View source for Engineering:Small Satellite Launch Vehicle

{{Short description|Indian small-lift launch vehicle}}
{{Use Indian English|date=September 2020}}
{{Infobox rocket
|name           = Small Satellite Launch Vehicle
|image          = Mrm7669 Launch of SSLV-D1 from Satish Dhawan FLP.jpg
|caption        = SSLV D1 lifting off from [[Astronomy:Satish Dhawan Space Centre First Launch Pad|Satish Dhawan Space Centre First Launch Pad]]

|function       = [[Engineering:Small-lift launch vehicle|Small-lift launch vehicle]]
|manufacturer   = [[Company:NewSpace India Limited|NSIL]], ISRO<ref>{{cite web |url=https://www.nsilindia.co.in/sslv-manufacturing |title=SSLV MANUFACTURING |website=/www.nsilindia.co.in|access-date=2022-08-07}}</ref>
|country-origin = India
|cpl            = {{INRConvert|35|c|lk=on}} (expected)<ref name=":4" /><ref name="ET_20200331"/><ref name="TH_20190111"/><ref>{{cite web|url=https://www.dnaindia.com/science/report-why-isro-s-maiden-sslv-mission-failed-despite-successful-launch-of-new-rocket-2974773 |title=Why ISRO's maiden SSLV mission failed despite successful launch of new rocket |publisher=Dnaindia.com |date=2022-08-08 |accessdate=2022-08-13}}</ref>

|height         = {{cvt|34|m}}
|diameter       = {{cvt|2|m}}
|mass           = {{cvt|120|t}}
|stages         = 3+1<ref>{{cite news|title=ISRO is developing a small rocket to cash in on the small-satellite boom|url=https://www.thenewsminute.com/article/isro-developing-small-rocket-cash-small-satellite-boom-73143|access-date=2 September 2018}}</ref>
|capacities =
  {{Infobox rocket/payload
  |location     = [[Astronomy:Low Earth orbit|low Earth orbit]]
  |altitude     = {{cvt|500|km}}<ref name=SSLV_UMv2/>
  |inclination  = 45.0°
  |kilos        = {{cvt|500|kg}}
  }}
  {{Infobox rocket/payload
  |location     = [[Astronomy:Sun-synchronous orbit|Sun-synchronous orbit]]
  |altitude     = {{cvt|500|km}}<ref name=SSLV_UMv2/>
  |kilos        = {{cvt|300|kg}}
  }}
| comparable = {{Plainlist|
* [[Engineering:Minotaur I|Minotaur I]]
* [[Engineering:Start-1|Start-1]]
* Kuaizhou
* Electron rocket
}}
|status         = Active
|sites          = [[Astronomy:Satish Dhawan Space Centre|Satish Dhawan Space Centre]]
|launches       = 2
|first          = 03:48 [[Physics:Coordinated Universal Time|UTC]], 7 August 2022.<ref name = "ISROTWT_20220801">{{Cite tweet|number=1554003107545092096|user=ISRO|title=The launch of the SSLV-D1/EOS-02 Mission is scheduled for Sunday, August 7, 2022, at 9:18 am (IST) from Satish Dhawan Space Centre (SDSC), Sriharikota. ISRO invites citizens to the Launch View Gallery at SDSC to witness the launch.|author=Indian Space Research Organisation|date=1 August 2022|access-date=1 August 2022}}</ref>
|stagedata =
  {{Infobox rocket/stage
  |type         = stage
  |stageno      = First
  |name         = SS1
  |solid        = yes
  |engines      = S85
  |fuel         = Solid ([[Chemistry:Hydroxyl-terminated polybutadiene|HTPB]] based)
  |thrust   = 2,496 kN (vac)<ref name="VSSC_SSLV">{{cite web |title=Small Satellite Launch Vehicle |url=https://www.vssc.gov.in/VSSC/SSLV.html |access-date=5 November 2021}}</ref>
  |burntime = 94.3 s<ref name="VSSC_SSLV"/>
  |propmass = {{cvt|87000|kg}}<ref name="SSLVD1_PK"/>
  |diameter = 2 m
  |height   = 22.5 m
  }}
  {{Infobox rocket/stage
  |type         = stage
  |stageno      = Second
  |name         = SS2
  |solid        = yes
  |engines      = S7
  |fuel         = Solid ([[Chemistry:Hydroxyl-terminated polybutadiene|HTPB]] based)
  |thrust   = 234.2 kN (vac)<ref name="VSSC_SSLV"/>
  |burntime = 113.1 s<ref name="VSSC_SSLV"/>
  |propmass = {{cvt|7700|kg}}<ref name="SSLVD1_PK"/>
  |diameter = 2 m
  |height   = 3.2 m
  }}
{{Infobox rocket/stage
  |type         = stage
  |stageno      = Third
  |name         = SS3
  |solid        = yes
  |engines      = S4
  |fuel         = Solid ([[Chemistry:Hydroxyl-terminated polybutadiene|HTPB]] based)
  | thrust   = 160 kN (vac)<ref name="VSSC_SSLV"/>
  | burntime = 106.9 s<ref name="VSSC_SSLV"/>
  | propmass = {{cvt|4500|kg}}<ref name="SSLVD1_PK"/>
  | diameter = 1.7 m
  | height   = 2.8 m
  }}
  {{Infobox rocket/stage
  |type         = stage
  |stageno      = Fourth
  |name         = Velocity Trimming Module (VTM)
  |fuel         = MMH+MON3 [[Engineering:Liquid-propellant rocket|Liquid]]
  |engines       = 16×50N bipropellant thrusters<ref name="VSSC_SSLV"/>
  |propmass = {{cvt|50|kg}}<ref name="SSLVD1_PK"/>
  | diameter = 2 m
  }}
|success=1|fail=1|last=10 February 2023, EOS-07}}

