Laser Relativity Satellite

LARES (Laser Relativity Satellite) is an Italian Space Agency scientific satellite and it  was launched by the new European launch vehicle Vega.
The satellite, completely passive, is made of tungsten alloy and houses 92 cube corner retroreflectors that are used to track the satellite via laser from stations on Earth. LARES's body has a diameter of about 36.4 centimetres (14 in) and weighs about 400 kilograms (882 lb).
It has the perigee of 1,442.4 km, apogee of 1,459.8 km

i.e. , LARES was inserted in an orbit with 1,400 kilometres (870 mi) of perigee, an inclination from 60 to 86 degrees and reduced eccentricity. The satellite is tracked by the International Laser Ranging Service stations. The aim of the LARES mission is the measurement of the Lense–Thirring effectwith an accuracy of about 1%  to calculate its distance and orbit, with a high degree of precision. The LARES satellite may also be used for measurements in the fields of geodynamics and satellite geodesy. 

GOLIAT Satellite launch

GOLIAT is the first Romanian satellite.
The project has been started in 2005 by ROSA, having an initial budget of approximately 400.000 euro. GOLIAT is a nanosatellite based on the American Cubesat standard, cube-shaped 10x10x10 cm and weighting 1 kg.

Its Downlink Frequency is 437.4850 MHz .
This Satellite is of type Cubesat.   and it is launched on 13 February, 2012  at  Kourou.  The launching vehicle used is  Vega. It has the  Apogee of 1450.00,  perigee of  354.00 and its inclination is   71.00    
 The dimensions of satellite are 10cmx10cmx10cm and it has a weight of  1.000 Kg.
There are three scientific experiments onboard: SAMIS which aims to measure the meteorites flux, Dose-N which should measure the cosmic radiation dose on an Earth orbit and the acquisition of images from a 3Mpixels and 21x28 m ground resolution camera installed on the satellite.

Information Gathering Satellite (IGS) - Optical-4

Japan has launched a new Information Gathering Satellite (IGS) known as Optical-4 and the launch vehicle used is  H-2A (H-IIA).  It did show the vehicle successfully lifted off from the Yoshinobu Launch Complex at the Tanegashima Space Center (TNSC)  in Kagoshima Prefectureat 04:36 UTC on Friday.

H-2A's first stage has a length of 37.2 meters, a diameter of 4 meters and a mass of 114 tons.
The stage burns a mixture of liquid oxygen and liquid hydrogen, developing a liftoff thrust of 1,098 kN.
The  burning time is of 390 seconds.

Launch log of remaining 10 Indian National Satellite System (INSAT)

 INSAT-3A  is launched on 10 April 2003. it is In service and providing services.

INSAT-3B is launched on 22 May 2000. it is In service and providing services.

INSAT-3C  is launched on 24 January 2002. it is In service and providing services.

KALPANA-1  is launched on 12 September 2002. it is In service and providing services.

GSAT-2  is launched on 8 May 2003. it is In service and providing services.

INSAT-3E  is launched on 28 September 2003. it is In service and providing services.

EDUSAT  is launched on 20 September 2004. it is In service and providing services.

 INSAT-4A  is launched on 22 December 2005. it is In service and providing services.

INSAT-4C  is launched on 10 July 2006 and it is not placed in orbit due to launch failure of GSLV-F02.

 INSAT-4B  is launched on 12 March 2007. it is In service and providing services.

 INSAT-4CR  is launched on 2 September 2007 and it is in  geo-synchronous orbit.

Launch log of first 10 Indian National Satellite System (INSAT)

INSAT-1A is launched on 10 April 1982 but it is deactivated on 6 September 1982.

INSAT-1B 30 August 1983 Completed mission life.

INSAT-1C is launched on22 July 1988 and Abandoned in November 1989.

INSAT-1D is launched on 12 June 1990 and it has completed mission life.

