Tuesday, May 18, 2010

Japanese Solar Sail Headed For Venus and Beyond

Jeremy Hsu SPACE.com Senior Writer
space.com – Sun May 16, 1:00 pm ET

An ambitious solar sail mission designed by Japan is poised for launch tomorrow could become the first successful mission powered solely by sunlight, but that's not all. The spacecraft is also aimed at Venus and beyond, and could pave the way for a future hybrid space engine.

The solar sail will hitch a ride aboard an H-2A rocket slated for launch on Monday (Tuesday local time) from Japan's Tanegashima Space Center. That rocket carries the main mission of the Japan Aerospace Exploration Agency (JAXA), the Venus Climate Orbiter called Akatsuki — which means "Dawn" in Japanese.

But only Akatsuki has a planned meet-up with Venus, even though the sail — called Ikaros (Interplanetary Kite-craft Accelerated by Radiation Of the Sun) — will also launch along the same trajectory toward the mysterious planet.

"This will be the world's first solar powered sail craft employing both photon propulsion and thin film solar power generation during its interplanetary cruise," said a JAXA mission website.

Venus would mark just a six-month pit stop for the solar sail during a three-year trek toward the far side of the sun.

"To me it's a very bold activity to be conducting a technology test like this on an interplanetary mission," said Louis Friedman, an executive director of the Planetary Society in Pasadena, Calif. "I think it shows a lot of foresight on their part."

Past solar sail demonstrations have fallen short of achieving actual solar-propelled spaceflight, but that certainly has not stopped JAXA from planning an ambitious technological debut. Even Ikaros itself represents just a stepping stone to a "hybrid" space engine that incorporates solar sail technology, mission planners have said.

Space Hybrid Vehicle

The kite-shaped Ikaros relies upon the pressure of sunlight for propulsion, but it also carries thin film solar cells built within its sail. Such cells could generate electricity from the same sunlight pushing the solar sail along.

That won't do much good by itself for a solar sail without an engine. But JAXA hopes that the power-gathering demonstration could eventually lead to spacecraft with ion-propulsion engines that draw electricity from solar cells and also take advantage of solar sail propulsion — a hybrid propulsion system.

"They want to ultimately have a solar electric [ion propulsion] and solar sail vehicle that would be used for outer planetary missions," Friedman told SPACE.com.

Yet the history of solar sail tests presents a sobering reminder of the troubles that can arise. The California-based Planetary Society attempted to fly its Cosmos-1 solar sail in 2005, but lost their prototype because of a Russian rocket malfunction. NASA's NanoSail-D was also lost in the third failed flight of SpaceX's Falcon 1 rocket in 2008.

A British shoebox-sized mission slated for launch next year might also test solar sail propulsion, but would mainly test the sails as brakes for taking defunct satellites down.

Japan did deploy a solar sail from a sounding rocket in 2004, but did not actually attempt to demonstrate controlled flight. If that represented the dry run, then Ikaros comes as the real deal.

True Solar Sailing

Ikaros is designed to unfurl its sail during its first stage by taking advantage of its spinning momentum, and then actively deploying the rest of the way during a second stage.

"The membrane is deployed, and kept flat, by its spinning motion," the JASA mission website stated. "Four masses are attached to the four tips of the membrane in order to facilitate deployment."

The Planetary Society still has ambitions to someday launch a solar sail mission into deep space, but its first planned solar sail test would involve a much smaller spacecraft than Ikaros, which stretches almost 66 feet (20 meters) at the diagonal of its square sail.

A refitted NASA solar sail might weigh a little less than 10 pounds (4.5 kg) compared to the 700-pound (315 kg) Ikaros.

The Planetary Society would aim first for launch to low-Earth orbit, before eventually launching a second mission that lasted perhaps weeks. Only the third mission would try for interplanetary traveler status, Freidman said.

For now, Friedman and the Planetary Society will share technological information and results from the JAXA mission, and keep an eye on their own hopes for the future.

"We wish we were first, of course, but it doesn't matter," Friedman said. "It's about advancing solar sail technology."


Unknown said...

Cool project.

Solar material provided by PowerFilm Solar in Ames, Iowa. It's a thin-film flexible solar photovoltaic that's used by the military.


HeribertoGarber said...

成人免費線上看 日本情色視訊 ut聊天網 免費線上色情片 yam交友 女優影片分享 露點 成人免費影片觀看 偷拍貼圖站 美女聊天室 愛情 歐美情趣圖片 女優18禁 台灣絲襪美少女 85cc免費小短片影城 免費a片直撥網 av情色影片 卡通色情影片區 一夜情 影音383 完美女人影片試看 美少女 性美女愛 辣妹強姦 人妻av下載 成人 成人視訊 空姐絲襪 a片a圖論壇 偷拍寫真 85cc 免費影片欣 微風成人區成人寫真 成人嘟嘟網免費看 www.7777th.com 杜雷斯免費貼圖區 援交妹貼圖區 嘟嘟情人色網 dudu 台南鋼管秀 pub 日本av線上 洪爺影片交流區 大大奶的 ab 女傭 sex888 okk 免費下載 巨乳人妻 敏感帶 後宮無碼光碟網 限制級 0204成人影片 無碼性愛影片 走光照

Anonymous said...


Eunic毓燕eMatte0215 said...

the food is delicious!............................................................

ismail loas said...

Xvideo porn movie ledporn watch ! and free girl xxx porn tube look for you hardsexporn free ...