Interesting facts of the Space Age

Discussion in 'General Science & Technology' started by elena_r, Sep 2, 2013.

  1. elena_r Banned Banned

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    It tends to get helpful to be furnished with useful information and improve your general knowledge over some interesting issues. Some may be aware of these facts while there are many others who may not have any idea about the same. A little sharing can help in imparting information and data which can provide useful knowledge to the viewer. The beginning of the space age started way back in the year 1957 on October 4th when the Soviet Union had successfully launched their first artificial satellite into the orbit. It was named Sputnik and this marked the beginning of the Space Age. Its original translation of the Sputnik is fellow traveler of the Earth and related to it, the traveler is the earth and its companion is the satellite Sputnik. The Sputnik which was the size of a basketball orbited the earth once in every 96.2 minutes, travelling at a speed of approximately 29,000 kilometers per hour. Known as The PS-1 or Elementary Satellite – 1, it weighed eighty three kilograms and was equipped with two radio transmitters to broadcast radio pulses and a thermometer. Its radio pulses were detectable and it was visible all around the earth. It could provide atmospheric information to earth which could be picked up by any amateur radio operator. It also provided the scientist with valuable information and its launch triggered new political, technological, military and scientific developments.


    The US who had been working on their own space program and had experienced two failed launches was shocked with the launch of the Sputnik along with the rest of the world. With the launch of the Sputnik, their confidence as one of the most advanced technological power was shattered. Sputnik maintained contact with the earth for twenty one days and thereafter lost radio contact. After a period of fifty seven days in space, Sputnik, the world’s first artificial satellite burnt up when it made its entry again in the Earth’s atmosphere. While many were speculating about the launch, Soviets once again launched Sputnik II which took off on November 3rd, the same year. This was larger and heavier and took the first animal into space, a dog named Laika, who was nicknamed Muttnik. It is reported that within the six days in orbit, at some point of time, the satellite’s battery died and all life support systems failed and Laika is now remembered as one of the heroes of Space Age. The launch of Sputnik had great influence on engineers and scientists who were determined to have an experience in space. It gave the Soviets information about life in space and also gave the world the inclination to explore the outer space. Sputnik III was then launched on May 15th 1958.
     
    Last edited: Sep 2, 2013
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  3. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    As things turned out, Sputnik was of much greater use to the US Navy than to the USSR:
    This link has many more Transit details, including:
    "The Transit system also provided the first world-wide time-keeping service, allowing clocks everywhere to be synchronised with 50 micro-second accuracy. The transit satellite broadcast on 150 and 400 MHz. The two frequencies were used to allow the bending of the satellite radio beacons by the ionosphere to be canceled out, thereby improving location accuracy."

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    Note the long pole with mass at the end. That pole was a "self-deploying" flat ribbon coil wound on a spool at launch. The stressed ribbon "wanted" to be a tube and did so as it unwound. That was another APL invention - gravity gradient stabilization keeping the transmitted beam / signal efficient pointed to earth (great reduction in power required). To damp out the oscillations, magnet material with large hysterious loop was used - A zero energy required highly reliable orientation system that would never "wear out" APL also was one of the first, if not the first to use "momentum wheels" to change the rotational orientation, say about the pole axis. I. e. a wheel with that axis (not necessarily on it just parallel to it) is given some more momentum (or less) and the torque that does than also turns the satellite by the reaction torque. When the torque is removed (zero applied) the satellite continues to slowly rotate keeping total angular moment same a before torque was applied. When satellite has rotation angle desired, an "equal" but opposite torque is applied that stops the satellite rotation, but now at a different rotational orientation.

    Transit 4A, launched June 29, 1961, was the first satellite to use a radioactive power source (a SNAP-3) And that type of nuclear power is what has power the "New Horizons," satellite APL sent on its way to Pluto 10 years ago. It is soon to again come to life in 2015 as is now nearing Pluto, as discussed in next quote.

