Author Topic: LIVE: SCATSat-1/Alsat-2B - PSLV C35 - September 26, 2016 (03:42 UTC)  (Read 34437 times)

Offline input~2

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8 more objects have been cataloged:

2016-059B/41784 in 658 x 708 km x 98.20°
2016-059D/41786 in 661 x 704 km x 98.20°
2016-059E/41787 in 661 x 703 km x 98.20°
2016-059F/41788 in 661 x 702 km x 98.20°
2016-059G/41789 in 661 x 699 km x 98.20°
2016-059H/41790 in 717 x 734 km x 98.12°
2016-059J/41791 in 660 x 699 km x 98.21°
2016-059K/41792 in 661 x 699 km x 98.20°

Offline Rocket Science

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Congrats to all the teams, well done! Thanks to NSF for the great coverage! :)
"Remember the victims of Manchester"

Offline jcm

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8 more objects have been cataloged:

2016-059B/41784 in 658 x 708 km x 98.20°
2016-059D/41786 in 661 x 704 km x 98.20°
2016-059E/41787 in 661 x 703 km x 98.20°
2016-059F/41788 in 661 x 702 km x 98.20°
2016-059G/41789 in 661 x 699 km x 98.20°
2016-059H/41790 in 717 x 734 km x 98.12°
2016-059J/41791 in 660 x 699 km x 98.21°
2016-059K/41792 in 661 x 699 km x 98.20°


59H presumably ScatSat.   Perigees for the rest look a bit lower than expected, would be interesting to hear
how close to plan the restart burns of PS4 were.
-----------------------------

Jonathan McDowell
http://planet4589.org

Offline vyoma

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http://www.isro.gov.in/update/26-sep-2016/pslv-c35-successfully-launches-eight-satellites-two-different-orbits-single

PSLV-C35 Successfully Launches Eight Satellites into Two Different Orbits in a Single Flight
In its thirty seventh flight (PSLV-C35), ISRO's Polar Satellite Launch Vehicle successfully launched the 371 kg SCATSAT-1 Satellite along with seven co-passenger satellites today morning (September 26, 2016) from Satish Dhawan Space Centre SHAR, Sriharikota. This is the thirty sixth consecutively successful mission of PSLV.  The total weight of all the eight satellites carried on-board PSLV-C35 was 675 kg. PSLV-C35 is the first PSLV mission to launch satellites carried onboard into two different  orbits. This PSLV mission was the longest of the PSLV missions conducted till date and was completed in 2 hours 15 minutes and 33 seconds after lift-off.

After PSLV-C35 lift-off at 0912 hrs (9:12 am) IST from the First Launch Pad with the ignition of the first stage, the subsequent important flight events, namely, strap-on ignitions and separations, first stage separation, second stage ignition, payload fairing separation, second stage separation, third stage ignition and separation, fourth stage ignition and cut-off, took place as planned. After a flight of 16 minutes 56 seconds, the vehicle achieved a polar Sun Synchronous Orbit of 724 km inclined at an angle of 98.1 degree to the equator (very close to the intended orbit) and 37 seconds later the primary satellite SCATSAT-1 was separated from the PSLV fourth stage.

After separation, the two solar arrays of SCATSAT-1 satellite were deployed automatically and ISRO's Telemetry, Tracking and Command Network (ISTRAC) at Bangalore took over the control of the satellite. In the coming days, the satellite will be brought to its final operational configuration following which it will begin to provide weather related services using its scatterometer payload.  The data sent by SCATSAT-1 satellite will help provide weather forecasting services to user communities through the generation of wind vector products as well as cyclone detection and tracking.

After the successful separation of SCATSAT-1, the PSLV-C35 mission continued. Still carrying the seven co-passenger satellites, the fourth stage of PSLV coasted over the South polar region and then started ascending towards the Northern hemisphere. A safe distance between the orbiting SCATSAT-1 and PSLV-C35 fourth stage was maintained by suitably manoeuvring the stage.

At 1 hour 22 minutes and 38 seconds after lift-off as the fourth stage was in the North polar region, the two engines of PSLV fourth stage were reignited and fired for 20 seconds. As a result of this, it entered into an elliptical orbit measuring 725 km on one side of the Earth and 670 km on the other.   

And 50 minutes later, as the PSLV fourth stage was again coasting near the south pole, its engines were fired for another 20 seconds. This second firing made the fourth stage to enter into a circular orbit of 669 km height inclined at an angle of 98.2 degree to the equator.

