India’s Polar Satellite Launch Vehicle returned to flight Friday, four months after the rocket suffered a payload fairing separation failure while launching a navigation satellite last August. Liftoff of Friday’s mission, which is carrying the Cartosat-2F remote sensing spacecraft, occurred at 09:28 local time (03:58 UTC) from the Satish Dhawan Space Centre at Sriharikota.
Cartosat-2F is the latest spacecraft in India’s fleet of remote sensing satellites. The seventh satellite based on ISRO’s Cartosat-2 design, it is the third such spacecraft to be deployed in the space of a year. The satellite will be operated by the Indian Space Research Organisation (ISRO), who is also responsible for conducting Friday’s launch.
Friday’s launch was India’s first since a PSLV rocket failed during the launch of the IRNSS-1H navigation satellite last August. During that launch, the rocket’s payload fairing – termed a “heat shield” by ISRO – failed to separate from the nose of the rocket. With the fairing’s additional weight, the rocket entered a much lower orbit than had been planned and when the spacecraft separated it was trapped inside the fairing, unable to maneuver or to deploy its solar panels and antennae.
An investigation into the failure concluded that a bellow in the separation mechanism had failed to pressurize, and as a result the rocket had been unable to shed its fairing. The anomaly marked the PSLV’s first loss of mission since its maiden flight failed in September 1993, although the rocket did also suffer a partial failure in September 1997. Between the 1997 and 2017 incidents, PSLV completed thirty-six consecutive missions successfully.
Friday’s return to flight marked PSLV’s forty-second launch overall. The payload consists of the Cartosat-2F remote sensing satellite and thirty-one smaller spacecraft that are being carried as secondary payloads. These include satellites from Canada, Finland, France, Korea, the United Kingdom and the United States as well as India.
ISRO’s Cartosat constellation consists of a series of satellites in sun-synchronous orbit making panchromatic and multispectral images of the Earth’s surface. The satellites are used for both civilian and military purposes, although ISRO has been notably more secretive about the later satellites in the series. Official publications about Friday’s launch do not refer to the satellite by name, instead describing it as a “Cartosat-2 series satellite”.
The original satellite in the series, Cartosat-2, was a primarily civilian satellite. It was deployed in January 2007 and followed into orbit by the military Cartosat-2A in April 2008. Cartosat-2B was deployed in July 2010. These initial satellites carried only a panchromatic imaging payload, with the multispectral imager being introduced with the upgraded Cartosat-2C, which was deployed in June 2016. Further satellites – Cartosat-2D and 2E – were launched in February and June of 2017 as ISRO began to increase the size of the constellation.
At the time of Cartosat-2E’s launch, it was expected to be the last Cartosat-2 spacecraft, with a new Cartosat-3 series to begin launching in 2018. When it first appeared in launch schedules, Cartosat-2F was referred to as Cartosat-2ER, suggesting that it may have been built as a ground-spare.
The Cartosat-2 series is based on ISRO’s IRS-2 bus. Each spacecraft has a mass of about 710 kilograms (1,570 lb) and is designed for a five-year service life. The satellites are equipped with reaction wheels, magnetorquers and hydrazine-fuelled reaction control thrusters to provide three-axis stabilization, while a pair of solar arrays generate up to 986 watts of electrical power for the spacecraft.
Joining Cartosat-2F for the journey into orbit were thirty-one smaller spacecraft with a combined mass of about 600 kilograms (1,300 lb). These included ISRO’s INS-1C and Microsat-TD. Indian Nanosatellite 1C (INS-1C) is an 11-kilogram (25 lb) spacecraft which carries the Miniature Multispectral Technology Demonstration (MMX-TD) experiment, an imaging payload for ISRO’s Space Applications Centre that will be used for mapping, vegetation monitoring and studies of aerosols and clouds in the atmosphere.
Microsat-TD is a technology demonstration payload which will test a modular spacecraft bus derived from Indian Mini Satellite 1 (IMS-1), a small imaging satellite that was launched in 2008. Microsat-TD carries an imaging payload with panchromatic and infrared capabilities.
