RLV airframe under construction

[danger007]

i have a high regard for our X president and equally for his associates..the success we reached are the results of many such kalams

I disagree with you... He is a complete gentlemen with master mind.... yeah we might have many .... but Kalam is unique, he is always my inspiration...

 

[Hyperion]

AVATAR RLV-TSTO

 

[neehar]

I disagree with you... He is a complete gentlemen with master mind.... yeah we might have many .... but Kalam is unique, he is always my inspiration...

i understand ur thoughts he is a great inspiration to many people like us..he has high moral values and strength to lead nation ..but through my example ..i was referring to technical expertise only

 

[BlueDot_in_Space]

@any member.

What's FADS(Flush Air Data System ) and why it's a critical technology for 5th fighter program?

For a fly by wire system, air data system provides parameters like air speed, pressure, angle etc. Tejas uses pitot tubes as sensor for the air data system. Protruding pitot tube is not good for stealth designs and requirement is that a sensor should be flush with the aircraft body. here comes Flush air data system that conforms with the surface maintaining stealth design. They are also more accurate

Hypersonic flight regimes are another area where probe based air data systems cannot be used because the vehicle nose reaches such high temperatures that the protruding boom may fail structurally. This is the reason why ISRO worked on developing FADS

 

[S-DUCT]

^
Nice Explanation!
thanks

 

[anant_s]

Interesting to see the re-entry vehicle nose shapes. A capsule similar to this is proposed to be a part of India's first manned mission and considering the thermal loads and material strength requirements during re-entry any reasearch done here will immensely contribute towards Re Launch Vehicle project sucess as well.

Heres another interesting paper on thermal shield tiles

Silica Tile System Development: A Key Technology Element in Spacecapsule Recovery Experiment
By:
A Subramoniam, PD-SRE and N.C. Bhat, APD-SRE,
Indian Space Research Organisation (ISRO)
--------------------------------------------------------------------------------

Spacecapsule Recovery Experiment (SRE) has heralded a new era to Indian Space Research program by successfully re-entering into earth's atmosphere and splashing in sea at predicted impact zone. With SRE, India and ISRO in particular demonstrated the capability in bringing back orbiting spacecraft and recover it at the desired location. For SRE, the de-boost starts over Mexico in southnorth pass of SRE. The flight covers almost half the globe and splash down occurs at Bay of Bengal in north south pass en route north pole. The flight from 100 km down to about 30 km is very critical. The module enters 100 km at a speed of 29000 km/hr (Mach 30) and experience aero-breaking and drag, which results in generation of hot plasma layers surrounding the capsule body. The peak heating of 258 W/cm2 at the stagnation region occurs at 50 km at Mach 20. To prevent capsule body from such a hostile environment SRE heat shield is configured with Carbon Phenolic Ablative and Silica Tile systems over composite base structure. It is worth mentioning that without meticulous development and realisation of Silica tile system by ISRO, it would not have been possible to conduct the re-entry experiment successfully.

SRE re-entered in earth's atmosphere on 22nd January 2007. Figure 1 shows re-entry operation sequence and its timeline. At 9:00 IST de-boost command is activated over Mexico. Its de-boost performance was as expected. The re-entry started at 100 Km over Lucknow (India). A minute laterdue to severe heating and formation of plasma, capsule went to RF blackout phase. This was very critical phase (of about two minutes) when maximum heating and aerodynamic breaking has to take place and capsule to sustain the hostile re-entry environment. At the same time due to RF blackout no ground communication can be established with spacecraft. Figure 2 shows a typical heating profile on the capsule.

Development of highly insulative low-density Silica tiles and its attachment systems were one of the major challenges. The ceramic silica tile system required development of a number of materials like Silica tiles, strain isolation pad, gap fillers, special emissivity coatings and high temperature adhesives.

The silica tile system is designed to meet,

1. Low Thermal Conductivity to keep back wall temperature with acceptable limits.

2. The tile density must as low as possible (< 0.4 gm/cc) so as the mass of TPS shall not increase the total SRE mass. It is critical in Silica tile case as it covers almost 90% of external surface of heat shield.

3. The SRE Spacecraft was designed to stay in space for 90 days. Hence, all these new TPS materials have to meet the deep vacuum specifications and vacuum degassing constraints.

4. Further RF transparency of tiles protecting the antenna has to be ensured even in hot condition.

The Silica tile is made of amorphous silica fibres, which is moulded in to the form of block and impregnated with ceramic binder. These blocks are dried and sintered to achieve the properties required. The blocks are later machined to suit the outer surface of the base structure. These tiles can with stand temperature upto 1400oC and very low thermal conductivity so as to keep back-wall temperature within acceptable limit of 120C. The first flight of SRE has about 264 Nos of tiles of 14 different types.

