Antenna for joint NASA-ISRO radar satellite needs fix, delaying launch
The large deployable antenna for a joint NASA-ISRO radar satellite, dubbed NISAR, that was targeting a spring launch will require an extra coat of reflective material, thus delaying the satellite’s launch until the second half of this year.
In a March 22 statement, NASA said a new launch date for the NASA-ISRO Synthetic Aperture Radar (NISAR) mission will be set at the end of April because of work to protect the spacecraft’s reflector, an antenna that is 12 meters across when fully deployed, from temperatures when in its stowed configuration. “Testing and analysis identified a potential for the reflector to experience higher-than-previously-anticipated temperatures in its stowed configuration in flight,” NASA said in the statement. To prevent those increased temperatures, a “special coating” will be applied to the antenna so that it reflects more sunlight.
That work, NASA said, requires shipping the antenna, currently with the rest of the NISAR spacecraft in India, to a facility in California that can apply the coating. NASA did not state how long the process of applying the coating, as well as shipping the antenna to California and then back to India, will take.
It appears that the need for this additional coat was discovered during environmental testing by ISRO engineers in India as part of its preparation for launch on India’s GSLV rocket. Based on the JPL website for this mission, it appears this antenna system was built by JPL.
NASA is providing the mission’s L-band synthetic aperture radar, a high-rate communication subsystem for science data, GPS receivers, a solid-state recorder and payload data subsystem. ISRO is providing the spacecraft bus, the S-band radar, the launch vehicle and associated launch services.
Though the purpose of the final environmental testing prior to launch is specifically to find such issues and correct them, the question remains why this issue occurred. One can’t help wondering if the many management problems detailed at JPL in several reports (here, herej, here) might have contributed, including the organization’s total commitment since 2022 to Diversity, Equity, and Inclusion quotas, making skin color and sex the primary qualifications for hiring, rather than skill, education, or talent.
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The large deployable antenna for a joint NASA-ISRO radar satellite, dubbed NISAR, that was targeting a spring launch will require an extra coat of reflective material, thus delaying the satellite’s launch until the second half of this year.
In a March 22 statement, NASA said a new launch date for the NASA-ISRO Synthetic Aperture Radar (NISAR) mission will be set at the end of April because of work to protect the spacecraft’s reflector, an antenna that is 12 meters across when fully deployed, from temperatures when in its stowed configuration. “Testing and analysis identified a potential for the reflector to experience higher-than-previously-anticipated temperatures in its stowed configuration in flight,” NASA said in the statement. To prevent those increased temperatures, a “special coating” will be applied to the antenna so that it reflects more sunlight.
That work, NASA said, requires shipping the antenna, currently with the rest of the NISAR spacecraft in India, to a facility in California that can apply the coating. NASA did not state how long the process of applying the coating, as well as shipping the antenna to California and then back to India, will take.
It appears that the need for this additional coat was discovered during environmental testing by ISRO engineers in India as part of its preparation for launch on India’s GSLV rocket. Based on the JPL website for this mission, it appears this antenna system was built by JPL.
NASA is providing the mission’s L-band synthetic aperture radar, a high-rate communication subsystem for science data, GPS receivers, a solid-state recorder and payload data subsystem. ISRO is providing the spacecraft bus, the S-band radar, the launch vehicle and associated launch services.
Though the purpose of the final environmental testing prior to launch is specifically to find such issues and correct them, the question remains why this issue occurred. One can’t help wondering if the many management problems detailed at JPL in several reports (here, herej, here) might have contributed, including the organization’s total commitment since 2022 to Diversity, Equity, and Inclusion quotas, making skin color and sex the primary qualifications for hiring, rather than skill, education, or talent.
Readers!
Please consider supporting my work here at Behind the Black. Your support allows me the freedom and ability to analyze objectively the ongoing renaissance in space, as well as the cultural changes -- for good or ill -- that are happening across America. Fourteen years ago I wrote that SLS and Orion were a bad ideas, a waste of money, would be years behind schedule, and better replaced by commercial private enterprise. Only now does it appear that Washington might finally recognize this reality.
In 2020 when the world panicked over COVID I wrote that the panic was unnecessary, that the virus was apparently simply a variation of the flu, that masks were not simply pointless but if worn incorrectly were a health threat, that the lockdowns were a disaster and did nothing to stop the spread of COVID. Only in the past year have some of our so-called experts in the health field have begun to recognize these facts.
Your help allows me to do this kind of intelligent analysis. I take no advertising or sponsors, so my reporting isn't influenced by donations by established space or drug companies. Instead, I rely entirely on donations and subscriptions from my readers, which gives me the freedom to write what I think, unencumbered by outside influences.
You can support me either by giving a one-time contribution or a regular subscription. There are four ways of doing so:
1. Zelle: This is the only internet method that charges no fees. All you have to do is use the Zelle link at your internet bank and give my name and email address (zimmerman at nasw dot org). What you donate is what I get.
2. Patreon: Go to my website there and pick one of five monthly subscription amounts, or by making a one-time donation.
3. A Paypal Donation or subscription:
4. Donate by check, payable to Robert Zimmerman and mailed to
Behind The Black
c/o Robert Zimmerman
P.O.Box 1262
Cortaro, AZ 85652
You can also support me by buying one of my books, as noted in the boxes interspersed throughout the webpage or shown in the menu above.
Robert commented: “Though the purpose of the final environmental testing prior to launch is specifically to find such issues and correct them, the question remains why this issue occurred.”
I decided early in my career that I was glad I didn’t become a thermal engineer. In theory we know how to control temperatures well, but in practice the hardware and the thermal surfaces act in ways that were not predicted.
One instrument I designed (with an experienced thermal engineer doing the radiator parts and the thermal conduction to the radiators) had to go through thermal vacuum testing three times, with modifications to the thermal control system between each one. He never did get the sensors as cold as specified, but he got them cold enough to give good data.
Even in college, the thermal dynamics textbook had tables of thermal characteristics for various materials, but they didn’t always agree with each other. My favorite example was bulk copper having a coefficient for convection that was an order of magnitude different than the coefficient for a copper teakettle. You read that right, and I wrote it right. An order of magnitude! The professor kindly put a copper-clad steel boiler on the final exam. Which coefficient to use? I chose the teakettle on the ir-rationalization that thickness of the material made for some unjustifiable difference in convection properties. With an order of magnitude difference in the possible answer, I decided right then and there to never become a thermal engineer, and my observations since have reinforced that choice.
The Merlin vacuum engine operates with a combustion chamber at extremely high pressure and extremely high temperature, but the launch videos show on the outside, just a couple of inches away, a string of oxygen ice bouncing around on the engine. It took rocket scientists a while to figure out how to do that kind of thermal control. Goddard started finding that problem a century ago.
Why would this thermal issue occur on NISAR? Because the darnedest things happen when you’re building and operating spacecraft. You might think your car is fussy and has an obstinate personality, but cars are mature compared with the constant hissy fits that spacecraft throw. You would think that they were three-year-olds or Democrats.