Lift Luar Angkasa

[Ache]

Saya cukup paham konsep yang diberikan. Benar-benar menerapkan konsep fisika dengan cermat.
Salah satu saja yang saya agak kurang pas. Daripada dikaitkan dengan satelit alam (bulan, asteroid), lebih baik dikaitkan pada stasiun luar angkasa. Yah, kan sekaligus jadi akses suplai energi, dan akan lebih fungsional.

Dari segi konsepnya saya kira cukup realistis. Tapi, masalahnya adalah adanya resiko dan kendala yang sangat besar terkait konstruksi dan operasionalnya. Baik dari segi teknis maupun alam, dan tentu saja dana. Biaya konstruksi dan operasional pasti membutuhkan biaya yang luar biasa banyak.
Kendala, alam, dinamika atmosfer, seperti petir, badai, burung-burung, serta benda-benda langit lainnya yang lalu-lalang. Belum lagi seandainya terjadi masalah teknis lainnya. Kerugiannya bukan nilai yang kecil. Dan tidak ada konsep antisipasi yang mampu mengcover berbagai kendala tersebut.

Yah, yang menjadikannya seakan tidak mungkin adalah kendala-kendala tadi yang belum mampu untuk diantisipasi.

Seandainya benar terealisasi, tentu suatu yang sangat membanggakan. Tapi, saya pikir, nanti akan banyak sekali menemui kendala, dan pasti membutuhkan waktu yang sangat lama. Saya juga cenderung tidak yakin ini akan bertahan dalam jangka waktu yang lama, walapun dialokasikan untuk operasional jangka panjang.

David Smitherman of NASA has published a paper that identifies "Five Key Technologies for Future Space Elevator Development":[1]

1. Material for cable (e.g. carbon nanotube and nanotechnology) and tower
2. Tether deployment and control
3. Tall tower construction
4. Electromagnetic propulsion (e.g. magnetic levitation)
5. Space infrastructure and the development of space-based industry and economy

Two different ways to deploy a space elevator have been proposed.

Traditional way

One early plan involved lifting the entire mass of the elevator into geostationary orbit, and simultaneously lowering one cable downwards towards the Earth's surface while another cable is deployed upwards directly away from the Earth's surface.

Tidal forces (gravity and centrifugal force) would naturally pull the cables directly towards and directly away from the Earth and keep the elevator balanced around geostationary orbit.[citation needed] As the cable is deployed, Coriolis forces would pull the upper portion of the cable somewhat to the West and the lower portion of the cable somewhat to the East; this effect can be controlled by varying the deployment speed.[citation needed]

However, this approach requires lifting hundreds or even thousands of tons on conventional rockets, an expensive proposition.

Cable seeding design

Bradley C. Edwards, former Director of Research for the Institute for Scientific Research (ISR), based in Fairmont, West Virginia proposed that, if nanotubes with sufficient strength could be made in bulk, a space elevator could be built in little more than a decade, rather than the far future. He proposed that a single hair-like 18-metric ton (20 short ton) 'seed' cable be deployed in the traditional way, giving a very lightweight elevator with very little lifting capacity. Then, progressively heavier cables would be pulled up from the ground along it, repeatedly strengthening it until the elevator reaches the required mass and strength. This is much the same technique used to build suspension bridges.

The 18 tonnes needed for a seed cable may be reasonably lightweight; the proposed average mass is about 200 grams per kilometer.[citation needed] In comparison, conventional copper telephone wires running to consumer homes weigh about 4 kg/km[citation needed].

Loop elevator design

This is a less well developed design, but offers some other possibilities.

If the cable provides a useful tensile strength of about 62.5 GPa or above, then it turns out that a constant width cable can reach beyond geostationary orbit without breaking under its own weight. The far end can then be turned around and passed back down to the Earth forming a constant width loop, which would be kept spinning to avoid tangling. The two sides of the loop are naturally kept apart by coriolis forces due to the rotation of the Earth and the loop. By increasing the thickness of the cable from the ground a very quick (exponential) build-up of a new elevator may be performed (it helps that no active climbers are needed, and power is applied mechanically.) However, because the loop runs at constant speed, joining and leaving the loop may be somewhat challenging, and the carrying capacity of such a loop is lower than a conventional tapered design

http://en.wikipedia.org/wiki/Space_e...r_construction

[Ache]

Lalu ini ganjalan keselamatannya:

# 1 Cable strength
# 2 Satellites
# 3 Meteoroids and micrometeorites
# 4 Failure cascade
# 5 Corrosion
# 6 Radiation
# 7 Material defects
# 8 Weather
# 9 Vibrational harmonics
# 10 In the event of failure

* 10.1 Cut near the anchor point
* 10.2 Cut up to about 25,000 km
* 10.3 Elevator climbers

http://en.wikipedia.org/wiki/Space_elevator_safety

[lethologica]

Carbon nanotubes could cause cancer, warn scientists

Carlton Reid May 21 2008, 8:12am

Used in sports equipment such as bicycle components and tennis rackets, carbon nanotubes could be the new asbestos, says journal

A new report has warned that carbon nanotubes may pose a similar health risk to asbestos.

