'The solution is to replace, clean up, retest and proceed.'
'There is nothing to worry about if corrected.'
Indian astronaut and Indian Air Force Group Captain Shubhanshu 'Shuks' Shukla and three other astronauts will be able to fly to the International Space Station only after SpaceX repairs its Falcon 9 rocket, said National Aeronautics and Space Administration.
SpaceX can fit the rocket with a new booster (ISRO did that earlier for one of its rockets) and save time or the faulty one, a senior official at the Indian Space Research Organisation said.
The SpaceX's Falcon 9 rocket with Dragon spacecraft carrying Commander Peggy Whitson of the US, Mission Pilot Shukla, Mission Specialist Sławosz Uznański-Wiśniewski of the European Space Agency/Poland, and Mission Specialist Tibor Kapu of Hungary was supposed to fly to the ISS on Wednesday.
The flight was known as Axiom Mission 4 or Ax-4 Mission managed by the US company Axiom Space.
The rocket flight was aborted in order to plug the liquid oxygen leak identified during post-static fire Falcon 9 rocket inspections.
'NASA, Axiom Space, and SpaceX are standing down from the launch opportunity on Wednesday, June 11, of Axiom Mission 4 to the International Space Station to allow additional time for SpaceX teams to repair a liquid oxygen leak identified during post-static fire Falcon 9 rocket inspections,' NASA said.
'A new launch date for the fourth private astronaut mission will be provided once repair work is complete, pending range availability,' the US space agency added.
'As part of launch vehicle preparation to validate the performance of booster stage of Falcon 9 launch vehicle, seven second of hot test was carried out on the launch pad. It is understood that LOX (liquid oxygen) leakage was detected in the propulsion bay during the test,' ISRO Chairman Dr V Narayanan said.
'Based on the discussion on this topic by ISRO team with the experts of Axiom and SpaceX it has been decided to correct the leak and carry out necessary validation test before clearing for the launch. Hence the launch of Axiom 04 slated for 11th June 2025 for sending first Indian Gaganyatri to ISS is postponed,' Narayanan added.
'Standing down from tomorrow's Falcon 9 launch of Ax-4 to the @Space_Station to allow additional time for SpaceX teams to repair the LOx leak identified during post-static fire booster inspections. Once complete - and pending Range availability -- we will share a new launch date,' SpaceX said.
NASA omitted to mention ISRO in its statement while mentioning Axiom Space and SpaceX.
Similarly ISRO Chairman Narayanan omitted NASA's name but mentioned Axiom and SpaceX in his message.
On the other hand, SpaceX did not mention the names of NASA, Axiom Space or ISRO.
SpaceX's Vice President-Build and Flight Reliability William Gerstenmaier had told the media earlier that company officials had detected a liquid oxygen leak in the rocket booster and in the steering systems of the fifth engine.
According to Gerstenmaier, the liquid oxygen leak was seen on the booster during its entry on its last mission. The company reuses its booster to save on costs.
The rocket uses rocket grade kerosene as fuel and super cooled liquid oxygen as oxidiser.
Gerstenmaier had said the leak was not repaired when the booster was refurbished for the next flight or the leak was not detected then.
According to SpaceX, the Ax-4 Mission will be the second flight for the first stage booster. It was previously used for the Starlink mission.
That apart, SpaceX team also found an issue with the Thrust Vector Control (TVC) systems in the fifth engine in the booster. The first stage booster has nine engines.
"Leaks in a liquid propulsion system are typical. Even after testing, such observation could happen due to nano particles settling at valve seats or something like that," a senior ISRO official told this correspondent.
"The solution is to replace, clean up, retest and proceed. It requires time and facility support. There is nothing to worry about if corrected," the ISRO official added.
There are two options for SpaceX. First is to replace the problem item with a new one or repair the existing system and get the launch vehicle ready for flight. The latter one will take time if there is no stand-by for the problem system.
Be that as it may, the Ax-4 Mission can be launched on any day till June 30 and there are launch opportunities from the second week of July, said Dana Weigel, manager, ISS programme, NASA.
ISRO's fuel leak experience
ISRO has faced fuel leak in its Geosynchronous Satellite Launch Vehicle-D5 (GSLV-D5) rocket in 2013 and in the Polar Satellite Launch Vehicle (PSLV) for the country's first moon mission-Chandrayaan-1.
A few hours prior to the lift off the GSLV-D5 with GSAT-14 satellite on August 19, 2013, fuel started leaking from its second stage.
The second stage was replaced with a new one and some critical components in the strap-on motors of the first stage were also replaced as a matter of precaution, an ISRO official had told this correspondent then.
Similarly, there were anxious moments before the PSLV rocket went up carrying the Chandrayaan-1 spacecraft.
During the fuel loading of the rocket's second stage, fuel started leaking from the joint between the rocket and the ground equipment.
The leak was detected at the tricky tibia joint between the propellant filling unit and the launcher, K Radhakrishnan, then director, Vikram Sarabhai Space Centre and later ISRO chairman, had then told this correspondent.
The ISRO team had to be fully alert as it was a hypergolic fuel-oxidizer combination which meant spontaneous ignition in case the two came into contact. Probable simultaneous leaks in both the fuel and oxidizer lines could have caused a catastrophic fire, Radhakrishnan had then said.
The rain prior to that launch was a blessing in disguise.
The fuel filling restarted but with constraints in its rate of flow and its ideal ratio of the fuel UH 25 (a mix of unsymmetrical dimethylhydrazine and hydrazine hydrate) and the oxidizer (nitrogen tetroxide), Radhakrishnan had said.
Venkatachari Jagannathan can be reached at venkatacharijagannathan@gmail.com
Feature Presentation: Aslam Hunani/Rediff.com
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