The Silica Thermal protection system is bonded on to the composite base structure by means of high temperature adhesive. A Strain isolation pad is used to isolate the structural deformations and differential coefficients of thermal expansion. The SIP is located between the tile and the base structure. Figure 3 shows Silica tile system.

Tests were done in Kinetic heating simulation, plasma arc jet, rocket exhaust, thermo vac cycling, thermal shock, acoustics etc, for qualifying TPS. While basic laboratory level processes were developed in ISRO, the industries were enabled to set up the facilities for large-scale production. A large number of samples were characterized in thermovac facilities to ensure the space environment compatibility of Silica tiles and Silica tile system.



The Flight results of SRE suggest that thermal response of Silica tiles were better than expected as shown in Figure 4. The tile surfaces were apparently intact after splash down except for some minor damages during recovery operations. Figure 5 compares the pre-launch SRE tile surfaces with recovered SRE Spacecraft. The spacecraft body was floating in seawater for about 2 hours prior to its recovery, which caused minor surface cracks on tile surfaces and seawater deposits on tile surfaces.

With the success of Spacecapsule Recovery experiment, ISRO has demonstrated the capabilities for development of critical technologies needed like providing stable platform for microgravity experiments, Navigation Guidance & Control for system for end to end mission, parachute and floatation systems for terminal phase and new materials developments like Silica tile system. It is prudent to recall here the unstinted efforts by Advance Material and Ceramics Group of VSSC, Trivandrum in realisation of the Silica tiles.

Welcome to ISAMPE

 

[Abingdonboy]

Interesting to see the re-entry vehicle nose shapes. A capsule similar to this is proposed to be a part of India's first manned mission and considering the thermal loads and material strength requirements during re-entry any reasearch done here will immensely contribute towards Re Launch Vehicle project sucess as well.

Heres another interesting paper on thermal shield tiles


Welcome to ISAMPE

Have Indian companies been able to devlop such heat sheilding tiles that are more affordable than the ones NASA developed for their space shuttle? IIRC each individual tile cost >$100,000 USD.

 

[narcon]

@any member.

What's FADS(Flush Air Data System ) and why it's a critical technology for 5th fighter program?

www.nasa.gov/centers/dryden/pdf/88073main_H-1277.pdf

 

[anant_s]

Have Indian companies been able to devlop such heat sheilding tiles that are more affordable than the ones NASA developed for their space shuttle? IIRC each individual tile cost >$100,000 USD.

Tried to search but couldnot find much information. However i saw a video on NDTV (Pallav Bagla's report), where they demonstrated an In-house developed ceramic tile (don't know if it was completely cermaic or not) with a honey-comb structure. But i remember right the thing was a small lab prototype and it is not clear if the technology exists to undertake production on an industrial level and hence can't compare the cost.

 

[Rajaraja Chola]

But I still recommend that we don't try to bring the two orgs too close...what if DRDO TEACHES something to ISRO ???

@Blue_*** - can you please put up pics of the space suit....it's about time buddy .

I think ISRO shouldnt transfer any tech to DRDO nor DRDO to ISRO, atleast publicly.
Internationally ISRO is considered civilian space group, while DRDO represents a defence org. So a distance have to be maintained atleast publicly.

 

[Persian Achaemenid Empire]

Excellent

 

[Hyperion]

Yes, they have. Read it sometime back in a journal, and the cost was way way way < USD100,000 / tile. If memory serves me well, it was something around USD500.00 / tile.

Imagine, even the RLV project, has a total cost of USD5million for the whole of design stage. Now those are some nice numbers that don't hurt the pocket.

Have Indian companies been able to devlop such heat sheilding tiles that are more affordable than the ones NASA developed for their space shuttle? IIRC each individual tile cost >$100,000 USD.

 

[Guynextdoor2]

I think ISRO shouldnt transfer any tech to DRDO nor DRDO to ISRO, atleast publicly.
Internationally ISRO is considered civilian space group, while DRDO represents a defence org. So a distance have to be maintained atleast publicly.

No, no- I was just trying my hand at some humor. How come people have become serious so suddenly?

 

[Abingdonboy]

Yes, they have. Read it sometime back in a journal, and the cost was way way way < USD100,000 / tile. If memory serves me well, it was something around USD500.00 / tile.

Imagine, even the RLV project, has a total cost of USD5million for the whole of design stage. Now those are some nice numbers that don't hurt the pocket.

Could you provide the link mate?

 

[Hyperion]

Mate, unfortunately can't. Read it in a journal (not online), sometime back.

Could you provide the link mate?