Author Topic: Explorer 1  (Read 4138 times)

Offline TJL

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Explorer 1
« on: 10/09/2007 10:39 PM »
With all the talk this month regarding the 50th anniversary of the beginning of the space age, it dawned on me that the first (successful) satellite launch by the United States took place at night.
Was wondering why they didn't feel it was important to have as much visibility as possible on that launch?
Thank you

Offline edkyle99

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RE: Explorer 1
« Reply #1 on: 10/09/2007 11:49 PM »
Quote
TJL - 9/10/2007  5:39 PM

With all the talk this month regarding the 50th anniversary of the beginning of the space age, it dawned on me that the first (successful) satellite launch by the United States took place at night.
Was wondering why they didn't feel it was important to have as much visibility as possible on that launch?
Thank you

My recollection is that a night launch was performed to allow visual tracking further down range.  Three previous suborbital Jupiter-C launches had also been at night, to allow visual tracking of the test nose cones during reentry.  

 - Ed Kyle

Offline Andy_Small

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Re: Explorer 1
« Reply #2 on: 10/10/2007 01:26 AM »
when Explorer I launched did it have as much TV coverage as say a Freedom 7 Launch?

Offline dwmzmm

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Re: Explorer 1
« Reply #3 on: 10/10/2007 01:39 AM »
Quote
Andy_Small - 9/10/2007  8:26 PM

when Explorer I launched did it have as much TV coverage as say a Freedom 7 Launch?

Or did you mean Vanguard?!
Dave, NAR # 21853 SR.

Offline edkyle99

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RE: Explorer 1
« Reply #4 on: 10/10/2007 01:54 AM »
Quote
edkyle99 - 9/10/2007  6:49 PM

Quote
TJL - 9/10/2007  5:39 PM

With all the talk this month regarding the 50th anniversary of the beginning of the space age, it dawned on me that the first (successful) satellite launch by the United States took place at night.
Was wondering why they didn't feel it was important to have as much visibility as possible on that launch?
Thank you

My recollection is that a night launch was performed to allow visual tracking further down range.  Three previous suborbital Jupiter-C launches had also been at night, to allow visual tracking of the test nose cones during reentry.  

 - Ed Kyle

An updated/correction on this.  According to Richard S. Lewis in "Appointment on the Moon", the launch time (the window was 10:30 pm to 2:30 am Eastern Standard Time) was selected to "equalize the time the satellite would be in daylight and darkness on its first orbit".  This was meant to minimize thermal stress on the batteries and radios.

 - Ed Kyle

Offline edkyle99

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Re: Explorer 1
« Reply #5 on: 10/10/2007 02:03 AM »
Quote
Andy_Small - 9/10/2007  8:26 PM

when Explorer I launched did it have as much TV coverage as say a Freedom 7 Launch?

The Army didn't start briefing the press until five days before the planned liftoff, and then only in confidence with no official press release allowed until after the launch.   There was no TV after the Vanguard debacle to the best of my knowledge, but also probably because Redstone was still a secret Cold War missile system at the time.  Locals gathered on the beach to watch only because rumors had spread that the launch was on.  Spotlights at the pad would have helped clue the locals as well.

Keep in mind too that the Vanguard national launch coverage was a rare deal back then that required a massive effort to set up the remote network feeds, etc.  There weren't any communication satellites back then!

 - Ed Kyle

Online catdlr

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Re: Explorer 1
« Reply #6 on: 07/27/2016 02:37 AM »
Bump...

Explorer 1: First US Satellite and Launch Team in blockhouse, January 31,1958 HD

 
Dan Beaumont Space Museum

Published on Jul 26, 2016

'First complete documentary on Explorers I and III produced for "THE BIG PICTURE" -- "Army Satellites" reveals the dramatic, suspenseful story of how the Army--when the prestige of the United States throughout the world had been shaken by events beyond its control--stirred the hearts and emotions of the American people with an epic display of scientific and technical teamwork.

The story depicts the drama of the crucial 84 days before launching Explorer I. The story begins on the morning of November 8, 1957, at Huntsville, Alabama. THE BIG PICTURE cameras cover a sudden meeting called by Major General John B. Medaris with his staff which included Dr. Wernher von Braun.

From this point, the film develops with dramatic sequences leading into the final "countdown" in the blockhouse at Cape Canaveral, Florida.

"Army Satellites" is an actual step-by-step documentary filmed over a five month period by Army Signal Corps cameramen and is narrated by Alexander Scourby. With this issue of THE BIG PICTURE, the series has reached a total of 229 individual episodes since it started in 1951 as a public service feature for television stations totaling 328 in the United States.'