The '''Small Satellite Launch Vehicle''' ('''SSLV''') is a [[Engineering:Small-lift launch vehicle|small-lift launch vehicle]] developed by [[Astronomy:ISRO|ISRO]] with payload capacity to deliver {{cvt|500|kg}} to [[Astronomy:Low Earth orbit|low Earth orbit]] ({{cvt|500|km}}) or {{cvt|300|kg}} to [[Astronomy:Sun-synchronous orbit|Sun-synchronous orbit]] ({{cvt|500|km}})<ref name=SSLV_UMv2>{{cite web |url=http://nsilindia.co.in/sites/default/files/u1/SSLV%20Technical%20Brochure%20V12.pdf|title=SSLV technical brochure V12|date=20 December 2019|url-status=live|archive-url=https://web.archive.org/web/20191220153651/http://nsilindia.co.in/sites/default/files/u1/SSLV%20Technical%20Brochure%20V12.pdf|archive-date=20 December 2019|access-date=20 December 2019}}</ref> for launching small satellites, with the capability to support multiple orbital drop-offs.<ref>Gunter's space page: [https://space.skyrocket.de/doc_lau/sslv.htm SSLV]</ref><ref name=":1">{{cite web |url=https://space.skyrocket.de/doc_lau/sslv.htm|title=SSLV|website=space.skyrocket.de|access-date=2018-12-09}}</ref><ref name="DoS_20190118">{{cite web |url=http://pibphoto.nic.in/documents/rlink/2019/jan/p201911802.pdf|title=Department of Space presentation on 18 January 2019|date=18 January 2019|access-date=30 January 2019}}</ref> SSLV is made keeping low cost, low turnaround time in mind with launch-on-demand flexibility under minimal infrastructure requirements.<ref>{{cite web |last=U. |first=Tejonmayam |date=7 August 2022 |title=SSLV-D1/EOS-02 mission: Rocket injected satellites but orbit achieved is less than expected, Isro says |url=https://timesofindia.indiatimes.com/india/sslv-d1/eos-02-mission-rocket-injected-satellites-but-orbit-achieved-is-less-than-expected-isro-says/articleshow/93403176.cms |access-date=2022-08-07 |website=The Times of India |language=en}}</ref>

The maiden flight SSLV-D1 was conducted on 7 August 2022,<ref name = "ISROTWT_20220801"/><ref name="toi-20220719">{{cite web |last=Kumar |first=Chethan |url=https://timesofindia.indiatimes.com/india/another-chandrayaan-3-test-done-on-sunday-sslv-launch-planned-for-august/articleshow/92982060.cms |title=Another Chandrayaan-3 test done on Sunday; SSLV launch planned for August |work=The Times of India |date=19 July 2022 |access-date=19 July 2022}}</ref> from the First Launch Pad, but failed to orbit.<ref name="Tribune_20201006"/> A second flight SSLV D2 was conducted on 10 February 2023 that  successfully delivered payloads to orbit.<ref name=pib>{{Cite news |date=10 February 2023 |title=Successful flight of Small Satellite Launch Vehicle (SSLV) |work=Press Information Bureau |url=https://pib.gov.in/PressReleaseIframePage.aspx?PRID=1897963 |access-date=14 February 2023}}</ref>

In the future, a dedicated launch site in [[Astronomy:Kulasekharapatnam Spaceport|Kulasekharapatnam, Tamil Nadu]] will handle SSLV launches to [[Astronomy:Sun-synchronous orbit|Sun-synchronous orbit]].<ref name=":6">{{cite web |date=16 September 2020 |title=Design, Fabrication, Integration, Testing, Supply and Commissioning of Vehicle Telecommand Systems |url=https://www.isro.gov.in/sites/default/files/tenders/pt_ro14-02-13437.pdf |archive-url=https://web.archive.org/web/20220806201323/https://www.isro.gov.in/sites/default/files/tenders/pt_ro14-02-13437.pdf |archive-date=6 August 2022 |quote=The proposed systems will be used as a part of new commanding requirement for Small Satellite Launch Vehicle (SSLV) Launch Complex (SLC) Site at Kulasekarapatnam, Tamilnadu.}}</ref><ref name="AstrotalkUK">{{cite web|url=https://astrotalkuk.org/episode-90-an-update-on-isros-activities-with-s-somanath-and-r-umamaheshwaran/|title=Episode 90 – An update on ISRO's activities with S. Somanath and R. Umamaheshwaran|publisher=AstrotalkUK|date=24 October 2019|access-date=30 October 2019}}</ref><ref name="timesofindia.indiatimes.com">{{Cite news|url=https://timesofindia.indiatimes.com/india/india-to-get-its-second-spaceport-land-acquisition-work-begins-in-tamil-nadu/articleshow/72323869.cms|title = India to get its second spaceport, land acquisition work begins in Tamil Nadu &#124; India News - Times of India|newspaper = The Times of India}}</ref><ref name=":2">{{cite news|title="Industrialised" PSLV by 2022|newspaper=The Hindu|url=https://www.thehindu.com/news/national/kerala/industrialised-pslv-by-2022/article30647297.ece|issn=0971-751X|date=2020-01-25|access-date=2020-01-25}}</ref> After entering the operational phase, the vehicle's production and launch operations will be done by a consortium of Indian firms along with [[Company:NewSpace India Limited|NewSpace India Limited]] (NSIL).<ref name=":3">{{cite web |last=Sorensen |first=Jodi |url=https://spaceflight.com/spaceflight-inc-purchases-and-fully-manifests-first-ever-commercial-sslv-mission-from-newspace-india-limited-nsil-the-commercial-arm-of-isro-india/ |title=Spaceflight Inc. Purchases and Fully Manifests First-Ever Commercial SSLV Mission from NewSpace India Limited (NSIL), the Commercial Arm of ISRO, India |work=[[Company:Spaceflight, Inc.|Spaceflight]] |date=2019-08-06 |access-date=2019-08-06}}</ref><ref name=":0">{{cite news |last=Singh |first=Surendra |url=https://timesofindia.indiatimes.com/india/isro-to-rope-in-industry-majors-for-mini-pslv-project/articleshow/64034805.cms |title=ISRO to rope in industry majors for mini-PSLV project |work=The Times of India |date=4 May 2018 |access-date=2 September 2018}}</ref><ref>{{cite news|url=https://www.business-standard.com/article/companies/there-s-big-money-to-make-in-space-business-for-indian-firms-antrix-chief-118090200228_1.html|title=There's big money to make in space business for Indian firms: Antrix chief|last=IANS|date=2018-09-02|work=Business Standard India|access-date=2018-09-02}}</ref>

