Ye Olde Rocket Forum

Go Back   Ye Olde Rocket Forum > Weather-Cocked > FreeForAll
User Name
Password
Auctions Register FAQ Members List Calendar Today's Posts Search Mark Forums Read


Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 09-01-2017, 01:44 AM
blackshire's Avatar
blackshire blackshire is offline
Master Modeler
 
Join Date: Jan 2009
Location: Fairbanks, Alaska
Posts: 6,507
Default PSLV failure (link)

Hello All,

Today ISRO’s Polar Satellite Launch Vehicle, in its 41st flight, has experienced its first total failure since 1997 (see: http://www.youtube.com/watch?v=bcwA...eature=youtu.be ). Carrying the Indian IRNSS-1H navigation satellite toward an initial parking orbit, from which its liquid propellant fourth stage was to re-start to inject the satellite into a GTO (Geosynchronous Transfer Orbit), the PSLV vehicle flew normally until the heat shield (payload fairing) failed to jettison at T+203 seconds. (The night launch is at 14:30—and the heat shield jettison failure is at 17:55—in the above-linked video.) Also:

The growing apprehension and dismay can be seen and heard on the faces, and in the voices, of the launch team members as the dead weight of the heat shield caused the trajectory to vary more and more from the planned one. Despite its extra burden, the PSLV managed to reach a 167.4 km x 6554.8 km orbit, inclined 19.18 degrees to the Earth’s equator, although the fourth stage and the still-attached heat shield—with IRNSS-1H trapped inside—will decay within days or weeks.
__________________
Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see:
http://www.lulu.com/content/paperba...an-form/8075185
http://www.lulu.com/product/cd/what...of-2%29/6122050
http://www.lulu.com/product/cd/what...of-2%29/6126511
All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com.
NAR #54895 SR
Reply With Quote
  #2  
Old 09-01-2017, 11:24 AM
Woody's Workshop Woody's Workshop is offline
Craftsman
 
Join Date: Mar 2012
Location: Reed City, Michigan
Posts: 258
Default

That purely sucks. I wonder what failed in releasing the heat shield?
Reply With Quote
  #3  
Old 09-01-2017, 07:25 PM
blackshire's Avatar
blackshire blackshire is offline
Master Modeler
 
Join Date: Jan 2009
Location: Fairbanks, Alaska
Posts: 6,507
Default

Quote:
Originally Posted by Woody's Workshop
That purely sucks. I wonder what failed in releasing the heat shield?
While ISRO is still just at the beginning of its investigation, I read that the heat shield jettison command is pre-programmed rather than commanded from the ground (I think this is probably the case with most launch vehicles), but:

If the wire leads to the explosive nuts and/or bolts aren't broken or improperly connected, the command sequencer can fail to issue the separation command (or other commands) for numerous reasons. Faulty programming ("garbage-in, garbage-out"), electrical power fluctuations (or insufficient current to operate the command sequencer or fire the pyrotechnic charges), or any number of other anomalies can result in such a failure. For example:

The heat shield of the last ELDO (European Launcher Development Organisation) Europa I rocket launched from Woomera in Australia (not one of them, nor the single Europa II launched from Kourou, French Guiana, reached orbit, due to various failures) failed to jettison for a maddeningly simple reason. The pyrotechnic charges' electrical cable connector (which was a newly-adopted, standard industrial part rather than an aerospace-rated part) wasn't rated for vacuum use (it wasn't vented), and it burst due to the internal air pressure as the vehicle left the atmosphere, breaking the electrical connection. Also:

As it approached Venus for the first successful flyby of another planet, the command sequencer of the overheated Mariner 2 spacecraft balked, failing to issue the pre-programmed command to the instruments to begin scanning Venus. JPL had to transmit an "Encounter Sequence On" command across 34,000,000 miles of interplanetary space from the Goldstone tracking station to get Mariner 2 to switch on its instruments. In this case, the excessive heating of the spacecraft caused--or at least contributed to--the problem (Mariner 2 fell silent just a little over two weeks after its December 14, 1962 Venus flyby).
__________________
Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see:
http://www.lulu.com/content/paperba...an-form/8075185
http://www.lulu.com/product/cd/what...of-2%29/6122050
http://www.lulu.com/product/cd/what...of-2%29/6126511
All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com.
NAR #54895 SR
Reply With Quote
  #4  
Old 09-02-2017, 12:32 PM
frognbuff frognbuff is offline
Aggressor Aerospace
 
Join Date: Oct 2012
Location: Colorado Springs, CO
Posts: 590
Default

All unmanned launch vehicle are autonomous. The only commands from the ground they can receive and respond to in flight are the Range Safety ARM (which shuts down liquid propulsion and prevents any staging events) and DESTRUCT commands. In other words, the commands you don't want to send.

Even manned SLVs have minimal, if any, opportunity for intervention from the Ground. The flight crew typically has the ability to initiate an abort.
Reply With Quote
  #5  
Old 09-03-2017, 08:19 PM
blackshire's Avatar
blackshire blackshire is offline
Master Modeler
 
Join Date: Jan 2009
Location: Fairbanks, Alaska
Posts: 6,507
Default

Quote:
Originally Posted by frognbuff
All unmanned launch vehicle are autonomous. The only commands from the ground they can receive and respond to in flight are the Range Safety ARM (which shuts down liquid propulsion and prevents any staging events) and DESTRUCT commands. In other words, the commands you don't want to send.

