LinkSpace - The New Player

[Shpaget]

Apparently there is a new player in town - a private Chinese company that has the goal of developing a reusable rocket with propulsive landing. Kind of like SpaceX thing.

Their current project is a smallish (20 m tall, 1,8 m diameter, 33 t) kerolox rocket with 200 kg of payload capacity to 500 km Sun synchronous orbit.

From their website http://linkspace.com.cn :

Quote

In July 2016, LinkSpace in the country for the first time achieved the rocket hover technology through single engine vector control. 

How have we missed that?

But according to https://www.nextbigfuture.com/2017/09/linkspace-is-a-chinese-startup-that-will-try-to-make-reusable-rockets-like-spacex.html

Quote

The launcher will have a takeoff thrust of about 400 kN (∼90,000 lbf). The first stage of the vehicle will consist of four liquid-oxygen/kerosene engines with gas generator cycle. Each single booster will have a thrust of 100 kN (22,480 lbf).

Unless they have some major low throttling capability (or some wacky engine configuration), how are they going to achieve stable deceleration with four engines?

 

In any case, I look forward to seeing more from these guys.

[Zeiss Ikon]

Quote

Unless they have some major low throttling capability (or some wacky engine configuration), how are they going to achieve stable deceleration with four engines?

If they have 100% reliable timing on restarts, they could just do a suicide burn with all four engines.  That actually uses less fuel than a less, um, vigorous deceleration, though it's much more stressful to watch...

And three-around-one wouldn't be that wacky an engine layout, let them land on the center nozzle.

Edited September 19, 2017 by Zeiss Ikon

[Ultimate Steve]

1 hour ago, Zeiss Ikon said:

And three-around-one wouldn't be that wacky an engine layout, let them land on the center nozzle.

Heh. I remember one of my early KSP rocket designs had four engines, three around one (but three were SRB's, so it doesn't really count).

Rocket Lab should watch out for these guys. If (big if) they're flying within the next 3-5 years, can maintain their advertised price (found on Reddit somewhere, 20-30% less than Electron) and payload capacity (slightly more than Electron), then Electron could be in trouble.

[Shpaget]

Three around one is rather inefficient usage of area, but yeah it would work.

My middle of the night insomniac ballpark eyeballing suggests they will still need to do the suicide burn, even with one engine. 30 ton entire rocket wet mass would suggest much less than 10 t dry mass on first stage, so 100 kN on one engine is too much for hover. IIRC, Merlins on F9 boosters can go down to 70%, but that still isn't low enought (assuming these guys achieve similar capability). 

Regarding Rocket Lab, yeah this is goong to be some serious competition, especially since China Gov can reasonably be expected to subsidize their company.

[NSEP]

-SpaceLink Joined the Game

-RocketLab: 1v1 me.

-SpaceLink: K

[p1t1o]

13 hours ago, Shpaget said:

How have we missed that?

Its China, so all normal bets are off. It could be 100% legit new rocketry developments. Or it could be propaganda. Or it could be a straight copy of SpaceX technology.

Surprise-surprise, it bears a significant resemblance to a SpaceX Falcon.

Notably, I couldnt find any pictures of real hardware, only that CGI diagram.

I'll wait and see with this one.

[wumpus]

15 hours ago, Zeiss Ikon said:

If they have 100% reliable timing on restarts, they could just do a suicide burn with all four engines.  That actually uses less fuel than a less, um, vigorous deceleration, though it's much more stressful to watch...

And three-around-one wouldn't be that wacky an engine layout, let them land on the center nozzle.

Cross section efficiency is critical to aero drag, and that is a lot more important at those sizes.  They might get away with three-around-one with multi-nozzle per engine (a common Russian design).  Throttle control would be extreme (I'm less convinced this is an issue:  the merlin engine was designed to land with parachutes, yet still manages to throttle deeply enough to land.  The New Shepherd was designed for powered landing and can hover.  Perhaps they can throttle all engines enough that 2x2 will work fine.

Rendering is cheap.  When you can put a clip together like "how not to land a rocket" you are ready to play with the big boys (or course, I wouldn't call Rocket Labs "big boys", but they have fired a rocket and even got ignition on the second stage).

