Small Satellite Launch Vehicle

Small Satellite Launch Vehicle

SSLV D1 lifting off from Satish Dhawan Space Centre First Launch Pad
Function	Small-lift launch vehicle
Manufacturer	NSIL, ISRO[1]
Country of origin	India
Cost per launch	₹35 crore (US$4.9 million) (expected)[2][3][4][5]
Size
Height	34 m (112 ft)
Diameter	2 m (6 ft 7 in)
Mass	120 t (120 long tons; 130 short tons)
Stages	3+1[6]
Capacity
Payload to low Earth orbit	500 kg (1,100 lb)
Payload to Sun-synchronous orbit	300 kg (660 lb)
Associated rockets
Comparable	Minotaur I Start-1 Kuaizhou Electron rocket
Launch history
Status	Active
Launch sites	Satish Dhawan Space Centre
Total launches	2
Successes	1
Failures	1
First flight	03:48 UTC, 7 August 2022.[7]
Last flight	10 February 2023, EOS-07
First stage – SS1
Diameter	2 m
Propellant mass	87,000 kg (192,000 lb)[8]
Motor	S85
Thrust	2,496 kN (vac)[9]
Burn time	94.3 s[9]
Fuel	Solid (HTPB based)
Second stage – SS2
Diameter	2 m
Propellant mass	7,700 kg (17,000 lb)[8]
Motor	S7
Thrust	234.2 kN (vac)[9]
Burn time	113.1 s[9]
Fuel	Solid (HTPB based)
Third stage – SS3
Diameter	1.7 m
Propellant mass	4,500 kg (9,900 lb)[8]
Motor	S4
Thrust	160 kN (vac)[9]
Burn time	106.9 s[9]
Fuel	Solid (HTPB based)
Fourth stage – Velocity Trimming Module (VTM)
Diameter	2 m
Propellant mass	50 kg (110 lb)[8]
Engines	16×50N bipropellant thrusters[9]
Fuel	MMH+MON3 Liquid

The Small Satellite Launch Vehicle (SSLV) is a small-lift launch vehicle developed by ISRO with payload capacity to deliver 500 kg (1,100 lb) to low Earth orbit (500 km (310 mi)) or 300 kg (660 lb) to Sun-synchronous orbit (500 km (310 mi))^[10] for launching small satellites, with the capability to support multiple orbital drop-offs.^[11][12][13] SSLV is made keeping low cost, low turnaround time in mind with launch-on-demand flexibility under minimal infrastructure requirements.^[14]

The maiden flight SSLV-D1 was conducted on 7 August 2022,^[7][15] from the First Launch Pad, but failed to orbit.^[16] A second flight SSLV D2 was conducted on 10 February 2023 that successfully delivered payloads to orbit.^[17]

In the future, a dedicated launch site in Kulasekharapatnam, Tamil Nadu will handle SSLV launches to Sun-synchronous orbit.^{[18][19][20][21]} After entering the operational phase, the vehicle's production and launch operations will be done by a consortium of Indian firms along with NewSpace India Limited (NSIL).^[22][23][24]

Vehicle description

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 Polar Satellite Launch Vehicle (PSLV). The development cost of SSLV is ₹169.07 crore (US$24 million)^[16][2] and the manufacturing cost is expected to be ₹30 crore (US$4.2 million) to ₹35 crore (US$4.9 million).^[3][23][4]

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.^[25][26] The launch vehicle can be assembled both vertically like the existing PSLV and Geosynchronous Satellite Launch Vehicle (GSLV) and horizontally like the retired Satellite Launch Vehicle (SLV) and Augmented Satellite Launch Vehicle (ASLV).^[27]

The first three stages of the vehicle use HTPB based solid propellant, with a fourth terminal stage being a Velocity-Trimming Module (VTM) with eight 50 N thrusters for reaction control and eight 50 N axial thrusters for changing velocity.^[9] With these VTM can add delta-v of up to 172 m/s.^[28]

The first stage (SS1) and third stage (SS3) of SSLV are newly developed while second stage (SS2) is derived from third stage (HPS3) of PSLV.^[29][30][31]

Vehicle characteristics:^[32][33]

• Height: 34 meters
• Diameter: 2 meters
• Mass: 120 tonnes

Payloads capabilities^[10][34]

• 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 sun-synchronous orbit.