37 seconds later, the Dual Launch Adapter was successfully separated from the PSLV-C35 fourth stage. 30 seconds after this event, ALSAT-1N was the first co-passenger satellite to be separated successfully. Following this, the NLS-19, PRATHAM, PISAT, ALSAT-1B, ALSAT-2B, and Pathfinder-1 were separated from the PSLV fourth stage in a predetermined sequence thereby successfully completing PSLV-C35 mission.

Of the seven co-passenger satellites carried by PSLV-C35, two – PRATHAM weighing 10 kg and PISAT weighing 5.25 kg – are University/Academic institute satellites and were built with the involvement of students from IIT-Bombay and PES University, Bangalore and its consortium, respectively.

The remaining five co-passenger satellites were international customer satellites from Algeria (three – ALSAT-1B, ALSAT-2B and ALSAT-1N), Canada (one- NLS-19) and the United States (one – Pathfinder-1).

With today’s launch, the PSLV’s capability to launch satellites into two different orbits has been successfully demonstrated. The total number of satellites launched by India’s workhorse launch vehicle PSLV has now reached 121, of which 42 are Indian and the remaining 79 are from abroad.

Offline worldtimedate

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Quote
In a first for India’s PSLV, the fourth stage re-ignited two times -- each for about 20 seconds -- to nudge the mission’s seven other satellite payloads into a slightly lower orbit.

The PSLV’s fourth stage never had to fire more than once on any earlier mission, but Indian engineers tested the rocket’s ability to conduct multiple firings after finishing its job on a launch in June.

"This was two missions in one mission achieved today," said B. Jayakumar, ISRO’s mission director for Monday’s flight, known as PSLV-C35 in the organization’s launch sequence.

Quote
"The re-start of the upper stage and placing satellites in different orbits also has improved the marketability of PSLV the flexibility and versatility of PSLV and this also puts PSLV in a very unique position of advantage," said S. Rakesh, director of the ISRO Propulsion Complex.

Quote
The PSLV’s market share has grown as Russian rockets, such as the Dnepr launcher jointly managed with Ukraine, have been grounded or removed from the marketplace.

Source : India declares success on PSLV’s most complex mission

worldtimedate [ http://www.world-timedate.com/ ]

Offline worldtimedate

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Quote
In a first, Indian Space Research Organisation (ISRO)'s PSLV C-35 rocket launched a total of eight satellites, into two different orbits.

Quote
The rocket was re-ignited twice during its flight to place the set of satellites in different orbits. Due to the re-ignition, the Monday's launch is by far the longest PSLV launch by ISRO.

ISRO said though it had launched several PSLV rockets in the past, this launch is "the first mission of PSLV in which it had launched its payloads into two different orbits," ISRO said.

Source : In a first, PSLV puts 8 satellites in two different orbits

worldtimedate [ http://www.world-timedate.com/ ]

Offline s^3

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A dumb question.

Sun synch orbits are repetitive. So even if rest of the satellites were launched @ SCATSAT altitude and then slowly ( 2-3 burns of local thrusters )could have been brought down to their intended orbit at the cost of onbord fuel of each satellite.
Of course you may have to live with a shift in reference frame or wait for one cycle before thruster operations to do this.

Then what was achieved by extending the launch operation over 2 hours and spending some PS4 fuel in 2 reburns?

 

Online Jarnis

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A dumb question.

Sun synch orbits are repetitive. So even if rest of the satellites were launched @ SCATSAT altitude and then slowly ( 2-3 burns of local thrusters )could have been brought down to their intended orbit at the cost of onbord fuel of each satellite.
Of course you may have to live with a shift in reference frame or wait for one cycle before thruster operations to do this.

Then what was achieved by extending the launch operation over 2 hours and spending some PS4 fuel in 2 reburns?

Save propellant on the sats?

Make the orbit possible for sats with no maneuvering capability?

Offline vineethgk

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A dumb question.

Sun synch orbits are repetitive. So even if rest of the satellites were launched @ SCATSAT altitude and then slowly ( 2-3 burns of local thrusters )could have been brought down to their intended orbit at the cost of onbord fuel of each satellite.
Of course you may have to live with a shift in reference frame or wait for one cycle before thruster operations to do this.

Then what was achieved by extending the launch operation over 2 hours and spending some PS4 fuel in 2 reburns?

Save propellant on the sats?

Make the orbit possible for sats with no maneuvering capability?
And PS4 did a small change in inclination for the sats too. Might be more fuel consuming than change in altitude?