[sevenperforce]

 

Tethered hover tests.

[IncongruousGoat]

5 hours ago, p1t1o said:

Or it could be a straight copy of SpaceX technology.

This is unlikely. SpaceX have been very careful to keep the fine details of their technology secret. In fact, they've gone so far as to take out no patents on their technology, because they know Chinese companies have been known to have low regard for U.S. patent law. I mean, sure, LinkSpace can copy some superficial stuff-but there's more to rocket science than booster layouts, and knowing what SpaceX has done is not the same as knowing how they did it.

[Shpaget]

Yeah, manufacturing high grade materials involves a lot of know how and tiny procedures that are hard to replicate without involvement of someone who knows those little tricks and trade secrets.

[p1t1o]

1 hour ago, IncongruousGoat said:

This is unlikely. SpaceX have been very careful to keep the fine details of their technology secret. In fact, they've gone so far as to take out no patents on their technology, because they know Chinese companies have been known to have low regard for U.S. patent law. I mean, sure, LinkSpace can copy some superficial stuff-but there's more to rocket science than booster layouts, and knowing what SpaceX has done is not the same as knowing how they did it.

True, but as you say, the Chinese are not averse to "acquiring" things they like. Its a known factor, if you do business with China, you've got to secure yourself. This *did* kind of spring out of the woodwork.

"Not taking out patents" doesnt actually do anything to secure your IP.

But anyway, I know Im Mr. Cynicism.

Edited September 20, 2017 by p1t1o

[Shpaget]

27 minutes ago, p1t1o said:

"Not taking out patents" doesnt actually do anything to secure your IP.

But applying for a patent requires divulging some of that IP.

I would consider the practice of not applying for a patent analogous to "security through obscurity" concept, which is not a good approach in security if not backed up by some other mechanism. Unfortunately, when it comes to intellectual property, there are few other mechanisms available and patents are the only way to enforce ownership, and we all know how China prosecutes infringements of western patents.

[YNM]

I think this is near-clean-sheet attempt. The only thing I wonder is why do they start small.

There's actually a link to an (apparently) older site - so it's older than Sept. 2017, the earliest posts I found was from July 2014 (post already dead however). I think it might have changed name, the actual name was Ling or Feiying. It mentions family members and crowdfunding. It started with solid rockets, then it went with injector designs. It even had solid rocket launch attempts back in Dec. 2015 (probably of interest to those thinking amateurs can take orbital rocket building !). All things considered, it's not as "dirty" as you think.

Edited September 20, 2017 by YNM

[KSK]

1 hour ago, Shpaget said:

But applying for a patent requires divulging some of that IP.

I would consider the practice of not applying for a patent analogous to "security through obscurity" concept, which is not a good approach in security if not backed up by some other mechanism. Unfortunately, when it comes to intellectual property, there are few other mechanisms available and patents are the only way to enforce ownership, and we all know how China prosecutes infringements of western patents.

Well unless those Western patents are also valid in China then they're fair game for anyone to use inside China. Provided that the patented technology isn't exported to a country where the patents are actually in force. If you're referring to Chinese patents held by Western companies then you may have a point although anecodotally, the Chinese government is getting tougher on that as well, because even China needs some inward investment and continued disregard for IP law is an excellent way of discouraging that investment.

Assuming that you're filing patents to protect your technology (as opposed to just having a big pile of patents to use as lawsuit poker chips or, more charitably, having patents that you can wave at investors to prove that your company has something worth investing in), then they're a good way of protecting said technology but they're not the answer to everything:

• Do you plan to actually enforce them?
• Can you afford to enforce them?
• As already alluded to on this thread, do you mind that your patent will be published, thus disclosing your technology to anyone with a web browser and the ability to spell your company name?
• If your patented Little Widget only really works with your (already patented) Big Machine, then was another patent for the Widget actually worth it?
• Can you realistically keep your technology secret, relying on contract law if necessary to enforce confidentiality? In which case, how much will a breach of confidence damage your company?
• Can you rely on actual security through obscurity rather than patent protection? Can you obfuscate your technology to the point where your competitors could reverse engineer it but its probably not worth their time? 
• Can you rely on first-mover advantage and then good business practices to stay ahead of the competition (again, instead of patent protection). OK your competitors can do what you do but can they do it as well? Do they offer comparable customer service? Can they compete with you on price?

