Chandrayan-2 Mission

Prithwiraj · Post by **Prithwiraj** » 18 Jul 2019 02:23

prasannasimha wrote:The cryogenic stage is actually self pressurized so if the Hrlium tank failed the mission **may** have still been succesful ( the annoyncements from ISRO sort of confirm it). However they havevused Helium aa ullage pressutizing ahent as precaution or some specific reason so they qould not like to take a chancr.
Snother thing is this rocket will be the one going for GSP so they would take extra precautions to see no catast.ophic failure occurs.
All space agencies have had problrms.
People forget the recent catastrophic explosions of the Falcon eocket and Long March.
Its a part of rocketry - after sll its a contolled explosion

Just on a lighter note --- you must be "high" on helium Sir or your keyboard needs to get replaced

UlanBatori · Post by **UlanBatori** » 18 Jul 2019 06:12

If there is a He tank next to the LH2 tank I wonder if the He will liquefy since LH2 is at temp lower than He boiling point. Maybe that's why it's not leaking? (JUST KIDDING!!!) But the difficulties of operating different systems close to cryogenic systems are being learned still, no doubt. OTOH, LOX is used in many industrial applications, so pipe fittings that can be placed close to an LOX tank should be available in plenty. LH2 is a different proposition. Could it be that loading LH2 was what caused the problem to be revealed, though the LOX tank was the destination of the pipe?

I say this because I would think they had tested the He tank with LOX in ground tests quite a few times. And the He tank for the LH2 may have different fittings. But they may not have tested the He tank for the LOX with LH2 sitting close by? (a very dangerous exercise)

Karthik S · Post by **Karthik S** » 18 Jul 2019 11:37

Rescheduled at 2:43 PM on Monday, July 22.

JTull · Post by **JTull** » 18 Jul 2019 15:55

Chandrayaan-2 launch at 2.43pm on July 22

The Indian Space Research Organisation (Isro), which had to call off the July 15 launch of Chandrayaan-2 in the eleventh hour, on Thursday announced July 22 as the rescheduled date for launch.

Confirming TOI's report from July 15, which had said that the next launch could be as early as July 22 (Monday) and that a decision could be taken by Wednesday, Isro, in an official statement released on Thursday said: "Chandrayaan-2 launch is now rescheduled on July 22, 2019 at 2.43pm", from the second launchpad at the spaceport in Sriharikota.

An expert committee constituted to analyse the issue-the July 15 launch was cancelled after a leak in the cryogenic stage of the launch vehicle was detected-has suggested remedial action, which has
been implemented.

Sources said that the new launch date was finalised late on Wednesday. "The expert committee identified the root cause of the technical snag and all corrective actions are implemented," Isro said, without elaborating on what the "root cause" was.

Chandrayaan-2 is India's second Moon mission, which unlike its first mission (Chandrayaan-1), involves Isro soft-landing a lander (Vikram) and operating a robotic rover (Pragyan) on the lunar surface, while an Orbiter goes circles Moon in a 100km X 100km orbit.

Cleared in September 2008, one month before India launched its first lunar mission, the cost of Chandrayaan-2 is Rs 978 crore, and it will carry 14 payloads, including a passive payload from US' Nasa.
If India manages to successfully land Vikram on Moon-Isro chairman K Sivan has said the landing process is the 'most terrifying'-it will only be the fourth nation after the erstwhile USSR (now Russia), US and China to do so.

While Isro has a host of objectives for Chandrayaan-2, including its hopes of unraveling some secrets about the evolution of the solar system, the most critical will be to re-confirm the presence of water on Moon, and it try and map its presence.

While Isro's quick turnaround from July 15 is indicative of how keen the agency is on utilising the earliest available launch window, it also shows that the glitch that prevented the initial launch was a "not serious," as one source said. On July 15, Isro had said that it had called off the launch exercising "abundant caution".

Mort Walker · Post by **Mort Walker** » 18 Jul 2019 16:08

Singha · Post by **Singha** » 18 Jul 2019 16:59

the general mahaul is they are confident of fixing it on the launchpad itself and confidence in publishing the 22 July date.
by tomorrow it will get fixed and some 72 hr kind of monitoring will start.

good to know monitoring sensors are strong and pervasive and could detect such tiny problem.

Singha · Post by **Singha** » 18 Jul 2019 17:09

UlanBatori wrote:What is the little rocket strapped at the bottom of each booster?
I didn't realize that the main Vikas liquid rocket does not ignite until 114 seconds into launch, just 26 sesconds before booster dropoff. Seems a big waste, not to fire the liquid engine at liftoff. This must be the part about dropping the first stage (boosters) before doing serious horizontal acceleration.
Also, strapping on a couple more boosters should be possible with the same diameter stack, hain? So the payload can be boosted a good deal. We need those aerodynamic-glide boosters to get away from these limitations.

I had asked about the little rocket and some guru replied but forgot the answer.