== Vehicle description ==
[[File:SSLV-D1, EOS-02 - EOS-02 and AzaadiSAT on Velocity Trimming Module (VTM) in cleanroom before encapsulation 01.jpg|left|thumb|EOS 02 spacecraft and VTM upper stage integrated in a cleanroom facility.]]
The SSLV was developed with the aim of launching small satellites commercially at drastically reduced price and higher launch rate compared to [[Engineering:Polar Satellite Launch Vehicle|Polar Satellite Launch Vehicle]] (PSLV). The development cost of SSLV is {{INRConvert|169.07|c|lk=on|year=2021}}<ref name="Tribune_20201006">{{cite web|last=Service|first=Tribune News|title=ISRO plans to launch new rocket before December 2020 |url=https://www.tribuneindia.com/news/nation/isro-plans-to-launch-new-rocket-before-dec-2020-151852|publisher=Tribuneindia News|access-date=2020-10-07}}</ref><ref name=":4">{{cite web|date=16 December 2021|title=Satellite Launch Vehicle|url=https://pqars.nic.in/annex/255/AU2164.pdf|quote=The development of SSLV is in the final stages and the first developmental flight of SSLV is targeted during the first quarter of 2022. The Government has sanctioned a total cost of Rs.169.07 Crores for the development project including the development & qualification of the vehicle systems and the flight demonstration through three development flights (SSLV-D1, SSLV-D2 & SSLV-D3)}}</ref> and the manufacturing cost is expected to be {{INRConvert|30|c|lk=on}} to {{INRConvert|35|c|lk=on}}.<ref name="ET_20200331">{{cite news|title=ISRO readying for low cost satellite launch vehicles|url=https://economictimes.indiatimes.com/news/science/isro-readying-for-low-cost-satellite-launch-vehicles/articleshow/73808029.cms|access-date=31 January 2020}}</ref><ref name=":0"/><ref name="TH_20190111">{{cite web |url=https://www.thehindubusinessline.com/news/science/chandrayaan-2-mission-planned-for-middle-of-april-isro/article25968158.ece|title=Chandrayaan-2 Mission planned for middle of April|website=@businessline| date=11 January 2019 |access-date=2019-07-28}}</ref>

The projected high launch rate relies on largely autonomous launch operation and on overall simple logistics. To compare, a PSLV launch involves 600 officials while SSLV launch operations would be managed by a small team of about six people. The launch readiness period of the SSLV is expected to be less than a week instead of months.<ref>{{cite news|url=http://www.spacetechasia.com/indias-19-upcoming-missions-and-isros-small-satellite-launch-vehicle-sslv/|title=India's 19 upcoming missions, and ISRO's Small Satellite Launch Vehicle (SSLV)|date=2018-08-28|publisher=SpaceTech Asia|access-date=2018-09-02}}</ref><ref>{{cite news|title=ISRO developing vehicle to launch small satellites|publisher=Frontline|url=https://frontline.thehindu.com/science-and-technology/article24801393.ece|access-date=2021-07-23}}</ref> The launch vehicle can be assembled both vertically like the existing PSLV and [[Engineering:Geosynchronous Satellite Launch Vehicle|Geosynchronous Satellite Launch Vehicle]] (GSLV) and horizontally like the retired [[Astronomy:Satellite Launch Vehicle|Satellite Launch Vehicle]] (SLV) and [[Astronomy:Augmented Satellite Launch Vehicle|Augmented Satellite Launch Vehicle]] (ASLV).<ref>{{cite news|url=https://www.thehindu.com/news/national/kerala/design-for-small-satellite-launchvehicle-ready/article25792402.ece|title=Design for Small Satellite Launch Vehicle ready|date=2018-12-21|newspaper=The Hindu|access-date=2018-12-21}}</ref>

The first three stages of the vehicle use [[Chemistry:Hydroxyl-terminated polybutadiene|HTPB]] based solid propellant, with a fourth terminal stage being a Velocity-Trimming Module (VTM) with  eight 50&nbsp;N thrusters for reaction control and eight 50&nbsp;N axial thrusters for changing velocity.<ref name="VSSC_SSLV"/> With these VTM can add [[Astronomy:Delta-v|delta-v]] of up to 172&nbsp;m/s.<ref name=":10">{{Cite web |last=Ramachandran |first=R. |date=2022-08-26 |title=First SSLV flight fails to put satellites in correct orbit |url=https://frontline.thehindu.com/science-and-technology/first-sslv-flight-fails-to-put-satellites-in-correct-orbit/article65787339.ece |access-date=2022-08-31 |website=frontline.thehindu.com |language=en |quote=According to a former ISRO scientist, the VTM can correct for a velocity shortfall of up to 172 metres/s. The rocket used for SSLV-D1 was a 34 m tall, 2 m diameter vehicle having a lift-off mass of 120 t.}}</ref>