Four Dove CubeSats were carried as part of Planet Labs’ Flock-3p’ mission. Three-unit CubeSats, these Doves carry technology demonstration payloads in support of Planet’s large commercial Earth imaging constellation. US firm Planet uses hundreds of CubeSats in low Earth orbit to provide near-real-time coverage of the planet’s surface to its customers.
PSLV also carried four Lemur-2 CubeSats for US-based Spire Global. Also three-unit satellites, these will be the sixty-eighth to seventy-first Lemur-2 spacecraft to launch. Each Lemur carries two payloads: SENSE, an Automatic Identification System (AIS) receiver to relay tracking data from ships at sea, and STRATOS which measures the occultation of signals from GPS satellites as the pass through the atmosphere in order to study atmospheric conditions such as temperature, pressure and humidity.
Four 0.25-unit SpaceBEE CubeSats will be used as a proof-of-concept for a proposed future constellation of many tiny communications satellites. Each satellite measures 10 by 10 by 2.5 centimeters (3.9 by 3.9 by 1.0 inches), not including two antennae that will be deployed once in orbit. DemoSat-2 is another US CubeSat that will be used for communications experiments – using the three-unit form factor.
A further experimental communications payload aboard Friday’s launch is Telesat Canada’s LEO-1 Vantage. LEO-1 is the second of two demonstration satellites that Telesat ordered to investigate development of a constellation of communications satellites into low Earth orbit.
The first demonstrator, LEO-2, was lost when Russia’s Soyuz-2-1b/Fregat-M rocket failed to achieve orbit last November. LEO-1 was built in the United Kingdom by Surrey Satellite Technology Ltd (SSTL), based around its SSTL-42 bus, and carries a Ka-band communications payload.
Carbonite 2, or CBNT-2, is also based on the SSTL-42 platform. It will be operated by SSTL as a technology demonstrator and a prototype for a constellation of imaging satellites that the company is developing for Earth-i. Carbonite 2 follows the Carbonite 1 satellite, which launched aboard a PSLV in July 2015. The satellite has a mass of about 100 kilograms (220 lb).
A collaboration between NASA, the Korea Aerospace Research Institute (KARI) and Yonsei University, the CubeSat Astronomy by NASA and Yonsei using Virtual Telescope Alignment Experiment (CANYVAL-X) will use two CubeSats named Tom and Jerry – after the cartoon cat and mouse – to demonstrate formation-flying that could be used for future astronomy missions. The larger satellite, Tom, is a two-unit CubeSat equipped with a micro-cathode arc thruster (µCAT) maneuvering system and a small camera. Jerry, a single-unit CubeSat, is equipped with three laser diodes to aid alignment and a magnetorquer for attitude control.
Arkyd-6A is the first of two planned six-unit CubeSats that Planetary Resources will use to demonstrate systems and technology for their planned Arkyd-100 asteroid prospecting constellation. US company Planetary Resources aims to identify and mine resources from asteroids, using its Arkyd satellites to determine candidate asteroids for mining operations. Arkyd-6A follows the smaller Arkyd-3R demonstrator that was deployed from the International Space Station in July 2015. An earlier satellite, Arkyd-3, was lost in the failure of an Antares rocket in October 2014. Unlike its predecessors, Arkyd-6A carries an imaging system, with a mid-infrared payload which will be tested by imaging the Earth’s surface.
The CICERO-7 satellite, a six-unit CubeSat, is part of the Community Initiative for Cellular Earth Remove Observation (CICERO), constellation of satellites being deployed for American company GeoOptics Incorporated. CICERO-7 is the fifth member of the constellation to be deployed. The satellite was built by Tyvak Incorporated, and like Spire’s Lemur satellites, it will measure the occultation of signals from navigation satellites – both the GPS and Galileo systems – in order to map pressures, temperatures and humidity in the Earth’s atmosphere.