>> I didn't realize that the main Vikas liquid rocket does not ignite until 114 seconds into launch, just 26 sesconds before booster dropoff. Seems a big waste

I would think of the so called "first stage" as the real 2nd stage and the boosters as the real 1st stage only put around the 1st stage and not stacked vertically. its a short meaty missile 43m (like Ariane baba) and not long weak and thin like the Falcon which is 70m tall. can someone explain why we delay the fire ? seems to be we could have a greater payload to LEO by lighting all rockets at time t=0 ?

next steps in evolution are probably TSTO and changing over to Lo2+kerosene, or LH+LO2 which all the meaty rockets use. are we on it?

its hard to make out from the pix, if the Ariane which GSLV is most sibling to fires its mighty next gen vulcain engine right off the pad

Singha · Post by **Singha** » 18 Jul 2019 17:11

overall mankind is having to expended a tremendous amt of cost and fuel per kg to get anything into orbit.

some new breakthrough is needed to get to star wars level where even obi wan's personal spacecraft was smoothly able to travel the heavens.

SSSalvi · Post by **SSSalvi** » 18 Jul 2019 17:34

Sorry for late reaction.
There are some words like Jugaad, quickfix about ISRO's wording " Learning Curve".
Should there not be a learning curve in every new attempt? In fact the safety gates in Launch sequence software did its job of aborting the flyoff because the designers had put appropriate safety margins.
Coming to terming the 'Shielding the pipe/joint to continue with this mission as Juggad/Quickfix is in bad taste because this is a bold attempt to overcome the detected flaw for this flight.. and correct the problem with proper re-engineering /re-design of faulty subsystem for future flights. Remember that the fault has been IDENTIFIED precisely and how to avoid it in future is also known exactly.
Is it not prudent to continue with the setup instead of wasting all the efforts and preparations?
Many may not be aware that such a things have happened in the earlier phase of PSLV .. but then we did not have realtime broadcast and Internet in those days so people just came to know of those things next day in news paper.
In one such flight the count countdown stopped just short of Ignition. Fault was found to be that ( I think ) 3rd stage was getting hot due to atmospheric temperature at SHAR. The flight took of next day with a 'bandaged' 3rd stage. They had covered the stage literally with thermocole sheets by using ropes. Because the heat isolation was required only till the launch time. With the first bump of lift off it was thrown in air but the flight went smooth.
Afterwards the outer cover of stage was suitably modified in design.

===================================

Adding Later:

https://www.ndtv.com/blog/aborting-chan ... nt-2071657

A top scientist said the problem was relatively easy to resolve but had the mission not been aborted, it would have resulted in failure and a loss of Rs. 1,000 crore for India. The rocket and satellite had been saved so the launch could take place another day.

The decision to abort the launch, I am told, was taken not by ISRO Chairman K Sivan - an astute rocket engineer - but a responsible officer further down the pecking order, but fully endorsed by the Chairman. Only well-trained professionals can take such hard decisions. As one top scientist put it, the "stubborn" engineers at ISRO decided that aborting the mission was better than showing unprecedented fireworks to the President of India.

Of all those dumb people observing their screens during launch ^^^ this is the only guy ( Range Safety Officer ) who can intervene the launch process. .... OR Destroy the vehicle if need be on safe region .. think of the mental pressure and decision criticality in real time.

And NO JUGAAD!!

The problem was resolved without changing any component - just "tightening it worked".

Vivek K · Post by **Vivek K** » 18 Jul 2019 17:40

That is how development works! Thanks for the great historical note.

hnair · Post by **hnair** » 18 Jul 2019 17:45

singha, the Araine V fires the Vinci after the two SRB's flame stabilize. Same as shuttle. This is because they can shut it down unlike SRB. You can see the shock cone clearly in your photo

UB-sir, this is early stage for MKIII and every last part of the MKIII is bespoke for. Such tanks were probably tested as part of component-level (LPSC valiyamala), engine-level(IPRC Mahendragiri) and the full testing of the flight-grade stage (IPRC Mahendragiri). The last round of flight-tests too did not throw up this issue. There is no jugaad here, for such a complex system that is still being shaken-down. It is just unfortunate that Chandrayan2 is being lofted by the Mk3, so early in its life and that is a risk that ISRO took (if any). If this fix is considered jugaad, then those guys tweaking high-octane race cars at pits are also doing jugaad and endangering the race. Mk3 systems will slowly get into full production, private industry manufacturing etc, maybe by mid-2020 or so. And then the swap to the Kerolox will happen and yet another slow process of testing etc will happen.

Hoping for the best!

SSSalvi

Mort Walker · Post by **Mort Walker** » 18 Jul 2019 18:19

Take a look at ISRO’s orbital accuracy and you’ll find the answer as to why the S200 fires first to get away from the earth’s gravitational influence. The L110 Vikas isn’t just for pure thrust, but achieves accuracy. The S200 is a workhorse and can be used for delivering rose petals for DRDO development. Need to have it tried and true.

