SpaceX has performed a series of successful vertical landings which demonstrate the technology’s feasibility, but Chinese researchers have rejected the approach, the article said.Deng wrote that the vertical landing system needed carrying extra fuel for landing, which meant rockets could only carry smaller payloads into space....The Chinese launch vehicle academy researchers have said on their website that the parachute-airbag system will be assisted by multiple censors and a sophisticated flight control system to guide the descent. The final goal was to hit a small recovery zone as precisely as the vertical landing technology can achieve.
QuoteThe Chinese launch vehicle academy researchers have said on their website that the parachute-airbag system will be assisted by multiple censors
The Chinese launch vehicle academy researchers have said on their website that the parachute-airbag system will be assisted by multiple censors
Quote from: sanman on 03/17/2017 06:46 AMQuoteThe Chinese launch vehicle academy researchers have said on their website that the parachute-airbag system will be assisted by multiple censorsThose Chinese sure are serious about their censorship!
So it seems that in the comparison of fuel+legs against parachutes+airbags, that the latter is seen as a better option, at least at this juncture.
Deng Xinyu, a researcher on the Chinese rocket recovery programme, said that vertical landing involved many challenges and was extremely difficult to achieve.
Quote from: sanman on 03/17/2017 06:46 AMSo it seems that in the comparison of fuel+legs against parachutes+airbags, that the latter is seen as a better option, at least at this juncture.Neither parachutes or airbags scale well.Not too bad a solution for a smallsat launcher, but starts to get iffy at EELV size (not sure if Vulcan could return whole stage by parachute even if they wanted to). Parachutes and airbags are completely impractical at New Glen let alone ITS size.Also airbags and parachutes add quite a bit off mass, probably not as much mass as the extra fuel for a powered landing, but replacing cheap fuel with expensive hardware and extra refurbishment may end up more expensive in the end.
I think this quote is more telling:QuoteDeng Xinyu, a researcher on the Chinese rocket recovery programme, said that vertical landing involved many challenges and was extremely difficult to achieve.Is the real reason they rejected it because they don't think they can do it?
Quote from: FutureSpaceTourist on 03/17/2017 04:10 PMI think this quote is more telling:QuoteDeng Xinyu, a researcher on the Chinese rocket recovery programme, said that vertical landing involved many challenges and was extremely difficult to achieve.Is the real reason they rejected it because they don't think they can do it?Or not worth doing at this stage. Remember the economic viability of reusability has yet to be demonstrated.
Quote from: Dalhousie on 03/19/2017 06:47 PMQuote from: FutureSpaceTourist on 03/17/2017 04:10 PMI think this quote is more telling:QuoteDeng Xinyu, a researcher on the Chinese rocket recovery programme, said that vertical landing involved many challenges and was extremely difficult to achieve.Is the real reason they rejected it because they don't think they can do it?Or not worth doing at this stage. Remember the economic viability of reusability has yet to be demonstrated.That's kind of like saying "the ability of an aircraft carrrier to win a war has yet to be demonstrated, so we're going to keep sinking all our money into battleships" in 1940.
Quote from: ChrisWilson68 on 03/19/2017 07:30 PMQuote from: Dalhousie on 03/19/2017 06:47 PMQuote from: FutureSpaceTourist on 03/17/2017 04:10 PMI think this quote is more telling:QuoteDeng Xinyu, a researcher on the Chinese rocket recovery programme, said that vertical landing involved many challenges and was extremely difficult to achieve.Is the real reason they rejected it because they don't think they can do it?Or not worth doing at this stage. Remember the economic viability of reusability has yet to be demonstrated.That's kind of like saying "the ability of an aircraft carrrier to win a war has yet to be demonstrated, so we're going to keep sinking all our money into battleships" in 1940.What you are proposing is like saying we should stop all investment in battleships in 1902 because there is some interesting work happening in heavier than air flight in a few places.Note that there is nothing that says that China is not interested in further work this field.They have merely decided that one approach is not viable.
