Swarms of dust-sized particles would explore planets
Apr 20,2007 00:00 by Bend_Weekly_News_Sources

En­gi­neers are de­sign­ing a new breed of plan­e­tary ex­plor­ers: ti­ny, shape-shift­ing de­vices that ride the wind like dust par­t­i­cles and al­so to com­mu­ni­cate, fly in for­ma­tion and take sci­en­tif­ic mea­sure­ments.

The specks might even be the first ex­plor­ers from Earth to vis­it plan­ets out­side our so­lar sys­tem, the de­sign­ers claim.

A “smart” dust par­t­i­cle would con­sist of a com­put­er chip about a millimeter wide en­cased in a pol­y­mer ma­te­ri­al that wrin­kles or smooth’s out when elec­tri­cal­ly ac­ti­vat­ed. Wrinkl­ing the sur­face would in­crease air drag on the par­t­i­cle, mak­ing it float high­er. Smooth­ing would cause it to sink.

Swarms of so-called nano-nauts might be the first ex­plor­ers from Earth on plan­e­tary sys­tems out­side our own, re­search­ers say. De­sign­ers of the par­t­i­cles say they might be de­liv­ered to the al­ien worlds via space­crafts that use ion pro­pu­sion, a pow­er­ing sys­tem that al­lows for slow but steady accelerati­on and ef­fi­cient en­er­gy use. (Im­age cour­te­sy Cal­tech)

Sim­u­la­tions show that by switch­ing be­tween rough and smooth modes, the par­t­i­cles can grad­u­al­ly hop to­wards a tar­get, even in swirling winds, re­search­ers say.

“The con­cept of us­ing smart dust swarms for plan­e­tary ex­plo­ra­tion has been talked about for some time, but this is the first time an­y­one has looked at how it could ac­tu­al­ly be achieved,” said John Bark­er of the Uni­ver­si­ty of Glas­gow, Scot­land. He de­scribed pos­si­ble ap­pli­ca­tions of smart dust at the U.K. Roy­al As­tro­nom­i­cal So­ci­ety’s na­tion­al meet­ing in Pres­ton, U.K. on April 18.

“Com­puter chips of the size and soph­ist­ica­tion needed to make a smart dust par­t­i­cle now ex­ist,” Barker said. “We are look­ing through the range of pol­y­mers avail­a­ble to find one that matches our re­quire­ments for high defor­ma­tion us­ing min­i­mal volt­ages.” 

The specks would use wire­less net­work­ing to com­mu­ni­cate and form swarms; “we en­vis­age that most of the par­t­i­cles can on­ly talk to their near­est neighbors but a few can com­mu­ni­cate at much long­er dis­tances,” Bark­er added. “In our sim­u­la­tions we’ve shown that a swarm of 50 smart dust par­t­i­cles can organize them­selves in­to a star for­ma­tion, even in tur­bu­lent wind.” The abil­i­ty to fly in for­ma­tion would enable the chips to pro­cess in­form­a­tion col­lect­ively and beam sig­nals back to an or­bit­ing space­craft, he pre­dic­ted.

To be use­ful, the par­t­i­cles would need to car­ry sen­sors. Cur­rent chem­i­cal sen­sors tend to be rath­er large for the sand-grain sized par­t­i­cles that could be car­ried by the thin Mar­tian at­mos­phere, Bark­er said. Ve­nus’s at­mos­phere, on the oth­er hand, is much thicker and could car­ry sen­sors up to a few centimeters in size, so these could the­o­ret­i­cal­ly be used there now.

Mean­while, “miniaturization is com­ing on rapid­ly,” Bark­er not­ed. Chips avail­a­ble by 2020 will have com­po­nents just a few nanometers (mil­lionths of a mil­li­me­ter) across, so that smart par­t­i­cles would be­have more like large mo­le­cules than dust grains, he ar­gued. These would-be ex­plor­ers are be­ing dubbed nano-nauts.

Bark­er’s re­search group at Glas­gow thinks it will be some years be­fore smart dust is ready to launch in­to space, he said. “We are still at an ear­ly stage, work­ing on sim­u­la­tions and com­po­nents. We have a lot of ob­sta­cles to over­come be­fore we are even ready to phys­i­cal­ly test our de­signs. How­ev­er, the po­ten­tial ap­pli­ca­tions of smart dust for space ex­plo­ra­tion are very ex­cit­ing. Our first close-up stud­ies of extra-so­lar plan­ets could come from a smart dust swarm de­liv­ered to anoth­er so­lar sys­tem.”

Courtesy Royal Astronomical Society
and World Science staff