Vips · Post by **Vips** » 18 Jul 2019 19:06

Chandrayaan-2 launch at 2.43pm on July 22.

The Indian Space Research Organisation (Isro), which had to call off the July 15 launch of Chandrayaan-2 in the eleventh hour, on Thursday announced July 22 as the rescheduled date for launch.

Confirming TOI's report from July 15, which had said that the next launch could be as early as July 22 (Monday) and that a decision could be taken
by Wednesday, Isro, in an official statement released on Thursday said: "Chandrayaan-2 launch is now rescheduled on July 22, 2019 at 2.43pm",
from the second launchpad at the spaceport in Sriharikota.

An expert committee constituted to analyse the issue-the July 15 launch was cancelled after a leak in the cryogenic stage of the launch vehicle was detected-has suggested remedial action, which has been implemented.

Sources said that the new launch date was finalised late on Wednesday. "The expert committee identified the root cause of the technical snag and all corrective actions are implemented," Isro said, without elaborating on what the "root cause" was.

While Isro's quick turnaround from July 15 is indicative of how keen the agency is on utilising the earliest available launch window, it also shows that the glitch that prevented the initial launch was a "not serious," as one source said. On July 15, Isro had said that it had called off the launch exercising "abundant caution".

prasannasimha · Post by **prasannasimha** » 18 Jul 2019 19:34

There are reasons for SRB's to be fired first in GSLV - they provide the maximal bang for buck cost wise while traveling through the dense atmosphere as they are fuel dense. One we cross Qmax (period of maximal atmospheric resistance to the vehicle )the L110 fires (I have to be corrected wrt to that) Till we get the clusterable semicryo lower stage engines working we will be totally dependent on that and then we may choose to go for eliminating SRB's Cryo lower stages are also possible but add to complexity and cost.
So GSLV is one approach with what technology we have at hand and is incremental.
I dont know what UB is talking about Jugaad etc- the launch countdown is designed exactly to detect events like this . SpaceX had a catastrophic explosion at Wallops Island because of a failure of a helium tank. Would that have been acceptable ? Multiple countries have had in the past one year launch aborts for eg ULA on an NRO mission, Space X Soyz and a Long March - so are they all Juagaad ?
We must stop self flagellation .
The good thing is the launch sequence checks could detect it - a problem was found and a fix has been made. There will be some changes made thereafter.
No country gives this techno;logy to another country. Other countries who ahve developed it have had their fare share of events and setbacks.
Lets not be so easy to blame ourselves.
If successful we will be claiming apna maal success ho gaya tha- we ust equally be ready to learn and correct ourselves isn't it ?
Remember Beresheet was lost just recently and 50% of moon landings have failed before whipping our backs.

UlanBatori · Post by **UlanBatori** » 18 Jul 2019 22:49

hnair wrote:There is no jugaad here,

Pls note, I did not use the term "jugaad". Development & testing resources are welcome, but I admire innovation. That is true science & engg.
Engineer == "Ingenieur". One who uses ingenuity.
I did suggest that He tank connected to LOX tank may not have been tested close to LH2. "Component level testing" and probably also test-cell. Looks like it just needed tightening the fitting further to account for the loosening due to cold.

Anyway, a delay by a few days is not at all a big deal. The noise is because desi dork media had to extend their hotel stay etc. Launch director and team have to be absolutely brutal about insisting on a perfect countdown b4 deciding to launch. I remember an interview with John Young, first pilot of the Space Shuttle.

When will the Shuttle be considered "routine"?

When you folks quit coming to watch the launches.

(They bring their high-zoom cameras etc mainly in the hope of scooping the Big Blast).

disha · Post by **disha** » 18 Jul 2019 23:09

Singha wrote:
UlanBatori wrote:What is the little rocket strapped at the bottom of each booster? ...
I had asked about the little rocket and some guru replied but forgot the answer.

The little "rocket" strapped at the bottom of each booster in GSLV Mk III are oil cans. They are needed for the Flex Nozzle, so that the flex nozzle can be moved around. Thanks to KrishG for pointing that out.

Imagine a 2 MT thrust solid rocket motor booster having steerable nozzles. This is a rocket technology which takes some 20-30 years to develop from scratch.

---

Every few months, all the threads go into a whine mode. This thread was to track the C-2 mission and we come back to re-re-re-re-re-discuss how Short, Dark, Rice Eating our rockets are.

All missions have an objective and as long as the objectives are met successfully in given cost, why do we care? If ISRO is going to put molasses in its SRB calling it as semi-solid rocket motor booster and takes an Indian to the moon at a cheaper rate than others., Then why the dhoti shivering of us having SDRE rocket while others having TFTA?

So coming back to the thread topic, I was looking forward to somebody posting videos of C-2 Pragyan being tested on Earth by ISRO. But I guess I have to go to Baki channels to see that. :-(

Indranil · Post by **Indranil** » 19 Jul 2019 00:16

Prasanna ji, well put.

