"Long before it's in the papers"
January 28, 2015


Craft “ready” to map outer solar system

Oct. 7, 2008
Courtesy NASA
and World Science staff

The first NASA sat­el­lite to im­age and map the dy­nam­ic in­ter­ac­tions at the out­er so­lar sys­tem—where a hot wind from the Sun hits cold out­er space—is ready for launch Oct. 19, agen­cy of­fi­cials say.

The two-year mis­sion is to beg­in from the Kwa­ja­lein At­oll, a part of the Mar­shall Is­lands in the Pa­cif­ic Ocean. 

Artist's con­cept of a mo­ment in the com­plex and un­u­su­al launch se­quence for IBEX. The plan is to put the craft in­to an ex­treme­ly high or­bit us­ing a rock­et known as Peg­a­sus. This will de­liv­er IBEX to an al­ti­tude of about 120 miles. IBEX would then use an in­ter­nal hy­dra­zine fu­el sys­tem over sev­er­al or­bits go to to about 4,400 miles up.

Called the In­ter­stel­lar Bound­a­ry Ex­plor­er or IBEX, the craft is to or­bit un­usu­ally far above Earth to in­ves­t­i­gate and cap­ture im­ages of pro­cesses at the far­thest reaches of the so­lar sys­tem. Known as the in­ter­stel­lar bound­a­ry, this is where the so­lar sys­tem meets in­ter­stel­lar space. 

This bound­a­ry shields Earth “from the vast ma­jor­ity of dan­ger­ous ga­lac­tic cos­mic rays, which oth­er­wise would pen­e­trate in­to Earth’s or­bit and make hu­man space­flight much more dan­ger­ous,” said IBEX prin­ci­pal in­ves­ti­ga­tor Da­vid J. Mc­Co­mas, of the South­west Re­search In­sti­tute in San An­to­nio, Tex­as.

The out­er so­lar sys­tem be­gan to be re­vealed when the Voy­ag­er 1 and Voy­ag­er 2 space­crafts left the in­ner so­lar sys­tem and head­ed to­ward the in­ter­stel­lar bound­a­ry. 

These crafts “are mak­ing fas­ci­nat­ing ob­serva­t­ions of the lo­cal con­di­tions at two points be­yond the ter­mina­t­ion shock that show to­tally un­ex­pected re­sults and chal­lenge many of our no­tions,” said Mc­Co­mas. 

The ter­mina­t­ion shock is where the so­lar wind, the tor­rent of high-energy par­t­i­cles cast out­ward from the sun, slows down as it hits the gas and dust float­ing in the gal­axy.

Oth­er space­craft have con­tin­ued the ex­plora­t­ion of the in­ter­stel­lar bound­a­ry. Re­cent­ly, a pair of the agen­cy’s sun-focused sat­el­lites, the So­lar Ter­res­tri­al Rela­t­ions Ob­serv­a­to­ry mis­sion, de­tected a higher-energy ver­sion of the par­t­i­cles IBEX will ob­serve in the he­lio­sphere. The he­lio­sphere is an ar­ea that con­tains the so­lar wind. It stretches from the sun to a dis­tance sev­er­al times the or­bit of Plu­to. 

Im­ages from the new craft are ex­pected to let sci­en­tists un­der­stand the glob­al in­ter­ac­tion be­tween our sun and the gal­axy for the first time. IBEX has two sensors that collect particles. The sat­el­lite would spin as it or­bits Earth so that over six months, each sen­sor col­lects par­ti­cles from every part of the sky. This al­lows the crea­tion of an all-sky map every six months.

“What makes the IBEX mis­sion un­ique is that it has an ex­tra kick dur­ing launch” to push it in­to a high or­bit, said Wil­lis Jen­kins, pro­gram ex­ec­u­tive for the craft at NASA Head­quar­ters in Wash­ing­ton. “An ex­tra sol­id-state mo­tor pushes the space­craft fur­ther out of low-Earth or­bit where the Peg­a­sus launch ve­hi­cle leaves it.”

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The first NASA satellite to image and map the dynamic interactions at the outer solar system—where the hot wind from the Sun slam into cold, outer space—is ready for launch Oct. 19, agency officials say. The two-year mission is to begin from the Kwajalein Atoll, a part of the Marshall Islands in the Pacific Ocean. Called the Interstellar Boundary Explorer or IBEX, the craft is to orbit unusually far above Earth to investigate and capture images of processes at the farthest reaches of the solar system. Known as the interstellar boundary, this is where the solar system meets interstellar space. This boundary shields Earth “from the vast majority of dangerous galactic cosmic rays, which otherwise would penetrate into Earth’s orbit and make human spaceflight much more dangerous,” said IBEX principal investigator David J. McComas, of the Southwest Research Institute in San Antonio, Texas. The outer solar system began to be revealed when the Voyager 1 and Voyager 2 spacecrafts left the inner solar system and headed toward the interstellar boundary. These crafts “are making fascinating observations of the local conditions at two points beyond the termination shock that show totally unexpected results and challenge many of our notions,” said McComas. The termination shock is where the solar wind, the torrent of high-energy particles cast outward from the sun, slows down as it hits the gas and dust floating in the galaxy. Other spacecraft have continued the exploration of the interstellar boundary. Recently, a pair of the agency’s sun-focused satellites, the Solar Terrestrial Relations Observatory mission, detected a higher-energy version of the particles IBEX will observe in the heliosphere. The heliosphere is an area that contains the solar wind. It stretches from the sun to a distance several times the orbit of Pluto. Images from the new craft are expected to let scientists understand the global interaction between our sun and the galaxy for the first time. “What makes the IBEX mission unique is that it has an extra kick during launch” to push it into a high orbit, said Willis Jenkins, program executive for the craft at NASA Headquarters in Washington. “An extra solid-state motor pushes the spacecraft further out of low-Earth orbit where the Pegasus launch vehicle leaves it.”