Exclusive: More than 10yrs after it was launched, #MeghaTropiques, @isro & @CNES joint weather modelling satellite that was studying water cycle & energy exchanges in the tropics has reached what’s called “end of mission”. 1/n
The satellite, which was launched in October 2011 and initially estimated to have a life of five years has worked for five-years-and-six-months more than initial estimations and sent in at least 5TB of raw data which has yielded around 30TB of data sitting on various servers. 2/n
A senior Isro scientist said: “As on date, the satellite still has 120kg of fuel and end of mission is also not because of failures in communication, solar panels or any other systems or because we lost communication. All of those are still working.” 3/n
The decision to declare “end of mission” was taken because the satellite had developed an “attitude problem” which rendered the data unusable. 4/n
In layman’s terms, another scientist explained: “When my face is in front of yours and I’m seeing you, that’s my attitude to see you. Now, if my face is vibrating continuously, your image will be blurred. This is happening with the satellite; there’s no ground trace limit.” 5/n
The problem was first noticed some time in early or mid March and given that it is a scientific mission there are minimum requirements. Even if payloads are healthy, the mission won’t continue if data is not usable. 6/n
“Each day, it does 14 orbits & is expected to yield data in each orbit. For the past many months, it yielded data for about 4-5 orbits,” the first scientist said. 7/n
What Next: At present, Megha-Tropiques is in an orbit around 870km away from Earth. As is the procedure, Isro will now have to fire the engines again and reduce the altitude through orbit reduction manoeuvres. 8/n
Sources said that the plan is to bring the satellite down to an orbit that is less than 300km away from Earth. This will be controlled. After this, which is expected to be done within the next fortnight, the satellite will be monitored for more than two months. 9/n
Once the ground stations lose the telemetry connection, the spacecraft will be declared as debris and its responsibilities would be with the Directorate of Space Situational Awareness and Management (DSSAM). 10/n
“As per estimations, it could re-enter the atmosphere in two-three months, which would be as per the shortest time. Or, it could take as long as 18 months,” the source said. 11/n
@isro & @CNES are now planning another joint mission, #Trishna, meant for accurate mapping of land surface temperatures. In his last address, former chairman Sivan K had said “Trishna will be the benchmark for temperature data at best resolution and repeatability globally”. 12/n
According to @CNES, Trishna — Thermal infraRed Imaging Satellite for High-resolution Natural resource Assessment — will acquire imagery of Earth’s surface in the thermal infrared with a resolution and revisit frequency never seen before. n/n
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Today, @isro said it accomplished another significant milestone on March 21, when the PSLV Orbital Experimental Module-3 (#POEM3) successfully re-entered Earth’s atmosphere in a controlled manner, leaving minimal orbital debris. 1/n
Pic: Isro
#POEM3 was part of the #PSLVC58 mission that launched #XPoSat on Jan 1, 2024. After deploying satellites into their intended orbits, the spent rocket stage was transformed into a stabilised platform for conducting experiments. 2/n
“The last stage of PSLV or POEM was deorbited from 650km to 350 km, which facilitated its early reentry, and was passivated to remove residual propellants to minimise any accidental break-up risks,” Isro said. 3/n
In what astronomers are calling “unexpected” but “beautiful surprise”, @IIABengaluru Indian Astronomical Observatory (#IAO) in #Hanle & Merak, Ladakh, captured stunning images of an intense red-coloured aurora on Nov 5.
Pics: IIA
The IAO, operated by the Indian Institute of Astrophysics (IIA), Bengaluru, is renowned for its astronomical research and observations. 2/n
Auroras, typically observed at high latitudes like Scandinavia, are a breathtaking curtain of light caused by the interaction between the Earth’s magnetosphere and incoming solar wind carrying charged particles and magnetic fields. 3/n
As @isro burns the midnight oil on Earth, waiting to hear again from #Vikram & #Pragyan, principal investigators of instruments on the two have begun sifting through data for new findings. 1/n
Among many things the global scientific community is expected to learn from Vikram and Pragyan’s work before they went to sleep is new knowledge about the lunar soil, which will be useful for future missions, including ambitious projects aiming to send humans back to #Moon. 2/n
“It would have been easy if there was a way we could know if they would wake up, but we have to wait and see how systems behave after Sunrise,” Isro chairman S Somanath said. 3/n
On a day India’s solar sat began its 1.5 mn-km journey, its lunar mission achieved all its objectives, paving the way for @isro to put #Vikram & #Pragyan to sleep on Sunday. Read on for exclusive details from project director P Veeramuthuvel. 1/n
Sunday, which is the 12th day since India achieved the historic soft-landing on the lunar surface, will see both Vikram and Pragyan retire for the night, Chandrayaan-3 project director P Veeramuthuvel told me. 2/n
Isro late on Saturday said: “The rover completed its assignments. It is now safely parked and set into Sleep mode. #APXS & #LIBS payloads are turned off. Data from these payloads is transmitted to the Earth via the Lander.” 3/n
While several of its teams continue to romance #Moon, Isro is in the last leg of prep for a "Surya Namaskara". #AdityaL1 slated to launch just hrs from now. Read on to know exclusive details on why launch profile is for 63 mins, about #AOP & more… 1/n
#AdityaL1 will be launched in the 59th flight of #PSLV, after several yrs of devp. PSLV-C57, in XL configuration, will place #AdityaL1 in a highly eccentric Earth-bound orbit, an elliptical orbit whose Perigee is expected to be around 235km & Apogee more than 19,000km. 2/n
From there, #AdityaL1 will perform multiple orbital manoeuvres using LAM (liquid apogee motors) to reach the Lagrange Point-1 or #L1 about 1.5-million-km away. That is 1/100th of the distance between Earth and Sun. 3/n
In the “first-ever in-situ” measurements in the lunar polar region, the Laser-Induced Breakdown Spectroscope — #LIBS — onboard #Pragyan has “unambiguously confirmed the presence of Sulphur (S) in the lunar surface near the south pole”. 1/n
“LIBS is a scientific technique that analyses the composition of materials by exposing them to intense laser pulses. High-energy laser pulse is focused onto the surface of a material (rock or soil). The laser pulse generates an extremely hot and localised plasma,” Isro said. 2/n
The collected plasma light is spectrally resolved & detected by detectors such as charge coupled devices. “Since each element emits a characteristic set of wavelengths of light when it's in a plasma state, the elemental composition of the material is determined,” Isro added. 3/n