a collection of my published and unpublished articles

Showing posts with label spacecraft. Show all posts
Showing posts with label spacecraft. Show all posts

Saturday, November 1, 2008

History changed on 4th October 1957, to be exact — a 100-tonne modified Soviet rocket blasted off from Kazakhstan carrying a small metal ball (58 cm. or 22.8 inches in diameter), weighed only 83.6 kg. or 183.9 pounds, equipped with only a couple of simple radio transmitters and took about 98 minutes to orbit the Earth on its elliptical path.- the world’s first satellite. Known as Sputnik (‘Companion’ or ‘Satellite’), the basketball-sized sphere became a sensation as it circled the planet transmitting a ‘beep beep’ signal. The world was never the same again.

That launch ushered in new political, military, technological, and scientific developments. While the Sputnik launch was a single event, it marked the start of the space age and the U.S.-U.S.S.R space race. Since then, spaceflight technologies have grown up. High-performance rocket fuels, miniaturized guidance electronics and ultra-light spacecraft materials, to name a few, make frequent and complex trips to space possible.

Half a century after Sputnik, space technology is part of our everyday lives. We rely on satellites for TV and long-distance phone calls, weather forecasting, navigation and disaster monitoring. Space observatories are studying the birth of planets, stars, galaxies and the Universe itself. Spacecraft have visited almost every major body in the Solar System. And 12 people have walked on the Moon.


Sputnik program

The Sputnik program was a series of unmanned space missions launched by the Soviet Union in late 1957 to demonstrate the practicability of artificial satellites for exploring the upper atmosphere as part of the International Geophysical Year. It included Sputnik 1, the first man-made object to orbit earth.
The Russian name "Спутник" means literally "co-traveler","traveling companion" or "satellite", and its R-7 launch vehicle was designed initially to carry nuclear warheads.
The surprise launch of Sputnik 1, coupled with the spectacular failure of the United States' first two Project Vanguard launch attempts, shocked the United States, which responded with a number of early satellite launches, including Explorer I, Project SCORE, and Courier 1B. The Sputnik crisis also led to the creation of the Advanced Research Projects Agency, DARPA and NASA, and to major increases in U.S. government spending on scientific research and education.

Early flights
Sputnik 1 was launched on October 4, 1957. The satellite was 58 cm (about 23 in) in diameter and weighed approximately 83.6 kg (about 183 lb). Each of its elliptical orbits around the Earth took about 96 minutes. Monitoring of the satellite was done by Amateur radio operators. 

Sputnik 2 was launched on November 3, 1957 and carried the first living passenger into orbit, a dog named Laika. The mission planners did not provide for the safe return of the spacecraft or its passenger, making Laika the first orbital casualty. This mission was promptly dubbed "Muttnick" by US humorists. 
The first attempt to launch Sputnik 3, on February 3, 1958, failed, but the second on May 15 succeeded, and it carried a large array of instruments for geophysical research. Its tape recorder failed, however, making it unable to measure the Van Allen radiation belts.
Sputnik 4 was launched two years later, on May 15, 1960.
Sputnik 5 was launched on August 19, 1960 with the dogs Belka and Strelka, 40 mice, 2 rats and a variety of plants on board. The spacecraft returned to earth the next day and all animals were recovered safely.
Sputnik 40 and Sputnik 41
Sputnik 40, also called Sputnik PS2, Radio Sputnik 17 and Mini-Sputnik, was a 1⁄3-scale model amateur radio satellite launched from the Mir space station on 3 November 1997 to commemorate the 40th anniversary of Sputnik 1. The spacecraft body resembled Sputnik 1 and was built by students at the Polytechnic Laboratory of Nalchik in Kabardino-Balkaria. The transmitter was built by students from Jules Reydellet College in Réunion, with technical support from AMSAT-France. Its batteries expired on 29 December 1997 and the VHF transmitter fell silent. 
Sputnik 41 was launched a year later, on 10 November 1998. It also carried a transmitter.


Next 50 years…

If the last 50 years mark the beginning of a new era for the human race, who knows what will be achieved in the next half century? This October will mark the 50th anniversary of Sputnik 1, the first artificial satellite of Earth. Fifty years from now, scientists, explorers – even tourists, I expect – will be on Mars, will be cruising through the asteroid belt, and will be beginning the exploration of Jupiter and the outer planets. Perhaps you will be one of the first people to spend a holiday on the Moon or set foot on Mars.

