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In 1968 Shirley Chisholm became the first Black woman elected to the United States Congress. In 1972 she launched a campaign for the Democratic presidential nomination, breaking another political barrier.
MORE →Reflects the personal views, recollections, and perspective of the author, Mike Davis.
This is a personal recollection on the Move fire on May 13, 1985
 Cutaway diagram of Explorer 19 | |
| Names | AD-A Air Density experiment-A |
|---|---|
| Mission type | Air density |
| Operator | NASA |
| COSPAR ID | 1963-053A |
| SATCAT no. | 00714 |
| Spacecraft properties | |
| Spacecraft | Explorer XIX |
| Spacecraft type | Air Density Explorer |
| Bus | AD-A |
| Manufacturer | Langley Research Center |
| Launch mass | 7.7 kg (17 lb) |
| Dimensions | 3.66 m (12.0 ft) diameter |
| Power | Solar cells and Rechargeable batteries |
| Start of mission | |
| Launch date | 19 December 1963, 18:49:25 GMT |
| Rocket | Scout X-4 (S-122R) |
| Launch site | Vandenberg, PALC-D |
| Contractor | Vought |
| Entered service | 19 December 1963 |
| End of mission | |
| Decay date | 10 May 1981 |
| Orbital parameters | |
| Reference system | Geocentric orbit |
| Regime | Low Earth orbit |
| Perigee altitude | 590 km (370 mi) |
| Apogee altitude | 2,394 km (1,488 mi) |
| Inclination | 78.6° |
| Period | 115.9 minutes |
| Instruments | |
| Satellite Drag Atmospheric Density | |
Explorer program | |
Explorer 19, (Air Density experiment A, or AD-A), was a NASA satellite launched on 19 December 1963, as part of the Explorer program. It was the third of six identical Explorer satellites launched to study air density and composition, and the second to reach orbit.[1] It was identical to Explorer 9.[2]
Explorer 19 was launched while Explorer 9, the first satellite in the series, was still active, so that densities in two different portions of the atmosphere were sampled simultaneously. The spacecraft consisted of alternating layers of aluminium foil and Mylar polyester film. Uniformly distributed over the aluminum surface were 5.1 cm (2.0 in) diameter dots of white paint for thermal control. The sphere was packed in a tube 21.6 cm (8.5 in) in diameter and 48.3 cm (19.0 in) long and mounted in the nose of the fourth stage of the launch vehicle. Upon separation of the fourth stage, the sphere was inflated by a nitrogen gas bottle, and a separation spring ejected it out into its own orbit. The two hemispheres of aluminum foil were separated with a gap of Mylar at the spacecraft's equator and served as the antenna. A 136.620 MHz, 15 mW beacon was carried for tracking purposes. The spacecraft was successfully orbited, but its apogee was lower than planned. The beacon did not have sufficient power to be received by ground tracking stations, making it necessary to rely solely on the SAO Baker-Nunn camera network for tracking.[3]
This experiment was designed to determine nonsystematic changes of upper atmospheric density by conducting studies of the drag on a 3.6 m (12 ft) diameter, low-density sphere caused by short-term variations in solar activity. Density values near perigee were deduced from sequential observations of the spacecraft position using optical (Baker-Nunn camera network) and radio/radar tracking techniques.[4]
The objective of this experiment was to determine atmospheric density as a function of altitude, latitude, and time by measuring atmospheric drag on a low mass-to-area ratio (0.7680 kg per m2) spherical satellite. The orbit was Sun-synchronized so that near-polar densities would always be obtained along noon and midnight meridians.[5]
Explorer 19 was launched from Launch Area 3 at the Wallops Flight Facility (WFF), atop a Scout X-4 launch vehicle with the serial number S-122R. It was the second spacecraft launched from Wallops Island to achieve orbit.. The launch occurred at 18:49:25 GMT on 19 December 1963, and resulted in Explorer 19 being deployed into an orbit with an apogee of 2,394 km (1,488 mi), a perigee of 590 km (370 mi), 78.6° of inclination and a period of 115.9 minutes.[6] Upon separation of the fourth stage, the sphere was inflated by a nitrogen gas bottle, and a separation spring ejected it out into its own orbit. The two hemispheres of aluminium foil were separated with a gap of Mylar at the spacecraft's equator and served as the antenna. A 136.620 MHz, 15 mW beacon was carried for tracking purposes, but the beacon failed on the first orbit and the SAO Baker-Nunn camera network had to be relied upon for tracking. Power was supplied by solar cells and rechargeable batteries.[3]
Explorer 19's launch vehicle placed it into a slightly lower than planned orbit.[2]
This article incorporates text from this source, which is in the public domain.
This article incorporates text from this source, which is in the public domain.
This article incorporates text from this source, which is in the public domain.
This article incorporates text from this source, which is in the public domain.
Source: Wikipedia. Article content is retrieved live through the MediaWiki API.
Explorer 19, (Air Density experiment A, or AD-A), was a NASA satellite launched on 19 December 1963, as part of the Explorer program. It was the third of six identical Explorer satellites launched to study air density and composition, and the second to reach orbit. It was identical to Explorer 9.
