M28

M28, M-28, or M/28 may refer to:

Project Echo

Project Echo was the first passive communications satellite experiment. Each of the two American spacecraft, launched in 1960 and 1964, was a metalized balloon satellite acting as a passive reflector of microwave signals. Communication signals were bounced off them from one point on Earth to another.

Echo 1

NASA's Echo 1 satellite was built by Gilmore Schjeldahl's G.T. Schjeldahl Company in Northfield, Minnesota. The balloon satellite functioned as a reflector, not a transceiver, so that after it was placed in a low Earth orbit, a signal would be sent to it, reflected or bounced off its surface, and then returned to Earth.

During ground inflation tests, 40,000 pounds (18,000 kg) of air was needed to fill the balloon, but while in orbit, several pounds of gas were all that was required to fill the sphere. At launch, the balloon weighed 156.995 pounds (71.212 kg) which included 33.34 pounds (15.12 kg) of sublimating powders of two types. The first weighing 10 pounds (4.5 kg) with a very high vapor pressure, the second with a much lower vapor pressure. According to NASA, "To keep the sphere inflated in spite of meteorite punctures and skin permeability, a make-up gas system using evaporating liquid or crystals of a subliming solid were incorporated inside the satellite."

Video clip

Video clips are short clips of video, usually part of a longer recording. The term is also more loosely used to mean any short video less than the length of a traditional television program.

On the Internet

With the spread of Internet global accessing (fastest Internet broadband connection of TCP with accumulator cables and semi fast connection), video clips have become very popular online. By mid-2006 there were tens of millions of video clips available online, with new websites springing up focusing entirely on offering free video clips to users and many established and corporate sites adding video clip content to their websites. With the spread of broadband Internet access, video clips have become very popular online. Whereas most of this content is non-exclusive and available on competing sites, some companies produce all their own videos and do not rely on the work of outside companies or amateurs.

While some video clips are taken from established media sources, community or individual-produced clips are becoming more common. Some individuals host their created works on vlogs, which are video blogs. The use of Internet video is growing very fast. Between March and July 2006, YouTube grew from 30 to 100 million views of videos per day. More recent developments includes the BBC's iPlayer, which was released for open beta testing in July 2007.