Indian Space Research Organisation (ISRO) is gearing up for its first launch in the new year to place four payloads in the polar orbit using a single rocket for the first time on January 10.
With ISRO's mission readiness review committee okaying the launch of the polar satellite launch vehicle (PSLV-C7) on Saturday, a team of scientists and technicians on Sunday began countdown procedures at the Satish Dhawan Space Centre in Sriharikota for a perfect lift-off on Wednesday at 9.23 am.
"The actual countdown begins 52 hours prior to the launch time. All the systems on board the spacecraft have been checked and the operational devices are being monitored. After checking the flight parameters and preparedness, the committee has authorised the launch," an ISRO official said in Bangalore.
The 295-tonne PSLV, being launched six months after the GSLV (geo-satellite launch vehicle) mission carrying Insat-4C satellite was aborted on July 10, will carry Cartosat-2, space capsule recovery experiment (SRE-1), an Indonesian satellite ((Lapan-Tubsat) and Argentina's Pehuensat-1 into a 635 km high polar sun synchronous orbit (SSO).
"As the countdown begins early on Monday, fuelling operations will commence at the first launch pad where the rocket has been mounted," the official said.
As a workhorse for ISRO's polar orbit missions since its first launch in 1994, the PSLV has placed seven Indian remote sensing satellites, an amateur radio satellite (Hamsat) and four small satellites for overseas customers into 550-800 km high polar SSOs.
The PSLV was also used to put the country's exclusive meteorological satellite — Kalpana-1 in a geo-synchronous transfer orbit (GTO). An enhanced version is under preparation for launching India's first spacecraft mission to the moon —Chandrayaan-1 in 2008.
"For the first time, we are using a dual launch adopter (DLA) in the 44-metre four-stage launch vehicle to accommodate the four payloads. The first and the third stages as well as the six strap-on (surrounding the first stage) are using solid propellant," the official pointed out.
Incidentally, the first stage is one of the largest solid propellant boosters in the world. Its second and fourth stages, however, use liquid propellants.
The vehicle has S-band telemetry and C-band transponder systems for monitoring its health and flight stations. It also has a sophisticated auxiliary system like stage and payload firing separation systems.
As in the previous spacecraft — PSLV-C6, which was launched in May 2005, with two payloads of Cartosat-1 (1,156 kg) and Hamsat (42 kg), the capacity of PSLV-C7 has been equally enhanced to take the combined payload of 1,192 kg.
"As the main payload, the 680 kg Cartosat-2 has been mounted over the DLA, with the 550 kg SRE placed inside it. Similarly, the 56 kg Lapan-Tubsat is mounted on the equipment bay, while the 6 kg nano-satellite (Pehuensat) is positioned on the top," the official disclosed.
As the 12th spacecraft in the Indian Remote Sensing (IRS) satellite services, Cartosat-2 is an advanced remote sensing satellite capable of providing scene-specific spot imagery. It will join the other six IRS satellites in service — IRS-IC, IRS-1D, Oceansat-1, Technology Experiment Satellite (TES), Resourcesat and Cartosat-1.
The agile satellite carries a Panchromatic camera to provide imagery with a spatial resolution of more than one metre and a swath of 9.6 km. It can be steered up to 45 degree along as well as across the track.
The data will be used for cartographic applications, urban and rural infrastructure development and management as well as application in land information system and geographical information system.
Cartosat-2 will orbit around the earth 14 times a day, with each orbit taking 97.4 minutes. It will revisit the same spot once in four days.
The SRE capsule will demonstrate the technology of an orbiting platform for performing experiments in micro-gravity conditions. After completing the experiment, the capsule will be de-orbited and recovered for re-use.
"The SRE will be launched into a 635 km polar SSO and will stay in the orbit for 13-30 days during which its two payloads will be operated to perform metallurgical experiments," the official noted.
The SRE mission will provide valuable experience in vital areas such as navigation, guidance and control during the re-entry phase, hypersonic aero-thermodynamics, facilitating the development of reusable thermal protection system, recovery through deceleration and floatation, besides acquisition of technology for reusable launch vehicles.
SRE-1 carries two experiments — an isothermal heating furnace (IHF) and a biomimetic (biomineralisation of inorganic materials).
The Lapan-Tubsat is a cooperative venture between Technical University of Berlin and the Indonesian Space Agency Lapan. It is an earth observation satellite and will demonstrate control systems.
The Pehuensat has been developed by Argentina school of engineering, with the Argentina Association for Space & Technology and Amsat Argentina. Weighing just six kg, the nano-satellite is intended to gain experience for designing more complex missions for educational, technological and scientific fields.