Tests on mice suggest that exposure to carbon nanotubes could lead to cancer of the lining of the lungs.

Nature Nanotechnology journal said inhalation of carbon nanotubes by mice led to inflammation and lesions.

In 2005, BikeBiz.com reported on a similar health alert, raised at the International Congress of Nanotechnology in San Francisco.

The authors of the new report said: "Research and business communities continue to invest heavily in carbon nanotubes for a wide range of products under the assumption that they are no more hazardous than graphite.

"Our results suggest the need for further research and great caution before introducing such products into the market if long-term harm is to be avoided."

Inhalation of carbon nanotubes would be at the source of manufacture, not in finished items. Should the research prove to be accurate there would be health and safety implications for those companies - mostly in the Far East - which manufacture with carbon nanotubes.

In the bike trade, Easton has led the way with carbon nanotubes. In 2004, BikeBiz.com reported that financial trends spotter The Motley Fool said carbon nanotubes would be "the next big thing."

The scientific report behind the current story is an 'advance publication' story, it has yet to appear in the paper journal.

'Carbon nanotubes introduced into the abdominal cavity of mice show asbestos-like pathogenicity in a pilot study' was authored by scientists at MRC/University of Edinburgh, School of Materials, University of Manchester, Woodrow Wilson International Center for Scholars, Washington DC, Institute of Occupational Medicine, Edinburgh and School of Life Sciences, Edinburgh.

The report abstract says:

Carbon nanotubes have distinctive characteristics, but their needle-like fibre shape has been compared to asbestos, raising concerns that widespread use of carbon nanotubes may lead to mesothelioma, cancer of the lining of the lungs caused by exposure to asbestos.

Here we show that exposing the mesothelial lining of the body cavity of mice, as a surrogate for the mesothelial lining of the chest cavity, to long multiwalled carbon nanotubes results in asbestos-like, length-dependent, pathogenic behaviour. This includes inflammation and the formation of lesions known as granulomas. This is of considerable importance, because research and business communities continue to invest heavily in carbon nanotubes for a wide range of products5 under the assumption that they are no more hazardous than graphite. Our results suggest the need for further research and great caution before introducing such products into the market if long-term harm is to be avoided.

http://www.bikebiz.com/news/29551/Ca...arn-scientists

Kira-kira bakal mengganggu space elevator ga ya?

[blackwarr]

tapi bukan ny klo ada meteor lewat bakal nabrak yah??
klo parah bisa rugi besar itu

[Menara_Jakarta]

tapi bukan ny klo ada meteor lewat bakal nabrak yah??
klo parah bisa rugi besar itu

Inilah yang mesti diantisipasi.

[Antasari_Azhar]

Revisi dikit dong, Lift Luar Angkasa pertama kali dipikirkan tahun 1895 oleh ilmuwan Rusia Konstantin Tsiolkovsky yang terinspirasi dari menara Eiffel.

[Menara_Jakarta]

Revisi dikit dong, Lift Luar Angkasa pertama kali dipikirkan tahun 1895 oleh ilmuwan Rusia Konstantin Tsiolkovsky yang terinspirasi dari menara Eiffel.

Terima kasih atas revisinya, Anda benar:


Lift luar angkasa adalah struktur yang didesain untuk mengirim material dari permukaan bumi ke luar angkasa. Banyak proposal telah diusulkan dan melibatkan perjalanan melalui struktur dan bukan dengan menggunakan roket. Konsepnya seringkali mengacu pada struktur yang menjangkau orbit geostasioner dari permukaan bumi.

Konsep lift luar angkasa berawal dari ide seorang ilmuwan Rusia Konstantin Tsiolkovsky, yang pada tahun 1985 mengajukan struktur kompresi atau yang disebut Menara Tsiolkovsky.

LIft luar angkasa juga kadang-kadang disebut elevator luar angkasa, jembatan luar angkasa, tangga menuju luar angkasa, menara orbit, atau elevator orbit.