    There were 38 APL satellites used in only the transit program the Navy relied upon to know where is subs would be if needing to launch an ICBM, but Transit satelites needed to be up-dated from the ground every two days, to correct the internally stored orbit data (ephemeris) so APL invented the DISCOS - the first satellites whose orbit was precisely determined by gravity. The did not require any update corrections for sunshine pressure, residual air drag, Earth's magnetic forces on currents in the satellite, etc. and still only one was needed for a very accurate postion fix, not three like the GPS system now in use.

    The main satellite of DISCOS was an EXACTLY non-magnetic (gold / platinum alloy) sphere about 1 cm in diameter. The rest of the satellite had tiny thrusters and fired them as need to keep the full satellite in same orbit as that tiny sphere. Hold it in the center of its small chamber (follow the tiny sphere's orbit exactly). DISCOS was very expensive to build as the exact center of mass had to known. - Every resistor and drop of solder's weight and location measured - Why GPS was made - it is relatively cheaper to make. More on Discos here: http://www.sciforums.com/threads/a-note-global-warming-threads.40077/page-52#post-3150200

    By now, more than 300 satellites designed and many built by APL where I worked for 30 years have been launched, including two that visited the closest and most distant planets Mercury and Pluto (lost it status as a planet, after the one now arriving there was launched):
    Pluto is so far away and power is limited so the huge volume of data to be collected will take nine months to send back to APL. Let hope it wakes up again OK after nine years of intermittent sleeping during its more than 3 billion mile trip. If it does, more research work for it (and APL) in the Kuiper Belt is planned.

    This link gives facts about Messenger, APL's satellite that has for 10 years and still is giving very detailed data on Mercury: http://messenger.jhuapl.edu/
    A fact most find surprising is that it is energetically harder to go to Mercury than to Pluto! MESSENGER was the first (only?) satellite to orbit mercury.

    Just before the 24 October 2014 orbit adjust, MESSENGER was in an orbit with an altitude at closest approach of 26 kilometers (16.1 miles) above the surface of Mercury. With a velocity change of 19.37 meters per second (43.33 miles per hour), the spacecraft's four largest monopropellant thrusters (with a small contribution from four of the 12 smallest monopropellant thrusters) nudged the spacecraft to an orbit with a closest approach altitude of 185.2 kilometers (115.1 miles). This maneuver also increased the spacecraft's speed relative to Mercury at the maximum distance from Mercury, adding about 7.4 minutes to the spacecraft's eight-hour, five-minute orbit period. APL not only designed and built the MESSENGER satellite but still controls it for NASA.

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    MESSENGER's radar looks thru the constant cloud cover to photogragh surface. Each pixel is 160 Km wide. (100K miles)
    On 12 December 2014, MESSENGER had made 3682 obits at various altitudes in 1357 (earth) days needing occasional boosts as it has residual "air" drag.

    Space craft technology is very similar to that needed for implantable devices as both need:
    light weight / small sizes
    low power to operate
    Extreme quality control (you don't get to "go there" and repair)
    Remote RF control
    telemetry telling how it is operating (or what is the problem if it is not)
    Affordable cost - more important for mass produced implantable devices than NASA.
    Resistance to an environment that is actively trying to destroy the device.

    So it is natural that APL/JHU space department, with its close connection the world leading JHU hospital, should have not only designed more than 200 space craft that were launched but be a leader in implantable medical devices as well. For some details on some of my biomedical projects at APL, see: http://www.sciforums.com/threads/ti...self-through-bloodstream.113489/#post-3251031
     
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  5. danshawen Valued Senior Member

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    I probably owe Sputnik a debt of thanks as well. Eisenhower's fear of falling behind in the cold war space race begat many follow-on satellite projects for many applications, including world telecommunications. The Communications Satellite Act of 1962, signed into law by John Kennedy a month before his assassination, created Comsat Corporation, the US signatory to Intelsat, an international satellite consortium acting on a vision provided by Arthur C. Clarke of a world communication system based on the use of geostationary satellites orbiting at a distance of 22,300 miles above the Earth's surface.

    I joined Comsat Labs in 1981, and enjoyed over 20 years of collaboration with some of the best international teams of engineering excellence on the planet. Among other things, the R&D facilities funded by Intelsat in suburban Clarksburg, MD made satellite telecommunications competitive with fiber optics, at the time, considered to be a game-changing competitor. Competition is usually a good and healthy thing, but a growing crescendo over telecom monopolies like Ma Bell eventually reached the halls of congress, and Comsat corporation, a government created monopoly was eventually 'merged' with Lockheed Martin in 2000, and its regulated international business is about all that survived the takeover.