The first stage (SS1) and third stage (SS3) of SSLV are newly developed while second stage (SS2) is derived from third stage (HPS3) of [[Engineering:Polar Satellite Launch Vehicle#Third stage (PS3)|PSLV]].<ref name="SSLV_introvid">{{Cite AV media |url=https://www.isro.gov.in/sslv-d1-eos-02-mission/sslv-d1-eos-02-mission-videoenglish |title=SSLV-D1/EOS-02 Mission Video_English |date=2022-08-06 |time=2 minute 30 seconds}}</ref><ref>{{cite web |date=19 February 2020 |title=Expression of Interest for Manufacturing of Composite motor cases of ISRO's launch vehicles |url=https://www.isro.gov.in/sites/default/files/tenders/public_tender_297.pdf |archive-url=https://web.archive.org/web/20200605011244/https://www.isro.gov.in/sites/default/files/tenders/public_tender_297.pdf |archive-date=5 June 2020 |access-date=6 August 2022 |quote=It may be specifically noted that process toolings of composite motor case for 2nd stage of SSLV is interchangeable with composite motor case for 3rd stage of PSLV to maximum extent.}}</ref><ref name="RajarajanPressMeet">{{Cite AV media |url=https://www.youtube.com/watch?v=GBNVR1-j7Cc&t=160s |title=SHAR Director Rajarajan Press Meet |date=15 August 2022 |language=English |time=2 minutes 40 seconds |quote=Two solid stages are new, fully developed. That is SS1 with 85-90 tonnes and SS3 with 4.5 tonnes whereas SS2 is almost identical to the HPS3 of PSLV.}}</ref>

'''Vehicle characteristics''':<ref>{{cite news|url=https://twitter.com/orfonline/status/964400636279205888|title=ORF on Twitter|website=twitter,com|access-date=2018-09-02}}</ref><ref>{{citation|last=Narayan Prasad |title=Dr. Somnath on ISRO's Roadmap and Indian Launch Vehicles at Toulouse Space Show 2018|date=2018-07-04|url=https://www.youtube.com/watch?v=PSLsLlkneiw&t=339|access-date=2018-09-02}}</ref>

* Height: 34 meters
* Diameter: 2 meters
* Mass: 120 tonnes
'''Payloads capabilities'''<ref name="SSLV_UMv2" /><ref>{{Cite web |title=Indian Space Research Organisation |url=https://www.isro.gov.in/sslv_CON.html |access-date=2023-06-05 |website=www.isro.gov.in}}</ref>

* Single/Multi Satellites - Nano, Micro, Mini satellites
* 500 kg in 500 km orbit at 35° to 55° inclination range.
* Up to 300 kg into 500 km [[Astronomy:Sun-synchronous orbit|sun-synchronous orbit]].

== SSLV Launch Complex ==
{{main|Astronomy:Kulasekharapatnam Spaceport}}
The early developmental flights and those to inclined orbits will launch from [[Place:Sriharikota|Sriharikota]],<ref name="AstrotalkUK"/> at first using existing launch pads and later from dedicated facility called SSLV Launch Complex (SLC) in Kulasekharapatnam.<ref>{{cite web|title=Message from Chairman's desk|url=https://www.isro.gov.in/update/01-jan-2019/message-chairmans-desk|publisher=Indian Space Research Organisation|website=isro.gov.in|date=1 January 2019|access-date=30 October 2019|archive-date=2 January 2019|archive-url=https://web.archive.org/web/20190102052022/https://www.isro.gov.in/update/01-jan-2019/message-chairmans-desk|url-status=dead}}</ref><ref name=":6" /> Tenders related to manufacturing, installation, assembly, inspection, testing and Self Propelled launching Unit (SPU) were released in October 2019.<ref>{{cite web|title=TENDER NOTICE NO. SDSC SHAR/Sr.HPS/PT/13/2019-2020|quote=REQUEST FOR PROPOSAL (RFP) FOR SUPPLY, INSTALLATION AND COMMISSIONING OF RAIL TRACK FOR SLC PROJECT |url=https://www.isro.gov.in/sites/default/files/tenders/pt13-03-11483.pdf|website=isro.gov.in|publisher=ISRO|access-date=30 October 2019}}</ref><ref>{{cite web|title=TENDER NOTICE NO. SDSC SHAR/Sr.HPS/PT/RO/03/2019-2020|quote=REQUEST FOR PROPOSAL (RFP) FOR PROCUREMENT, MANUFACTURE, SUPPLY, TESTING and {{sic|COMMIS|IONING|nolink=y}} OF SELF PROPELLED UNITS FOR SLC |url=https://www.isro.gov.in/sites/default/files/tenders/pt-_ro_03_-_01-_12041.pdf|website=isro.gov.in|access-date=30 October 2019}}</ref><ref>{{cite web |url=https://www.isro.gov.in/sites/default/files/tenders/pt11-03-11486.pdf|title=TENDER NOTICE NO. SDSC SHAR/Sr.HPS/PT/11/2019-2020|quote=RFP document for Supply of Stainless Steel Tanks|website=isro.gov.in |publisher=ISRO|access-date=30 October 2019}}</ref>

This new spaceport, under development, near Kulasekharapatnam in Tamil Nadu will handle SSLV launches to [[Astronomy:Sun-synchronous orbit|Sun-synchronous orbit]] when complete.<ref name="timesofindia.indiatimes.com"/><ref>{{cite web|url=https://thewire.in/space/isro-kulasekarapattinam-thoothukudi-sdsc-sriharikota-sslv-pslv-gslv-antrix|title=ISRO's Second Spaceport, for New SSLV Rocket, to Come up in Tamil Nadu|publisher=The Wire|access-date=2020-01-08}}</ref><ref>{{cite AV media|url=https://www.ndtv.com/india-news/design-phase-for-indias-manned-mission-to-space-over-astronauts-have-undergone-medical-training-isro-2157703|title=4 IAF Pilots Selected, Design Phase Of Manned Mission Over|type=Video|time=8 minutes|date=2020-01-02}}</ref>

