Ajay Kumar at 07:49, 2 September 2023

2023-09-02T07:49:31Z

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{{Infobox spaceflight
| name = GSAT-4
| image = GSAT-4.jpg
| image_caption = GSAT-4

| mission_type = [[Communications satellite|Communication]]
| operator = [[ISRO]]
| website =
| COSPAR_ID =
| SATCAT =
| mission_duration = 7 years (planned)<br/>Failed to orbit

| spacecraft_bus = [[I-2K]]
| manufacturer = [[Indian Space Research Organisation Satellite Centre|ISRO Satellite Centre]]<br/>[[Space Applications Centre]]
| dry_mass =
| launch_mass = {{convert|2220|kg|lb}}
| power = 2,760 watts

| launch_date = {{start-date|15 April 2010, 10:57|timezone=yes}} UTC
| launch_rocket = [[Geosynchronous Satellite Launch Vehicle|GSLV Mk.II]] D3
| launch_site = [[Satish Dhawan Space Centre|Satish Dhawan]] [[Satish Dhawan Space Centre Second Launch Pad|SLP]]
| launch_contractor =

| orbit_epoch = Planned
| orbit_reference = [[Geocentric orbit|Geocentric]]
| orbit_regime = [[Geostationary orbit|Geostationary]]
| orbit_periapsis =
| orbit_apoapsis =
| orbit_inclination =
| orbit_period =
| orbit_longitude = 82° East
| orbit_slot =
| apsis = gee

| trans_band = Ka-band
| trans_frequency =
| trans_bandwidth =
| trans_capacity =
| trans_coverage =
| trans_TWTA =
| trans_EIRP =
| trans_HPBW =
| programme = [[GSAT]]
| previous_mission = [[GSAT-3]]
| next_mission = [[GSAT-5P]]
}}
'''GSAT-4''', also known as '''HealthSat''', was an experimental [[communication satellite|communication]] and [[navigation satellite|navigation]] [[satellite]] launched in April 2010 by the [[Indian Space Research Organisation]] on the maiden flight of the [[Geosynchronous Satellite Launch Vehicle]] Mk.II rocket.<ref>{{cite web|url=http://www.isro.org/rep2006/Communication.htm|title=Indian Communication Satellites|archive-url=https://web.archive.org/web/20071223032607/http://www.isro.org/rep2006/Communication.htm|archive-date=23 December 2007|publisher=Indian Space Research Organisation}}</ref> It failed to reach orbit after the rocket's third stage malfunctioned.<ref name="TH-failure">{{cite web|url=http://www.thehindu.com/news/article398070.ece|title=India's indigenous GSLV D3 rocket fails in mission|last=Subramanian|first=T. S.|date=15 April 2010|work=The Hindu|access-date=15 April 2010}}</ref> The third stage was the first Indian-built [[Cryogenic fuel|cryogenic-fuelled]] upper stage, and was making its first flight. The ISRO suspects that the failure was caused by the third stage not igniting.<ref name="TH-failure2">{{cite web|url=http://www.thehindu.com/sci-tech/science/article399411.ece|title=Why didn't the cryogenic engine ignite?|last=Subramanian|first=T. S.|date=17 April 2010|work=The Hindu|access-date=17 April 2010}}</ref>

==Satellite==
Weighing around two tons, GSAT-4 carried a multi-channel, [[Ka-band]], [[bent pipe]] and regenerative [[transponder]], and a navigation payload in the C, L1, and L5 bands. Designed to guide civil and military aircraft, GSAT-4 was to have employed several new technologies such as a bus management unit, miniaturised dynamically tuned gyros, lithium-ion battery, 70 volt bus for Ka-band [[traveling-wave tube amplifiers|travelling-wave tube amplifiers]], and electric propulsion. GSAT-4 also incorporated technological experiments like on-board structural dynamic experiment, thermal control coating experiment and vibration beam accelerometer. With a lift-off mass of about {{convert|2180|kg}}, the spacecraft was to have generated a maximum of 2,760 W of power.<ref name="missionbooklet"/><ref name="krebs"/>

GSAT-4 was also to have been the first Indian spacecraft to employ [[ion propulsion]].<ref name="missionbooklet">{{cite web|url=http://isro.org/gslv-d3/pdf/GSLV-D3_GSAT-4%20Brochure.pdf|title=GSLV-D3 / GSAT-4|publisher=ISRO|access-date=15 April 2010|date=April 2010|archive-url=https://web.archive.org/web/20140207165809/http://www.isro.org/gslv-d3/pdf/GSLV-D3_GSAT-4%20Brochure.pdf|archive-date=7 February 2014|url-status=dead}}</ref> Four [[Hall effect thruster]]s would have been used for north–south station keeping operations. Two types of Hall effect thrusters are developed by ISRO Satellite Centre (ISAC) and Liquid Propulsion Systems Centre (LPSC).