INSAT-2A is launched on 10 July 1992 .  it is the India's First Indigenous communication
Satellite and it has completed mission life.

INSAT-2B is launched on 23 July 1993 and it has completed mission life.

INSAT-2C  is launched on 7 December 1997 and it has completed mission life.

INSAT-2D is launched on 4 June 1997 and it became inoperable on 4 October 1997.

 INSAT-2DT is launched on In-orbit procurement and it has completed mission life.

 INSAT-2E is launched on 3 April 1999 and now it is now In service.

Indian National Satellite System, INSAT-1 and INSAT-2 series:

 INSAT-1A, the first satellite was launched in 10 April 1982 but could not fulfill the mission. But it deactivated on 6 September 1982
The Indian National Satellite (INSAT) system of geostationary satellites was
commissioned with the launch of INSAT-1B in 30 August 1983..

 INSAT system created a revolution in India’s television and radio broadcasting,
telecommunications and meteorological sectors. It enabled the rapid expansion
of  TV and modern telecommunication facilities to even the remote areas and offshore
islands.
INSAT space segment consists of 21 satellites. out of them, 11 are
in presently in service, making India to have one of the largest domestic
communication satellite systems. The satellites are monitored and controlled by
Master Control Facilities at Hassan and Bhopal.

DIFFERENCE OF COMMUNICATION SATELLITE FROM COMMUNICATION RELAY:

    For communication satellites the range is much higher than that of communication relay. Communication Satellite can cover up to several thousands of  kilometers.

    For communication relay,  the uplink and the downlink frequency is the same. But for communication satellites the uplink and the downlink frequencies are different in order to avoid interference.

Different frequency bands used in satellite communication are

    Ultra high frequency band (UHF).


420-450 MHz
Also known as 70 centimeters (cm). This is the lowest frequency amateur UHF band. Groundwave coverage is quite limited compared to 2 meters due to high absorption. Satellite, EME and terrestrial DXing are popular on this band. Fast scan TV has also found a home on 430 MHz. Lots of FM activity between 440-450 MHz. Lots of machines are linked to 2 meters! The longest Element of a beam for this band is about 12 to 13 inches on the low end!

902-928 MHz
Not much activity on this band so far due to a lack of suitable equipment.
Also this is a shared band with other services.

1200-1300 MHz
1.2 GHz is a HUGE band with lots of room for experimenters. EME and satellite are popular up here and in some parts of the US there are very active FM repeaters. Antennas are VERY small! Not a lot of terrestrial DXing but during contests there is some activity. Antennas for small signal work are quite impressive with lots of elements on short booms. Dishes are practical on this band.



   C-Band:
All C-Band downlink frequencies will fall between a minimum of 3.4 Ghz and a maximum of 4.8 Ghz
   
X-Band:

x- band ranges from 8 to 12 GHz.

 Ku-Band:
All Ku-Band downlink frequencies will fall between a minimum of 10.7 Ghz and a maximum of 12.75 Ghz

 Ka-Band:
Ka band ranges from 26.5 to 40 GHz

Bhaskara-I Satellite

It is the First Indian low orbit Earth Observation Satellite.
Launch Date : June 7, 1979

Weight : 444 Kg

Orbit : 619 x 562 km inclined at 50.7 deg
        and it was launched by Soviet Intercosmos rocket.

Bhaskara 1 and 2: Named after a 12th Century Indian mathematician/astronomer.

Bhaskara-1 was launched on 7th June 1979 from Kapustin Yar aboard the

Kosmos-3M launch vehicle. 