== History ==

=== Development ===
In 2016, a National Institute of Advanced Studies report by Rajaram Nagappa proposed development path of a 'Small Satellite launch Vehicle-1' to launch strategic payloads.<ref>{{cite web |last=Nagappa |first=Rajaram |date=December 2015 |title=The Promise of Small Satellites for National Security |url=http://isssp.in/wp-content/uploads/2016/01/Promise-of-Small-Satellites_R33-2015.pdf |url-status=live |archive-url=https://web.archive.org/web/20170114103119/http://isssp.in/wp-content/uploads/2016/01/Promise-of-Small-Satellites_R33-2015.pdf |archive-date=14 January 2017 |access-date=21 March 2022 |quote=By appropriate choice from among the solid propellant stages available with ISRO and DRDO, a launch vehicle could be configured and designated Small Satellite Launch Vehicle (SSLV-1). The performance of SSLV-1 was estimated using the in house developed trajectory-modelling programme QuoVadis. The performance runs show that SSLV-1 is capable of putting a 350 kg satellite in a polar orbit of 511 km x 497 km orbit and a 400 kg satellite in an orbit of 425 x 401 km (higher payloads are possible in equatorial orbit). This payload capability allows the launch of microsatellites with optical imaging and radar imaging payloads as well as individual intelligence satellites. Satellite life for the 400 kg mass satellite may be short in the 400 km orbit.}}</ref> In National Space Science Symposium 2016,<ref>{{cite web |date=7 February 2016 |title=NSSS 2016 |url=http://spl.gov.in/nsss2016/Program/web/overallProgram.html |url-status=dead |archive-url=https://web.archive.org/web/20160207110310/http://spl.gov.in/nsss2016/Program/web/overallProgram.html |archive-date=7 February 2016}}</ref> then Director of [[Astronomy:Liquid Propulsion Systems Centre|Liquid Propulsion Systems Centre]], S. Somanath also acknowledged a need for identifying a cost effective launch vehicle configuration with 500&nbsp;kg payload capacity to LEO<ref>{{cite web |date=7 February 2016 |title=Future of Space Transportation by S. Somanath (Director, Liquid Propulsion Systems Centre) |url=http://spl.gov.in/nsss2016/Program/web/SPS/SPS-1-2.pdf |url-status=dead |archive-url=https://web.archive.org/web/20160207164654/http://spl.gov.in/nsss2016/Program/web/SPS/SPS-1-2.pdf |archive-date=7 February 2016}}</ref> and by November 2017, development of such launch vehicle was underway.<ref>{{cite web |author=Surendra Singh|date=Nov 22, 2017 |title=Isro news: A rocket that can be made in 3 days {{!}} India News - Times of India |url=https://timesofindia.indiatimes.com/india/isros-plan-a-rocket-that-can-be-made-in-3-days/articleshow/61746668.cms |access-date=2022-03-20 |website=The Times of India |language=en}}</ref>

By December 2018, the [[Company:Vikram Sarabhai Space Centre|Vikram Sarabhai Space Centre]] (VSSC) completed the design for the vehicle.<ref>{{Cite news |last=Rajwi |first=Tiki |date=2018-12-21 |title=Design for Small Satellite Launch Vehicle ready |language=en-IN |work=The Hindu |url=https://www.thehindu.com/news/national/kerala/design-for-small-satellite-launchvehicle-ready/article25792402.ece |access-date=2022-03-20 |issn=0971-751X}}</ref>

In December 2020, all booster segments for SSLV first stage (SS1) static test (ST01) were received and assembly was done in Second Vehicle Assembly Building (SVAB).<ref>{{cite web |date=2021-01-01 |title=SDSC-SHAR Website |url=https://www.shar.gov.in/sdscshar/index.jsp |access-date=2022-03-14 |website= |archive-url=https://web.archive.org/web/20210101084024/https://www.shar.gov.in/sdscshar/index.jsp |archive-date=1 January 2021 |url-status=dead}}</ref>

The first static fire test (ST01) of the SS1 first-stage booster conducted on 18 March 2021 was unsuccessful.<ref>{{cite web|title=చిన్న ఉపగ్రహ వాహకనౌక మోటారులో సాంకేతికలోపం |url=https://www.eenadu.net/apmukyamshalu/mainnews/general/25/121057539|access-date=2021-03-23|website=eenadu.net|language=te}}</ref><ref>{{cite web |date=27 April 2022 |title=Department of Space, Annual Report 2021-22 |url=https://www.isro.gov.in/sites/default/files/article-files/node/17661/annual_report_english.pdf |archive-url=https://web.archive.org/web/20220427032718/https://www.isro.gov.in/sites/default/files/article-files/node/17661/annual_report_english.pdf |archive-date=27 April 2022 |quote=The first static test of SS1 solid motor was conducted and the performance of SS1 ignition system, propellant system and Flex Nozzle Control (FNC) system was evaluated. Various design modifications have been incorporated to resolve the anomalies observed in the first static test (…)}}</ref> About 60 seconds into the test, oscillations were observed and after 95 seconds, the nozzle of SS1 stage disintegrated. The nominal duration of test was 110 seconds.<ref name="ET20210323">{{cite news|title=Static test of first stage solid motor of India's mini rocket SSLV unsuccessful|newspaper=The Economic Times|url=https://economictimes.indiatimes.com/news/science/static-test-of-first-stage-solid-motor-of-indias-mini-rocket-sslv-unsuccessful/articleshow/81653164.cms|access-date=2021-03-23}}</ref> To qualify for flight, SSLV's solid first stage SS1 has to perform two consecutive nominal static fire tests.<ref name="ET20210323" />

The SSLV Payload Fairing (SPLF) functional qualification test was completed in August 2021.<ref>{{cite web |date=29 September 2021 |title=Monthly Summary of Department of space for the month of August 2021 |url=https://www.isro.gov.in/sites/default/files/article-files/monthly-summary-of-department-of-space-last-1-year/sep |archive-url=https://web.archive.org/web/20211229224451/https://www.isro.gov.in/sites/default/files/article-files/monthly-summary-of-department-of-space-last-1-year/august_-_2021_-_monthly_summary.pdf |archive-date=29 December 2021}}</ref>

The second static fire test of SSLV first stage SS1 was conducted on 14 March 2022 at SDSC-SHAR and met the required test objectives.<ref name=":5">{{cite web |title=Ground testing of Solid Booster Stage (SS1) for Small Satellite Launch Vehicle (SSLV) |url=https://www.isro.gov.in/update/14-mar-2022/ground-testing-of-solid-booster-stage-ss1-small-satellite-launch-vehicle-sslv |work=[[Astronomy:ISRO|ISRO]] |date=14 March 2022 |access-date=14 March 2022}}</ref><ref>{{cite web |title=RFP to make small rocket SSLV to be issued after 3/4 successful launches |url=https://ahmedabadmirror.com/rfp-to-make-small-rocket-sslv-to-be-issued-after-34-successful-launches/81824866.html |access-date=2022-03-15 |website=Ahmedabad Mirror |language=en}}</ref>

=== Operational history ===

==== SSLV-D1 ====
The first developmental flight of the SSLV occurred on 7 August 2022. The flight mission was named SSLV-D1. The SSLV-D1 flight failed to achieve its mission objectives.