ISRO's rockets are not the most efficient in the world. The focus was not on building that. The focus was on capability augmentation at the fastest and cheapest way. which they have done. Now the focus will shift to efficiency with the SC, metholox, clustered-engines and reusable technologies.

I am looking forward to the Admire project. That is more interesting to me than the moon shot. The day when we have an reusable ELV TSTO based on the L40-based 1st stage and C75-based second stage will be one of the my happiest day as an ISRO fan.

UlanBatori · Post by **UlanBatori** » 19 Jul 2019 06:40

Namaskaram.

prasannasimha wrote: I dont know what UB is talking about Jugaad etc-

I didn't. I tried to explain that leaving a helium tank leaking and going ahead, would have been a recipe for disaster.
Hope keyboard/screen problem resolved.

prasannasimha · Post by **prasannasimha** » 19 Jul 2019 08:20

Why is a helium tank used on cryogenic engine
Ullage space pressurization is least important as fully cyogenic engine is self pressurizing by its very nature.
It is required for engine spin start and precooling the engine prior to propellant flow as the LOX and LH2 should be in liquid state when pumped onto combustion chamber to ensure adequate mass flow. So helium flow in engine actually starts earlier to stage separation to precool and spin start the engine. Semi cryo requires helium for RP1 tank ullage space pressurization otherwise the fuel will try to become spherical during coasting with sputter supply to fuel exit ( I may be correcred wrt last statement)

mridulmm · Post by **mridulmm** » 19 Jul 2019 08:30

Just leaving it here to appreciate how effective ISRO's checks are and ISRO's success in catching the issue on Chandrayaan 2, not to downplay spaceX capabilities, spaceflight is still a very complicated task:

https://spaceflightnow.com/2019/07/15/s ... -accident/

SpaceX points to leaky valve as culprit in Crew Dragon test accident

Investigators believe a leak of propellant inside the Crew Dragon spacecraft’s propulsion system led to the capsule’s explosion April 20 during a ground test at Cape Canaveral, and a senior SpaceX official said Monday that delays are making it “increasingly difficult” to fly astronauts on the commercial spaceship before the end of the year.

Engineers are replacing valves inside the Crew Dragon’s launch abort propulsion system to prevent similar leaks from happening in the future, according to Hans Koenigsmann, SpaceX’s Vice President of build and flight reliability.

The explosion sent a cloud of toxic vapors into the sky over Cape Canaveral Air Force Station, but winds drove the material offshore, and no one was injured in the accident.

In a press briefing Monday, Koenigsmann described the preliminary findings of a joint SpaceX-NASA investigation board set up to determine the cause of the April 20 explosion, which occurred on a test stand at Cape Canaveral Air Force Station during a test of the Crew Dragon’s SuperDraco launch abort engines.

A leaky check valve inside the propulsion system allowed nitrogen tetroxide oxidizer, which the Crew Dragon’s eight SuperDraco rocket engines consume mixed with hydrazine fuel, to enter high-pressure helium tubes during ground processing, SpaceX said.

The helium system is used to quickly pressurize the propulsion system, allowing the SuperDraco thrusters to fire up during a launch emergency and push the Crew Dragon and its astronaut crew away from a failing rocket.

“If you have a propellant tank, and you fill that tank, and you do have a check valve, it’s conceivable that the check valve leaks backwards … and you push propellant into the pressurization system,” Koenigsmann said. “The amount might be a cup or something like that, or more than a cup, it depends on how the system is being built up. And then it’s there for a while after loading, and when you pressurize you basically open the valves really, really fast.”

The abort propulsion system needs to pressurize up to 2,400 pounds per square inch to force propellant into the SuperDraco thrusters, which SpaceX designed to nearly instantaneously ignite and power up to 16,000 pounds of thrust. The eight SuperDraco engines are clustered around the Crew Dragon capsule in four pods.

The Crew Dragon carries 16 smaller Draco thrusters for in-space maneuvers. They operate at lower pressure than the SuperDraco escape engines.

SpaceX accomplished a successful test of the lower-pressure Draco thrusters before pressing on to a SuperDraco hot fire test April 20. As the abort system pressurized, roughly 100 milliseconds before the SuperDraco engines were set to ignite, “we think that this slug (of nitrogen tetroxide) was driven back into the check valve,” Koenigsmann said Monday.

“Imagine a lot of pressure driving back a slug of liquid (that) has significant force, and that basically destroyed the check valve and caused an explosion,” Koenigsmann said.

The explosion destroyed the Crew Dragon spacecraft, the same vehicle that successfully launched to the International Space Station on an unpiloted test flight March 2. The capsule returned to Earth six days later and splashed down in the Atlantic Ocean.

The April 20 test-firing was key milestone as SpaceX teams readied the same spacecraft for an in-flight abort test, in which the SuperDraco engines will be ignited to push the capsule away from a Falcon 9 rocket about a minute after liftoff.

Koenigsmann said workers recovering debris from the spacecraft found burns within the faulty check valve, and the investigation’s preliminary findings line up with video and telemetry data. The SuperDraco thrusters were recovered intact after the accident, and SpaceX officials are confident the engines themselves were not at fault in the explosion.

