Author Topic: LIVE: SCATSat-1/Alsat-2B - PSLV C35 - September 26, 2016 (03:42 UTC)  (Read 38661 times)

Offline vyoma

  • Full Member
  • ****
  • Posts: 995
  • India
  • Liked: 223
  • Likes Given: 101
Re: SCATSat-1/Alsat-2B - PSLV C35 - September 26 2016 03:50 UTC
« Reply #40 on: 09/21/2016 06:04 AM »
Mission page is up:
http://isro.gov.in/launcher/pslv-c35-scatsat-1
http://isro.gov.in/Spacecraft/scatsat-1

Quote
PSLV-C35 / SCATSAT-1
PSLV-C35

India’s Polar Satellite Launch Vehicle, in its thirty-seventh flight (PSLV-C35), will launch the 377 kg SCATSAT-1 for ocean and weather related studies and seven co-passenger satellites into polar Sun Synchronous Orbit (SSO). Co-passenger satellites are from Algeria, Canada and USA as well as two satellites from Indian Universities/ Academic Institute.

SCATSAT-1 will be placed into a 720 km Polar SSO whereas; the two Universities/ Academic Institute Satellites and the five foreign satellites will be placed into a 670 km polar orbit. This is the first mission of PSLV in which it will be launching its payloads into two different orbits.

PSLV-C35 will be launched from the First Launch Pad (FLP) of Satish Dhawan Space Centre (SDSC) SHAR, Sriharikota. It will be the fifteenth flight of PSLV in ‘XL’ configuration (with the use of solid strap-on motors).

The PSLV-C35 is scheduled to be launched on Monday morning at 9:12 hrs (IST) on September 26, 2016 from SDSC SHAR , Sriharikota.

Offline vineethgk

  • Full Member
  • ****
  • Posts: 682
  • India
  • Liked: 149
  • Likes Given: 256
Re: SCATSat-1/Alsat-2B - PSLV C35 - September 26 2016 03:50 UTC
« Reply #41 on: 09/21/2016 06:50 AM »
I wonder why this mission uses the XL configuration. Does the combined payloads weigh more than 1000 kg?

Offline Ohsin

  • Full Member
  • ****
  • Posts: 1469
  • Liked: 1449
  • Likes Given: 2381
Those are not PSOMs of XL variety..
"Well, three cheers to Sharma, but our real baby is INSAT."

Offline vineethgk

  • Full Member
  • ****
  • Posts: 682
  • India
  • Liked: 149
  • Likes Given: 256
Strange. Are these the old S-9 strapons? Or have they redesigned the S-12 to make it shorter?

EDIT: Are we seeing the return of standard PSLV configuration (PSLV-G??) after a long period of time? When was it launched last - C7/Cartosat-2 in 2007 or C16/Resourcesat-2 in 2011?
« Last Edit: 09/21/2016 10:41 AM by vineethgk »

Offline cbing92

  • Member
  • Posts: 5
  • Chennai, India
  • Liked: 1
  • Likes Given: 12
Strange. Are these the old S-9 strapons? Or have they redesigned the S-12 to make it shorter?

EDIT: Are we seeing the return of standard PSLV configuration (PSLV-G??) after a long period of time? When was it launched last - C7/Cartosat-2 in 2007 or C16/Resourcesat-2 in 2011?

The last PSLV-G launch was PSLV C16 carrying Resourcesat-2 on 20 April 2011.

Online Skyrocket

  • Extreme Veteran
  • Senior Member
  • *****
  • Posts: 2016
  • Frankfurt am Main, Germany
  • Liked: 252
  • Likes Given: 58
Yes, this is clearly a PSLV-G version.

For a complete flight history of PSLV see here: http://space.skyrocket.de/doc_lau/pslv.htm

Offline ZachS09

Strange. Are these the old S-9 strapons? Or have they redesigned the S-12 to make it shorter?

EDIT: Are we seeing the return of standard PSLV configuration (PSLV-G??) after a long period of time? When was it launched last - C7/Cartosat-2 in 2007 or C16/Resourcesat-2 in 2011?