The rocket had a three stage configuration with a fourth Velocity Trimming Module (VTM). In its D1 configuration, the rocket was 34m tall with a diameter of 2m and a lift-off mass of 120t.<ref>{{cite web |title=SSLV-D1/EOS-02 Mission - ISRO |url=https://www.isro.gov.in/launcher/sslv-d1-eos-02-mission |access-date=2022-08-07 |website=www.isro.gov.in |archive-date=7 August 2022 |archive-url=https://web.archive.org/web/20220807071752/https://www.isro.gov.in/launcher/sslv-d1-eos-02-mission |url-status=dead }}</ref>

The rocket carried [[Engineering:EOS 02|EOS 02]], an Earth observation satellite that weighed 135&nbsp;kg and [[Engineering:AzaadiSAT|AzaadiSAT]], a CubeSat payload that weighed 8&nbsp;kg, developed by Indian students to promote inclusivity in [[Engineering:Science, technology, engineering, and mathematics|STEM]] education. The SSLV-D1 was supposed to place the two satellite payloads in a circular orbit of altitude 356.2&nbsp;km with 37.2° inclination.

The official explanation by the ISRO for the mission failure was software malfunction.<ref name=":8">{{Cite tweet|number=1556136626278912002|user=isro|title=SSLV-D1/EOS-02 Mission: Maiden flight of SSLV is completed. All stages performed as expected. Data loss is observed during the terminal stage. It is being analysed. Will be updated soon.|author=Indian Space Research Organization|date=2022-08-07}}</ref><ref name=":9">{{Cite tweet|number=1556208112138215424|user=isro|title=SSLV-D1/EOS-02 Mission update: SSLV-D1 placed the satellites into 356 km x 76 km elliptical orbit instead of 356 km circular orbit. Satellites are no longer usable. Issue is reasonably identified. Failure of a logic to identify a sensor failure and go for a salvage action caused the deviation. A committee would analyse and recommend. With the implementation of the recommendations, ISRO will come back soon with SSLV-D2. A detailed statement by Chairman, ISRO will be uploaded soon.|author=Indian Space Research Organization|date=2022-08-07}}</ref><ref name="SSLVD1_FARS" /> According to the ISRO, the mission software detected an accelerometer anomaly during the second stage separation. This caused the rocket navigation to switch from a closed loop guidance to an open loop guidance.<ref>{{Cite news |last=Subramanian |first=T. s |date=2022-08-11 |title=ISRO chief S. Somanath interview {{!}} 'An anomaly for two seconds led to SSLV mission's underperformance' |language=en-IN |work=The Hindu |url=https://www.thehindu.com/opinion/interview/an-anomaly-for-two-seconds-in-one-of-accelerometers-in-launch-vehicle-led-to-sslv-missions-underperformance-isro-chief/article65758052.ece |access-date=2022-08-12 |issn=0971-751X}}</ref> Even though, this switch in guidance mode was part of the redundancy built into the rocket's navigation, it could not salvage the mission.

During the open loop guidance mode, the final VTM stage only managed to fire for 0.1s instead of the intended 20s.<ref name="thewire1">{{cite web |title=ISRO's Maiden Small Satellite Rocket Flight Ends in Doubt After Engine Fails to Fire |url=https://thewire.in/space/sslv-suffers-data-loss-at-terminal-stage-isro |access-date=2022-08-07 |website=The Wire}}</ref> This led to the two satellites as well as the VTM stage of the rocket being injected into an unstable elliptical transatmospheric orbit of 360.56×75.66 km with an inclination of 36.56°.<ref name="SSLVD1_FARS" />

The SSLV-D1’s final VTM stage had 16 hydrazine ([[Chemistry:Monomethylhydrazine|MMH]]+[[Chemistry:Mixed oxides of nitrogen|MON3]]) fueled  thrusters. Eight of those were to provide altitude control and the remaining eight for controlling the orbital velocity.<ref>{{cite web |last=Clark |first=Stephen |title=India's new small satellite launcher fails to put satellites into correct orbit – Spaceflight Now |url=https://spaceflightnow.com/2022/08/07/indias-new-small-satellite-launcher-fails-to-put-satellites-into-correct-orbit/ |access-date=2022-08-08 |language=en-US}}</ref> The VTM stage also provided pitch, yaw and roll control during the orbital insertion maneuvers.<ref>{{Citation |title=SSLV-D1/EOS-02 Mission launch is scheduled for Aug 7, 2022 at 9:18 hrs IST from SDSC, Sriharikota |url=https://www.youtube.com/watch?t=2307&v=m0tsABQCW1M |language=en |access-date=2022-08-08}}</ref> The three main stages of the SSLV-D1 functioned normally. But, that was not enough to impart adequate impulse for the two satellite payloads to achieve stable orbits. For the injection of the two satellite payloads into their intended stable orbits, the VTM stage had to fire for at least 20 seconds, to impart enough additional orbital velocity and altitude corrections. Instead the VTM kicked-in at 653.5s and shut itself down at 653.6s, post lift-off.<ref>{{Citation |title=SSLV-D1/EOS-02 Mission launch is scheduled for Aug 7, 2022 at 9:18 hrs IST from SDSC, Sriharikota |url=https://www.youtube.com/watch?t=3348&v=m0tsABQCW1M |language=en |access-date=2022-08-08}}</ref> Following the partial firing of the VTM stage, the EOS 02 was released at 738.5s and AazadiSAT at 788.4s, post-liftoff. These failures transpired, resulting in the satellites entering an unstable orbit and subsequently destroyed upon reentry.

