Indian Space Program: News & Discussion - Sept 2016

[Mort Walker]

^^^Bringing back the 1st & 2nd stages may make some sense from a fiscal point of view, but from a physics point of view, you have to carry your fuel up to orbit that you need to come back down. There are trade-offs in that you'll have a smaller payload. Right now ISRO needs to have GSLV to carry at least 10 tons into geosynchronous orbit. That is the first order of business instead of copycat of Space-X since ISRO can do a GSLV for nearly $50 million USD. The next order of business are a constellation of earth observation satellites for national security, navigation, communications, and weather & environment. After that, planetary missions to the heavenly bodies. The Indian taxpayer needs practical solutions for their livelihood and not some made for TV show.

Both Musk and Takla (Bezos) are showboats who are most likely running losses in these space ventures and counting on tax-write offs until they secure contracts.

Until Space X and Blue Origin can make consistent launches, its all bullshit. United Space Alliance has big defense contracts that aren't going anywhere. Space X last fiasco of losing the Zuma satellite pisses off a lot of people in the Pentagon. Consistent space launches are a risky business that aren't easy to do. ISRO does have consistency and will build on it.

[ArjunPandit]

Why are Boeing and Lockheed Martin not competing with Space-X for reusable first stage and heavier payloads?

Possibly due to their weapons' connection, there is still a bit of stigma on space weaponization

[Indranil]

Don't count Boeing and LockMart out. They know this game well. The challenge from Space-X is welcome to them and they will answer accordingly.

In the USA many invincible top companies have disappeared completely in various industries because they did not innovate. There is a good possibility that innovative spaceX and blue origin (under development) may wipe out boeing and lockheed space launch business. We will find out in another 5 to 10 years. ISRO should seriously consider bringing back first stage semi cryo they are working on and make it reusable just like space X and blue origin. My 2 cents.

That is the plan! Why do you think they are doing all this HEX/LEX experiments?

I hope they don’t have to cut the payload in half to recover the stages as in the case of falcon 9.

[JTull]

Why are Boeing and Lockheed Martin not competing with Space-X for reusable first stage and heavier payloads?

Possibly due to their weapons' connection, there is still a bit of stigma on space weaponization

NASA is also developing Space Launch System (CLS) for 70k kg to LEO, but it will cost about $1bln per launch as compared to $90mln for Falcon Heavy. Tells you everything there's to it.

Heavy Rockets

[prasannasimha]

India is having its own reusable vehicle program. There are two competing teams with one trying rlv approach and the other like Elion musk with either verticle or airbag landing. There are old lot's with the concept planning.
More importantly this year we will be having the satellite docking experiment that has a lot of repercussions for us. Think satellite refuelling etc and our small steps to human flight though we keep denying it but are building the required blocks. The pad abort test will also be done this year. The GSLV Mk3 and semicryo cluster will be our turning points.

[nam]

Our RLV plan of landing back the first stage/full rocket like a shape shuttle is probably more efficient than what Spacex is doing. There is no need to hold extra propellant, nor worry about hitting a bulls eye.

You just glide the rocket back to a airfield!

It is one of those "why we didn't think of that". Ofocurse our RLV plan is much more ambitious with a scramjet and all.

Regarding the cost of our launch, ISRO needs to ofload launch vehicle manufacturing to private sector, with condition that they will reduce the cost further. Antrix needs to do aggressive bids and private sector reduce the cost of launch.

[sudeepj]

Our RLV plan of landing back the first stage/full rocket like a shape shuttle is probably more efficient than what Spacex is doing. There is no need to hold extra propellant, nor worry about hitting a bulls eye.

You just glide the rocket back to a airfield!

It is one of those "why we didn't think of that". Ofocurse our RLV plan is much more ambitious with a scramjet and all.

Regarding the cost of our launch, ISRO needs to ofload launch vehicle manufacturing to private sector, with condition that they will reduce the cost further. Antrix needs to do aggressive bids and private sector reduce the cost of launch.

Every approach has a trade off.. Gliding the rocket back to land like the space shuttle is going to incur a weight penalty because of the ablative layer that is used. Landing it vertically means not using the fuel load to its fullest extent.

I wonder if its possible to just land the liquid engine and let go of the fuel tanks that do not have any moving parts and they dont cost a lot to manufacture.

[nam]

If we want to compare weight, you have consider propellent weight, those landing legs as well. I don't know what material spacex rockets are made of, however they do reentry so need heat resistant similar to rlv. Of course for lesser temperature.