Thilina Heenatigala
General Secretary
Sri Lanka Astronomical Association

Instructor
Royal College Astronomical Society

Friday, October 31, 2008

 

"Studies of ancient climates suggest Earth is now on a fast track to global warming, World Scientists say Humans are Causing Global Warming, Impact of Global Warming on Weather Patterns Underestimated, NASA Study Shows Antarctic Ice Sheet Shrinking, Arctic Lakes Disappear; Researchers Blame Global Climate Change", these were the some of the headlines I have noticed off and on line since 2005. All these craters around one topic "Global Warming", more recently former USA Presidential candidate Al Gore's "An Inconvenient Truth" movie which is about Global warming was a big hit. Frankly I enjoyed watching it; it's very well done movie to make the public alert about "Global climate change." 

But in the first article of "FOCUS", I'm not going to talk about Global Warming; obviously my article has some link in astronomy. Last few weeks I was following the Climate Changing issue very much (we had a program at British Council also), but I was pretty amazed when CNN announced in there program, "that the worldwide astronomers suggest the "Sunshade" as a solution to the current Global Warming." 

So what is this space “Sunshade”? I first learned about this theory about 2 or 3 years ago through an article. This theory was first purposed by James Early of the Lawrence Livermore National Laboratory in 1989. The earlier ideas were for bigger, heavier structures that would have needed manufacture and launch from the moon, which is pretty futuristic. But recently Roger Angel, a University of Arizona Regents' Professor suggests launching a constellation of trillions of small free-flying spacecraft a million miles above Earth into an orbit aligned with the sun, called the L-1 orbit. The spacecraft would form a long, cylindrical cloud with a diameter about half that of Earth, and about 10 times longer. About 10 percent of the sunlight passing through the 60,000-mile length of the cloud, pointing lengthwise between the Earth and the sun would be diverted away from our planet. The effect would be to uniformly reduce sunlight by about 2 percent over the entire planet, enough to balance the heating of a doubling of atmospheric carbon dioxide in Earth's atmosphere. 

The lightweight flyers designed by Angel would be made of a transparent film pierced with small holes. Each flyer would be two feet in diameter, 1/5000 of an inch thick and weigh about a gram, the same as a large butterfly. It would use "MEMS" technology mirrors as tiny sails that tilt to hold the flyers position in the orbiting constellation. The flyer's transparency and steering mechanism prevent it from being blown away by radiation pressure. Radiation pressure is the pressure from the sun's light itself. 

The total mass of all the fliers making up the space sunshade structure would be 20 million tons. At $10,000 a pound, conventional chemical rocket launch is prohibitively expensive. Angel proposes using a cheaper way developed by Sandia National Laboratories for electromagnetic space launchers, which could bring cost down to as little as $20 a pound. 

The sunshade could be deployed by a total 20 electromagnetic launchers launching a stack of flyers “every 5 minutes for 10 years”. The electromagnetic launchers would ideally run on hydroelectric power, but even in the worst-case environmental scenario with coal-generated electricity, each ton of carbon used to make electricity would mitigate the effect of 1000 tons of atmospheric carbon.

But it still perpetuates our unfortunate habit of trying to solve problems created by technology with more technology. If unforeseen consequences of technologies like automobiles and electricity created the problem of global warming, what makes us think another large-scale technology like trillions of orbiting spacecraft won't lead to even worse unforeseen consequences?

And here’s the summary,
• Each flyer would be two feet in diameter, 1/5000 of an inch thick and weigh about a gram, the same as a large butterfly. Not really a big number? Consider how many would be needed. 
• To build such a cloud, 20,000 billions 'butterflies' would need to be sent into space. 
• This would represent about 20 million tons. 
• And even with the electromagnetic space launchers developed at Sandia National Laboratories which promise to send objects in space for about $20 per pound, the total cost would be about $1,000 billion. 
• Of course, you will need to launch these trillion spacecraft. With each such launch sending out 800,000 flyers, the project would require 20 million launches over a decade.
• And Angel summarizes the costs: "It could be developed and deployed in about 25 years at a cost of a few trillion dollars. With care, the solar shade should last about 50 years. So the average cost is about $100 billion a year, or about two-tenths of one percent of the global domestic product." 
• Even if these numbers look — rightly — astronomic — please remember that the monthly U.S. trade deficit is in the $60 to $70 billion range — per month!
While I keep an open mind about the theory, I would like if you could make your comments about the theory, so we could start an online discussion.

-Thilina Heenatigala.



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Note from the writer

This blog contains some of the articles I have written over the years. It's not the complete list as my writing have become more frequent and not really finding time to update the blog.

Hope to update it properly one day, enjoy the pieces I have already uploaded.

Cheers!
Thilina Heenatigala

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