Monday, 8 July 2013

Mengenal IPTEK Pembuatan Kapal Selam Nuklir Canggih

Memahami Pembuatan Kapal Selam Canggih

 

A nuclear submarine is a submarine powered by a nuclear reactor. The performance advantages of nuclear submarines over "conventional" (typically diesel-electric) submarines are considerable: nuclear propulsion, being completely independent of air, frees the submarine from the need to surface frequently, as is necessary for conventional submarines; the large amount of power generated by a nuclear reactor allows nuclear submarines to operate at high speed for long durations; and the long interval between refuellings grants a range limited only by consumables such as food.

Current generations of nuclear submarines never need to be refueled throughout their 25-year lifespans. 

Conversely, the limited power stored in electric batteries means that even the most advanced conventional submarine can only remain submerged for a few days at slow speed, and only a few hours at top speed; recent advances in air-independent propulsion have eroded this disadvantage somewhat. 

The high cost of nuclear technology means that relatively few states have fielded nuclear submarines. Some of the most serious nuclear and radiation accidents ever to occur have involved Soviet nuclear submarine mishaps.


The VMF Typhoon class submarine, is nuclear-powered and the world's largest-displacement submarine.

The Science and Technology of Nuclear Submarine

The main difference between conventional submarines and nuclear submarines is the power generation system. Nuclear submarines employ nuclear reactors for this task. They either generate electricity that powers electric motors connected to the propeller shaft or rely on the reactor heat to produce steam that drives steam turbines (cf. nuclear marine propulsion). 

Reactors used in submarines typically use highly enriched fuel (often greater than 20%) to enable them to deliver a large amount of power from a smaller reactor and operate longer between refuelings – which are difficult due to the reactor's position within the submarine's pressure hull.

The nuclear reactor also supplies power to the submarine's other subsystems, such as for maintenance of air quality, fresh water production by distilling salt water from the ocean, temperature regulation, etc. All naval nuclear reactors currently in use are operated with diesel generators as a backup power system. 

These engines are able to provide emergency electrical power for reactor decay heat removal, as well as enough electric power to supply an emergency propulsion mechanism. Submarines may carry nuclear fuel for up to 30 years of operation. The only resource that limits the time underwater is the food supply for the crew and maintenance of the vessel.


The stealth weakness of nuclear submarines is the need to cool the reactor even when the submarine is not moving; about 70% of the reactor output heat is dissipated into the sea water. This leaves a "thermal wake", a plume of warm water of lower density which ascends to the sea surface and creates a "thermal scar" that is observable by thermal imaging systems, e.g., FLIR.

Another problem is that the reactor is always running, creating steam noise, which can be heard on SONAR, and the reactor pump (used to circulate reactor coolant), also creates noise, as opposed to a conventional submarine, which can move about on incredibly silent electric motors.

Lihat Juga:


Sumber:

Wikipedia

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Sunday, 7 July 2013

Memacu Perkembangan Pendidikan Antariksa di Indonesia

"Mars is there, waiting to be reached."
*Buzz Aldrin*


Karir Militer

Buzz Aldrin graduated third in his class at West Point in 1951, with a bachelor of science degree in mechanical engineering. He was commissioned as a Second Lieutenant in the U.S. Air Force and served as a jet fighter pilot during the Korean War. He flew 66 combat missions in F-86 Sabres and shot down two Mikoyan-Gurevich MiG-15 aircraft. The June 8, 1953, issue of Life magazine featured gun camera photos taken by Aldrin of one of the Russian pilots ejecting from his damaged aircraft.

Subsequent to the war, Aldrin was assigned as an aerial gunnery instructor at Nellis Air Force Base in Nevada, and next was an aide to the dean of faculty at the United States Air Force Academy, which had recently begun operations in 1955. 

He flew F-100 Super Sabres as a flight commander at Bitburg Air Base, Germany, in the 22d Fighter Squadron. In 1963 Aldrin earned a doctor of science degree in astronautics from Massachusetts Institute of Technology. His graduate thesis was "Line-of-sight guidance techniques for manned orbital rendezvous", the dedication of which read, "In the hopes that this work may in some way contribute to their exploration of space, this is dedicated to the crew members of this country’s present and future manned space programs. 

If only I could join them in their exciting endeavors!" On completion of his doctorate, he was assigned to the Gemini Target Office of the Air Force Space Systems Division in Los Angeles before his selection as an astronaut. His initial application to join the astronaut corps was rejected on the basis of having never been a test pilot; that prerequisite was lifted when he re-applied and was accepted into the third astronaut class.