Teknologi saat ini tidak mampu menciptakan struktur yang kuat namun juga ringan untuk lift luar angkasa. Hal ini disebabkan total massa untuk konstruksi jika menggunakan bahan konvensional terlalu besar. Konsep rencana terbaru dari pembuatan lift luar angkasa adalah penggunaan bahan berbasis karbon nanotube. Telah diketahui bahwa kekuatan bahan karbon nano-tube dalam skala mikroskopis sangatlah kuat jika dibandingkan dengan bahan lainnya yang telah ada sehingga secara teoritis dapat dipakai untuk pembuatan lift luar angkasa. Material terbaru dapat digunakan dalam pembuatan lift ke tempat lain di tata surya, seperti Mars, yang memiliki gravitasi yang lebih lemah daripada Bumi

http://id.wikipedia.org/wiki/Lift_luar_angkasa

[Andaman_Nikobar]

The Space Elevator Comes Closer to Reality

ALBUQUERQUE, NEW MEXICO -- Make way for the ultimate high-rise project: the space elevator. Long viewed as science fiction "imagineering", researchers are gathering momentum in their pursuit to propel this uplifting concept into actuality.

Still, the mental picture needed to grasp the elevator to space idea…well, you can't be weak of mind.

Forget the roar of rocketry and those bone jarring liftoffs, the elevator would be a smooth 62,000-mile (100,000-kilometer) ride up a long cable. Payloads can shimmy up the Earth-to-space cable, experiencing no large launch forces, slowly climbing from one atmosphere to a vacuum.

Earth orbit, the Moon, Mars, Venus, the asteroids and beyond - they are routinely accessible via the space elevator. And for all its promise and grandeur, this mega-project is made practical by the tiniest of technologies - carbon nanotubes.

Seen as an engineering undertaking for the opening decades of the 21st century, the space elevator proposal was highlighted here during the 2002 Space and Robotics Conferences, held March 17-21, and sponsored by the Aerospace Division of the American Society of Civil Engineers.

Thought experiment

Science fiction writers have been deploying space elevators for years.

Space visionary, Arthur Clarke, centered his novel of the late 1970s, The Fountains of Paradise, on the notion. Also, among other writers, Kim Stanley-Robinson's Red Mars noted the soaring splendor of an elevator to space. Furthermore, the scheme has bounced around technical journals for decades. Some call it a "thought experiment", but others point out that space exploration B.C. -- "Before Cable" -- will pale contrasted to what's possible within ten to fifteen years.

"Even though the challenges to bring the space elevator to reality are substantial, there are no physical or economic reasons why it can't be built in our lifetime." That's the matter-of-fact feeling of physicist, Bradley Edwards of Eureka Scientific in Berkeley, California, but carrying out heavy lifting design work in Seattle, Washington.

Edwards told SPACE.com that he's been wrapped up in space elevator work for some three years, supported by grants from NASA's Institute for Advanced Concepts (NIAC) program. "I'm convinced that the space elevator is practical and doable. In 12 years, we could be launching tons of payload every three days, at just a little over a couple hundred dollars a pound," he said.

"In 15 years we could have a dozen cables running full steam putting 50 tons in space every day for even less, including upper middle class individuals wanting a joyride into space. Now I just need the $5 billion, Edwards added.

And so it grows

For a space elevator to function, a cable with one end attached to the Earth's surface stretches upwards, reaching beyond geosynchronous orbit, at 21,700 miles (35,000-kilometer altitude). After that, simple physics takes charge.

The competing forces of gravity at the lower end and outward centripetal acceleration at the farther end keep the cable under tension. The cable remains stationary over a single position on Earth. This cable, once in position, can be scaled from Earth by mechanical means, right into Earth orbit. An object released at the cable's far end would have sufficient energy to escape from the gravity tug of our home planet and travel to neighboring the moon or to more distant interplanetary targets.

Putting physics aside the toughest challenge has been finding a super-strong cable material. "That's what has kept this idea in science fiction for 40 years," Edwards said. But the right stuff in terms of cable material is no longer thought of as "unobtainium", he said.

The answer is carbon-nanotube-composite ribbon. Small fibers of the material are set down side-by-side, then interconnected to form a growing ribbon.

Stronger than steel

The hurdle to date, Edwards said, has been the commercial fabrication of carbon nanotubes. Both U.S. and Japanese firms, among others, are ramping up production of carbon nanotubes, with tons of this now exotic matter soon to be available. "That quantity of material is going to be around well before five years time. It's not going to take long," he said.

Given the far stronger-than-steel ribbon of carbon nanotubes, a space elevator could be up within a decade. "There's no real serious stumbling block to this," Edwards explained.

"The making of carbon nanotubes is moving very quick," said Hayam Benaroya, a professor in the Department of Mechanical and Aerospace Engineering at Rutgers in Piscataway, New Jersey. "We're moving from the scientific stage of just developing them to actual commercial entities producing them in ton-like quantities," he said.

"Perhaps within our lifetimes we might actually see real designs of skyhooks and space tethers, these kinds of things. They may be feasible at reasonable cost," Benaroya said.