In a written statement, SpaceX said the failure of the check valve — made of titanium — in a high-pressure NTO (nitrogen tetroxide) environment was “sufficient to cause ignition of the check valve and led to an explosion.”

SpaceX engineers tested the check valve failure hypothesis at the company’s test site in McGregor, Texas.

“We found out that … when the pressure is high, and you drive a slug with a lot of energy into a titanium component, that you can have this rather violent reaction,” Koenigsmann said.

He added that the result was surprising. Engineers did not expect titanium, a material commonly used for decades on space vehicles around the world, could react so explosively in such an environment.

“We still are not done with the testing,” Koenigsmann said. “We have preliminary results, basically, but we know enough … that you should actually make sure that no oxidizer can move over to the pressurant side, and then cause problems when you pressurize the system for flight.”

SpaceX is replacing four check valves in the Crew Dragon’s abort system with burst disks, which seal off the flow path between the propellant tanks and the plumbing for the abort system’s gaseous pressurization system.

“A burst disk is basically a device that is completely sealing left from right, and only opens when you have pressure that exceeds its rating, and then it opens and works,” Koenigsmann said. “That is basically the functionality that we need for the escape system for it to work properly in the case of a vehicle abort.”

Koenigsmann said the hardware changes inside the propulsion system will be “relatively small.”

“The burst disk we have now is definitely the safer approach overall going forward,” Koenigsmann said. “We didn’t really expect this to be a problem prior to that (accident), but that’s what you learn when you test. You find out some components might be better off exchanged with other components.”

The check valves are designed with a spring to open and close as needed.

“The problem is that sometimes the spring is a little bit sticky,” Koenigsmann said. “The valve has moving parts, and so that’s why things sometimes, especially at low pressure, are not quite sealing as well as they’re supposed to in check valves.”

On rockets and spacecraft, burst disks are designed for a single use. The burst disks block the pathway between the propellant and pressurization systems until they rupture during the engine startup sequence.

SpaceX originally intended the Crew Dragon spacecraft to use its SuperDraco thrusters for propulsive helicopter-like landings on the ground, assuming they were not needed for a launch abort. The company nixed those plans entirely in 2017, electing to use parachutes for the capsule to splash down in the ocean.

Koenigsmann said the investigation into the accident is still ongoing. He estimated the SpaceX-led inquiry, which includes NASA participation, is about 80 percent complete.

SpaceX wants to make sure the failure mode in the nitrogen tetroxide pressurization system will not cross over to other parts of the Crew Dragon spacecraft, such as the fuel system that feeds hydrazine to the SuperDraco thrusters.

“Through this process, we will continue to learn things that will help us fly safer,” said Kathy Lueders, NASA’s commercial crew program manager.

“When you have something like a test anomaly like this one — as big as this one — then you look at other systems,” Koenigsmann said. “You make sure you don’t have vulnerabilities in … other systems, on the fuel side, and so on.

“We must characterize the basic physics of this how does this happen? How do NTO and titanium ignite, and what does it mean for flammability,” he said. “So, in general, we still have work ahead of us.”

Schedules for commercial crew test flights remain murky

In a conference call with reporters Monday, Lueders declined to offer a schedule for SpaceX’s next two Crew Dragon test flights.

After completing the unpiloted test flight to the space station in March, known as Demo-1, SpaceX was gearing up for the in-flight abort test when the capsule exploded at Cape Canaveral. SpaceX was building a second space-worthy Crew Dragon spacecraft for the first test flight with astronauts to the International Space Station, known as Demo-2.

At the time of the April 20 explosion, SpaceX and NASA aimed to conduct the in-flight abort test in July, followed by the Demo-2 mission with astronauts as soon as September.

Lueders was non-committal when asked about the chances of astronauts flying to space on a Crew Dragon this year.

“Obviously, there’s always a chance that we’re going to fly crew on a SpaceX vehicle this year,” she said. “But I think, right now, we’re playing very close attention to the work thats being done coming out of the anomaly investigation, along with … getting through parachute testing and other key tests, along with conducting our in-flight abort test. All those things need to occur before we’re going to be confident that these systems will safely fly our crews.”

SpaceX also suffered a parachute mishap during a drop test in April to demonstrate the Crew Dragon’s ability to safely land with three parachutes, in case one of the four main chutes failed to unfurl. The remaining parachutes did not fully open during the April drop test over Nevada, and a metal test sled built to simulate the weight of a Crew Dragon capsule impacted the ground.

SpaceX is expected to redo the abort system hotfire test on the next Crew Dragon spacecraft before proceeding to the in-flight escape test.

“We’re going to fly when we feel like the certification work’s been done to be able to safely fly our crews,” Lueders said. “I hope it’s this year, but we’re going to fly when it’s the right time, and when we know that we’ll be flying our crew safely.”