The strap-on boosters looked shorter because they did not have their nose cones on yet.
« Last Edit: 09/21/2016 01:41 PM by ZachS09 »
"Liftoff of Falcon 9: the world's first reflight of an orbital class rocket."

Offline vineethgk

  • Full Member
  • ****
  • Posts: 682
  • India
  • Liked: 149
  • Likes Given: 256
Strange. Are these the old S-9 strapons? Or have they redesigned the S-12 to make it shorter?

EDIT: Are we seeing the return of standard PSLV configuration (PSLV-G??) after a long period of time? When was it launched last - C7/Cartosat-2 in 2007 or C16/Resourcesat-2 in 2011?

The strap-on boosters looked shorter because they did not have their nose cones on yet.
Nope. Take a look at the strapons of PSLV-XL in the previous launch.

http://forum.nasaspaceflight.com/index.php?topic=39448.msg1549125.msg#1549125

Offline isro-watch

  • Member
  • Full Member
  • ***
  • Posts: 314
  • Liked: 13
  • Likes Given: 4
Notice that the ISRO website mentions it is as a XL launch vehicle.

But, I m completely surprised and cannot make out why an XL is used. The weight of satellites is almost equal to the last CA version launch for Singaporean satellites.

Online Skyrocket

  • Extreme Veteran
  • Senior Member
  • *****
  • Posts: 2016
  • Frankfurt am Main, Germany
  • Liked: 252
  • Likes Given: 58
Notice that the ISRO website mentions it is as a XL launch vehicle.

But the images prove this to be incorrect

But, I m completely surprised and cannot make out why an XL is used. The weight of satellites is almost equal to the last CA version launch for Singaporean satellites.

A CA should be enough for the weight - but i think this time a dual launch structure is also flown, so we have a greater launch mass than in the Singaporean mission, which might push it over the CA limit.

Offline isro-watch

  • Member
  • Full Member
  • ***
  • Posts: 314
  • Liked: 13
  • Likes Given: 4
Yeah, you are correct.
If I zoom into the image, the strapon is named as PSOM unlike XL version strap ons which have always been named as PSOMXL .
« Last Edit: 09/21/2016 06:45 PM by isro-watch »

Offline Stan Black

  • Senior Member
  • *****
  • Posts: 2730
  • Liked: 102
  • Likes Given: 98
Notice that the ISRO website mentions it is as a XL launch vehicle.

But the images prove this to be incorrect

But, I m completely surprised and cannot make out why an XL is used. The weight of satellites is almost equal to the last CA version launch for Singaporean satellites.

A CA should be enough for the weight - but i think this time a dual launch structure is also flown, so we have a greater launch mass than in the Singaporean mission, which might push it over the CA limit.

Quote
Currently, two versions of PSLV are operational, namely PSLV-XL (with six extended version of Strap-on motors) and the PSLV Core-alone (without Strap-on motors).
http://www.isro.gov.in/sites/default/files/article-files/budget-accounts/outcomebudget2016-2017.pdf

Online Skyrocket

  • Extreme Veteran
  • Senior Member
  • *****
  • Posts: 2016
  • Frankfurt am Main, Germany
  • Liked: 252
  • Likes Given: 58
Notice that the ISRO website mentions it is as a XL launch vehicle.

But the images prove this to be incorrect

But, I m completely surprised and cannot make out why an XL is used. The weight of satellites is almost equal to the last CA version launch for Singaporean satellites.

A CA should be enough for the weight - but i think this time a dual launch structure is also flown, so we have a greater launch mass than in the Singaporean mission, which might push it over the CA limit.

Quote
Currently, two versions of PSLV are operational, namely PSLV-XL (with six extended version of Strap-on motors) and the PSLV Core-alone (without Strap-on motors).
http://www.isro.gov.in/sites/default/files/article-files/budget-accounts/outcomebudget2016-2017.pdf

Yes, i know that. But apparently it is not correct.

Or it means, that this is valid for future missions and the C35 simply uses up already existing resources.

Or the images are not from the upcoming launch.

Offline Steven Pietrobon

  • Member
  • Senior Member
  • *****
  • Posts: 11745
  • Adelaide, Australia
    • Steven Pietrobon's Space Archive
  • Liked: 2560
  • Likes Given: 369
Or the images are not from the upcoming launch.

