Chethan Kumar Profile picture
Feb 4 19 tweets 5 min read
#Thread #Space #UPDATE 

@isro has officially said the NASA-Isro SAR (#NISAR), a LEO observatory being jointly developed with @NASA “shall be launched from Indian soil in Q1 of 2024”, and its science operations will begin 90 days after it reaches the intended orbit. 1/n

Pic: JPL
The synthetic aperture radar (SAR) payloads mounted on integrated radar instrument structure (IRIS) and the spacecraft bus are together called an observatory. 2/n
The observatory will map the entire globe in 12 days & provide spatially & temporally consistent data for understanding changes in Earth’s ecosystems, ice mass, vegetation biomass, sea-level rise, groundwater & natural hazards - earthquakes, tsunamis, volcanoes & landslides. 3/n
“It'll carry L &S dual band SAR — 1st dual frequency radar imaging mission in said bands using advanced Sweep SAR to provide space-borne SAR data with high repeat cycle, high res, & larger swath,” Isro’s dedicated page for #NISAR, which went live late on Feb 3, reads. 4/n
@NASAJPL & @isro are realising the observatory which will not only meet respective national needs but also will feed the science community with data encouraging studies related to surface deformation measurements through repeat-pass InSAR technique, Isro added. 5/n
NASA is responsible for providing the L-Band SAR payload system in which the Isro supplied S-Band SAR payload and both these systems will make use of a large size (about 12m diameter) common unfurlable reflector antenna. 6/n
In addition, NASA would provide engineering payloads for the mission, including a payload data subsystem, high-rate science downlink system, GPS receivers and a solid state recorder. 7/n
Isro is responsible for providing the S-SAR data handling system, high-rate downlink system, spacecraft bus systems, the GSLV launch system and mission operations related services. 8/n
The observatory carries a 12m wide deployable mesh reflector mounted onto a deployable 9m boom developed by JPL which will be used by both the L-Band and S-Band SAR payload systems. 9/n
“The IRIS hosts S-SAR and L-SAR tiles along with their electronics and data handling systems. The spacecraft incorporates all the attitude (orientation) and orbit control elements, power systems, thermal management systems,” Isro added. 10/n
Launch: “The target launch readiness date is January 2024,” Isro said. It encompasses time interval that takes NISAR from ground, encapsulated in launch vehicle fairing… 11/n
…to after separation & ends with the completion of solar array deployment & observatory in an Earth-pointed orientation and in two-way communication with the ground. “The launch sequence is a critical event,” Isro added. 12/n
Commissioning: According to Isro, the first 90 days after launch will be dedicated to commissioning, or in-orbit checkout (IOC), the objective of which is to prepare the observatory for science operations. 13/n
“Commissioning is divided into sub-phases of initial checkout (Isro & JPL engineering payload checkout), spacecraft checkout, instrument checkout. Philosophically, sub-phases are designed as a step-by-step build up in capability to full observatory ops,” says Isro. 14/n
The full observation operations will begin with the physical deployment of all deployable parts (notably the boom and radar antenna, but not including the solar arrays which are deployed during launch phase)... 15/n
…checking out the engineering systems, turning on the radars and testing them independently and then conducting joint tests with both radars operating. 16/n
Science Ops: “Science ops phase begins at the end of commissioning & extends for 3yrs & contains all data collection required to achieve the level-one science objectives… 17/n
…During this phase, the science orbit will be maintained via regular manoeuvres, scheduled to avoid or minimise conflicts with science observations,” Isro said. 18/n
Extensive calibration & validation activities will take place throughout the first 5 months, with yearly updates of 1-month duration. Observation plan for both L&S instruments, along with engineering activities will be generated pre-launch via frequent coordination. n/n