Quote from: Dalhousie on 03/20/2017 12:02 AMQuote from: ChrisWilson68 on 03/19/2017 07:30 PMQuote from: Dalhousie on 03/19/2017 06:47 PMQuote from: FutureSpaceTourist on 03/17/2017 04:10 PMI think this quote is more telling:QuoteDeng Xinyu, a researcher on the Chinese rocket recovery programme, said that vertical landing involved many challenges and was extremely difficult to achieve.Is the real reason they rejected it because they don't think they can do it?Or not worth doing at this stage. Remember the economic viability of reusability has yet to be demonstrated.That's kind of like saying "the ability of an aircraft carrrier to win a war has yet to be demonstrated, so we're going to keep sinking all our money into battleships" in 1940.What you are proposing is like saying we should stop all investment in battleships in 1902 because there is some interesting work happening in heavier than air flight in a few places.Note that there is nothing that says that China is not interested in further work this field.They have merely decided that one approach is not viable. In 1902, it would be 40 years before aircraft carriers were demonstrated to win wars. In 1940, that would be demonstrated within 5 years.So, you think it's 1902 with respect to reusable rockets and I think it's 1940. In other words, if reusable rockets demonstrate economic viability within 5 years, I'm right. If they demonstrate economic viability only after 40 more years, you're right.Place your bets now. SpaceX, Blue Origin, ULA, Arianespace, Russia, and China have placed theirs.
The Chinese are doing reusability to lower their domestic launch costs. They not competiting inter nationally, so any saving is a success.
Quote from: ChrisWilson68 on 03/20/2017 03:40 AMQuote from: Dalhousie on 03/20/2017 12:02 AMQuote from: ChrisWilson68 on 03/19/2017 07:30 PMQuote from: Dalhousie on 03/19/2017 06:47 PMQuote from: FutureSpaceTourist on 03/17/2017 04:10 PMI think this quote is more telling:QuoteDeng Xinyu, a researcher on the Chinese rocket recovery programme, said that vertical landing involved many challenges and was extremely difficult to achieve.Is the real reason they rejected it because they don't think they can do it?Or not worth doing at this stage. Remember the economic viability of reusability has yet to be demonstrated.That's kind of like saying "the ability of an aircraft carrrier to win a war has yet to be demonstrated, so we're going to keep sinking all our money into battleships" in 1940.What you are proposing is like saying we should stop all investment in battleships in 1902 because there is some interesting work happening in heavier than air flight in a few places.Note that there is nothing that says that China is not interested in further work this field.They have merely decided that one approach is not viable. In 1902, it would be 40 years before aircraft carriers were demonstrated to win wars. In 1940, that would be demonstrated within 5 years.So, you think it's 1902 with respect to reusable rockets and I think it's 1940. In other words, if reusable rockets demonstrate economic viability within 5 years, I'm right. If they demonstrate economic viability only after 40 more years, you're right.Place your bets now. SpaceX, Blue Origin, ULA, Arianespace, Russia, and China have placed theirs.Still a bad analogy.
Barring the STS, nobody has demonstrated technical reusability of an orbital launch system. Nobody has yet demonstrated economic viability of such systems.
It will take several years for this to happen, at best.
Maybe longer. In 1970 many of us thought we were on the verge of reusable rockets too.In 1940 nobody questioned the importance, indeed centrality, of heavier than air maritime aviation.
In 1902 nobody knew it it was possible (barring man-carrying kites). But you are missing the points here, not just making a poor historical analogy. The points are that 1) the Chinese may be quite justified in giving up one particular approach (not that they can't achieve it)
and 2) the case for reusability, is not yet as clearcut as wishful thinking would have it.
Again, we'll see. If it takes more than 40 years, you're right, it's 1902. If it takes five or fewer, you're wrong.
Quote from: ChrisWilson68 on 03/20/2017 06:22 AMAgain, we'll see. If it takes more than 40 years, you're right, it's 1902. If it takes five or fewer, you're wrong.In either case you are still wrong. The value of maritime aviation was demonstrated by 1916. I would hope that reusability in some form will have been demonstrated by 14 years from now. Assuming that progress rates will be comparable. Which is unlikely. But you are still missing the point. It's not the time scale, it's the readiness of the technology. To date nobody has reused a first stage, unless you want to count the SRBs.
Quote from: Dalhousie on 03/20/2017 10:48 PMQuote from: ChrisWilson68 on 03/20/2017 06:22 AMAgain, we'll see. If it takes more than 40 years, you're right, it's 1902. If it takes five or fewer, you're wrong.In either case you are still wrong. The value of maritime aviation was demonstrated by 1916. I would hope that reusability in some form will have been demonstrated by 14 years from now. Assuming that progress rates will be comparable. Which is unlikely. But you are still missing the point. It's not the time scale, it's the readiness of the technology. To date nobody has reused a first stage, unless you want to count the SRBs. You're still not getting it. I specifically said "demonstrated to win wars" because that's the equivalent of your "demonstrated economic reuse". Lots related to reuse has been demonstrated already. Asking that economic reuse be demonstrated by a competitor is like asking that aircraft carriers demonstrate they can win a war by winning a war. By the time that happens, it's too late.Anyway, I'm sure you won't get that either, but I'm confident other readers of this thread will understand, so I'm done with the conversation now.