    I could not stomach the vision of LMGT, which was to extend Reagan's Star Wars initiative to include all of NATO, so I was among the many who left for greener pastures as the globalization of the telecommunications industry meant that most of those jobs in the US would be lost to engineering teams in parts of the world sporting lower wages and standards of living.
     
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  7. Fraggle Rocker Staff Member

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    I will always have fond memories of Sputnik, because it changed my life. In October 1957, I was in my second year of high school (grade 10). As a science and math major, I got very little respect from the other students, especially the girls.

    Then suddenly, literally overnight, the Space Race began. Science and math majors were heroes because we were going to make sure that America beat the commies in outer space.

    The jocks who used to sneer at us were opening doors for us. Pachucos who used to shake us down for our lunch money stayed discreetly near us when we walked through tough neighborhoods. And the girls, oh those wonderful girls... they lined up to get dates with us.

    This lasted until the end of the 1970s, when the Religious Redneck Retard Revival made science and any form of rational thinking "counter to God's will." Fortunately by then I had a great, high-paying job as a computer programmer, so the girls still loved me.

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    I love Sputnik.
     
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  8. cosmictraveler Be kind to yourself always. Valued Senior Member

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    I remember this about atomic bombs when attending elementary school.

     
  9. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    note down in right corner the credit to Johns Hopkins Applied Physic Lab. Both Messenger & Discovery, now starting to send back photos from Pluto, after a 9+ year trip to get there were designed and built at APL/JHU where I worked for 30 years. The two hardest to reach planets (well Pluto was a planet when APL's craft started its trip to it) were reached by APL made, from concept, design to launch satellites. Strange as it may seem, it takes more energy to orbit Mercury than to reach Pluto.

    More on both APL satellites and its Transit System,with 38 satellites used by US Navy before GPS existed, is in post 2 .
    More on Messenger, including last picture it took just before planed crash into surface, out of fuel after many years of data collection while orbiting Mercury at: http://www.theverge.com/2015/5/1/8527957/messenger-last-image-mercury

    Two closely related things of interest to note in above messenger photo:
    (1) The solar flux in Mercury's orbit is very intense - the sun side of the satellite has a curved shadow casting shadow the satellite can live in and is highly reflective, but some solar energy will be absorbed, so the back side of that shield is very black, to radiate the absorbed energy away. The satellite body is mainly gold foil wrapped to reflect that IR radiation which hits the satellite's main body away. This only works if the shield is always between the satellite body and the sun. How that is achieved is point (2):

    (2) Note that on the opposite of the satellite from the shield is a long rod with mass at the end. It does not need to be as long as the rod shown in the first photo of post two as the gradient of solar gravity is much stronger at Merury's orbit than at Earth's orbit. APL/JHU invented this "gravity gradient" system which the 38 TRANSIT satellites used to keep the transmitting antennae always pointing down to the earth's ocean (and Navy ships). The most clever part of the invention, discussed more in post 2, was how the initial oscillations in angle were killed with zero energy required. Other APL inventions & "firsts" are also discussed in post 2.

    If I sound proud of the fantastic work APL's space and fabrication divisions did - it is because I am. Once when satellite contract given to much better known JPL was over budget and behind schedule, NASA transferred contract to APL. Despite the hole we were in at the start, we completed it on time and under budget! Soon after that, NASA adopted APL's "Smaller, Better, and Cheaper" guide lines for all contractors. They had to, as their budget was being cut.

    After 10 years working on the controlled fusion problem in the "research center" I spent most of the next 20 in the "space department" but often was more concerned with small implantable medical devices* or energy systems. The highly creative, educated, and talented technical staff at APL was declared to be a "national resource" while I worked there - not just an honor, but with practical impact - Contracts facilitated and access to critical strategic materials.

    * Near the end of post 2 is a list of 8 reasons why small implantable medical devices are a natural activity for a space department building satellites.
     
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