Offline s^3

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In an earlier launch ( IRS 1D ) a malfuction put the saellite in an elliptical orbit of 300 x 823 km. The correction to the initial orbit would have consumed too much fuel so the satellite was placed in an elliptical sunsynchronous orbit. The manoeuvres consumed about 67 kg of its fuel, leaving slightly over 16 kg.

Still the sat functioned for several years.

In the latest launch there is no much change in the orbits .. so whether it was a necessity or attempt for future more complex mission?

Offline vineethgk

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In an earlier launch ( IRS 1D ) a malfuction put the saellite in an elliptical orbit of 300 x 823 km. The correction to the initial orbit would have consumed too much fuel so the satellite was placed in an elliptical sunsynchronous orbit. The manoeuvres consumed about 67 kg of its fuel, leaving slightly over 16 kg.

Still the sat functioned for several years.

In the latest launch there is no much change in the orbits .. so whether it was a necessity or attempt for future more complex mission?
I guess it could be both. The smaller companions of SCATSAT may have preferred a lower orbit for their needs while the SCATSAT required a higher orbit. So, this may have been ISRO's test to see whether it could meet both requirements in a flexible single mission. Now, we might see more of the kind in the coming years.

Offline Sam Ho

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In an earlier launch ( IRS 1D ) a malfuction put the saellite in an elliptical orbit of 300 x 823 km. The correction to the initial orbit would have consumed too much fuel so the satellite was placed in an elliptical sunsynchronous orbit. The manoeuvres consumed about 67 kg of its fuel, leaving slightly over 16 kg.

Still the sat functioned for several years.

In the latest launch there is no much change in the orbits .. so whether it was a necessity or attempt for future more complex mission?
I guess it could be both. The smaller companions of SCATSAT may have preferred a lower orbit for their needs while the SCATSAT required a higher orbit. So, this may have been ISRO's test to see whether it could meet both requirements in a flexible single mission. Now, we might see more of the kind in the coming years.
I would guess the different deployment orbits are for orbital debris mitigation.  A satellite at 660km typically has an orbital lifetime right around the 25 year limit and therefore needs no end-of-life deorbit burn.  I believe the smaller of the secondaries don't even have any propulsion.

Offline vyoma

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SCATSat-1 products are here, showing Hurricane Matthew and Hurricane Chaba: http://www.isro.gov.in/pslv-c35-scatsat-1/scatsat-1-latest-products

Offline m.prasad

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This is not the 1st time ISRO is launching payloads in different orbits. PSLV-C3 achieved this long back. TES & BIRD were ejected into 568 Km SSO where as PROBA was pushed into 568 x 638 km Elliptical Orbit (as per Kiran Kumar in the C35-post-launch-press-meet with a Tamil news channel). So technically this is 2nd time to achieve such feat. Of course, first time with multi-burn technology. :)

Does any one know how ISRO had achieved this in C3?

Thx
~Prasad

Offline vyoma

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Does any one know how ISRO had achieved this in C3?


They used fourth stage reaction control thrusters (RCS) to change orbit: http://www.isro.gov.in/update/22-oct-2001/pslv-launch-successful-places-three-satellites-orbit

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The flight profile for PSLV-C3 mission had been modified to place the three satellites in their specified orbits -- the Indian satellite, TES and the German satellite, BIRD, in a 568 km sun-synchronous orbit and the third satellite, the Belgian PROBA in a 568 x 638 km elliptical orbit - which require firing the reaction control thrusters of PSLV fourth stage for about 500 seconds after the separation of first two satellites.

Offline vyoma

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http://isro.gov.in/scatsat-1-wind-products-beta-version-released

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SCATSAT-1 Wind Products (BETA Version) Released

SCATSAT-1 was launched on September 26, 2016 and was injected into 720 km orbit with the required inclination of 98°. The satellite was put into the orbit at 9:30 AM local time and then was slowly allowed to drift and it will be arrested to 8:45 AM local time. Ku-band Scatterometer of SCATSAT-1 is the main sensor on board this satellite and the data is very useful for Atmospheric and Oceanographic Applications. The Scatterometer payload of SCATSAT-1 is identical to OSCAT payload of Oceansat-2. Back scatter coefficient (sigma – 0) and Wind products are main products from this satellite.

