“The peak of Old Space occurred in 1969 when the United States of America put a man on the surface of the Moon and return him safely to Earth. This year, 2019, is the 50th anniversary of that event. But what happened after the success of NASA’s Apollo program? As many of you know, the public lost interest in space, and humanity’s activities in space went into deep freeze for a long time. I am profoundly aware of that space “ice age” because I lived through it; I was born in 1959. However, a robust recovery is finally underway, since about 2005. This recovery is called by many as New Space. And it is very different from Old Space. I will discuss this revolutionary paradigm shift. And this shift is important to all of humanity. Because of New Space, all countries, including the country of Mauritius, can participate in space. In a nutshell, New Space has vastly lowered the barriers to getting involved in space. Therefore, I hope your country will passionately embrace this golden opportunity to explore and to exploit outer space for your own national needs.”
By Professor George Maeda, Kyushu Institute of Technology (Kyutech), Japan.
There are many different types of orbits. In this post, we will mainly look at Geocentric orbits. A Geocentric is simply an orbit around the planet Earth, such as that of the Moon or of artificial satellites. Orbits may be classified in many ways.
- Low Earth orbit (LEO): geocentric orbits with altitudes below 2,000 km (100–1,240 miles).
- Medium Earth orbit (MEO): geocentric orbits ranging in altitude from 2,000 km (1,240 miles) to just below geosynchronous orbit at 35,786 kilometers (22,236 mi). Also known as an intermediate circular orbit. These are “most commonly at 20,200 kilometers (12,600 mi), or 20,650 kilometers (12,830 mi), with an orbital period of 12 hours.”
- Geosynchronous orbit (GSO) and geostationary orbit (GEO) are orbits around Earth matching Earth’s sidereal rotation period. Although terms are often used interchangeably, technically a geosynchronous orbit matches the Earth’s rotational period, but the definition does not require it to have zero orbital inclination to the equator, and thus is not stationary above a given point on the equator, but may oscillate north and south during the course of a day Thus, a geostationary orbit is defined as a geosynchronous orbit at zero inclination. Geosynchronous (and geostationary) orbits have a semi-major axis of 42,164 km (26,199 mi). This works out to an altitude of 35,786 km (22,236 mi). Both complete one full orbit of Earth per sidereal day (relative to the stars, not the Sun).
- High Earth orbit: geocentric orbits above the altitude of geosynchronous orbit 35,786 km (22,240 miles).
- Inclined orbit: An orbit whose inclination in reference to the equatorial plane is not 0.
- Polar orbit: An orbit that passes above or nearly above both poles of the planet on each revolution. Therefore, it has an inclination of (or very close to) either 90 degrees or −90 degrees.
- Polar Sun-synchronous orbit (SSO): A nearly polar orbit that passes the equator at the same local solar time on every pass. Useful for image-taking satellites because shadows will be the same on every pass.
- Non-inclined orbit: An orbit whose inclination is equal to zero with respect to some plane of reference.
- Ecliptic orbit: A non-inclined orbit with respect to the ecliptic.
- Equatorial orbit: A non-inclined orbit with respect to the equator.
- Near equatorial orbit: An orbit whose inclination with respect to the equatorial plane is nearly zero. This orbit allows for rapid revisit times (for a single orbiting spacecraft) of near equatorial ground sites.
The CubeSat standard was created by California Polytechnic State University, San Luis Obispo and Stanford University’s Space Systems Development Lab in 1999 to facilitate access to space for university students. Since then the standard has been adopted by hundreds of organizations worldwide. CubeSat developers include not only universities and educational institutions, but also private firms and government organizations.
The CubeSat standard facilitates frequent and affordable access to space with launch opportunities available on most launch vehicles.
Until 2013, university education and research activities accounted for the majority of CubeSat launches. Since then, over half of CubeSat launches have been for non-academic purposes. Today, most newly deployed CubeSats are used for commercial or amateur projects.
CubeSat applications usually involve experiments which can be miniaturized and provide services for Earth observation and amateur radio applications. Some CubeSats are used to demonstrate spacecraft technologies or as feasibility demonstrators that can help to justify the cost of a larger satellite.
In some cases CubeSats may be used for low-cost scientific experiments that may verify underlying theories. In many cases, CubeSats represent a first national satellite for non-spacefaring nations. Finally, several future missions to the Moon and beyond are in the planning stages for CubeSats.
CubeSats have allowed the creation of an entire spaceflight subculture. Since it only takes one or two years to build and launch these tiny spacecraft, and the cost is only a small fraction of money spent on traditional satellites, many more people have entered the space exploitation community. For example, university students can see the results of their work while still working on degrees. Of course, these advantages have also led to important innovations.
It all started in 1999, when professors Jordi Puig-Suari of Cal Poly and Bob Twiggs of Stanford proposed a reference design for the CubeSat. Their goal was to enable graduate students to design, build, test and operate limited capabilities of artificial satellites within the time and financial constraints of a graduate degree program.
The first launched CubeSats were placed into orbit in June 2003 on a Russian Eurockot.
Note: The above is a partial text from online articles. The whole article may be found at the references below.