Even manned SLVs have minimal, if any, opportunity for intervention from the Ground. The flight crew typically has the ability to initiate an abort.
Mercury and Apollo [Gemini had ejection seats] had provision for the capsule launch escape system to be triggered by ground command (as does the Soyuz today; one Soyuz pad abort and one ascent abort, both initiated by ground command, have occurred). During early ascent, the Space Shuttle's abort options were very limited indeed. Had the Soviet Buran Shuttle become operational, its abort options would have been much more robust and survivable, as it was capable of fully automated flight (as its one space flight demonstrated) and its liquid-propellant Energia carrier rocket's engines could be shut down in an emergency.

The old converted Atlas ICBMs (and at least some of the core-only Titan IIIs flown from Vandenberg) used radio command guidance, which allowed steering corrections (and would have allowed other commands such as payload fairing jettison, if they included provision for that as a backup to the pre-programmed onboard system; they may not have done so) to be sent from the ground.

Japan's (ISAS's) L-4S (and at least the early variants of their M [Mu] series of satellite launch vehicles) used no active guidance at all, relying on spin stabilization, but the final stage had a jettisonable "service module" that de-spun it, aimed it in azimuth and elevation, and re-spun it in the desired orientation, after which the final-stage rocket motor was ignited by a radio-command-adjustable timer. Their latest vehicle in that series (the Epsilon) is designed to decide for itself whether it is transgressing the range safety criteria, and will destroy itself if it is doing so, and is unable to correct the situation via other means. (They may not have flown that system yet; JAXA announced that the first Epsilon launches would use the regular human-monitored & commanded range safety system, then the autonomous system in "monitoring mode" to verify its performance, and then later they would use it exclusively.)
__________________
Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see:
http://www.lulu.com/content/paperba...an-form/8075185
http://www.lulu.com/product/cd/what...of-2%29/6122050
http://www.lulu.com/product/cd/what...of-2%29/6126511
All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com.
NAR #54895 SR
Reply With Quote
  #6  
Old 09-04-2017, 04:18 PM
frognbuff frognbuff is offline
Aggressor Aerospace
 
Join Date: Oct 2012
Location: Colorado Springs, CO
Posts: 590
Default

As I said, all UNMANNED SLVs are autonomous. Your references to Mercury, Apollo, Soyuz, and Shuttle therefore add nothing to this discussion. They certainly aren't relevant to PSLV fairing jettison.

As for Atlas with command guidance updates, I believe that ended with Atlas G (I could be wrong and welcome a citation to the contrary), which last flew in 1989. The last Titan III flew in 1992. The Mu-3S flew out in 1995. So, once again, I assert no unmanned SLV accepts commands from the ground except for Range Safety commands. The ones that did are gone.
Reply With Quote
  #7  
Old 09-04-2017, 11:40 PM
blackshire's Avatar
blackshire blackshire is offline
Master Modeler
 
Join Date: Jan 2009
Location: Fairbanks, Alaska
Posts: 6,507
Default

Quote:
Originally Posted by frognbuff
As I said, all UNMANNED SLVs are autonomous. Your references to Mercury, Apollo, Soyuz, and Shuttle therefore add nothing to this discussion. They certainly aren't relevant to PSLV fairing jettison.

As for Atlas with command guidance updates, I believe that ended with Atlas G (I could be wrong and welcome a citation to the contrary), which last flew in 1989. The last Titan III flew in 1992. The Mu-3S flew out in 1995. So, once again, I assert no unmanned SLV accepts commands from the ground except for Range Safety commands. The ones that did are gone.
You mentioned manned SLVs before I did, and I never said that unmanned SLVs don't use autonomous separation systems (I said that it’s probably the case with most launch vehicles because I’m not familiar with the Iraqi [the one test of their Scud-based SLV years ago failed], Iranian, or North Korean SLVs). I find the evolution of today's systems, whose forerunners were often ground-commanded (including in early Soviet vehicles; Luna 3's R-7 ICBM-based launch vehicle used radio command guidance to hit its trans-lunar trajectory to photograph the lunar far side), interesting, and:

A nation that is building and flying its first SLVs might very well use more "primitive" systems to begin with. For example, ISRO's first satellite rocket, the SLV-3, used open-loop guidance throughout the burning periods of its first three guided stages (the fourth and final stage was spin-stabilized), while current SLVs (including ISRO's) only use open-loop guidance during the earliest portion of ascent. Also:

ISRO's ASLV (Augmented Satellite Launch Vehicle, an SLV-3 with two additional strap-on first stage motors, which burned together to serve as its first stage) initially used a very simple system--a timer--to ignite the first stage of the core vehicle, but the second ASLV failed when the two strap-on motors burned out slightly earlier than expected. This left the core stage with no thrust vector control for just long enough that it tilted too far, and it broke up due to the aerodynamic forces (the first ASLV had failed when the first core stage motor failed to ignite). ISRO changed to using sensors in the strap-on motors that detected their burnout, which triggered the first core stage motor to ignite.

The last Titans that used radio command guidance were Titan 34B vehicles (core-only, constant-diameter ones that housed the Agena third stage inside the 10' diameter payload fairing along with the satellite or satellites). The online references that I’ve seen say that they used inertial guidance, but a Martin Marietta Titan family booklet that I had said that they used radio command guidance.
__________________
Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see:
http://www.lulu.com/content/paperba...an-form/8075185
http://www.lulu.com/product/cd/what...of-2%29/6122050
http://www.lulu.com/product/cd/what...of-2%29/6126511
All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com.
NAR #54895 SR
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump



All times are GMT -5. The time now is 07:05 AM.


Powered by: vBulletin Version 3.0.7
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Ye Olde Rocket Shoppe © 1998-2024