or OSIRIS-REx, spacecraft has been mapping Bennu with cameras, mineral-sniffing spectrometers and a Canadian-built laser to measure its roughness.<\/p>\n<p>Shaped like a spinning top, Bennu measures around 1,614 feet (492 meters) wide. At the time of Tuesday\u2019s rehearsal, the asteroid was located about 179 million miles (288 million kilometers) from Earth. At that distance, it takes 16 minutes for commands from ground teams to reach the OSIRIS-REx spacecraft.<\/p>\n<p>\u201cThis time lag prevented live commanding of flight activities from the ground during the rehearsal,\u201d NASA said in a statement. \u201cAs a result, the spacecraft performed the entire rehearsal sequence autonomously.\u201d<\/p>\n<p>Ground controllers uplinked the descent sequence to the spacecraft ahead of time, and OSIRIS-REx flew the descent profile on autopilot, just as it will on the actual sampling attempt.<\/p>\n<p>OSIRIS-REx has been scouting sites for its sample collection run, but scientists discovered Bennu is more rugged than expected.<\/p>\n<p>The spacecraft\u2019s sampling rehearsal Tuesday targeted a location dubbed Nightingale, the mission\u2019s primary sample collection site located within&nbsp;a 460-foot (140-meter) crater in Bennu\u2019s northern hemisphere. The site is surrounded by boulders and sharp terrain, and that forced engineers to develop&nbsp;upgraded navigation capabilities to allow the spacecraft to guide itself to a safe touch-and-go landing.<\/p>\n<p>OSIRIS-REx uses a capability called natural feature tracking to take a series of images with a navigation camera to autonomously identify rocks, craters and other markings on the asteroid\u2019s surface, yielding data on position and relative velocity. The spacecraft\u2019s computer compares the imagery with a map of hazards loaded into the computer before the descent. If OSIRIS-REx detects it is approaching a dangerous area, it can command an abort and back away from Bennu.<\/p>\n<p>The natural feature tracking algorithms were successfully tested during Tuesday\u2019s rehearsal. The spacecraft\u2019s cameras captured higher-resolution views of the Nightingale sampling location when OSIRIS-REx was flying directly over the site, allowing ground teams to update and refine the natural feature tracking capability before the real sampling attempt in October.<\/p>\n<p>\u201cMany important systems were exercised during this rehearsal \u2014 from communications, spacecraft thrusters, and most importantly, the on-board natural feature tracking guidance system and hazard map,\u201d Dante Lauretta, OSIRIS-REx\u2019s principal investigator from the University of Arizona, Tucson. \u201cNow that we\u2019ve completed this milestone, we are confident in finalizing the procedures for the TAG (Touch-And-Go) event. This rehearsal confirmed that the team and all of the spacecraft\u2019s systems are ready to collect a sample in October.\u201d<\/p>\n<p>OSIRIS-REx also extended its sample collection arm, known as TAGSAM, during Tuesday\u2019s rehearsal. The spacecraft also moved&nbsp;its two solar array wings to a \u201cY-wing\u201d configuration to safely position them away from the asteroid\u2019s surface, just as they will be positioned during the touch-and-go landing.<\/p>\n<figure id=\"attachment_46947\" aria-describedby=\"caption-attachment-46947\" style=\"width: 985px\" class=\"wp-caption alignnone\"><img fetchpriority=\"high\" decoding=\"async\" class=\"size-full wp-image-46947\" src=\"http:\/\/spaceflightnow.com\/wp-content\/uploads\/2020\/08\/updatedtagpose.jpg\" alt=\"\" width=\"985\" height=\"501\" srcset=\"https:\/\/spaceflightnow.com\/wp-content\/uploads\/2020\/08\/updatedtagpose.jpg 985w, https:\/\/spaceflightnow.com\/wp-content\/uploads\/2020\/08\/updatedtagpose-300x153.jpg 300w, https:\/\/spaceflightnow.com\/wp-content\/uploads\/2020\/08\/updatedtagpose-768x391.jpg 768w, https:\/\/spaceflightnow.com\/wp-content\/uploads\/2020\/08\/updatedtagpose-678x345.jpg 678w\" sizes=\"(max-width: 985px) 100vw, 985px\"><figcaption id=\"caption-attachment-46947\" class=\"wp-caption-text\">This illustration shows NASA\u2019s OSIRIS-REx spacecraft descending towards asteroid Bennu to collect a sample of the asteroid\u2019s surface. Credit: NASA\/Goddard\/University of Arizona<\/figcaption><\/figure>\n<p>The TAGSAM arm was later retracted back to a stowed position after OSIRIS-REx began flying away from Bennu at the conclusion of the rehearsal Tuesday.<\/p>\n<p>During the mission\u2019s real sampling run, a device mounted on the end of the spacecraft\u2019s TAGSAM arm will contact the asteroid surface for several seconds and fire compressed nitrogen gas. The gas cartridge will disrupt the rock at the sampling site, and the spacecraft will capture some of the material in a chamber for return to Earth.<\/p>\n<p>Scientists hope to gather&nbsp;at least 2.1 ounces (60 grams) of pristine samples from Bennu\u2019s surface, and return the material to Earth in September 2023 for analysis in sophisticated laboratories. Scientists will examine the specimens to search&nbsp;for signs of organic matter and other chemicals critical to the origin of life.<\/p>\n<p>Built and operated by Lockheed Martin, the OSIRIS-REx spacecraft launched from Cape Canaveral in September 2016. A limited number of personnel managed Tuesday\u2019s checkpoint rehearsal from a Lockheed Martin control center in Colorado, plus sites at the Goddard Space Flight Center in Maryland and the University of Arizona.<\/p>\n<p>Other team members participated remotely due to the coronavirus pandemic, NASA said.<\/p>\n<p>Earlier this year, mission managers decided to give teams more time to prepare for OSIRIS-REx\u2019s sampling attempt as officials adjusted to new operations schemes to minimize risks from COVID-19.<\/p>\n<p>That decision delayed OSIRIS-REx\u2019s second sampling rehearsal from June 23 to Aug. 11, and pushed back the actual sampling run from Aug. 25 to Oct. 20.<\/p>\n<p>If the first sampling attempt turns up empty in October, scientists have penciled in opportunities for additional tries before the spacecraft departs Bennu next year&nbsp;to begin the return trip to Earth.<\/p>\n<p><b><i>Email the author.<\/i><\/b><\/p>\n<p><em><strong>Follow Stephen Clark on Twitter: @StephenClark1.<\/strong><\/em><\/p>\n","protected":false},"excerpt":{"rendered":"<p>\ufeff NASA\u2019s OSIRIS-REx spacecraft moved within about 131 feet, or 40 meters, of asteroid Bennu this week in the $1 billion mission\u2019s final practice run before a touch-and-go landing on the asteroid in October to collect samples for return to Earth. During the sampling rehearsal Tuesday, engineers monitoring the spacecraft\u2019s maneuvers from Earth confirmed that [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[2],"tags":[1519,1526,1790,472,190,2020,1527,1561],"class_list":["post-12275","post","type-post","status-publish","format-standard","hentry","category-news","tag-asteroids","tag-bennu","tag-goddard-space-flight-center","tag-lockheed-martin","tag-nasa","tag-new-frontiers","tag-osiris-rex","tag-planetary-science"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/12275"}],"collection":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/comments?post=12275"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/12275\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=12275"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=12275"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=12275"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}