LAS VEGAS — A joint Earth science mission by the United States and India is set for launch next week despite lingering concerns about technical issues on recent Indian missions.
NASA and the Indian Space Research Organisation (ISRO) separately announced July 21 that they had set a launch date of July 30 for the NASA-ISRO Synthetic Aperture Radar (NISAR) mission. NISAR will lift off on an Indian rocket from the Satish Dhawan Space Centre in India at 8:10 a.m. Eastern.
NISAR is an Earth science mission featuring a L- and S-band radars that will map the world’s land and ice surfaces twice every 12 days. Scientists expect the data from those radars to be valuable in applications ranging from agriculture to disaster management.
The mission is the largest joint project between NASA and ISRO. NASA is providing the L-band SAR system, along with a 12-meter deployable radar antenna and boom. ISRO is providing an S-band SAR system as well as the spacecraft bus and launch on a Geosynchronous Satellite Launch Vehicle (GSLV) Mark 2 rocket.
The announcement of a launch date comes after long delays in the mission’s development. That included an issue with the spacecraft’s large deployable radar antenna that required shipping the antenna from India back to the United States last year for modifications after concerns the antenna would get warmer than expected while stowed. The antenna was shipped back to India late last year, but the mission’s launch still slipped from March to July.
In the lead up to the NISAR launch, ISRO has suffered problems with two other missions. The NVS-02 navigation satellite, launched in January, was stranded in a geostationary transfer orbit after the failure of the spacecraft’s propulsion system. ISRO said a propellant valve failed to open but has not disclosed additional details on the cause and potential commonality with other spacecraft.
ISRO’s most recent launch, of the EOS-09 radar imaging satellite, failed May 17 when the third stage of the Polar Satellite Launch Vehicle (PSLV) malfunctioned in flight. ISRO said immediately after the failure there was a drop in chamber pressure in the stage but has not disclosed other details about the failure.
The PSLV stage that malfunctioned on the EOS-09 launch is not used on the GSLV Mark 2. However, industry sources say the failure as well as the NVS-02 anomaly raise questions about quality control and oversight by ISRO for the NISAR mission.
At a July 21 press conference about NISAR, NASA officials did not discuss how they concluded they could proceed with the launch. “We like ISRO to answer any questions about their launch vehicles, but obviously we’ve been getting a lot of data from them,” said Nicky Fox, NASA associate administrator for science, when asked about those recent anomalies.
That press conference did not include any ISRO representatives, which NASA attributed to the time difference: the briefing started at 12 p.m. Eastern or 9:30 p.m. Indian Standard Time. ISRO has not provided any details on steps it took to identify and correct any issues from those recent anomalies for NISAR.
The launch is the culmination of a more than decade of effort between NASA and ISRO on the mission. Paul Rosen, project scientist for NISAR at the Jet Propulsion Laboratory, said at the briefing work on what would become NISAR traced back to a recommendation in the 2007 Earth science decadal survey to pursue a radar mission, initially with a lidar instrument as well.
“It’s difficult programmatically to get an international partner who has the same kinds of objectives that you have that align in time with your own programs,” he said, as NASA tried to find another country to work with on the mission.
In 2011, after NASA dropped plans to include a lidar on the spacecraft, he said he went to India and found a receptive audience. That led to a mission design where each country contributed a radar system along with other elements, a partnership formalized around 2014.
NISAR is described as a 50-50 partnership between NASA and ISRO. At the briefing, Fox said that NASA’s share of NISAR cost the agency $1.2 billion, but deferred to ISRO on their costs. ISRO has not published a recent estimate of its cost but, in 2017, a government minister estimated its share of the mission to cost 7.88 billion rupees, or $91 million.