The Indian Space Research Organisation (ISRO) recently tasted success with the launch of the PSLV Orbital Experimental Module or ‘POEM’. This high-profile event was accompanied by the launch of three Singaporean satellites on the PSLV-C53, marking the second Polar Satellite Launch Vehicle (PSLV) mission of the year. Earlier in February 2022, ISRO had launched PSLV-C52 with the Earth observation satellite EOS-04 and two smaller satellites.
Role of NewSpace India Limited (NSIL)
These recent launches were part of the second dedicated commercial mission of NewSpace India Limited (NSIL). NSIL is the commercial arm of ISRO, dedicated to exploiting the advancements made in space technology in India and abroad.
The Singaporean Satellites
The Singaporean satellites launched include DS-EO, NeuSAR and SCOOB-I satellites. The DS-EO satellite carries an electro-optic, multispectral payload to provide full-colour images for land classification and assist in humanitarian and disaster relief efforts. NeuSAR, Singapore’s first small commercial satellite, carries a SAR (synthetic aperture radar) payload that can provide images during day and night under all weather conditions. The SCOOB-I satellite is the first in the Student Satellite Series (S3-I), functioning as part of a hands-on student training program from the Satellite Research Centre (SaRC) at Singapore’s NTU School of Electrical and Electronic Engineering.
Understanding POEM
POEM (PSLV Orbital Experimental Module), the highlight of this mission, is ISRO’s experimental initiative that conducts in-orbit scientific experiments during the fourth stage of the Polar Satellite Launch Vehicle (PSLV) launch vehicle as an orbital platform. In the PSLV-C53 mission, the spent last state has been utilised as a “stabilised platform” to perform experiments. This marks the first time that the fourth stage (PS4) would orbit the earth as a stabilised platform. To control the orientation of any aerospace vehicle within permitted limits, POEM employs a dedicated Navigation Guidance and Control (NGC) system for attitude stabilisation.
Components of POEM
POEM houses six payloads, two of which belong to Indian Space Start-ups, Digantara and Dhruva Space, facilitated by IN-SPACe and NSIL. Power for POEM is generated by solar panels mounted around the PS4 tank and a Li-Ion battery. It uses Four Sun Sensors, a Magnetometer, Gyros & NavIC for navigation. The module carries dedicated control thrusters using Helium gas storage and features a telecommand capability.
Notable UPSC Civil Services Examination Question
A previous year question in the UPSC Civil Services Examination was related to India’s satellite launch vehicles:
Statement 1: PSLVs launch satellites useful for Earth resources monitoring whereas GSLVs are designed mainly to launch communication satellites.
Statement 2: Satellites launched by PSLV appear to remain permanently fixed in the same position in the sky, as viewed from a particular location on Earth.
Statement 3: GSLV Mk III is a four-staged launch vehicle with the first and third stages using solid rocket motors; and the second and fourth stages using liquid rocket engines.
The correct response to this question was statement 1 only, shedding light on the primary duties of PSLVs and GSLVs in India’s space endeavours.