The main objectives were to conduct earth

observation experiments for applications related to hydrology, forestry, and

geology using a two-band TV camera system, and to conduct ocean-surface

studies using a two-frequency satellite microwave radiometer system. Secondary

objectives were to test engineering and data processing systems, to collect

limited meteorological data from remote platforms, and to conduct scientific

investigations in X-ray astronomy. Bhaskara 1 was a 444 kg 26-faced quasispherical

polyhedron with a 1.66 m height and 1.55 m diameter. Bhaskara-2 was

launched on 20 November 1981 also from Kapustin Yar. It was declared

operational after receipt of 300 television images of the Indian sub-continent. The

housekeeping telemetry was still being received until 1991. It re-entered orbit on

30 November 1991.

First Indian Experimental Satellite - Aryabhatta

Launch Date : April 19, 1975

Weight : 360 kg

Orbit : 619 x 562 km inclined at 50.7 deg



and it was launched by Soviet Intercosmos rocket..

Aryabhatta was named after a 5th Century Indian mathematician  (who is credited with inventing the concept of “zero”) was India’s first indigenous satellite. The objective of this satellite was to study astronomy sources and relations between the earth and the sun (ionosphere study).

The satellite was launched on 19 May 1975 aboard the Intercosmos launch vehicle but due a transformer failure it was out of service in four days.

SPACECRAFT ANTENNA (subsystem)

Antenna subsystem is also an essential component of satellite system. Basically four main type of antennas are used:
these are
1.Monopoles and dipoles (wire antennas)  which are mainly used in very high frequency and ultra high frequency to provide communication for TTC and M subsystem.

2. Horn antennas are mainly used at microwave frequencies. Horns are actually used as feeds for reflector.
3. Array antennas are actually phased array antennas which are used on satellites to form multiple beams from single aperture.
4. Reflector antennas are commonly used for earth station antennas and the most widely employed shape of it is the paraboloid with a feed placed at its focus.

About satellite communication

Satellite is the communication of the satellite in space with large number of earth stations on the ground. User will generate baseband signals, which is processed at the earth station and then transmitted to the satellite through  antennas. Now the user is connected to the earth station via some telephone switch or some dedicated link. The satellite receives the uplink frequency and the transponder present inside the satellite does the processing function and frequency down conversion in order to transmit the downlink signal at different frequency. The earth station then receives the signal from the satellite through parabolic dish antenna and processes it to get back the baseband signal.
This baseband signal is then transmitted to the respective user via dedicated link or other terrestrial system. Previously satellite communication system used large sized parabolic antennas with diameters around 30 meters because of the very faint and weak signals received.
 nowadays  satellites have become much stronger, bigger and powerful due to which antennas used have become automatically smaller in size. Thus the earth station antennas are now not large in size as the antennas used in olden days. A satellite communication system operates and works in the millimeter and microwave wave frequency bands from 1 Ghz to 50 Ghz. There are various frequency bands utilized by satellites but the most  recognized of them is the uplink frequency of 6 Ghz and the downlink frequency of 4 Ghz. Actually the uplink frequency band is 5.725 to 7.075 Ghz and the actual downlink frequency band is from 3.4 to 4.8 Ghz. 

TV and broadband services by satellites

For people who living in rural areas, satellite is the only option available to access TV and broadband services. And for immigrants living in a foreign country, satellite technology is often the only alternative to watch their national TV stations that are not offered in the mainstream services provided by the cable and TV companies in the United States.
At the same time, there are several advantages and disadvantages of using satellite to watch TV and access the internet.

satellite & types

WHAT IS SATELLITE?

 A Satellite is a solid object which revolves around some heavenly body due to the effect of gravitational forces which are mutual in nature.
We can categorize satellites in two types, namely Passive Satellites and Active satellites.
 Passive satellites are not like active satellites. Even a moon can be a passive satellite. Thus passive satellites are relay stations in space. A passive satellite can be further subdivided into two types, namely Natural satellites and artificial satellites. A moon is a natural satellite of earth. But spherical balloon with metal coated plastic serve as artificial satellites. Active satellites are complicated structures having a processing equipment called Transponder which is very vital for functioning of the satellite. These transponders serve dual purpose i.e. provides amplification of the incoming signal and performs the frequency translation of the incoming signal to avoid interference between the two signals.