{"id":15395,"date":"2016-07-04T23:12:50","date_gmt":"2016-07-04T15:12:50","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/scientists-on-edge-awaiting-junos-perilous-encounter-with-jupiter\/"},"modified":"2016-07-04T23:12:50","modified_gmt":"2016-07-04T15:12:50","slug":"scientists-on-edge-awaiting-junos-perilous-encounter-with-jupiter","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/scientists-on-edge-awaiting-junos-perilous-encounter-with-jupiter\/","title":{"rendered":"Scientists on edge awaiting Juno\u2019s perilous encounter with Jupiter"},"content":{"rendered":"
\"Credit:
This artist\u2019s concept shows Juno\u2019s approach path toward Jupiter for the July 4 insertion maneuver. Jupiter\u2019s intense radiation belts are also illustrated here. Credit: NASA\/JPL-Caltech<\/figcaption><\/figure>\n

Speeding toward Jupiter at nearly 40 miles per second, NASA\u2019s Juno spacecraft must brave a field of computer-zapping radiation and Jupiter\u2019s tenuous ring of ice and dust particles when it brakes into orbit around the planet Monday and zooms just 2,900 miles from the world\u2019s turbulent cloud tops.<\/p>\n

That may sound far, but it is 10 times closer than any previous mission, other than probes doomed to destruction sent into the atmosphere.<\/p>\n

The perils give pause to scientists and engineers working on the $1.1 billion mission, but officials said they did everything possible to equip Juno for the dangers of Jupiter and were cautiously optimistic the probe would complete a one-shot orbit insertion maneuver unscathed.<\/p>\n

\u201cJuno is going to go into the scariest part of the scariest place that we know about,\u201d said Heidi Becker, a physicist at NASA\u2019s Jet Propulsion Laboratory in Pasadena, California.<\/p>\n

Radiation belts surround Jupiter\u2019s equator, where the planet\u2019s strong magnetic field traps high-energy particles and accelerate them to nearly light-speed, posing a hazard to Juno unparalleled to any environment ever directly explored by a human-built spacecraft.<\/p>\n

\u201cJupiter\u2019s magnetic field has accelerated them to the point where they will go right through a spacecraft and strip the atoms apart inside your electronics and fry your brain if you don\u2019t do anything about it, so we did a lot about it,\u201d Becker said.<\/p>\n

The most critical electronic components aboard Juno are housed inside a vault with walls of pure titanium a third of an inch (1 centimeter) thick. Engineers expect the protective box, which measures about the size of an SUV\u2019s trunk, will block most of the dangerous particles from penetrating into Juno\u2019s sensitive computers and triggering a reset, or worse.<\/p>\n

\u201cIt\u2019s where we protect our valuables,\u201d said Rick Nybakken, Juno\u2019s project manager at JPL.<\/p>\n

Jupiter\u2019s magnetosphere, a bubble around the planet under the influence of its magnetic field, extends out 10 times farther than the magnetosphere around Earth. Juno crossed the magnetosphere\u2019s bow shock, a boundary between interplanetary space where the solar wind is dominant and Jupiter\u2019s magnetic field, about 10 days ago as it zoomed toward its rendezvous with the planet.<\/p>\n

If Jupiter\u2019s magnetosphere was visible in the night sky from Earth, it would appear as big as the moon, scientists said.<\/p>\n

Juno\u2019s three huge rectangular solar panels, arranged in a triangle configuration like an airplane\u2019s propeller, stretch 30 feet (9 meters) long and contain 18,698 solar cells to generate electricity. At Jupiter\u2019s distance a half-billion miles from the sun, where the cells receive about 4 percent of the solar energy as they did at Earth, the wings produce a mere 500 watts, equivalent to around five household light bulbs.<\/p>\n

The solar panels are also sensitive to radiation, so engineers added extra-thick cover glass to the each cell. Juno already set the record for the farthest solar-powered spacecraft from the sun.<\/p>\n

The trajectory Juno will follow Monday is clear of the worst of Jupiter\u2019s radiation, but the craft will still be exposed to doses many times worse than the radiation belts around Earth.<\/p>\n

Juno is targeting a section of space near Jupiter that may harbor scattered particles of ice and dust from the gas giant\u2019s narrow ring system, according to Scott Bolton, the mission\u2019s principal investigator from the Southwest Research Institute in San Antonio.<\/p>\n

Discovered in 1979 by NASA\u2019s Voyager 1 flyby probe, the rings of Jupiter contain flakes of ice and dust \u2014 tiny frozen moonlets \u2014 deposited around the planet by meteoroid impacts on Jupiter\u2019s larger moons.<\/p>\n

\"This
This image of Jupiter\u2019s rings came from NASA\u2019s Galileo mission, which became the first spacecraft to orbit the planet. Galileo explored Jupiter and its moons from 1995 through 2003. Credit: NASA, JPL, Galileo Project, (NOAO), J. Burns (Cornell) et al.<\/figcaption><\/figure>\n

\u201cTheres a vertical excent of these rings that isn\u2019t very well known,\u201d Bolton said Monday. \u201cJuno has to pass through these rings. We do not know how close to the planet they actually go, and if it gets hit even by a small piece of dust, it can do very serious damage.\u201d<\/p>\n