== Launch statistics ==

{{ #invoke:Chart | bar chart
| height = 300
| width = 500
| stack = 1
| group 1 =  1:  0:  0
| group 2 =  0:  0:  0
| group 3 =  0:  1:  0
| group 4 =  0:  0:  2

| colors = FireBrick : Orange : ForestGreen : LightBlue
| group names = Failure : Partial failure : Success : Planned
| units suffix = _launches
| x legends = 2022: 2023: 2024
| y tick marks = 2
}}

;Decade-wise summary of SSLV launches:
{| class="wikitable" style="margin: 1em auto 1em auto;background:#fff; font-size:95%;width:60%"
|-
! Decade
! Successful
! Partial success
! Failure
! Total
|-
| 2020s
| 1
| 0
| 1
| 2
|}

== Launch history ==
{| class="wikitable plainrowheaders collapsible"
|-
! scope="col" |Flight No.
! scope="col" |Date and
time ([[Physics:Coordinated Universal Time|UTC]])
! scope="col" | Rocket, <br /> configuration
! scope="col" |Launch site
! scope="col" |Payload
! scope="col" |Payload mass
! scope="col" |Orbit
! scope="col" |User
! scope="col" |Launch
outcome
|-
! rowspan="2" |D1
|7 August 2022<br />03:48<ref name="ISROTWT_20220801" />
|SSLV
|[[Astronomy:Satish Dhawan Space Centre First Launch Pad|First]]
|{{flagicon|India}} [[Engineering:EOS 02|EOS 02]]{{Line break}}{{flagicon|India}} [[Engineering:AzaadiSAT|AzaadiSAT]]<ref>{{cite web |title=AzaadiSAT – Space Kidz India |url=https://www.spacekidzindia.in/azaadisat/ |access-date=2022-07-08 |language=en-US}}</ref>
|143&nbsp;kg
|[[Astronomy:Low Earth orbit|LEO]] (intended)
[[Astronomy:Transatmospheric orbit|TAO]] (achieved)
|[[Astronomy:Indian Space Research Organisation|ISRO]]
|{{Failure}}
|-
| colspan="8" |The first developmental flight of SSLV. The mission target was a circular orbit of altitude 356.2&nbsp;km with 37.2° inclination. The mission carried two satellite payloads. The 135&nbsp;kg [[Engineering:EOS 02|EOS 02]], an Earth observation satellite and the 8&nbsp;kg [[Engineering:AzaadiSAT|AzaadiSAT]] [[Engineering:CubeSat|CubeSat]].<ref name="SSLVD1_PK">{{cite web |title=SSLV-D1/EOS-2 Mission Brochure |url=https://www.isro.gov.in/sites/default/files/sslvd1-eos2_-_mission_brochure.pdf |archive-url=https://web.archive.org/web/20220803133923/https://www.isro.gov.in/sites/default/files/sslvd1-eos2_-_mission_brochure.pdf |archive-date=3 August 2022 |access-date=4 August 2022}}</ref><ref name=":7">{{cite news |last=Madhumathi |first=D.S. |date=2019-08-07 |title=ISRO's mini launcher SSLV is unborn but has 2 flights booked |newspaper=The Hindu |url=https://www.thehindu.com/news/national/isros-mini-launcher-sslv-is-unborn-but-has-2-flights-booked/article28859854.ece |access-date=2019-08-16 |issn=0971-751X}}</ref><ref name="ar-2021">{{cite web |title=Department of Space, Annual Report 2020-2021 |url=https://www.isro.gov.in/sites/default/files/anual_report_2020-2021_english.pdf |url-status=live |archive-url=https://web.archive.org/web/20210304095412/https://www.isro.gov.in/sites/default/files/anual_report_2020-2021_english.pdf |archive-date=4 March 2021 |access-date=6 March 2021 |work=[[Astronomy:ISRO|ISRO]] |page=23 |quote=EOS-02: EOS-02 is configured around MicroSat-TD bus platform to demonstrate launch on demand capability with SSLV. It is expected to meet the ever-increasing user demands for cartographic applications, urban and rural management, coastal land use and regulation, utilities mapping, development and various other GIS application. The mission life of the satellite is 9 months.}}</ref>
Due to sensor failure coupled with shortcomings of onboard software, the stage as well as the two satellite payloads were injected into an unstable [[Astronomy:Transatmospheric orbit|transatmospheric Earth orbit]] measuring 356×76&nbsp;km and subsequently destroyed upon reentry.<ref name=":9" /> According to S. Somanath, an anomaly lasting 2 seconds in one of the accelerometers during second stage separation initiated salvage mode by onboard computer. [[Guidance, navigation, and control]] software switched from 'closed loop guidance' where it received real-time feedback from all sensors to an 'open loop guidance' where accelerometer data gets isolated and a predetermined path is followed.<ref>{{Cite news |last=Subramanian |first=T. s |date=2022-08-11 |title=ISRO chief S. Somanath interview {{!}} 'An anomaly for two seconds led to SSLV mission's underperformance' |language=en-IN |work=The Hindu |url=https://www.thehindu.com/opinion/interview/an-anomaly-for-two-seconds-in-one-of-accelerometers-in-launch-vehicle-led-to-sslv-missions-underperformance-isro-chief/article65758052.ece |access-date=2022-08-11 |issn=0971-751X}}</ref> This resulted in velocity shortfall from the required 7.3&nbsp;km/s to 7.2&nbsp;km/s. Being in salvage mode, Velocity-Trimming Module didn't rectify this shortfall which led to mission failure.<ref name=":10" /><ref name="thewire1" />
|-
! rowspan="2" |D2
|10 February 2023 <br /> 03:48 <ref>{{cite web |last=Kumar |first=Chethan |url=https://timesofindia.indiatimes.com/home/science/sslv-2nd-mission-to-carry-us-sat-eos-7-oneweb-sats-set-to-arrive-friday/articleshow/97357960.cms |title=SSLV 2nd mission to carry US Sat, EOS-7; OneWeb Sats set to arrive Friday |date=26 January 2023 |access-date=27 January 2023 |work=Times of India}}</ref><ref>{{Cite web |date=2023-01-04 |title=ISRO planning to launch second development SSLV flight in Feb: S Somanath |url=https://www.livemint.com/science/news/isro-planning-to-launch-second-development-sslv-flight-in-feb-s-somanath-11672838016053.html |access-date=2023-01-04 |website=mint |language=en}}</ref><ref>{{Cite web |date=Dec 5, 2022 |title=Sslv Hardware Ready, Launch Likely In '23 {{!}} Bengaluru News - Times of India |url=https://timesofindia.indiatimes.com/city/bengaluru/sslv-hardware-ready-launch-likely-in-23/articleshow/95989800.cms |access-date=2022-12-05 |website=The Times of India |language=en}}</ref>
|SSLV
|[[Astronomy:Satish Dhawan Space Centre First Launch Pad|First]]
|{{flagicon|India}} EOS-07{{Line break}}{{flagicon|USA}} Janus-1{{Line break}}{{flagicon|IND}} [[Engineering:AzaadiSAT|AzaadiSAT-2]]{{Line break}}&nbsp;
|156.3&nbsp;kg{{Line break}}11.5&nbsp;kg{{Line break}}7.3&nbsp;kg{{Line break}}Total = 334&nbsp;kg
|[[Astronomy:Low Earth orbit|LEO]]
|[[Astronomy:Indian Space Research Organisation|ISRO]]
|{{Success}}
|-
| colspan="8" |Second developmental flight of the SSLV.<ref>{{Cite news |last=Rajwi |first=Tiki |title=Second development flight of Small Satellite Launch Vehicle likely this year |language=en-IN |work=The Hindu |url=https://www.thehindu.com/news/national/kerala/second-development-flight-of-small-satellite-launch-vehicle-likely-this-year/article66001388.ece |date=12 October 2022 |access-date=13 October 2022 |issn=0971-751X}}</ref><ref name=":11">{{Cite web |title=SSLV-D2/EOS-07 MISSION |url=https://www.isro.gov.in/mission_SSLV_D2.html |access-date=2023-02-05 |website=www.isro.gov.in}}</ref><ref name="SSLVD1_FARS">{{Cite web |title=SSLV-D2/EOS-07 Mission: Second Developmental Flight of SSLV |url=https://www.isro.gov.in/mission_SSLV_D1_summary_D2.html |access-date=2023-02-05 |website=www.isro.gov.in}}</ref>
|}