Reel world high-wire act

Getting the first space elevator off the ground, factually, would use two space shuttle flights. Twenty tons of cable and reel would be kicked up to geosynchronous altitude by an upper stage motor. The cable is then snaked to Earth and attached to an ocean-based anchor station, situated within the equatorial Pacific. That platform would be similar to the structure used for the Sea Launch expendable rocket program.

Once secure, a platform-based free-electron laser system is used to beam energy to photocell-laden "climbers". These are automated devices that ride the initial ribbon skyward. Each climber adds more and more ribbon to the first, thereby increasing the cable's overall strength. Some two-and-a-half years later, and using nearly 300 climbers, a first space elevator capable of supporting over 20-tons (20,000-kilograms) is ready for service.

"If budget estimates are correct, we could do it for under $10 billion. The first cable could launch multi-ton payloads every 3 days. Cargo hoisted by laser-powered climbers, be it fragile payloads such as radio dishes, complex planetary probes, solar power satellites, or human-carrying modules could be dropped off in geosynchronous orbit in a week's travel time," Edwards said.

Using a laser beam to boost the climbers into space is doable, said Harold Bennett, president of Bennett Optical Research, Inc. of Ridgecrest, California. "If you do it right, you can take out 96 percent of the effect of the atmosphere on the laser beam through adaptive optics," he said. The strength of the pulsed laser beam is less than the intensity of the Sun, so birds, airplanes, or human eyes wouldn't be affected, he said.

Return on investment

Eric Westling, a Houston, Texas-based consultant on the space elevator, is bullish on the concept. Spending billions on a space elevator is small change for a big purpose.

"Other than the invention of some Buck Rogers engine, the space elevator is the only system for accessing space that is subject to the economics of scale. It's a true return on investment enterprise. The cost of space travel has to become an incidental part of the overall cost of what we're trying to get done," Westling said.

"It will change the world economy. It's worth what ever it costs to put it up," Westling said. An initial elevator, he added, is sure to give birth to even larger systems, capable of handling larger loads of up and down traffic.

"I'm looking at a business plan that shows some investor could triple his or her money in about 6 years, and the initial investment could be as low as $5 billion," Edwards said.

Building the impossible

The elevator to space concept does entail aggressive research work. As example, Edwards said he is looking into the environmental impacts stemming from elevator operations. Being studied too is impact of lightning, wind and clouds on an Earth-to-space cable system. Space elevators for use on other worlds, like Mars and the Moon are receiving attention as well.

One thing to keep in mind. Building the impossible is done here on Earth routinely, Edwards said.

Take for instance the $13.5 billion Millennium Tower envisioned for Hong Kong Harbor. This incredible skyscraper would be 170 stories tall. Elevator traffic within its walls is estimated at 100,000 people per day.

Edwards also points to the Gibraltar Bridge project. It would span the Straits of Gibraltar, linking Spain and Morocco at a projected cost of $20 billion. The bridge would use towers, twice as high as the world's tallest skyscraper. Roughly 1,000,000 miles (1,600,000 kilometers) of wire cables would be utilized in the project.

"I think those projects are a lot harder than what I'm talking about," Edwards said.

http://www.space.com/businesstechnol..._020327-1.html

[gemini2]

Apakah ini nantinya yang menjadi Menara Babel Versi II ? Bagaimana kita harus menyikapinya agar tidak terulang kesalahan yang sama: kita harus belajar dari sejarah.

[Menara_Jakarta]

Apakah ini nantinya yang menjadi Menara Babel Versi II ? Bagaimana kita harus menyikapinya agar tidak terulang kesalahan yang sama: kita harus belajar dari sejarah.

Ya, harus bener-bener diperhitungkan arsitekturnya.

[Dragon_knight95]

Ke luar angkasa perlu Paspor tidak ya? Apakah tahan terhadap tekanan? Apa yang terjadi bila dananya di korupsi? maaf banyak tanya

[Menara_Jakarta]

Ke luar angkasa perlu Paspor tidak ya? Apakah tahan terhadap tekanan? Apa yang terjadi bila dananya di korupsi? maaf banyak tanya

Itu tergantung masa depan nanti, tapi kemungkinan sih bisa iya pake paspor.

[vedoyz]

wew jd beneran bs di buat tu?kata temen saya ini hal yg tak mungkin kk...tp saya si optimis aja..hahaha

tp klo bs pasti mahal tu klo mau naek lift itu..

[Menara_Jakarta]

wew jd beneran bs di buat tu?kata temen saya ini hal yg tak mungkin kk...tp saya si optimis aja..hahaha

tp klo bs pasti mahal tu klo mau naek lift itu..

Banyak juga yang percaya kalo Lift Luar Angkasa akan direalisasikan pada abad ini juga.

[Ache]

Banyak juga yang percaya kalo Lift Luar Angkasa akan direalisasikan pada abad ini juga.

Gua juga yakin, tapi mungkin pas udah ganti generasi kali ya.