===Secondary payloads===
{{Main|GPS Aided Geo Augmented Navigation|TAUVEX}}
GSAT-4 carried the first [[GPS Aided Geo Augmented Navigation]], or GAGAN, navigation payload. GSAT-4 was also intended to carry to the [[Israel]]i [[TAUVEX|TAUVEX-2]] space telescope array. Due to concerns that the new upper stage may have reduced the rocket's payload capacity, ISRO decided to remove TAUVEX in order to decrease the mass of the payload.<ref name="krebs"/> GAGAN was still flown.<ref name="krebs">{{cite web|last=Krebs|first=Gunter D. |title=GSat 4 (HealthSat)|publisher=Gunter's Space Page |access-date=December 11, 2022|url=https://space.skyrocket.de/doc_sdat/gsat-4.htm}}</ref> GAGAN consisted of a Ka band [[bent pipe transponder]] and a regenerative transponder.<ref>{{cite web|title=Use of Space Technology in Fail-Safe Emergency Communication and Establishing Last Mile Connectivity|url=http://www.saarc-sdmc.org/sites/default/files/programmes_doc_upload/SDMC-2-Nilesh-Desai.pdf|date=24 May 2017|first=Nilesh M. |last=Desai|access-date=December 11, 2022}}</ref>

==Launch==
GSAT-4 was launched on the maiden flight of the GSLV Mk.II rocket, GSLV D3, flying from the [[Satish Dhawan Space Centre Second Launch Pad|Second Launch Pad]] at the [[Satish Dhawan Space Centre]]. Its third stage was fitted with a new Indian-built [[cryogenic engine]], which was intended to make the GSLV reliant on only Indian technology, since earlier launches had used Russian engines. GSLV D3 was the sixth flight of the [[Geosynchronous Satellite Launch Vehicle]] across all variants.

The rocket was {{convert|40.39|m}} in length minus its payload fairing, and consisted of a solid-fuelled [[S139]] first stage augmented by four [[L40H Vikas|L40H]] [[hypergolic propellant|hypergolically fuelled]] strapons, burning [[Unsymmetrical dimethylhydrazine|UDMH]] as fuel and {{N2O4}} as oxidiser. The second stage used the same hypergolic propellants, whilst the third stage was the new [[Cryogenic Upper Stage]] (CUS), burning [[liquid hydrogen]] oxidised by [[liquid oxygen]].

The rocket's first and second stages performed normally, and at the time controllers reported that third stage ignition had occurred. However, shortly afterwards the rocket began to under-perform, tumbling out of control, and deviating from its planned trajectory.<ref>{{cite web|url=http://www.ndtv.com/news/india/indias-gslv-mission-fails-20084.php|title=India's GSLV Mission fails|date=15 April 2010|access-date=15 April 2010|publisher=NDTV}}</ref> Around 300 seconds into the flight, contact with the rocket was lost. Initial analysis of the data suggested that the [[vernier thruster]]s, used to provide [[Attitude dynamics and control|attitude control]], had failed to ignite due to engineering problems.<ref name="TH-failure"/> On 17 April, ISRO announced that further analysis of the data indicated that the third stage main engine had not ignited either.<ref name="TH-failure2"/> According to ISRO, mission failed after the fuel turbo pump that supplied fuel to the cryogenic engine had stopped working a second after ignition.<ref>{{cite web|title=Cause of GSLV-D3 failure analysed|url=http://www.deccanherald.com/content/80490/cause-gslv-d3-failure-analysed.html|website=Deccan Herald|date=10 July 2010 |access-date=10 February 2018|archive-url=https://web.archive.org/web/20180210233110/http://www.deccanherald.com/content/80490/cause-gslv-d3-failure-analysed.html|archive-date=10 February 2018|location=Wayback Machine}}</ref>

==References==
{{Reflist}}

==External links==
{{Portal|Spaceflight}}
* "[https://web.archive.org/web/20111017185930/http://isro.org/gslv-d3/gslv-d3.aspx GSLV-D3]". ISRO. Retrieved 22 October 2011.

{{GSAT Satellites}}
{{Indian spacecraft}}
{{Orbital launches in 2010}}

{{Use Indian English|date=January 2014}}

[[Category:GSAT satellites]]
[[Category:Spacecraft launched in 2010]]
[[Category:Satellite launch failures]]
[[Category:2010 in India]]
[[Category:Spacecraft launched by GSLV rockets]]

GSAT-4 - Revision history

Ajay Kumar at 07:49, 2 September 2023