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More from @Chethan_Dash

Jan 27
#Update (2) #Space #Thread

@isro’s latest rocket, #SSLV, is geared for launch with the space agency aiming for an early Feb launch carrying three payloads. While the main payload will be #EOS7, the mission is also expected to launch #Janus1 from US' Antaris & an Indian sat. 1/n
The Earth observation satellite #SSLV is scheduled to carry will be in the small satellite class with its mass not exceeding 200kg, while the other two satellites sharing the ride will be smaller. 2/n
#SSLV can launch around 500kg sat in a 500km planar orbit and its key features — low cost, low turn-around time, flexibility to launch multiple sats, launch-on-demand, minimal infra requirements, etc,. — can make it a go-to LV for commercial launches in the future. 3/n
Read 10 tweets
Jan 26
#Updates #Space #Thread

Had to be away. But here are some developments. More to follow later this evening or early tomorrow.

First, the #RLVTDLEX date will be fixed after the lifting trial is done. Isro will use Chinook as opposed to Mi17 as planned earlier. 1/n Image courtesy: @isro
@isro, which has received a key payload #VELC for #AdityaL1 today, has completed survey and radiation studies at Fiji Islands for a temporary station being designed specifically for the Solar mission, while exploration of other sites is ongoing. 2/n
Fiji Islands is one of the options being explored to support the observatory-class space-based solar mission wherein the spacecraft will be placed in a halo orbit around L1. A final decision on location will be taken later based on the exact mission profile of the mission. 3/n
Read 12 tweets
Dec 9, 2022

@isro completed the first blow down test of the newly installed Trisonic Wind Tunnel at the Vikram Sarabhai Space Centre (VSSC), the space agency’s lead rocket-building agency, on Thursday. 1/n
Trisonic Wind Tunnel is a system to aid aerodynamic design of rockets and re-entry spacecrafts by characterising a scaled model by evaluating forces, moments, load distribution, unsteady pressures, acoustic levels etc. 2/n
Arguing that this is a major step towards India’s increasing self-reliance in the aerospace sector, Isro said: “The tunnel has an overall length of about 160m and has a maximum cross section of 5.4m… 3/n
Read 9 tweets
Dec 7, 2022
#Thread #Space #India

In line with its renewed mandate to hand hold and encourage private industry, @isro and @SocialAlphaIN have launched a new innovation platform for the space sector: SpaceTech Innovation Network or #SpIN. 1/n Image
This is India’s first dedicated platform for innovation curation & venture development for space entrepreneurial ecosystem. 2/n
“A one-of-its-kind public-pvt collaboration for space startups, SMEs, #SpIN is a step in providing stimulus to India’s space reform policies & will work towards identifying & unleashing mkt potential of most promising space tech innovators & entrepreneurs,” Isro said. 3/n
Read 10 tweets
Nov 28, 2022
#Breaking #Stars #Galaxies #Thread

Today, @RRI_Bangalore (in pic) said in a first-of-its-kind work, using data from an Indian telescope, scientists have determined properties of radio luminous galaxies formed just 200-mn yrs after #BigBang — a period known as #CosmicDawn. 1/n
Pointing out that telescopes, both ground and space-based, are aiming to capture faint signals from the depths of the cosmos to better the understanding of our Universe, RRI said they used the Shaped Antenna measurement of the background RAdio Spectrum-3 (#SARAS3) telescope. 2/n
For the study, SARAS-3, indigenously designed and built at RRI, was deployed over Dandiganahalli Lake and Sharavathi backwaters, located in Karnataka, in early 2020 (see pic). 3/n
Read 23 tweets
Nov 28, 2022
#JUSTIN #Thread #Space

Space-tech start-up @AgnikulCosmos today said it has established India’s first launchpad designed and operated by a private player. The facility, situated at Sriharikota, was inaugurated by Isro chairman S Somanath on Nov 25. 1/n
The facility which was designed by Agnikul and executed with support from Isro and Indian National Space Promotion and Authorization Center (IN-SPACe) has two sections to it — the Agnikul launchpad (ALP) and the Agnikul mission control centre (AMCC). 2/n
“Critical systems connecting these two sections, which are 4km away from each other are redundant to ensure 100% operationality during countdown… 3/n
Read 14 tweets

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