The images EXIF information shows that is not the case.

Filename - 6integrationofstrap-onstothepslv-c35corestageatmobileservicetower.jpg
ImageWidth - 4912
ImageLength - 7360
BitsPerSample -
PhotometricInterpretation - 2
Make - NIKON CORPORATION
Model - NIKON D800E
Orientation - Top left
SamplesPerPixel - 3
XResolution - 300
YResolution - 300
ResolutionUnit - Inch
Software - Adobe Photoshop CS5.1 Windows
DateTime - 2016:09:02 15:10:15
YCbCrPositioning - Co-Sited
ExifOffset - 314
ExposureTime - 1/60 seconds
FNumber - 13.00
ExposureProgram - Manual control
ISOSpeedRatings - 100
ExifVersion - 0230
DateTimeOriginal - 2016:09:02 11:10:23
DateTimeDigitized - 2016:09:02 11:10:23
ComponentsConfiguration - YCbCr
CompressedBitsPerPixel - 4 (bits/pixel)
ShutterSpeedValue - 1/60 seconds
ApertureValue - F 13.00
ExposureBiasValue - -0.67
MaxApertureValue - F 4.76
SubjectDistance - 0.05 m
MeteringMode - Multi-segment
LightSource - Auto
Flash - Flash not fired, compulsory flash mode
FocalLength - 62.00 mm
UserComment -
SubsecTime - 30
SubsecTimeOriginal - 30
SubsecTimeDigitized - 30
FlashPixVersion - 0100
ColorSpace - sRGB
ExifImageWidth - 4912
ExifImageHeight - 7360
InteroperabilityOffset - 1010
SensingMethod - One-chip color area sensor
FileSource - Other
SceneType - Other
CustomRendered - Normal process
ExposureMode - Manual
White Balance - Auto
DigitalZoomRatio - 1 x
FocalLengthIn35mmFilm - 62 mm
SceneCaptureType - Standard
GainControl - None
Contrast - Normal
Saturation - Normal
Sharpness - Normal
SubjectDistanceRange - Unknown

GPS information: -
GPSVersionID - 2.3.0.0

Thumbnail: -
XResolution - 72
YResolution - 72
ResolutionUnit - Inch
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline vineethgk

  • Full Member
  • ****
  • Posts: 682
  • India
  • Liked: 149
  • Likes Given: 256
Sept. 26 PSLV launch to be doubly special

Quote
On September 26, the PSLV satellite launcher will for the first time place its multiple passengers in two different orbits.
The flight is also significant as it will last two hours and 15 minutes, making it the PSLV’s longest ever.
Quote
Only the main passenger, ISRO’s 370-kg Scatsat-1 ocean and weather tracker, will get off first at a slightly higher orbit at 720 km. It will be out in the first 17 minutes, as is customary.
The remaining smaller satellites, weighing between 5 kg and 110 kg, will be ejected at 670 km — but after about two hours.
To make this possible, launch team engineers will shut down and restart the fourth and last stage of the vehicle (called PS4) twice during the flight, according to two senior officials in the know.
Quote
About the spacecraft
Scatsat-1 370 kg [Indian; main payload]
Alsat-1B 103 kg
Alsat-2B 110 kg
Alsat Nano 7 kg
[All 3 Algerian earth observation satellites]
Pathfinder-1 44 kg [BlackSky, U.S.]
NLS-19 8 kg [University of Toronto, Canada]
PISat 5.7 kg [Student sat from PESIT Bengaluru]
Pratham 10 kg [IIT-Bombay's Dept of Aerospace Engg]

If I haven't missed anything, the total payload mass excluding DLA comes to around 658 kg.

Online William Graham

  • Senior Member
  • *****
  • Posts: 3987
  • Liked: 71
  • Likes Given: 37
Strange. Are these the old S-9 strapons? Or have they redesigned the S-12 to make it shorter?

EDIT: Are we seeing the return of standard PSLV configuration (PSLV-G??) after a long period of time? When was it launched last - C7/Cartosat-2 in 2007 or C16/Resourcesat-2 in 2011?

The strap-on boosters looked shorter because they did not have their nose cones on yet.