"The Big Picture" episode TV-397


Reupload of a previously uploaded film, in one piece instead of multiple parts, and with improved video & sound.

Public domain film from the US National Archives, slightly cropped to remove uneven edges, with the aspect ratio corrected, and one-pass brightness-contrast-color correction & mild video noise reduction applied.
The soundtrack was also processed with volume normalization, noise reduction, clipping reduction, and/or equalization (the resulting sound, though not perfect, is far less noisy than the original).


Explorer 1 was the first successfully launched U. S. spacecraft. Launched late on 31 January 1958 (10:48 p.m. EST, or 03:48 UTC on 01 February) on an adapted Jupiter-C rocket, Explorer 1 carried instrumentation for the study of cosmic rays, micrometeorites, and for monitoring of the satellite's temperature.

The Jupiter-C launch vehicle consisted of four propulsive stages. The first stage was an upgraded Redstone liquid-fueled rocket. The second, third, and fourth stage rockets consisted of eleven, three, and one (respectively) Sergeant motors. The satellite itself was the fourth stage of the Jupiter-C rocket. It was cylindrical, 2.03 m long and 0.152 m in diameter. Four whip antennas were mounted symmetrically about the mid-section of the rocket. The spacecraft was spin stabilized.

The 4.82 kg instrumentation package was mounted inside of the forward section of the rocket body. A single Geiger-Mueller detector was used for the detection of cosmic rays. Micrometeorite detection was accomplished using both a wire grid (arrayed around the aft section of the rocket body) and an acoustic detector (placed in contact with the midsection). Data from the instruments were transmitted continuously, but acquisition was limited to those times when the spacecraft passed over appropriately equipped ground receiving stations. Assembly of data proceeded slowly also due to the fact that the satellite's spin-stabilized attitude transitioned into a minimum kinetic energy state, that of a flat spin about its transverse axis. This was deduced from the modulation of the received signal, which produced periodic fade-outs of the signal.

Explorer 1 was the first spacecraft to successfully detect the durably trapped radiation in the Earth's magnetosphere, dubbed the Van Allen Radiation Belt (after the principal investigator of the cosmic ray experiment on Explorer 1, James A. Van Allen). Later missions (in both the Explorer and Pioneer series) were to expand on the knowledge and extent of these zones of radiation and were the foundation of modern magnetospheric studies.

https://www.youtube.com/watch?v=yBAJwhSe9YU?t=001

Tony De La Rosa

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Re: Explorer 1
« Reply #7 on: 07/30/2016 04:19 PM »
Although Explorer 1 is an interesting footnote in history the Vanguard project is much more significant to history.  A surprising amount of the world around us we owe to the Vanguard project but surprisingly little to Explorer.  The very experiment that is so much touted for Explorer 1 owes its existence to the Vanguard project.  The ability to track both Sputnik and Explorer were due to the Vanguard project.  You can even track the history of the modern satellite navigation systems back to Vanguard.

Online catdlr

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Re: Explorer 1
« Reply #8 on: 11/08/2016 02:38 AM »
1st US Satellite: Explorer 1 Launch 1958 NASA; Spacecraft & Launch Vehicle Preparation

Jeff Quitney

Published on Nov 7, 2016
NASA & Space Miscellany playlist: https://www.youtube.com/playlist?list...

more at: http://scitech.quickfound.net/astro/n...

Overview of the first American satellite, Explorer 1, and its launch on January 31, 1958.

Excerpt from "US Space Explorations" NASA Langley Research Center film L-703.

Explorer 1 was the first satellite of the United States, launched as part of its participation in the International Geophysical Year. The mission followed the first two satellites the previous year; the Soviet Union's Sputnik 1 and 2, beginning the Cold War Space Race between the two nations.

Explorer 1 was launched on January 31, 1958 at 22:48 Eastern Time (equal to February 1, 03:48 UTC) atop the first Juno booster from LC-26 at the Cape Canaveral Missile Annex, Florida. It was the first spacecraft to detect the Van Allen radiation belt, returning data until its batteries were exhausted after nearly four months. It remained in orbit until 1970, and has been followed by more than 90 scientific spacecraft in the Explorer series.

Explorer 1 was given Satellite Catalog Number 4, and the Harvard designation 1958 Alpha 1, the forerunner to the modern International Designator...

http://nssdc.gsfc.nasa.gov/nmc/master...

Explorer 1 was the first successfully launched U. S. spacecraft. Launched late on 31 January 1958 (10:48 p.m. EST, or 03:48 UTC on 01 February) on an adapted Jupiter-C rocket, Explorer 1 carried instrumentation for the study of cosmic rays, micrometeorites, and for monitoring of the satellite's temperature.