Add to this the complexity is mastering the bulls eye manveour. How many test did spacex carry out to master it? Isro got the glide done in first attempt. They would probably be able to glide to a airfield in the next attempt.

[prasannasimha]

I think the reentry with the flip and controlled reentry is having a lesser reentry heat penalty than the glide aerobraking as speeds are different. The retrorocket firing is an active speed dissemination whereas aerobraking relies on friction to reduce speed causing greater heating.

[abhik]

I think the reentry with the flip and controlled reentry is having a lesser reentry heat penalty than the glide aerobraking as speeds are different. The retrorocket firing is an active speed dissemination whereas aerobraking relies on friction to reduce speed causing greater heating.

Yup, and you are also loosing weight in the process - the rocket is itself only about 5% of the lift off weight rest being propellant, after stage separation about 5-10% of propellant remains, So you could significantly reduce the landing weight.

[akashganga]

Interesting read - https://www.bloomberg.com/view/articles ... ce-program

I am a huge fan of isro. But I do not believe that isro's scramjet reusable shuttle will happen before 2030 if at all. If it was simple US companies with unlimited funds would have done it long ago. In the meantime reuse of stages even in limited numbers is already happening. They should experiment similar to spacex and blue origin. My 2 cents.

[nam]

Different objectives. Isro is targeting TSTO /SSTO with scramjet. Whereas as spacex reusable first stage.

For isro entire rlv is to be recovered. Having no constraints on resources and tech is why star war fans like spacex went for landing using thrust control. Sending a car in to space tells you the thought process.

If they had thought it through, they would have considered glide like isro. Simple and they already had the tech in x35b

[srai]

^^^
nam,

These guys live and breathe space-related technologies. They would have weighed the pros and cons of all available options and some more. Based on what they are trying to achieve in their overall vision and plan, they chose the designs that suited them the most with pros outweighing known trade-offs. Using their techniques, they are bringing the cost of launch to $90 million versus half-a-billion (or more) from other traditional competitors. Same techniques are being used for Mars launching & landing.

Not as simple to say an approach is better than another without a detailed look into a company’s decision making process. Every approach has its merits as well as short-comings.

[prasannasimha]

If they are targetting Mars aerobrsking will not be efficient and not possible if they use an interim moon base

[KrishnaK]

If we want to compare weight, you have consider propellent weight, those landing legs as well.

vs wings and landing gear.

[Singha]

spaceX has access to good engineers and technology but was not exactly flush with funds. their first 3 vanilla launches failed.
their first few landing attempts failed. they had to be frugal from day1.

like any smallish well run co they have delivered something different a more ponderous org like the aerospace biggies or nasa would find hard to deliver in that timeframe due to org inertia, existing stake in products, too many competing ideas and satraps etc etc.

there is a reason why sometimes big cos have to hive off "spin outs" to get things done.

when scramjet for use and throw applications for military missiles is not yet mature, it will take time for use in reusable stuff with high value payloads. until then reusing the costly and big 1st stage and any straps ons is best bet to keep cost down.

[ArjunPandit]

Reverse Whine:
I never heard NASA/Americans calling for leveraging the low cost advantage of India/ISRO, as we do with every technology from abroad. There is a lesson for many of us (not the ISRO guys) in this whine absence. We as a nation need to have self belief and can do attitude.

[la.khan]

Question: SpaceX launched a sports car on a Falcon Heavy rocket on 6th Feb. In less than 36 hours, the car has gone beyond the orbit of Mars. I thought a one way trip to Mars takes anywhere between 5-8 months depending on how close is Mars to Earth.

Elon Musk’s Tesla overshot Mars’ orbit and is headed to the asteroid belt

Elon Musk’s Tesla Roadster, which launched on top of SpaceX’s Falcon Heavy earlier today, is going farther out into the Solar System than originally planned. The car was supposed to be put on a path around the Sun that would take the vehicle out to the distance of Mars’ orbit. But the rocket carrying the car seems to have overshot that trajectory and has put the Tesla in an orbit that extends out into the asteroid belt between Mars and Jupiter.

What gives? Am I missing something?

[srai]

^^^
Comprehension bro It’s on its way. The trajectory is beyond what they had planned. Instead of Mars orbit being the furthest distance, its current trajectory will take it the asteroid belt.

[la.khan]

^^^
Comprehension bro It’s on its way. The trajectory is beyond what they had planned. Instead of Mars orbit being the furthest distance, its current trajectory will take it the asteroid belt.