SSLV Launch Complex

Main page: Astronomy:Kulasekharapatnam Spaceport

The early developmental flights and those to inclined orbits will launch from Sriharikota,^[19] at first using existing launch pads and later from dedicated facility called SSLV Launch Complex (SLC) in Kulasekharapatnam.^[35][18] Tenders related to manufacturing, installation, assembly, inspection, testing and Self Propelled launching Unit (SPU) were released in October 2019.^[36][37][38]

This new spaceport, under development, near Kulasekharapatnam in Tamil Nadu will handle SSLV launches to Sun-synchronous orbit when complete.^[20][39][40]

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.^[41] In National Space Science Symposium 2016,^[42] then Director of Liquid Propulsion Systems Centre, S. Somanath also acknowledged a need for identifying a cost effective launch vehicle configuration with 500 kg payload capacity to LEO^[43] and by November 2017, development of such launch vehicle was underway.^[44]

By December 2018, the Vikram Sarabhai Space Centre (VSSC) completed the design for the vehicle.^[45]

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).^[46]

The first static fire test (ST01) of the SS1 first-stage booster conducted on 18 March 2021 was unsuccessful.^[47][48] 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.^[49] To qualify for flight, SSLV's solid first stage SS1 has to perform two consecutive nominal static fire tests.^[49]

The SSLV Payload Fairing (SPLF) functional qualification test was completed in August 2021.^[50]

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.^[51][52]

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.^[53]

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

The official explanation by the ISRO for the mission failure was software malfunction.^[54][55][56] 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.^[57] 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.^[58] 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°.^[56]

The SSLV-D1’s final VTM stage had 16 hydrazine (MMH+MON3) fueled thrusters. Eight of those were to provide altitude control and the remaining eight for controlling the orbital velocity.^[59] The VTM stage also provided pitch, yaw and roll control during the orbital insertion maneuvers.^[60] 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.^[61] 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

Script error: No such module "Chart".

Decade-wise summary of SSLV launches

Launch history

Flight No.	Date and time (UTC)	Rocket, configuration	Launch site	Payload	Payload mass	Orbit	User	Launch outcome
D1	7 August 2022 03:48[7]	SSLV	First	EOS 02Template:Line break AzaadiSAT[62]	143 kg	LEO (intended) TAO (achieved)	ISRO	Failure
	The first developmental flight of SSLV. The mission target was a circular orbit of altitude 356.2 km with 37.2° inclination. The mission carried two satellite payloads. The 135 kg EOS 02, an Earth observation satellite and the 8 kg AzaadiSAT CubeSat.[8][63][64] Due to sensor failure coupled with shortcomings of onboard software, the stage as well as the two satellite payloads were injected into an unstable transatmospheric Earth orbit measuring 356×76 km and subsequently destroyed upon reentry.[55] 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.[65] This resulted in velocity shortfall from the required 7.3 km/s to 7.2 km/s. Being in salvage mode, Velocity-Trimming Module didn't rectify this shortfall which led to mission failure.[28][58]
D2	10 February 2023 03:48 [66][67][68]	SSLV	First	EOS-07Template:Line break Janus-1Template:Line break AzaadiSAT-2Template:Line break	156.3 kgTemplate:Line break11.5 kgTemplate:Line break7.3 kgTemplate:Line breakTotal = 334 kg	LEO	ISRO	Success
	Second developmental flight of the SSLV.[69][70][56]

Future launches

Date / time (UTC)	Rocket, Configuration	Launch site	Payload	Orbit	User
2024	SSLV	SHAR			ISRO
	Flight D3. Third developmental flight of the SSLV.[71]
2024[72]	SSLV	SHAR	BlackSky Global-5, 6, and two others	LEO	Spaceflight Industries
	Manifested on a future SSLV commercial flight, four 56 kg Blacksky Global satellites to ~500 km circular orbit with 50° inclination.[73][22][74]

See also

• Small-lift launch vehicle
• Indian Space Research Organisation
• Polar Satellite Launch Vehicle
• Geosynchronous Satellite Launch Vehicle
• LVM3
• Next Generation Launch Vehicle

References

External links

0.00 (0 votes) Original source: https://en.wikipedia.org/wiki/Small Satellite Launch Vehicle. Read more