## 2 Space Debris--A Primer
### The Useful Objects  
Since 1957, every few years, a new country has launched its own satellite for the first time and then has usually continued to do so until the present. Table 1 below shows a summary of first satellite launches by country (using its own rocket). The ensuing launch rates of space-faring nations were relatively stable and consistent up until a few years ago--by that time, there were \"only\" several thousand rocket launches by a few dozen launching agencies. Around ten years ago, however, a few companies decided that it was in everyone's best interests to launch several thousand (or several tens of thousand) of satellites into low Earth orbit. Current plans call for -88,000 satellites to be launched over the next few years--so the near-Earth region of space is going to get a lot fuller very soon. Table 2 below summarizes the planned launches of satellites by various companies that are intended to form some of the larger \"satellite constellations\" [2]. What has been the purpose or function of all these satellites that have been launched over the past 65+ years? Approximately two-thirds of them are for communication, whether it be personal, business, government, or military. Table 3 below shows the most common uses of satellites currently in Earth orbit and the percentage of such satellites for each of these uses [3]. Satellite constellations are needed in today's techno-centric society, and there are several reasons why they should replace our present-day, aging satellite networks. For example, today's satellites typically provide limited coverage areas--these coverage areas are either narrow bands (if they are in low Earth orbit) or small circles (if in geostationary orbit) on the Earth's surface. Alternatively, a system or constellation of satellites can provide a coverage area that encompasses almost the entire globe. Our demand for faster and faster broadband internet connection is pushing the limits of today's satellites. Streaming video \begin{table}
\begin{tabular}{c c c c} \hline
**Year** & **Country** & **Satellite** & **Rocket** \\ \hline
1957 & Soviet Union & Sputnik 1 & Sputnik-PS \\ \hline
1958 & United States & Explorer 1 & Juno I \\ \hline
1965 & France & Asterix & Diamant A \\ \hline
1970 & Japan & Ohsumi & Lambda-4S \\ \hline
1970 & China & Dong Fang Hong I & Long March 1 \\ \hline
1971 & United Kingdom & Prospero & Black Arrow \\ \hline
1979 &
\begin{tabular}{c} European \\ Space Agency \\ \end{tabular} & CAT-1 (Obelix) & Ariane 1 \\ \hline
1980 & India & Rohini 1 (RS-1) & SLV \\ \hline
1988 & Israel & Ofeq 1 & Shavit \\ \hline
1991 & Ukraine & Strela-3 & Tsyklon-3 \\ \hline
1992 & Russia & Kosmos 2175 & Soyuz-U \\ \hline
2009 & Iran & Omid & Safir-1A \\ \hline
2012 & North Korea & Kwangmyongsong-3 & Unha-3 \\ \hline
2018 & Republic of Korea & Dummy Satellite & Nuri (KSLV-II) \\ \hline \end{tabular}
\end{table} 
Table 1: History of first satellite launches by country. \begin{table}
\begin{tabular}{c c c} \hline
**Constellation** & **Manufacturer** & **Number** \\ \hline Boeing & Boeing Satellite & 6000 \\ \hline Starlink & SpaceX & 30,000 \\ \hline OneWeb & OneWeb and Airbus & 7000 \\ \hline Telesat LEO & Airbus SSTL, SS/Loral & 2000 \\ \hline Hongyun & CASIC & 100 \\ \hline Hongyan & CASC & 300 \\ \hline Kuiper & Amazon & 7000 \\ \hline Hanwha & Hanwha Systems & 2000 \\ \hline Guowang & China SatNet & 13,000 \\ \hline Gen4 & GlobalStar & 3000 \\ \hline Astra & SES & 14,000 \\ \hline \end{tabular}
\end{table} 
Table 2: Planned satellite constellation launches (approximate). content, streaming video games, HDTV, etc., are \"bandwidth hogs\", and current satellites simply cannot keep up. Furthermore, traditional $X00M satellites are very expensive and have a very lengthy design, manufacture, and launch timeline--so, by necessity, they are designed with a really long operational lifespan. The problem is, as a result of the very long lead time ahead of their launch, traditional satellites are frequently obsolete before they are launched and reach orbit!