Juno\u2019s Leros 1b main engine is supposed to ignite for 35 minutes Monday to put the spacecraft into an elliptical 53.5-day orbit around Jupiter. Engineers said the engine must fire for at least 20 minutes to achieve any safe orbit, or Juno will cruise past Jupiter and the mission will be lost.<\/p>\n

Ground controllers sent commands for Juno to open an engine cover June 20 in advance of Monday\u2019s firing, and the celestial mechanics of the burn require the engine nozzle to point ahead of the spacecraft directly into any potential incoming debris at a speed of 130,000 mph (209,000 kilometers per hour), relative to Jupiter.<\/p>\n

\u201cThe nozzle is open and vulnerable,\u201d Bolton said. \u201cWe\u2019re flying through faster than any object has ever gone with the nozzle facing forward. If any dust is in our way and hits that nozzle, it will knock a hole right through the coating that protects the nozzle and allows the engine to burn uninterrupted. So that\u2019s one of the big gambles.<\/p>\n

\u201cWe\u2019ve done everything we can,\u201d Bolton told reporters Monday. \u201cWe\u2019ve protected everything as best we can. We\u2019ve modeled it, but we\u2019re going into unknown territory, so we\u2019ve got the radiation and we\u2019ve got this dust and meteorite scare. That\u2019s part of what we\u2019re facing, but we\u2019re built like an armored tank.\u201d<\/p>\n

A microscopic dust grain as small as 10 microns \u2014 about the size of a water droplet in a cloud \u2014 could cause damage at Juno\u2019s velocity, Bolton said.<\/p>\n

Juno will face Jupiter\u2019s hazards for the first time at the riskiest part of its five-year journey since its launch in August 2011.<\/p>\n

The craft\u2019s main engine must fire at the right time, and in the correct direction, for Juno to swing into orbit.<\/p>\n

Ground controllers expect to receive confirmation from Juno\u2019s radio beacon that the burn is underway at 11:18:25 p.m. EDT (0318:25 GMT). Tones transmitted by Juno\u2019s low-power antenna will tell engineers about the status of the 35-minute engine firing.<\/p>\n

The signals come in at slightly different frequencies, giving officials information about the progress of the insertion maneuvers based on the pitch of the tone.<\/p>\n

\u201cAt the end of our journey here. what we\u2019re targeting is a space thats of tens of kilometers wide,\u201d Nybakken said. \u201cWe\u2019re going to hit that within 1.2 seconds after a journey of 1.7 billion miles (2.8 billion kilometers). That tells you just how good our navigation team is.\u201d<\/p>\n

Juno\u2019s primary rocket thruster, made in Britain by Moog-ISP, has fired up two times since its launch, successfully adjusting the probe\u2019s course on the trip to Jupiter. But Monday\u2019s event will occur under new conditions, at higher speeds and with radiation and a potentially disorienting magnetic field nipping at the spacecraft.<\/p>\n

\u201cThe third time should be a charm, but there\u2019s a nuance here, and the nuance here is this will be fisrt time we\u2019ve ever fired the main engine at Jupiter,\u201d Nybakken said. \u201cAnd it\u2019s a make-or-break for us.\u201d<\/p>\n

Programmers have uploaded commands for Juno to ignore its normal conservative safeguards, which typically kick in if something goes wrong to shut down non-critical systems and place the robot into safe mode. If a computer reset or another problem pops up during Monday\u2019s engine firing, Juno will reboot its computer and immediately resume the burn, a feature called \u201cauto restart.\u201d<\/p>\n

\u201cWhen we receive the last tone that tells us the burn is successful, that will be music to my ears,\u201d Nybakken said.<\/p>\n

\u201cWe need to get into orbit tonight, and I\u2019m very confident that we will,\u201d Nybakken said.<\/p>\n

Juno will repeat Monday\u2019s close brush by Jupiter 36 more times before its mission is complete Feb. 20, 2018, when the craft will head toward a crushing dive into the atmosphere.<\/p>\n

Jim Green, a space physicist based at NASA Headquarters in Washington, has been at the helm of the agency\u2019s planetary science division since 2006. NASA\u2019s Curiosity rover landed on Mars, the Messenger mission became the first probe to orbit Mercury, and the New Horizons spacecraft explored Pluto during Green\u2019s tenure, and he\u2019s also on the edge of his seat.<\/p>\n

\u201cWe have done everything humanly possible to make this mission a success,\u201d Green said. \u201cIt\u2019s still a cliffhanger for me, too.\u201d<\/p>\n

Email the author.<\/i><\/b><\/p>\n

Follow Stephen Clark on Twitter: @StephenClark1.<\/strong><\/em><\/p>\n","protected":false},"excerpt":{"rendered":"

This artist\u2019s concept shows Juno\u2019s approach path toward Jupiter for the July 4 insertion maneuver. Jupiter\u2019s intense radiation belts are also illustrated here. Credit: NASA\/JPL-Caltech Speeding toward Jupiter at nearly 40 miles per second, NASA\u2019s Juno spacecraft must brave a field of computer-zapping radiation and Jupiter\u2019s tenuous ring of ice and dust particles when it […]<\/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":[1183,1929,1606,472,1561,2612],"class_list":["post-15395","post","type-post","status-publish","format-standard","hentry","category-news","tag-jet-propulsion-laboratory","tag-juno","tag-jupiter","tag-lockheed-martin","tag-planetary-science","tag-swri"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/15395"}],"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=15395"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/15395\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=15395"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=15395"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=15395"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}