The Chungnam National University Sail 1 (CNUSail-1) spacecraft, also named Papillon, is a three-unit CubeSat built by South Korea’s Chungnam National University which will deploy a Kapton sail that will be used to deorbit the satellite. The sail will be deployed using four 1.42-metre-long (4.66 feet) booms, and will demonstrate technology that could be used for future solar sail missions.
Corvus-BC 3 is another six-unit CubeSat, which carries a multispectral imaging payload which its operator, US company Astro Digital, will use for area surveying. It is part of a planned constellation of up to 31 satellites. It is not the first satellite to be called Corvus-BC 3 – Astro Digital have re-used the name after the original Corvus-BC 3 was lost in last November’s Soyuz failure.
AMSAT’s Fox-1D satellite – developed in conjunction with the University of Iowa, Virginia Tech and the Pennsylvania State University’s Behrend College – is a single-unit CubeSat with an amateur radio payload. The satellite also carries the High Energy Radiation CubeSat Instrument (HERCI), an imaging system and a gyroscope experiment.
ICEYE-X1 satellite – also known as Proof of Concept 1 (POC-1) – is the first satellite to be launched for Finland’s ICEYE, who plan to deploy a constellation of radar-imaging satellites employing synthetic aperture radar (SAR) to image the Earth’s surface in near-real-time, regardless of light or weather conditions. The satellite is based on an S-Class platform developed by York Space Systems, with an imaging payload built in-house by ICEYE.
Built by the Space Systems Laboratory at the Massachusetts Institute of Technology, Microsized Microwave Atmospheric Satellite 2a (MicroMAS-2a) is a three-unit CubeSat which will be used to test a compact microwave spectrometer and radiometer payload in orbit. Two-thirds of the satellite contain vehicle systems including attitude control systems capable of maintaining three-axis stabilization.
The remaining third of the satellite, which includes the payload, were spun up to allow its instrument to sweep across the face of the Earth. The satellite will be used to produce images of the surface, as well as moisture and temperature profiles. MicroMAS-2a follows on from the MicroMAS-2 satellite that was deployed from the International Space Station in March 2015. Another satellite, MicroMAS-2b, is expected to fly aboard Virgin Orbit’s LauncherOne rocket later this year.
Korea Aviation University Satellite 5 (KAUSAT-5) carries an infrared imaging payload and Geiger counter to measure radiation in the satellite’s environment. A three-unit CubeSat, it is expected to operate for one year.
French spacecraft PicSat was developed by the Observatoire de Paris. The satellite will be used as a demonstrator, observing the exoplanet Beta Pictoris b as it transits across its parent star. It will use a photometric imaging system consisting of a photodiode connected via a fiber optic to a five-centimeter (2-inch) telescope, and will measure the number of incident photons. The instrument setup gives the satellite a very narrow field-of-view, reducing the impact of background light on its observations, at the expense of requiring very precise targeting.
The Scientific CubeSat with Instrument for Global Magnetic Field and Radiation [sic], or SIGMA – also known as KHUSAT-3 – is a three-unit CubeSat built by South Korea’s Kyung Hee University. Once in orbit the satellite will deploy a magnetometer boom and will measure magnetic fields and radiation in the low Earth orbit environment.
Another South Korean satellite, the Cube Laboratory for Space Technology Experimental Projects – STEP Cube Lab – was developed by Chosun University. Weighing in at 1.33 kilograms (2.93 lb), this single-unit CubeSat will test five payloads in orbit. These include a variable emittance radiator and a phase change material that will contribute to thermal control of the satellite. An off-the-shelf Fresnel lens will be used to focus sunlight onto a solar panel to demonstrate this as a method of generating more power. The satellite will also test a microelectromechanical (MEMS) solid-propellant thruster and a nonexplosive holddown and release mechanism.
Tyvak Incorporated’ Tyvak-61C satellite is a three-unit CubeSat which will carry out an astronomy mission, recording variations in the luminosity of the brightest stars.
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