== Future launches ==
{| class="wikitable plainrowheaders" style="width: 100%;"
|-
! scope="col" | Date / time ([[Physics:Coordinated Universal Time|UTC]])
! scope="col" | Rocket,<br />Configuration
! scope="col" | Launch site
! scope="col" | Payload
! scope="col" | Orbit
! scope="col" | User 
|-
|rowspan=2|2024
|SSLV
|[[Astronomy:Satish Dhawan Space Centre|SHAR]]
|
|
|[[Astronomy:Indian Space Research Organisation|ISRO]]
|-
| colspan="5" |Flight D3. Third developmental flight of the SSLV.<ref>{{cite web|url=https://pqals.nic.in/annex/1711/AU5386.pdf|title=Loksabha Q&A|publisher=DEPARTMENT OF SPACE|date=2023-04-05}}</ref>
|-
|rowspan=2|2024<ref>{{Cite web |title=SSLV {{!}} BlackSky Global 5 & 6 |url=https://nextspaceflight.com/launches/details/NextSpaceflight.com/launches/details/7099 |access-date=2023-09-06 |website=nextspaceflight.com |language=en}}</ref>
|SSLV
|[[Astronomy:Satish Dhawan Space Centre|SHAR]]
|{{flagicon|United States}} BlackSky Global-5, 6, and two others
|[[Astronomy:Low Earth orbit|LEO]]
|[[Company:Spaceflight Industries|Spaceflight Industries]]
|-
| colspan="5" |Manifested on a future SSLV commercial flight, four 56&nbsp;kg Blacksky Global satellites to ~500&nbsp;km circular orbit with 50° inclination.<ref>{{cite web |date=25 July 2019 |title=Application for Earth Exploration Satellite Service by BlackSky Global, LLC |url=https://fcc.report/IBFS/SAT-MOD-20190725-00067/1816346.pdf |archive-url=https://web.archive.org/web/20190728111320/https://fcc.report/IBFS/SAT-MOD-20190725-00067/1816346.pdf |archive-date=28 July 2019 |access-date=28 July 2019 |publisher=FCC |page=6 |quote=Global-5 through Global-8 are currently scheduled to be launched in November 2019 on a Small Satellite Launch Vehicle (SSLV) by the Indian Space Research Organization from its Satish Dhawan Space Center}} {{PD-notice}}</ref><ref name=":3" /><ref>{{Cite web |date=2021-02-25 |title=BlackSky Global to launch four earth observation satellites on board ISRO SSLV-D2 |url=https://www.thetechoutlook.com/news/science/blacksky-global-to-launch-four-earth-observation-satellites-on-board-isro-sslv-d2/ |access-date=2023-09-06 |website=The Tech Outlook |language=en-US}}</ref>
|}

== See also ==
* [[Engineering:Small-lift launch vehicle|Small-lift launch vehicle]]
* [[Astronomy:ISRO|Indian Space Research Organisation]]
* [[Engineering:Polar Satellite Launch Vehicle|Polar Satellite Launch Vehicle]]
* [[Engineering:Geosynchronous Satellite Launch Vehicle|Geosynchronous Satellite Launch Vehicle]]
* [[Engineering:LVM3|LVM3]]
* [[Engineering:Next Generation Launch Vehicle|Next Generation Launch Vehicle]]

== References ==
{{reflist}}

==External links==
{{Expendable launch systems}}
{{Indian space programme}}

[[Category:Expendable space launch systems]]

{{Sourceattribution|Small Satellite Launch Vehicle}}