Koenigsmann acknowledged the delays are making it less likely SpaceX can launch astronauts for the first time before the end of the year.

“I want to say I’m pretty optimistic at this point in time because we have a good path forward, but like I said, we’re still not quite done. We could find other things, so there’s always the unknown between now and then.

“End of the year? I don’t think it’s impossible, but it’s getting increasingly difficult, too,” Koenigsmann said.

NASA astronauts Bob Behnken and Doug Hurley are assigned to the Demo-2 mission, in which they will blast off from pad 39A at the Kennedy Space Center in Florida on top of a Falcon 9 rocket and dock with the International Space Station for a mission planned to last one-to-two weeks.

They will return to Earth for a parachute-assisted splashdown in the Atlantic Ocean east of Florida.

The Demo-2 flight will pave the way for crew rotation missions to the station, each carrying four astronauts. The Crew Dragon is designed for stays of up to 210 days at the space station, providing a lifeboat for crews before their regularly-scheduled trips back to Earth.

SpaceX is shuffling the lineup of Crew Dragon capsules on the company’s assembly line in Hawthorne, California, to replace the spacecraft lost in the April 20 accident. The capsule previously assigned to the Demo-2 mission will launch on the in-flight abort test, and the vehicle intended for the first crew rotation flight to the station will now launch on Demo-2.

NASA has awarded more than $3.1 billion in funding to SpaceX to develop the Crew Dragon spacecraft since the commercial crew initiative began in 2010. In a similar arrangement, the space agency has signed a series of commercial crew agreements and contracts with Boeing worth more than $4.8 billion over the same time period.

Boeing has also run into trouble during ground testing of abort engines on its CST-100 Starliner crew capsule. The company resumed ground firings of the Starliner’s service module rocket engines in May after halting the test series following a propellant leak in June 2018.

The Starliner capsule will take off on United Launch Alliance Atlas 5 rockets, and return to landings in the Western United States, slowed by parachutes and cushioned by airbags.

NASA said last year it would provide updates on launch planning dates for the commercial crew program “approximately monthly.” But NASA released the last formal update to the Boeing’s Starliner target launch dates April 3, when the agency said the Starliner’s unpiloted demonstration flight to the space station was set for no sooner than August, followed by the Starliner’s first test flight with a crew in late 2019.

The August schedule for the Starliner’s unpiloted demonstration mission to the space station, named Orbital Flight Test-1, is no longer achievable, at least partly due to slips in the Atlas 5 launch in ULA’s manifest. An Atlas 5 rocket was scheduled to blast off from Cape Canaveral on June 27 with the U.S. Air Force’s AEHF 5 communications satellite, but technical concerns have delayed the launch until no earlier than Aug. 8.

After the AEHF 5 launch, ULA ground teams will safe the launch pad and roll the Atlas 5’s mobile launch platform back to the Vertical Integration Facility south of the pad. Once the mobile launch table is inside the VIF, ULA needs about six weeks to stack the two-stage Atlas 5 rocket, its twin solid rocket boosters, and hoist the Starliner capsule on top of the launch vehicle.

The six-week timeline also includes time for a wet dress rehearsal, in which ULA will transfer the Atlas 5 to Cape Canaveral’s Complex 41 launch pad for a countdown fueling test. ULA does not conduct such a fueling test on most launch campaigns.

The time required to configure the launch pad after the liftoff of the AEHF 5 mission, assemble the new Atlas 5 launcher, conduct the wet dress rehearsal, and accomplish other unique tasks on the first space-bound Starliner means the OFT-1 launch will likely not occur before late September, or more likely early October.

That schedule does not account for any processing or testing issues encountered by Boeing’s team working on the Starliner spacecraft.

“We’re looking at both providers’ schedules pretty closely now,” Lueders said. “We’re working through with Hans and the SpaceX folks on the activities that need to occur and the timing for those as we’re moving towards our Demo-2 flight.

“We’re also working with Boeing as they’re getting ready for the uncrewed mission. I don’t think today I’m going be talking about either one of those schedules just because we’re taking the time right now to make sure we’re understanding all the work, and making sure we’re bringing forward joint (planning) dates over this next period of time.”

Kakarat · Post by **Kakarat** » 19 Jul 2019 12:01

Registration for Launch view gallery opens today evening, Any one planning to go?

juvva · Post by **juvva** » 19 Jul 2019 18:26

^
having a very hard time registering

juvva · Post by **juvva** » 19 Jul 2019 18:32

^
having a very hard time registering.
un responsive site.
now says it is closed.

Kakarat · Post by **Kakarat** » 19 Jul 2019 20:49

Luckily our registration went through, the registration got over in less than 10 minutes

Haridas · Post by **Haridas** » 19 Jul 2019 21:45

Mort Walker wrote:Take a look at ISRO’s orbital accuracy and you’ll find the answer as to why the S200 fires first to get away from the earth’s gravitational influence. The L110 Vikas isn’t just for pure thrust, but achieves accuracy. The S200 is a workhorse and can be used for delivering rose petals for DRDO development. Need to have it tried and true.