Buku-Buku Karya Beliau:

Books co-authored by Aldrin include Return to Earth (1973), Men From Earth (1989), Reaching for the Moon (2005), Look to the Stars (2009) and Magnificent Desolation (2009). He has also co-authored with John Barnes the science fiction novels Encounter with Tiber (1996) and The Return (2000). His book Mission to Mars was published in May 2013.

Neil Armstrong Hall of Engineering di Purdue University


Karir di NASA

Aldrin was selected as part of the third group of NASA astronauts selected in October 1963. Because test pilot experience was no longer a requirement, this was the first selection for which he was eligible. After the deaths of the original Gemini 9 prime crew, Elliot See and Charles Bassett, Aldrin and Jim Lovell were promoted to back-up crew for the mission. 

The main objective of the revised mission (Gemini 9A) was to rendezvous and dock with a target vehicle, but when this failed, Aldrin improvised an effective exercise for the craft to rendezvous with a coordinate in space. He was confirmed as pilot on Gemini 12, the last Gemini mission and the last chance to prove methods for extra-vehicular activity (EVA). Aldrin set a record for EVA, demonstrating that astronauts could work outside spacecraft.
On July 21, 1969, he became the second astronaut to walk on the Moon, keeping his record total EVA time until that was surpassed on Apollo 14. There has been much speculation about Aldrin's desire at the time to be the first astronaut to walk on the Moon. 

According to different NASA accounts, he had originally been proposed as the first to step onto the Moon's surface, but due to the physical positioning of the astronauts inside the compact lunar landing module, it was easier for the commander, Neil Armstrong, to be the first to exit the spacecraft.


"There's a need for accepting responsibility for a person's life and making choices that are not just ones for immediate short-term comfort. 
You need to make an investment, and the investment is in health and education."
*Buzz Aldrin*

Semoga dengan meningkatnya mutu pendidikan di Indonesia maka secara otomatis IPTEKS Antariksa Indonesia semakin maju.

Semangat!

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Saturday, 6 July 2013

Kuliah Umum: Impian Manusia Menuju Planet Mars

Curiosity on Mars - ACSER Distinguished Guest Lecture at UNSW 


Dr. René Fradet is the Deputy Director, Engineering and Science Directorate at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California. From 2009 through 2010, René was the Flight System Manager for the Mars Sample Laboratory (MSL) where he was responsible for the overall development of the MSL Flight System.

Before assuming his present leadership post at JPL, René was the founder, president and CEO of Alliance Spacesystems, also of Pasadena. René's company built a wide range of space mechatronic systems, most notably the Robot Arm for Curiosity, as well as the robot arms for the Phoenix lander and the earlier Spirit and Opportunity rovers.



Opportunity and its arm are still operational on Mars after almost ten years. Before founding Alliance, René was at JPL as the Deputy Spacecraft Manager on the New Millennium Program Deep Space One (DS1) Project. Deep Space One traveled far beyond Earth's orbit, visited both an asteroid and a comet, and was the first spacecraft to use an ion propulsion main engine rather than chemical propulsion for deep space missions. René was the co-leader responsible for the management of DS1 design, development and test, and was the chief Mechanical Engineer responsible for all associated mechanical activities.


NASA's Mars Science Laboratory mission set down a large, mobile laboratory - the rover Curiosity - at Gale Crater, using precision landing technology that makes many of Mars' most intriguing regions viable destinations for the first time. During the 23 months after landing, Curiosity will analyse dozens of samples drilled from rocks or scooped from the ground as it explores with greater range than any previous Mars rover.

Curiosity carries the most advanced payload of scientific gear ever used on Mars' surface, a payload more than 10 times as massive as those of earlier Mars rovers. Its assignment: Investigate whether conditions have been favourable for microbial life and for preserving clues in the rocks about possible past life.

This talk will survey the tremendous successes of Curiosity so far, from landing on Mars to photographing, sampling and inspecting her surface. Some of the challenges facing Curiosity in the future include robotically drilling on the surface of Mars. This will be the first time since the Apollo program that humanity has drilled rocks on a non-Earth body, and the first time ever for a robot explorer.


Sumber:
1. University of New South Wales, Sydney Australia
2. Jet Propulsion Laboratory
3. NASA
4. California Institute of Technology
5. http://acser.unsw.edu.au/index.html [The Australian Centre for Space Engineering Research]

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