 "Isro achieves another milestone with PSLV-C35 launch")
The Indian Space Research Organisation (Isro) achieved one more milestone on Monday through the launch of Polar Satellite Launch Vehicle (PSLV)-C35. The "exciting and complex" mission has got many firsts, including the first time that the Sriharikota space centre had two missions in a single month and the longest duration satellite launch mission, with eight satellites on board. This mission is technically two missions, said Isro officials, adding that they have hectic schedules ahead.
On Monday morning, the PSLV-C35 blasted-off from the first launch pad of Satish Dhawan Space Centre SHAR, Sriharikota, at 09:12 hrs. In its 37th flight (PSLV-C35), it launched the 371 kg SCATSAT-1, meant for weather related studies, and seven co-passenger satellites into polar sun synchronous orbit (SSO). The co-passenger satellites are from Algeria, one from Canada and one from the US, as well as PRATHAM from IIT Bombay and PISAT from Bengaluru's PES University.
Prime Minister Narendra Modi congratulated the team through a twitter message, stating, “Moment of immense joy & pride for India. Congratulations to @isro on successful launch of PSLV-C35/SCATSAT-1 & 7 co-passenger satellites. Our space scientists keep scripting history. Their innovative zeal has touched the lives of 125 crore Indians & made India proud worldwide.”
While the SCATSAT-1 was placed into a 720 km polar SSO, the satellites from the two Universities and the five foreign satellites have been placed into a 670 km polar orbit. This is the first mission of PSLV in which payloads were launched into two different orbits. This was the 15th flight of the PSLV in its ‘XL’ configuration (with the use of solid strap-on motors).
With this success, India has successfully launched 79 satellites for international customers.
A S Kiran Kumar, chairman, Isro, said that “...today is a landmark day. Using PSLV rocket we achieved the launch of eight satellites. After a long gap of over two hours the entire mission has gone on very successfully”.
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"Our own Scatrometer, which is a stop-gap arrangement between our Oceansat-1 and Oceansat-2. This is a satellite which is going to provide ocean wind vectors to the global community for numerical weather forecasting model... Along with this we have two more of the Indian satellite units, Pratham and Pisat, and we had our customer satellites," added Kumar.
After a long gap of almost two hours where the fourth stage has been manoeuvred and restarted and the entire mission has gone on very successfully, he said.
K Sivan, director, Vikram Sarabhai Space Centre, added that this mission is both exciting and an excellent mission and it is the longest one, with the longest launch spread over 2.15 hours, while the mission was concluded in the shortest time (35 days from design to execution).
B Jayakumar, mission director, Isro, said that typically a PSLV mission is around 20-25 minutes, whereas for this mission the PSLV functioned for 2.15 hours.
The mission had various associated technological issues, which were addressed for its success. There are so many peculiarities in this mission. It is one of the most complex missions which the Isro undertaken, in terms of manoeuvring, given the fact that this was the first time that the PSLV lifted-off twice (one was at 9.12 hours, second 12 minutes later), and considering the power management for 2.15 hours with efficient thermal management. When the vehicle is in space, one side will receive all the heat, on the other side it will see a drop in temperature. Passive thermal management was done effectively to address this issue.
With the successful competition and flexibility of PSLV, which was demonstrated on Monday, the launch vehicle will be more competitive in the customer market. “Whatever the customer demands, we can provide,” Jayakumar said.
The space research organisation is gearing up for further launches in the near future, including the much-awaited launch of GSLV Mark III. The geostationary communication satellite GSAT 18 is also scheduled to be launched during the first half of October 2016, onboard the Ariane-5 launch vehicle from Ariane Space in French Guiana.
“We are making sure that the GSLV Mark III's first launch is getting ready and we are gearing up for launch of our Mark III launch vehicle at the earliest. The initial activity of assembling the stages of GSLV Mark III has commenced and the work is going in full swing,” said the Isro chairman.
Payloads onboard
The primary satellite carried to space in Monday's mission is the SCATSAT-1, which is a follow-on mission for Oceansat-2. Isro officials have said that a few improvements have been made in the satellite’s hardware configuration. The satellite carries Ku-band scatterometer similar to the one flown onboard Oceansat-2.
The payload has been characterised with the objective of achieving data quality for climate data records, apart from facilitating routine meteorological applications. SCATSAT-1’s scatterometer will provide wind vector data products for weather forecasting, cyclone detection and tracking services to the users.
The mission life of the satellite is five years.
The two Algerian satellites, Alsat-1B and Alsat-2B, are remote sensing satellites, while the Alsat-1N is a technology demonstration nano-satellite for Algerian students.
On the other hand, the US satellite Pathfinder-1 is a commercial high resolution imaging micro satellite, while the Canadian NLS-19 satellite is a technology demonstration nano-satellite for experimentation in helping to reduce space debris and for tracking commercial aircraft.
IIT-B’s satellite Pratham’s mission objective is to estimate the total electron count with a resolution of 1km x 1km location grid, while Pisat from PES University and its consortium is a nano-satellite for remote sensing applications.