Beg to call out errororious statements above.
1) No rocket gets off earth's gravity influence during powered flight. The effective gravity ecperienced by craft is due to gravity at given altitude less centrifugal force due to tangential velocity component.
For GSLV S200 velocity increment reduces the effective gravity marginally. Use my Rocket ballistic simulator to see effective gravity during booster phase.

2) The accuracy of orbit insertion has largely no contribution by S200 and second stage. Accuracy is almost entirely dependent on INS system, control system software and last stage operation.

BTW the goat hearder is guru (prophet) in the field, he obviously has graduated elementary school physics eons ago (sharp dude, I dont mean to say senile due to age)

SSSalvi · Post by **SSSalvi** » 19 Jul 2019 22:10

https://timesofindia.indiatimes.com/ind ... 283493.cms

“Now, nothing in the initial approach is changing.
We’ll still take 22 days to insert Chandrayaan-2 into the lunar orbit because we need 17 days around Earth for five orbit raising manoeuvres, and then five days for the lunarcraft to travel close to Moon,” a senior scientist explained.
Also, the number of days Vikram needs to go around Moon in a 30kmX100km orbit before initiating deboosting procedures for landing will also be the same as planned initially—four days.
The only thing that will change is the number of days the spacecraft goes around Moon before lander separation. According to initial plans, the spacecraft was to go around in a 100kmX100km orbit for 28 days before separation, and now it will go around for 21 days.

Now, we will reach Moon about seven days later than the initial plan, but still in 22 days from launch. And yet, we have enough time left for landing on the same date,” the scientist added.
So, the total number of days of the mission will be reduced from 54 days to 47 days.

A shorter launch window on July 22—Isro chairman K Sivan had on June 12 said that all days of July after the 15th will only have one minute—another senior scientist said, won’t be a “problem”.
“You don’t need to worry about the length of the launch window. Look at the last 20 missions and you’ll know that we’ve launched on the dot. So the length of the window shouldn’t be a concern even now,” a scientist said.

Notice the technical details givenby ISRO.
No space agency gives so much detail. ( AND CREATE DISCUSSION SPACE HERE )

kit · Post by **kit** » 19 Jul 2019 22:43

SSSalvi wrote:https://timesofindia.indiatimes.com/ind ... 283493.cms

“Now, nothing in the initial approach is changing.
We’ll still take 22 days to insert Chandrayaan-2 into the lunar orbit because we need 17 days around Earth for five orbit raising manoeuvres, and then five days for the lunarcraft to travel close to Moon,” a senior scientist explained.
Also, the number of days Vikram needs to go around Moon in a 30kmX100km orbit before initiating deboosting procedures for landing will also be the same as planned initially—four days.
The only thing that will change is the number of days the spacecraft goes around Moon before lander separation. According to initial plans, the spacecraft was to go around in a 100kmX100km orbit for 28 days before separation, and now it will go around for 21 days.

Now, we will reach Moon about seven days later than the initial plan, but still in 22 days from launch. And yet, we have enough time left for landing on the same date,” the scientist added.
So, the total number of days of the mission will be reduced from 54 days to 47 days.

A shorter launch window on July 22—Isro chairman K Sivan had on June 12 said that all days of July after the 15th will only have one minute—another senior scientist said, won’t be a “problem”.
“You don’t need to worry about the length of the launch window. Look at the last 20 missions and you’ll know that we’ve launched on the dot. So the length of the window shouldn’t be a concern even now,” a scientist said.
Notice the technical details givenby ISRO.
No space agency gives so much detail. ( AND CREATE DISCUSSION SPACE HERE )

ISRO wants every Indian to be a wannabe astronaut

..and why not .. if NASA was able to capture the imagination of a nation....

SaiK · Post by **SaiK** » 20 Jul 2019 05:46

UlanBatori · Post by **UlanBatori** » 20 Jul 2019 10:29

Haridas wrote:
Mort Walker wrote: BTW the goat hearder has graduated elementary school physics eons ago

Thx, Honored. That is exactly where my pissiks education ended. May your goats eat only prime-quality Helium-contaminated Teflon Tape, and empty plastic bottles of Leak Detective (or do they use Hamam soap-bubble solution?)
So they recalculated everything to reduce from 28 days orbit to 21 days orbit?? Somebody counts very fast and accurately indeed.

I presume the Landing Schedule is auspicious and can't be moved back?