ISRO's gallery for the AstroSat mission has an image of an XL in a similar state of assembly. Note how much further the boosters come up the vehicle before they start to taper.

http://www.isro.gov.in/astrosat/astrosat-gallery

Offline worldtimedate

  • Full Member
  • *
  • Posts: 108
  • Liked: 5
  • Likes Given: 0
Quote

MUMBAI: It promises to be a historical Indian space mission for three reasons on September 26. It will be the first time that a satellite, Pratham, designed and developed by the students of IIT-Bombay will be launched. Second, only 18 days after successfully launching a weather satellite, Insat-3DR, another one, ScatSat-1, will be placed in orbit for the first time.

Third, in its 23-year-old history, it will be the first time that the highly proven four-stage PSLV will be launching satellites into two different orbits. For Monday's flight the launcher will be the advanced version of the PSLV called the PSLV-XL.

According to Isro, while the main satellite, ScatSat-1, will be placed into a 720-km polar sun synchronous orbit, the remaining ones will go into a 670-km polar sun synchronous orbit. For this complex manoeuvre, Isro had earlier carried out a test of successfully shutting down and restarting the fourth stage engine of the PSLV.


Source : Satellite built by IIT-Bombay set for launch

worldtimedate [ http://www.world-timedate.com/ ]
« Last Edit: 09/22/2016 07:32 PM by worldtimedate »

Offline worldtimedate

  • Full Member
  • *
  • Posts: 108
  • Liked: 5
  • Likes Given: 0
Here is another report on multiple rocket engine burn technology.

Quote

This is the first mission of PSLV in which it will be launching its payloads into two different orbits.

The multiple burn technology was first tested by ISRO while flying its PSLV rocket on December 16, 2015.


Launching of multiple satellites with a single rocket is nothing new for ISRO and it has been doing that for several years. The challenge, however, is to launch several satellites at different orbits with one rocket.

"Restarting a rocket engine soon after it is shut off is a critical technology that has to be mastered. Once a rocket engine is activated, then the heat generated is very high. The trick is to cool it down in the space and to restart it at a short gap," an industry expert had told IANS.

"This is entirely different from switching on and off the communication satellite's engines in the space. The interval between two restarts of a communication satellite engine will be in days. But in the case of restarting a rocket engine, the time gap will be in hours," the expert added.

"By that time the rocket's engine has to be cooled down. This part of the experiment is very critical," he explained.[/b]


Source : India to launch eight satellites in two different orbits on September 26

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

Offline worldtimedate

  • Full Member
  • *
  • Posts: 108
  • Liked: 5
  • Likes Given: 0
According to this Deccan Chronicle Report, the fourth stage will be cut off after 17 minutes of flight, then it will be restarted twice.

Quote

Satish Dhawan Space Centre director P. Kunhi Krishnan said the ScatSat-1 will be separated within 17 minutes of launch, after the fourth stage is shut off. The stage will be ignited briefly after 1 hour and 22 minutes and stopped. It will be started again about 40 minutes later, and the last satellite will be placed in orbit about 2 hours and 15 minutes after launch.

This multiple rocket engine burn technology was tested in two PSLV Missions before.

Quote
"We have demonstrated the fourth stage engine restart capability. The fourth stage was restarted once in case of PSLV C-29 and twice with respect to PSLV-C34", Mr Kunhi Krishnan told this newspaper.

Source : ISRO’s multi-orbit launch on anvil

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

Offline m.prasad

  • Member
  • Posts: 91
  • Liked: 5
  • Likes Given: 0
Couple of questions:

1. Does any one know weight of new DLA? Older one weighs ~250Kg.

2. Why can't ISRO use PSOM XL strap-ons (12T), in numbers 2, 3, 4, or 5 (without loosing vehicle balance during 1st stage of flight) based on the payload weight, instead of always going with 6 strap-on boosters when payload weight crosses PSLV-CA limit (assuming 9T boosters are retired at this moment) ?

Although cost saving is less, this approach would save few strap-ons for follow on launches. It has some positive impact on the frequency of the launches, which is current limited by manufacturing capacity limits :)

Thx
~Prasad

Tags: