Ask Physics Expert

Assignment:

Please read the given news and prepare 2 (two pages) about:

1) How we put satellites in orbit and

2) Why satellites should eventually fall back to earth.

http://news.yahoo.com/nasa-gives-1-hour-window-falling-satellite-030650758.html

CAPE CANAVERAL, Florida (AP) — The 6-ton NASA satellite on a collision course with Earth clung to space Friday, apparently flipping position in its ever-lower orbit and stalling its death plunge.

The old research spacecraft was targeted to crash via the atmosphere sometime Friday night or early Saturday, putting Canada and Africa in the potential crosshairs, though most of the satellite should burn up during re-entry. The United States was not entirely out of the woods; the possible strike zone skirted Washington State.

‘It just doesn't want to come down,’ said Jonathan McDowell of the Harvard-Smithsonian Center for the Astrophysics.

McDowell state the satellite's delayed demise describes how unreliable predictions can be. That said, ‘The best guess is that it will still splash in the ocean, just because there is more ocean out there.’

Until Friday, increased solar activity was causing the atmosphere to expand and the 35-foot, bus-size satellite to free fall more rapidly. However late Friday morning, NASA said the sun was no longer the main factor in the rate of descent and that the satellite's position, shape or both had modified by the time it slipped down to a 100-mile orbit.

‘In the last 24 hrs, something has happened to the spacecraft,’ said NASA orbital debris scientist Mark Matney.

On Friday night, NASA said it predicted the satellite to come crashing down between 11:45 p.m. and 12:45 a.m. EDT Saturday. This was going to be passing over the Atlantic, Pacific and Indian oceans at that time, and also Canada and Africa.

‘The risk to public safety is very remote,’ NASA said in a statement.

Any surviving wreckage is expected to be limited to a 500-mile swath.

The Upper Atmosphere Research Satellite, or UARS, will be the biggest NASA spacecraft to crash back to Earth, uncontrolled, as the post-Apollo 75-ton Skylab space station and the more than 10-ton Pegasus 2 satellite, both in 1979.

Russia's 135-ton Mir space station slammed via the atmosphere in 2001; however it was a controlled dive into the Pacific.

Some 26 pieces of the UARS satellite - representing 1,200 pounds of heavy metal - are expected to rain down somewhere. The biggest surviving chunk should be no more than 300 pounds (that is, 136 kilograms).

Earthlings can take comfort in the fact that no one has ever been hurt by falling space junk - to anyone's knowledge - and there has been no serious property damage. NASA put the chances that somebody somewhere on Earth would get hurt at 1-in-3,200. But any one person's odds of being struck were estimated at 1-in-22 trillion; given there are 7 billion people on the planet.

‘Keep in mind that we have bits of debris re-entering the atmosphere every single day,’ Matney said in short remarks broadcast on NASA TV.

In any case, finders definitely are not keepers.

Any surviving wreckage belongs to the NASA, and it is against the law to keep or sell even the smallest piece. There are no toxic chemicals on board, however sharp edges could be dangerous, so the space agency is warning the public to keep hands off and call police.

The $740 million UARS was launched in the year 1991 from space shuttle Discovery to study the atmosphere and the ozone layer. At time, the rules were not as firm for safe satellite disposal; now a spacecraft should be built to burn up upon re-entry or have a motor to propel it into a much higher, long-term orbit.

NASA shut UARS down in 2005 after lowering its orbit to hurry its end. The potential satellite-retrieval mission was ruled out following the 2003 shuttle Columbia disaster, and NASA didn’t want the satellite hanging around orbit posing a debris hazard.

Space junk is a growing problem in the low-Earth orbit. More than 20,000 pieces of debris, at least 4 inches in diameter, are being tracked on a daily basis. Such objects pose a serious threat to the International Space Station.

Physics, Academics

  • Category:- Physics
  • Reference No.:- M9394

Have any Question? 


Related Questions in Physics

Question oppositely charged parallel plates are separated

Question: Oppositely charged parallel plates are separated by 5.31 mm. A potential difference of 600 V exists between the plates. (a) What is the magnitude of the electric field between the plates? N/C (b) What is the ma ...

Question an object of mass m attached to a spring of force

Question: An object of mass m attached to a spring of force constant k oscillates with simple harmonic motion. The maximum displacement from equilibrium is A and the total mechanical energy of the system is E. What is th ...

Quesion when a nucleus of 235u undergoes fission it breaks

Quesion: When a nucleus of 235U undergoes fission, it breaks into two smaller, more tightly bound fragments. Part A: Calculate the binding energy per nucleon for 235U. Express your answer with the appropriate units. E=__ ...

Question a nylon rope used by mountaineers elongates 130 m

Question: A nylon rope used by mountaineers elongates 1.30 m under the weight of a 65.0-kg climber. If the rope is 45.0 m in length and 7.0 mm in diameter, what is Young's modulus for this material? The response must be ...

Question an object is 30 cm in front of a converging lens

Question: An object is 30 cm in front of a converging lens with a focal length of 10 cm. Use ray tracing to determine the location of the image. What are the image characteristics: (i) upright or inverted, (ii) magnifica ...

Question an object of mass m is traveling on a horizontal

Question: An object of mass m is traveling on a horizontal surface. There is a coefficient of kinetic friction µ between the object and the surface. The object has speed v when it reaches x=0 and encounters a spring. Th ...

Question in one of the classic nuclear physics experiments

Question: In one of the classic nuclear physics experiments at the beginning of the 20th century, an alpha particle was accelerated towards a gold nucleus and its path was substantially deflected by the Coulomb interacti ...

Question an object of mass m is dropped from height h above

Question: An object of mass m is dropped from height h above a planet of mass M and radius R. Find an expression for the object's speed as it hits the ground. Express your answer in terms of the variables m,M,h,R and app ...

Question one type of bb gun uses a spring-driven plunger to

Question: One type of BB gun uses a spring-driven plunger to blow the BB from its barrel. (a) Calculate the force constant of its plunger's spring if you must compress it 0.130 m to drive the 0.0580-kg plunger to a top s ...

Question an object is placed 30 cm to the left of a

Question: An object is placed 30 cm to the left of a converging lens that has a focal length of 15cm. Describe what the resulting image look like (i.e. image distance, magnification, upright or inverted images, real or v ...

  • 4,153,160 Questions Asked
  • 13,132 Experts
  • 2,558,936 Questions Answered

Ask Experts for help!!

Looking for Assignment Help?

Start excelling in your Courses, Get help with Assignment

Write us your full requirement for evaluation and you will receive response within 20 minutes turnaround time.

Ask Now Help with Problems, Get a Best Answer

Why might a bank avoid the use of interest rate swaps even

Why might a bank avoid the use of interest rate swaps, even when the institution is exposed to significant interest rate

Describe the difference between zero coupon bonds and

Describe the difference between zero coupon bonds and coupon bonds. Under what conditions will a coupon bond sell at a p

Compute the present value of an annuity of 880 per year

Compute the present value of an annuity of $ 880 per year for 16 years, given a discount rate of 6 percent per annum. As

Compute the present value of an 1150 payment made in ten

Compute the present value of an $1,150 payment made in ten years when the discount rate is 12 percent. (Do not round int

Compute the present value of an annuity of 699 per year

Compute the present value of an annuity of $ 699 per year for 19 years, given a discount rate of 6 percent per annum. As