Ok, makes sense as I read more articles on this.
Starman has gone dark

Starman and the car will continue their slow outward movement, and will eventually cross the orbit of Mars and then enter the asteroid belt, where it seems likely it’s going to get nailed by one of the many, many rocks there. But depending on the angle of its orbit, it might also leave the ecliptic and avoid death by smashing.

Either way, it won’t be for many years. We’re not sure what the Roadster’s velocity is, but it ain’t fast, and Mars is quite a distance away. It may be decades or centuries before it gets far enough to be in danger.

SpaceX Falcon Heavy LIVE: Where is the Starman right now? Where is the Tesla roadster?

According to new website ‘whereisroadster.com’, the very special payload is thousands of miles away from earth.

The current location at 11.25am GMT is 270547 miles (435403 km) from Earth, moving at a speed of 2315 miles/hour (3726 km/hour)

However, Earth has already had its last glimpse of the Tesla roadster and Starman as they head towards the red planet Mars after completing one final engine burn towards a “trans-Mars injection”.

[sanjaykumar]

How primitive. There oughtta be a law to put garbage in space.

[prasannasimha]

https://www.gadgetsnow.com/tech-news/li ... 831072.cms

Like SpaceX, Isro, too, has been working on reusable technology. The Isro chief told TOI, "Our research and development department is working on three technology demonstrators. First one on the orbital re-entry of the vehicle, second on the landing of the reusable launch vehicle on the airstrip and third on reusable rocket stages. Isro's research work on these three technologies is simultaneously going on and we hope to do a second technology demonstrator test (first experiment on reusable launch vehicle was in 2016) within two years."

[prasannasimha]

[prasannasimha]

If I remember right LPSC team wants to do vertical landing of the boosters and the RLV team an airbag landing

[Amber G.]

Question: SpaceX launched a sports car on a Falcon Heavy rocket on 6th Feb. In less than 36 hours, the car has gone beyond the orbit of Mars. I thought a one way trip to Mars takes anywhere between 5-8 months depending on how close is Mars to Earth.

...

Just to be clear time taken to reach Mars orbit, with any kind of rocket with current technology is about 10 months (between say about 150 days to 300 days, depends on a few factors but practically speaking can not be less than these values)

[Amber G.]

Question: SpaceX launched a sports car on a Falcon Heavy rocket on 6th Feb. In less than 36 hours, the car has gone beyond the orbit of Mars. I thought a one way trip to Mars takes anywhere between 5-8 months depending on how close is Mars to Earth.

...

Just to be clear time taken to reach Mars orbit, with any kind of rocket with current technology is about 10-11 months (between say about 150 days to 330 days, depends on a few factors but practically speaking can not be less than --
or more than these values)

[Amber G.]

Just to be clear time taken to reach Mars orbit, with any kind of rocket with current technology is about 10-11 months (between say about 150 days to 330 days, depends on a few factors but practically speaking can not be less than --or more than, these values by much )

[JayS]

Yes. But isn't that problem common to all the methods, irrespective of whether you land on bags, wheels or tripods? Orientaion using reaction motors is a very very precise operation. But it is a well solved problem, isn't it? Orbit raising and station keeping all require precision firing of the reaction rockets. Deorbiting or entering the atmosphere at the right attitude would also require the same.

Once I reach the atmosphere, why would I not use gravity and atmosphere to slow me down and glide me to my recovery spot: A splash in the sea or land on an airstrip. Why should I spend energy in trying to keep a toothpick balanced on its ends?

Obviously, the guys at SpaceX know more than me. But, I would love to know why that kind of tricky recovery is preferred. Yeah, it is more sexy than the mundane splash. I mean these days you can program parachute loaded objects to land within 100 mtrs of your destination even on windy days. Experienced parajumpers can land on the top of a moving car on non windy days.

The main aim of SpaceX reusability is to launch 10-12 times using same stages with minimum refurbishment. After that more detailed refurbishment and the cycle would continue for a few times. Which means recovery has to be in best condition possible. In fact there Mars mission planning (which is the ultimate aim as of now) is like - first time the launcher takes Manned capsule, comes back, get refueled and immediately launched with cargo/fuel capsule for Mars journey. Both time and refurbishing efforts need to be kept to minimum. That rules out splash down in sea because of high recovery time, possible damage on hitting water surface and sea water flooding which would need extensive requalification to make sure no corrosion and perfect performance in next use. The SRBs were never really economical and basically needed full rebuilding and perhaps were more costly than building fresh ones when everything is taken into account. Also recovery by parachute on land is not possible due to challenges associated with location of fall with unpowered trajectory.

