India launches X-ray astronomy satellite

India launched an astronomy satellite to start a year that will feature key tests for its human spaceflight program and a potential joint crewed mission with NASA. A Polar Satellite Launch Vehicle (PSLV) lifted off at 10:40 p.m. Eastern Dec. 31 (9:10 a.m. local Jan. 1) from the Satish Dhawan Space Centre. It deployed its primary payload, the XPoSat spacecraft, into a 650-kilometer orbit about 22 minutes later. The 469-kilogram satellite carries two instruments to conduct X-ray polarimetry measurements. Astronomers plan to use the data collected by XPoSat to study neutron stars, black holes and supernovae. After deploying XPoSat, the PSLV’s fourth stage maneuvered to a 350-kilometer orbit. Attached to the upper stage is a payload called PSLV Orbital Experimental Module (POEM) 3. It carries 10 experiments, such as fuel cells and thrusters, from ISRO, universities and companies expected to operate for about a month. Lowering POEM-3 to 350 kilometers is intended to mitigate debris by reducing the orbital lifetime of the upper stage. “As a responsible space agency, we decided to bring the fourth stage to a lower orbit so that the life of the stage in the orbit is much less, so we don’t create debris in that process,” said S Somanath, chairman of ISRO, in remarks after the launch. The launch was the first of 2024, based on Universal Time. It comes after a record-setting 2023 with about 220 orbital launch attempts worldwide. India conducted seven of those launches using the PSLV, Geosynchronous Satellite Launch Vehicle (GSLV) and Small Satellite Launch Vehicle, all of which were successful.

ISRO expects to roughly double that launch rate in 2024, with 12 to 14 launches planned for the year. Among them will be the GSLV launch of the NASA-ISRO Synthetic Aperture Radar (NISAR) Earth science mission, a joint effort of the two space agencies. That mission is slated for launch on March 30, NASA officials said at a session of the Fall Meeting of the American Geophysical Union in December.

The highlight of 2024 for ISRO, though, will be a series of test flights for its Gaganyaan human spaceflight program. The agency conducted the first such test in October, launching an uncrewed capsule on a suborbital flight to test its launch abort system.

“2024 is going to be the year of Gaganyaan,” Somanath said after the launch, starting with additional abort tests. “This year we are expecting two more such test flights of the test vehicle, followed by the unmanned mission.” That would be an orbital test of the Gaganyaan spacecraft without a crew on board.

That schedule would mean the first crewed Gaganyaan flight would take place no earlier than 2025. Prime Minister Narendra Modi, when he announced the program in August 2018, set a goal for the first launch to take place in 2022 to mark the 75th anniversary of India’s independence.

The next Indian astronaut to go to space, though, may do so on an American spacecraft. As part of a June 2023 summit meeting between Modi and President Joe Biden, the countries announced they would develop a “strategic framework for human spaceflight cooperation” by the end of the year. That would include, according to a joint statement, training of Indian astronauts at NASA’s Johnson Space Center and “a goal of launching a joint effort to the International Space Station in 2024.”

Neither government has released additional details about those plans, including that strategic framework, since then. A Nov. 9 fact sheet by the U.S. State Department on relations between the United States and India reiterated the goal of a joint mission to the ISS in 2024 and training of Indian astronauts at JSC.