The objectives of SCATSAT-1 Mission are:
 * To design, develop, launch and operate a state of art three axis body stabilised satellite providing ocean based remote sensing services to provide continuity of weather forecasting services to the user community

 * To develop remote sensing capability with respect to global day and night weather forecasting

 * To establish a ground segment to receive and process the payload data at a specified turn around time to meet the requirements of the user community

 * To develop related algorithms and data products at 50 km X 50 km and 25 km X 25 km grids to serve the well-established application areas and also to enhance the mission utility

Data Processing:

There are 14 to 15 orbits data available daily from SCATSAT-1 satellite. The data is being downloaded daily at Shadnagar and Antarctica ground stations together for all the orbits. The downloaded data at Antarctica is being transferred to Shadnagar for further processing and dissemination. Chains to receive, process and disseminate data products are developed in Integrated Multi-mission Ground Segment for Earth Observation Satellites (IMGEOS) environment. The systems are designed in such a way that the same can be used for future SCATSAT missions too.

Scatterometer provides back scatter coefficients over the oceans. With these values, sigma – 0 and wind vectors of the entire globe are getting computed and corresponding HDF products are being generated.  In contrary to OSCAT, here products are generated for pole to pole - North Pole (NP) to South Pole (SP) and SP to NP.           

Different types of products are getting generated for 50 km and 25 km grid sizes. Level-2B, Level-3 products are planned to be provided to all users through internet. Level-1B and Level-2A products will be enabled for access only for specific users.  Figure-1 and Figure-2 show global sigma-0 and global wind products respectively for October 18, 2016.

Data Dissemination:

Various types of products are planned to be disseminated through web portal and ftp server in near real time (within 50 minutes of data acquisition at Svalbard or Antarctica).  Level-1B, Level-2A and Level-2B products will be supplied to specific users. Level-2B and Level-3 products will be uploaded onto ftp and web portal so that the users can download products in near real time mode.

Beta Version of SCATSAT-1 Wind Products were released recently to all the users for their research and feedback. Validation of software and products is in progress and operational products will be released shortly.

SCATSat-1 data products beta: http://nrsc.gov.in/SCATSAT-1_Wind_Products

Offline vineethgk

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ISRO's Story of the Week - Polar Sea Ice Monitoring using SCATSAT-1 Data
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Ku-band Scatterometer on-board SCATSAT-1 (launched on September 26, 2016) is ISRO’s second space borne scatterometer similar to OSCAT on-board Oceansat-2. The payload instrument is a vital tool globally used to study wind patterns above the ocean, air-sea interactions, ocean circulation and their overall effects on weather patterns. Climate quality data will also provide accurate knowledge regarding Himalayan ice formation and melting, cyclones formation near Indian coastal line, Greenland ice melting etc.,

A hybrid classification technique has been developed to classify SCATSAT-1 data (2.25 km) for discriminating Sea ice and open ocean water. It uses σ0 composites in both the horizontal and vertical polarisations (σ0H and σ0V) and defines a normalised pseudo-polarisation quantity known as the Active Polarisation Ratio (APR).

A time series SCATSAT-1 data clearly shows the increasing Sea ice in the Arctic and decreasing Sea ice in the Antarctic from November 2016 to January 2017. It is shown in the 5-days interval animation prepared from the FCC of SCATSAT-1 (2.25 km) data over the Arctic and the Antarctic.


Offline Stan Black

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Brochure is out!
Source
I have checked the brochure and the one for flight C33 (IRNSS-1G) - it looks like all 3 pairs of SRBs separate only 2 seconds earlier this time than in the last -XL flight. Does that sound right for the old G version?

Yes and this is undoubtedly PSLV-G with its shorter PSOMs and the missing SITVC on PSOM-5 which was a modification on C7 and in place since. PSOMXL have SITVC on 4 and 5 both. But they are calling it XL not only in brochure and mission page but on that 'curtain raiser' video as well…

There is an edited brochure. Targeted orbit is different too.
http://www.isro.gov.in/sites/default/files/pslv-c35_finalbrochure.pdf
http://www.isro.gov.in/sites/default/files/flipping_book/PSLV_C35_5/files/assets/common/downloads/PSLV-C35%20Brochure.pdf

Offline vineethgk

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SCATSAT-1 operational products to be available from April 24, 2017 for all users
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SCATSAT-1 satellite carrying Ku-band Scatterometer was launched on September 26, 2016. This provides Back-Scattering coefficient (Sigma – 0) over whole globe and wind vector over ocean surface. This data is useful for various Atmospheric, Oceanographic as well as Land applications. ISRO is happy to announce the release of operational Sigma – 0 and Wind Products to all users from April 24, 2017 onwards. All old data sets (from October 12, 2016 to April 23, 2017) are planned to be reprocessed and will be made available shortly. These products will be available in 25 km and 50 km grids in HDF5 format.

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