Glide down is a very lucrative option and perhaps that's why ISRO chose it. Perhaps spaceX wanted to stick to tried and tested rocket configuration and just work on bringing it back. A completely new design config would require far more design, debugging and qualification efforts. They started pretty small after all. And once you get into some system config its very difficult to change it radically unless you are flush with funds. For all we know they would try gliding recovery in future. Even gliding has some disadvantages that you need to carry additional dead weight in terms of wings, tails etc over and above normal cylinder, cost of manufacturing/maintainace would be higher and things like that. After doing the math the actual difference would be less than what it seems prima facie. Also lets not forget, companies like SpaceX, Blue Origin are in a way dreamy companies to start with. Doing things in a sexy way is in their DNA.

I like ISRO's plan for TSTO. By deorbiting the second stage, they would recover entire launch vehicle. Since it would orbit the earth once, the recovery could be over land with parachutes very near to the launch pad itself. They also used to have this SSTO proposal (Avaatar IIRC), I remember, where the launch platform will TO like an aircraft, collect O2 in flight, go Cryo mode for outside Atm flight, do its work and come back. Something like that.

[JTull]

Using such large cluster (27) of engines is a first-one and has advantages. Apparently, the Falcon Heavy can launch to intended orbit even if 6 of those hadn't worked. Remember there's extra fuel to bring the boosters back for reuse.

They've shown the way on how to scale-up what is known to work. There are several lessons for the space industry, incl ISRO. Perhaps, large scale clustering with robust avionics is the way rather than developing different thrust engines with essentially the same design.

Link

[nam]

If we want to compare weight, you have consider propellent weight, those landing legs as well.

vs wings and landing gear.

I don't think the weight of propellant and landing legs be less than wings & landing gear.

They fire the rockets when they quite close to the landing zone. Till then it is all precision gliding, just like what the RLV would do. They are carrying all that weight only for 20-30 seconds of precision landing.

Both of them are gliding back. The difference is when it comes to landing, Spacex lands like a chopper, while RLV would land like a plane.

falcon lost it's third rocket in the star wars maneuver. Atleast in a RLV, we have a better chance of retrieving.

[Indranil]

How much fuel is required to slow down a 40 ton object from terminal velocity to zero?

[Indranil]

The weight of the landing gear and wings combined will be less than a ton.

[brar_w]

How much fuel is required to slow down a 40 ton object from terminal velocity to zero?

I haven't seen exact data but do note that Space X is actively pursuing making the landing and recovery more efficient. They will continue to work on this over the next many years as they mature BFR and beyond. Since it is a private company that would seek capital over its lifespan it was quite important for them to go out and prove that their concepts work beyond the lab. With over 20 recoveries and half a dozen re-launched boosters they are well on their way to doing this. Of course over time others will bring to market equally as good if not better solutions perhaps even Space X will find better ways. At the low payload end, it will be interesting to see how close to its goal DARPA's XS1 comes.

http://www.businessinsider.com/falcon-9 ... ery-2018-2

All four legs together "weigh less than a [Tesla] Model S," Musk has said, though presumably the weights are similar: about two tons. The booster could instead pack in that much more fuel, which would improve its odds of successfully rocketing payloads to orbit or launching heavier payloads — while giving the booster more control for landing.

The link below goes into some of the recovery penalty they are likely paying for both droneship based and land based booster recoveries. They will continue to work through this as they ultimately plan on eliminating things such as the landing legs etc.

https://www.reddit.com/r/spacex/wiki/faq/reusability

[Indranil]

Nice reads. Thank you.

It makes sense for SpaceX to land the boosters that way. There overall goal is to reuse the things like a modern day airliner.

But, for high frequency space launch of say once per week, landing the boosters/cores with wings makes more sense to me. It is cheaper and safer. For example, the core did not land as expected this time. The engines did not relight.

Parachute based recovery should only be tried for the lighter upper stages, and not on land. Slowing down about 5 tons with parachutes and recovering the floating object from the sea are all well solved problems.

[brar_w]

But, for high frequency space launch of say once per week, landing the boosters/cores with wings makes more sense to me. It is cheaper and safer. For example, the core did not land as expected this time. The engines did not relight.

