ISRO successfully places seven Singaporean satellites into intended orbit

ISRO successfully places seven Singaporean satellites into intended orbit

Subject :Science and tech

Section: Awareness in IT and computers

Context:

• ISRO successfully launched its proven PSLV rocket carrying seven Singaporean satellites from Satish Dhawan Space Centre in Sriharikota, Andhra Pradesh and placed them into intended orbits.

Details:

• PSLV-C56/DS-SAR Mission: The mission is successfully accomplished. PSLV-C56 vehicle launched all seven satellites precisely into their intended orbits.
• Primary payload-DS-SAR Radar Imaging Earth Observation satellite, developed under a partnership between DSTA (representing the Government of Singapore) and ST Engineering, Singapore.
• The satellite carries a Synthetic Aperture Radar (SAR) payload developed by Israel Aerospace Industries.
• The payload allows DS-SAR to provide for all-weather day-and-night coverage and it is capable of imaging at 1-metre resolution.
• A Core Alone version of the rocket means the vehicle would not use solid strap-on motors on its sides in the first stage.

The co-passenger satellites are:

1. VELOX-AM,a 23 kg technology demonstration microsatellite,
2. ARCADE Atmospheric Coupling and Dynamics Explorer (ARCADE), an experimental satellite,
3. SCOOB-II, a 3U nanosatellite flying a technology demonstrator payload,
4. NULloN by NuSpace, an advanced 3U nanosatellite enabling seamless Internet of Things connectivity in both urban and remote locations,
5. Galassia-2, a 3U nanosatellite that would be orbiting at low earth orbit and
6. ORB-12 STRIDER, a satellite developed under an international collaboration

A unique scientific experiment performed by ISRO:

• During the mission, the scientists decided to perform a unique scientific experiment in which the fourth stage of the rocket would be lowered into a 300 kilometer orbit after placing customer satellites at an altitude of 536 km” to mitigate the space debris problem”.
• Normally after a successful mission, a rocket before re-entering into the Earth’s atmosphere would travel for “decades” in an orbit as a space debris but with this experiment, the duration is now reduced to “two months”.
• India remains committed to reduced space debris and sustainable use of space for the benefit of all.

Near Equatorial Orbit (NEO):

• A near-equatorial orbit is an orbit that lies close to the equatorial plane of the object orbited. Such an orbit has an inclination near 0°.
• On Earth, such orbits lie on the celestial equator, the great circle of the imaginary celestial sphere on the same plane as the equator of Earth.
• A geostationary orbit is a particular type of equatorial orbit, one which is geosynchronous.
• A satellite in a geostationary orbit appears stationary, always at the same point in the sky, to observers on the surface of the Earth.
• Launch stations near the equator are: Guiana Space Centre in Kourou, French Guiana, or Alcantara Launch Centre in Brazil, Thumba and SDSC in India.
• Equatorial orbits can be advantageous for several reasons:
  • They provide some additional orbital speed to the launch vehicle by imparting the rotational speed of the Earth, 460 m/s, to the spacecraft at launch.
  • The added velocity reduces the fuel needed to launch spacecraft to orbit.
    • Since Earth rotates eastward, only launches eastward take advantage of this boost of speed.
    • Westward launches, in fact, are especially difficult from the Equator because of the need to counteract the extra rotational speed.
  • Communication: a spaceship in an equatorial orbit passes directly over an equatorial spaceport on every rotation, in contrast to the varying ground track of an inclined orbit.
  • Launches directly into equatorial orbit eliminate the need for costly adjustments to a spacecraft’s launch trajectory.
    • The manoeuvre to reach the 5° inclination of the Moon’s orbit from the 28° N latitude of Cape Canaveral was originally estimated to reduce the payload capacity of the Apollo Program’s Saturn V rocket by as much as 80%.