MS Explorer or MV Explorer was a Liberian-registered cruise ship, used for Antarctic cruising. She was the first cruise ship to sink there, after striking an iceberg on 23 November 2007. All passengers and crew were rescued. The ship was commissioned and operated by the Swedish explorer Lars-Eric Lindblad. Its 1969 expeditionary cruise to Antarctica was the forerunner for today's sea-based tourism in that region. The vessel was originally named MS Lindblad Explorer (until 1985), and MS Society Explorer (until 1992). Ownership of the vessel changed several times, the last owner being the Toronto-based travel company Gap Adventures which acquired Explorer in 2004. Explorer was abandoned in the early hours of 23 November 2007 after taking on water near the South Shetland Islands in the Southern Ocean, an area which is usually stormy but was calm at the time. Explorer was stated by the Chilean Navy to have sunk at an approximate position of 62°24′S 57°16′W, between the South Shetlands and Grahams Land in the Bransfield Strait; where the depth is roughly 600 metres (2,000 ft). The Royal Navy Antarctic Patrol Ship Endurance, whilst carrying out a hydrographic survey for the British Antarctic Survey and at the request of the Foreign and Commonwealth Office, later pinpointed Explorer's final resting place as 62°24′18″S 57°11′46″W, at an approximate depth of 1,130 metres (3,710 ft) – a distance of 4,373 m (14,350 ft) from her reported sinking position. This is broadly consistent with the direction of the prevailing current.
Windows Internet Explorer 8 (IE8) is a major version of the Internet Explorer web browser for Windows released by Microsoft on March 19, 2009 and is the successor to Internet Explorer 7. It was the default browser on Windows 7 and Windows Server 2008 R2. It is the first version of Internet Explorer to pass the Acid2 test, the last of the major browsers to do so. It is also the first version of Internet Explorer to include web development tools, as previous versions of Internet Explorer never had tools to develop websites. (In the later Acid3 Test, it only scores 24/100.) Additionally, it is the first version of Internet Expolrer to has a Compatibility View mode to optionally emulate older versions' rendering behavior, and color-coded tab groups where links opened in new tabs share the color of the website they originated from. According to Microsoft, security, ease of use, and improvements in RSS, CSS, and Ajax support were its priorities for IE8. It is the last version of Internet Explorer to run on Windows XP SP2+, Windows XP x64 Edition SP2, Windows Server 2003 SP2, Windows Vista RTM through SP1 and Windows Server 2008 RTM. It is the final Itanium version of Internet Explorer as well, although it is only available as pre-installed in the Itanium edition of Windows Server 2008 R2. The Itanium version does not support versions earlier than Windows Server 2008 R2. In addition, it is the last version of Internet Explorer supporting processors without PAE or SSE2.
Internet Explorer 11 (IE11) is the eleventh and final version of the Internet Explorer web browser. It was initially included in the release of Windows 8.1, Windows RT 8.1 and Windows Server 2012 R2 on October 17, 2013, and was later released for Windows 7 and Windows Server 2008 R2 on November 7, 2013. It is the successor to Internet Explorer 10, released the previous year, and was the original default browser in Windows 8.1 and Windows Server 2012 R2. It is also included in the release of Windows 10, Windows Server 2016 and Windows Server 2019. On April 16, 2019, it was made available to Windows Server 2012 and Windows Embedded 8 Standard as the final expansion of Internet Explorer 11 availability. At its release, Internet Explorer 11 also supported processors with PAE, SSE2 and NX bit, like its predecessor. 64-bit editions require an x86-64 CPU that must also support the CMPXCHG16b, PrefetchW and LAHF/SAHF instructions. Microsoft adjusted their product lifecycle policies to only support the most recent version of Internet Explorer offered for any given version of Windows on January 12, 2016, and later expanded to Windows Server 2012 and Windows Embedded 8 Standard on January 31, 2020. Support for Internet Explorer 11, now regarded as an "OS component", is bound to the version of the Windows it is installed on. Thus, Microsoft provides updates only to currently supported versions of Windows. This includes Windows 10 LTSC (formerly LTSB), and supported Windows Server versions, which will continue to receive IE11 updates until their respective end-of-support dates. The exception to this is the Windows 10 Semi-Annual Channel (SAC). For SAC versions of Windows 10, Internet Explorer 11 support ended on June 15, 2022, and it was permanently disabled on February 14, 2023. Any remaining icons or shortcuts were due to be removed on June 13, 2023, however, on May 19, 2023, various organizations disapproved, leading Microsoft to withdraw the change. Furthermore, despite Microsoft's alleged permanent IE11 disablement, IE11 can still be accessed in some capacity using unofficial methods. IE Mode, a feature of Microsoft Edge, enables Edge to display web pages using Internet Explorer 11's Trident layout engine and other core components. Through IE Mode, the underlying technology of Internet Explorer 11 partially exists on Windows that do not support Internet Explorer as a proper application, such as Windows 11 and later versions that derive from the Windows 11 codebase. Microsoft has announced support for IE Mode through at least 2029, with a one-year advance notice before retiring this variant of IE11. Internet Explorer 11 is retired and out of support. On most editions, such as Home and Pro, the desktop browser has been disabled and replaced by Microsoft Edge (with paid ESU exceptions until 2028). Some editions are exceptions, notably the Windows 10 China Government Edition. However, IE mode in Microsoft Edge remains, meaning IE 11's rendering engine will be supported through at least 2029 and retired only after a year's notice. The last edition with IE 11 support is Windows 10 IoT Enterprise LTSC 2021 (for specialized devices such as medical equipment controllers and ATMs), supported until January 13, 2032, at which point Internet Explorer 11 support fully ends.
Before the 1921 destruction of Tulsa’s Greenwood District, Black residents had created a remarkable center of business and community life. The district included stores, professional offices, entertainment venues and homes owned by Black citizens. Understanding Greenwood means learning what was built—not only what was burned.
MORE →The Greenwood District.