Reusable craft are in CASIC's plansBeijing (XNA) Jun 08, 2017China Aerospace Science and Industry Corp, one of the nation's major space contractors, said on Tuesday it is developing reusable spacecraft capable of taking off and landing at airports.Liu Shiquan, deputy general manager of CASIC, told the 2017 Global Space Exploration Conference, which opened on Tuesday in Beijing, that the cutting-edge spacecraft's key technologies and major parts - such as its engine - have passed ground tests and the program is proceeding smoothly.[...]
... I would hope that reusability in some form will have been demonstrated by 14 years from now. Assuming that progress rates will be comparable. Which is unlikely. But you are still missing the point. It's not the time scale, it's the readiness of the technology. To date nobody has reused a first stage, unless you want to count the SRBs.
I would hope that reusability in some form will have been demonstrated by 14 years from now
From ChinaSpaceFlight :https://twitter.com/cnspaceflight/status/886839417096216576
Quote from: eeergo on 07/17/2017 11:09 AMFrom ChinaSpaceFlight :https://twitter.com/cnspaceflight/status/886839417096216576There are two plans so far, parafoil and multi-parachute, both for laning a strap-on booster
Quote from: SmallKing on 07/17/2017 12:09 PMQuote from: eeergo on 07/17/2017 11:09 AMFrom ChinaSpaceFlight :https://twitter.com/cnspaceflight/status/886839417096216576There are two plans so far, parafoil and multi-parachute, both for laning a strap-on boosterThank you for the paper! Google-translating I get that the China Academy of Launch Vehicle Technology's Institute of Aerospace Systems Engineering and the Beijing Institute of Space Electrical and Mechanical have performed crane tests, air drop tests, real size (?) airbag prototype development and landing impact testing, and they have achieved an accuracy of several hundred meters in landing.How advanced are they into implementing it into a vehicle? Is this a "general" (vehicle-agnostic) development for now, or is it more geared toward the CZ-5/7 boosters? I assume the hypergolic old-generation boosters are not considered for recovery?
Well, looks like someone got right on this challenge… And they concluded there is one best way to do it!https://www.chinaspaceflight.com/satellite/Linkspace/Linkspace.html chinaspaceflight#flattery
Here's an article about research in China toward developing recoverable/reusable rocket stages to lower the cost of space launch:http://www.scmp.com/news/china/policies-politics/article/2079822/china-developing-system-recover-reuse-parts-space
Quote from: eeergo on 07/17/2017 11:09 AMFrom ChinaSpaceFlight :There are two plans so far, parafoil and multi-parachute, both for laning a strap-on booster
From ChinaSpaceFlight :There are two plans so far, parafoil and multi-parachute, both for laning a strap-on booster
Quote from: SmallKing on 07/17/2017 12:09 PMQuote from: eeergo on 07/17/2017 11:09 AMFrom ChinaSpaceFlight :There are two plans so far, parafoil and multi-parachute, both for laning a strap-on boosterInteresting paper, although I only read the abstract and looked at the pictures.It looks like they aim to go with one system for both stages, so mass efficiency is important to them up front. The problem with all these systems is the recover stresses don't align with the launch stresses. Unless you can spread those loads very efficiently in the axis at right angles to the thrust axis (typically the strongest axis on a VTO ELV stage) it will crumple. The other option is a re-design of the stage structure, which is likely to be quite extensive. Obvious questions are do they launch over land or sea? If it's land then low accuracy is not really an issue (as long as it's reasonably flat) but if it's sea then I'd guess it's got to get a lot better if they plan to land it on some kind of vessel. TBH if I had a clean sheet (and the cash) for an RLV design I'd launch from the vessel so the stage was over land for recovery. It took SX 5 attempts to land on the barge, but they nailed land landing first time out, admittedly after the experience of the earlier failed sea landings and Grasshopper. That suggests a stationery landing pad is a lot easier target.
I agree with youThey plan to land on land
It took SX 5 attempts to land on the barge, but they nailed land landing first time out, admittedly after the experience of the earlier failed sea landings and Grasshopper. That suggests a stationery landing pad is a lot easier target.
they manage to bring the stage back with steerable parachute and legs
Copying is what the Chinese do best.