The Jupiter-C launch vehicle consisted of four propulsive stages. The first stage was an upgraded Redstone liquid-fueled rocket. The second, third, and fourth stage rockets consisted of eleven, three, and one (respectively) Sergeant motors. The satellite itself was the fourth stage of the Jupiter-C rocket. It was cylindrical, 2.03 m long and 0.152 m in diameter. Four whip antennas were mounted symmetrically about the mid-section of the rocket. The spacecraft was spin stabilized.

The 4.82 kg instrumentation package was mounted inside of the forward section of the rocket body. A single Geiger-Mueller detector was used for the detection of cosmic rays. Micrometeorite detection was accomplished using both a wire grid (arrayed around the aft section of the rocket body) and an acoustic detector (placed in contact with the midsection). Data from the instruments were transmitted continuously, but acquisition was limited to those times when the spacecraft passed over appropriately equipped ground receiving stations. Assembly of data proceeded slowly also due to the fact that the satellite's spin-stabilized attitude transitioned into a minimum kinetic energy state, that of a flat spin about its transverse axis. This was deduced from the modulation of the received signal, which produced periodic fade-outs of the signal.

Explorer 1 was the first spacecraft to successfully detect the durably trapped radiation in the Earth's magnetosphere, dubbed the Van Allen Radiation Belt (after the principal investigator of the cosmic ray experiment on Explorer 1, James A. Van Allen). Later missions (in both the Explorer and Pioneer series) were to expand on the knowledge and extent of these zones of radiation and were the foundation of modern magnetospheric studies.

Public domain film from the US National Archives, slightly cropped to remove uneven edges, with the aspect ratio corrected, and one-pass brightness-contrast-color correction & mild video noise reduction applied.
The soundtrack was also processed with volume normalization, noise reduction, clipping reduction, and/or equalization (the resulting sound, though not perfect, is far less noisy than the original).

https://www.youtube.com/watch?v=8ahA8jxY1wQ?t=001

Tony De La Rosa

Offline rocketeer

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No live TV of Vanguard
« Reply #9 on: 11/10/2016 07:05 PM »
Ed Kyle replied to a query about live TV coverage of Explorer 1 (of which there was none), and mentioned a huge effort to set up network coverage of Vanguard TV-3 in that bygone era. In fact the oft-repeated story of live TV coverage of the Vanguard failure is a space-age urban myth. The first live TV of a launch from Cape Canaveral did not occur until November 1958 to cover the Pioneer 2 launch, although there was tape-delay TV coverage of the first two Pioneers in August and October of 1958. The true story of live Pioneer TV coverage at Cape Canaveral is told superbly in an article in Air & Space magazine (December 2000-January 2001). I did a careful analysis of the alleged live coverage of the first Vanguard for my June 2014 article in Spaceflight magazine. I discovered that motion picture film of the launch attempt was rushed from the Cape to a local airport and flown to New York for inclusion on the evening TV news program. How the appearance of a same-day film clip on the network news that evening got confused with live TV coverage is something of a mystery. It is repeated in numerous accounts of the Vanguard disaster, yet there was absolutely no mention of live Vanguard TV in coverage in the New York Times, nor are there any old kinescopes of Vanguard TV featured on YouTube. It is time to debunk the myth of Vanguard TV-3 live coverage once and for all...
 
     
« Last Edit: 01/07/2017 08:38 PM by rocketeer »

Online catdlr

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Re: Explorer 1
« Reply #10 on: 12/16/2017 02:57 AM »
bump for another historic video...

Launching of Explorer


NASA's Marshall Center
Published on Dec 15, 2017

This 1958 film covers the January 31, 1958 launching of Explorer, the first satellite launched by the United States. The project was a collaboration that included the Army Ballistic Missile Agency in Huntsville, Alabama, the Jet Propulsion Laboratory, and Dr. James van Allen of the University of Iowa. This film focuses on the development, preparation and launching of the Army’s Jupiter-C launch vehicle. Explorer was the US contribution to the International Geophysical Year 1957-1958. Explorer revolved around Earth in a looping orbit that took it as close as 354 kilometers (220 miles) to Earth and as far as 2,515 kilometers (1,563 miles). It made one orbit every 114.8 minutes, or a total of 12.54 orbits per day. The satellite itself was 203 centimeters (80 inches) long and 15.9 centimeters (6.25 inches) in diameter. Explorer 1 made its final transmission on May 23, 1958. It entered Earth's atmosphere and burned up on March 31, 1970, after more than 58,000 orbits.

https://www.youtube.com/watch?v=kpO4EAf9rC0?t=001

Tony De La Rosa

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