They are practically just getting started. Their goal is to get really good at this and then move to more precise landings by eliminating the legs altogether on their next rocket. Efficiency and reliability will only improve over time as they learn new things at each success and failure. They'll be doing something like 2 dozen (or more) launches a year on average for the next few years..I am sure as others join the race to re usability we will see similar and different solutions being proposed. But as things stand, SpaceX has a head start and is learning very rapidly since they have a lot of launches scheduled for the next few years. They would say that they are doing it already while many of their competitors, after dismissing them earlier, are only now begin to invest in something of their own.

https://www.nae.edu/Publications/Bridge ... 64334.aspx

[abhik]

Will a "winged" booster (RLV) be able to slow down, turn 180 degrees, comeback all the way back and land horizontally with ZERO active propulsion (i.e gliding all the way)? AFAIK the Energia reusable boosters concept which were planned to do something similar needed a jet engine to be attached. If you have to attach a another engine plus fuel, a "winged" booster may not look as enticing.

[Indranil]

But, for high frequency space launch of say once per week, landing the boosters/cores with wings makes more sense to me. It is cheaper and safer. For example, the core did not land as expected this time. The engines did not relight.

They are practically just getting started. Their goal is to get really good at this and then move to more precise landings by eliminating the legs altogether on their next rocket. Efficiency and reliability will only improve over time as they learn new things at each success and failure. They'll be doing something like 2 dozen (or more) launches a year on average for the next few years..I am sure as others join the race to re usability we will see similar and different solutions being proposed. But as things stand, SpaceX has a head start and is learning very rapidly since they have a lot of launches scheduled for the next few years. They would say that they are doing it already while many of their competitors, after dismissing them earlier, are only now begin to invest in something of their own.

https://www.nae.edu/Publications/Bridge ... 64334.aspx

Absolutely. It looks like I am being uncharitable to them in their GREAT accomplishment. What Elon's team has achieved is trend setter. No two ways about it.

[Indranil]

Will a "winged" booster (RLV) be able to slow down, turn 180 degrees, comeback all the way back and land horizontally with ZERO active propulsion (i.e gliding all the way)? AFAIK the Energia reusable boosters concept which were planned to do something similar needed a jet engine to be attached. If you have to attach a another engine plus fuel, a "winged" booster may not look as enticing.

The space shuttle glides back to the exact spot everytime. So, this is not the problem with the upper stage because you can deorbit based on your choice. But nobody will want to put ANY weight penalty on the upper stage. I think this stage should be retrieved by parachute, in the ocean, close to the shore. Pretty much like how all crew modules have been recovered. ISRO did a successful experiment regarding this.

The question is with the lower stages. You would size the first stage accordingly. How long does it burn? How fast? That will determine your speed, altitude and how far down range you are at separation. This a great problem to solve. ISRO's schematics have shown different methods of recovering the upper stage. But the first stage has always been shown to glide back. Thankfully India has a lot of experience in making hypersonic gliders from Prithvis to Shauryas.

As Brar said SpaceX has opened the gate. It is an existential problem for every Space agency to be able to reuse. The best is yet to come. And that will depend on many things. For example: Frequency of reuse and maximizing payload pull in opposite directions.

[Kakarat]

Details on preliminary design and location of new PSLV Integration Facilities (PIF) Project on First Launch Pad via recently issued 'Request For Proposal'.

[JayS]

Will a "winged" booster (RLV) be able to slow down, turn 180 degrees, comeback all the way back and land horizontally with ZERO active propulsion (i.e gliding all the way)? AFAIK the Energia reusable boosters concept which were planned to do something similar needed a jet engine to be attached. If you have to attach a another engine plus fuel, a "winged" booster may not look as enticing.

The space shuttle glides back to the exact spot everytime. So, this is not the problem with the upper stage because you can deorbit based on your choice. But nobody will want to put ANY weight penalty on the upper stage. I think this stage should be retrieved by parachute, in the ocean, close to the shore. Pretty much like how all crew modules have been recovered. ISRO did a successful experiment regarding this.

The question is with the lower stages. You would size the first stage accordingly. How long does it burn? How fast? That will determine your speed, altitude and how far down range you are at separation. This a great problem to solve. ISRO's schematics have shown different methods of recovering the upper stage. But the first stage has always been shown to glide back. Thankfully India has a lot of experience in making hypersonic gliders from Prithvis to Shauryas.

As Brar said SpaceX has opened the gate. It is an existential problem for every Space agency to be able to reuse. The best is yet to come. And that will depend on many things. For example: Frequency of reuse and maximizing payload pull in opposite directions.

IR, did you check the links I posted for you in Int'l Aerospace thread regarding this..? Seems SpaceX tried parachute recovery and rejected it.