I tried to do calculation of my savings bank passbook interest to check what SBI had done, and gave up.
BTW, no magic. I had the benefit of a recent presentation by someone who was heading to Chandrayaan Final Review the next day. Hence the gyan about having to drop the first stage short of the first landmass. Interesting geographic problem, and partly explains the 114-second delay in firing main liquid motor (he didn't say that part) despite what Raakit Equation says.

kit · Post by **kit** » 20 Jul 2019 15:07

Interesting to see that the launch platform itself has facilities for repair !!

prasannasimha · Post by **prasannasimha** » 20 Jul 2019 17:04

All equatorial or near equatorial plane launches have to be adjusted such that there are no spent stages etc dropping over inhabited land masses. Importantly Indonesia etc

Mort Walker · Post by **Mort Walker** » 20 Jul 2019 19:49

prasannasimha · Post by **prasannasimha** » 20 Jul 2019 20:00

Since the launch date was changed the major thing that needed to be changed is the duration of scouting of the chandrayaan vikram praguyaan complex in the 100x100 orbit so that descent occurs 7 days "earlier" than originally planned (ie same day since we launched late) to allow pragyaan to role out in first "hour" of the lunar day.

CE25 is one of the longest firing cryo stages in the world precisely because of the geopgraphical need for potential stage drop to be on the ground trace such that it the previous stages etc should not fall over Indoinesia. YUou can see it clearly when they show the ground track with the reassuring "stage separation Naarmal" announcements.

Mort Walker · Post by **Mort Walker** » 20 Jul 2019 20:03

prasannasimha wrote:All equatorial or near equatorial plane launches have to be adjusted such that there are no spent stages etc dropping over inhabited land masses. Importantly Indonesia etc

O 181019Z JUL 19

HYDROPAC 2326/19(63).
BAY OF BENGAL.
DNC 03.
1. HAZARDOUS OPERATIONS, ROCKET LAUNCHING
220830Z TO 221000Z JUL:
A. AREA WITHIN TEN MILES OF 13-43.2N 080-13.8E.
B. AREA BOUND BY
12-30N 082-40E, 13-15N 082-50E,12-45N 084-10E, 12-00N 084-00E.
C. AREA BOUND BY
11-35N 085-00E, 12-25N 085-10E,11-45N 087-15E, 10-55N 087-05E.
D. AREA BOUND BY
08-10N 094-20E, 09-00N 094-40E,08-25N 096-15E, 07-35N 095-55E.
2. CANCEL THIS MSG 221100Z JUL 19.//

GENERAL.//

prasannasimha · Post by **prasannasimha** » 20 Jul 2019 20:17

See the very long firing of CE 25 in a previous launch

disha · Post by **disha** » 20 Jul 2019 22:33

prasannasimha wrote:CE25 is one of the longest firing cryo stages in the world precisely because of the geopgraphical need for potential stage drop to be on the ground trace such that it the previous stages etc should not fall over Indoinesia. YUou can see it clearly when they show the ground track with the reassuring "stage separation Naarmal" announcements.

I do not think CE25 firing is correlated to stage drop parameters to avoid land mass. For S200 - definitely yes. For Payload fairing - maybe yes. If you notice, the L110 separation happens at 170 Km which is very much in space and the stage will burn up on re-entry.

The longest firing for CE25 is for orbital injection. The delta-V gained from L100 separation to cryo-stage shutoff is from 4.6 Km/s to 10.3 Km/s. That is a massive jump in delta-v - 5.7 Km/s. After payload separation, the stage itself is in orbit and burns up on re-entry in some few days to weeks.In essence, the CE25 gives a massive kick to the payload.

Both L110 and CE25 stages burn up on re-entry, so their sequences for separation are not influenced to avoid land mass.

Of course, sequences for S200 shutdown and L110 startup and separation of S200 strap-ons are to avoid the landmass.

prasannasimha · Post by **prasannasimha** » 20 Jul 2019 22:42

I had talked to an ISRO engineer and he said that the early stages have to drop of early (They could be designed to work for a longer time) but the constraint for them is that they have to fall off in safe zone leaving the Cryogenic stage to do a lot of firing. It can impart the delta V earlier than what it fires for(in fact it is throttled down).The cryogenic stage as you said adds at least another 4.5 Kms deltaV to the rocket.
This fact was realized early by both Goddard and Verner Von Braun early in rocketry that for the given fuel mass to thrust requirement relation cryogenics was the way to go.

disha · Post by **disha** » 20 Jul 2019 22:48

A good watch:

disha · Post by **disha** » 20 Jul 2019 23:11

prasannasimha wrote:I had talked to an ISRO engineer and he said that the early stages have to drop of early (They could be designed to work for a longer time) but the constraint for them is that they have to fall off in safe zone leaving the Cryogenic stage to do a lot of firing. It can impart the delta V earlier than what it fires for(in fact it is throttled down).The cryogenic stage as you said adds at least another 4.5 Kms deltaV to the rocket.

I see., What you imply and as I understand is that since the S200 boosters have to drop off early for GSLV MkIII (for other vehicles, it is early stages) the cryo-upper stage has to do more work.

On a different note, for all Polar launches, Dwarka in Gujarat is an excellent site with nothing all the way to Antartica. Anyway, this discussion can go to the Indian space thread.

disha · Post by **disha** » 20 Jul 2019 23:18

Excellent animation. I like the way the mission designers curve the trajectory of Chandrayaan-2 to be captured by Moon. I did not expect the "S curve capture" from top-down!