There's really no right or wrong answer.  Filing patents is a good rule-of-thumb I would say but that's about it. Speaking as somebody who's spent his career working with them in government, the public sector and the private sector.

 

 

 

[Zeiss Ikon]

Even with Merlin engines throttling to 70% (a figure that, to my eye, looks more like "throttle back for Max-Q" than "throttle down to hover" -- though if you do it with one engine out of nine, you've effectively got around 8% total thrust), Space-X is essentially doing a one-engine (or, for at least one landing, the "maximum damage" flight, a three-engine) suicide burn.  The only reason you really need any kind of throttling during a computer controlled thrust landing is to accommodate slightly variable ignition time -- if the motor lights fast, throttle back a little, but start the ignition sequence early enough you'll get down in one piece even with a maximum tolerance ignition delay.  Otherwise, you'd always want to minimize the fuel you can't use boosting your upper stage and payload, by burning as late and as hard as possible (minimizes gravity loss, maximizes aerobraking effect by holding high airspeed, hence high drag force, as long as possible).

[DerekL1963]

5 hours ago, p1t1o said:

"Not taking out patents" doesnt actually do anything to secure your IP.

True - but it does allow you to take advantage of the trade secrets laws.  The big downside there however is that (unlike patents) if someone indepently comes up with the same ideas, you have no legal recourse.

That being said, SpaceX's secret sauce almost certainly isn't technology, but implementation details...  Which are not impossible to reverse engineer.  I know at least two people, one of whom is writing flight code for a rocket business you'd recognize*, who could create and implement the requisite algorithms and control laws.  (Implying that if I know two, there's probably hundreds or thousands in reality.)  The same thing for the engines and the related valves, rocket plumbers aren't exactly rare (I know several).  Etc... etc...

Propulsive rocket landings aren't new after all.  Nor is hovering under rocket thrust.  Amateurs have done both.  Though they (briefly) used a parachute for stabilization, Armadillo Aerospace demonstrated the basic concepts six years ago - and the idea wasn't new then.  (ISTR Armadillo demonstrating the same basic idea, absent the shutdown of the motor, circa 2004.)
 

SpaceX's big secret could very well be that there isn't a secret.

* For reasons, I cannot divulge who or for who.  Sorry.

[Nibb31]

I think the big secrets are in their software. There aren't many big secrets around the hardware. Even the Merlin was based on an "open source" design by NASA with in-house refinements.

[wumpus]

2 hours ago, Nibb31 said:

I think the big secrets are in their software. There aren't many big secrets around the hardware. Even the Merlin was based on an "open source" design by NASA with in-house refinements.

Any idea how "open" those NASA designs are?  There were some discussions about how 3d printing would change amature rockets, and I was wondering how much of turbopump-based design could simply be appropriated.  It would be a huge step to include something like that (and of course, even more painful to simply throw away).

[Nibb31]

NASA worked on a whole series of low-cost and reusable engines in the 2000's (Fastrak/MC-1, RS-83/84, TR-106/107, etc...), which were all cancelled along with SLI/OSP/X-33. It's a bit depressing really.

Most of NASA's work is public, so with access to science publications and NTRS, you can get some pretty detailed information on them. SpaceX used a lot of the work done on MC-1 and TR-106 to develop the Merlin and Kestrel.

Edited September 21, 2017 by Nibb31

[Shpaget]

https://www.space.com/linkspace-reusable-suborbital-rocket-launch-success.html

They did a free flight test. The rocket reached the height of 300 m and then landed back where it started. The flight lasted 50 seconds.

Well done!

Is it me or does it seem that the initial acceleration is rather low?

The rocket also seems to hover for a long time before touching down.

[Wjolcz]

2 hours ago, Shpaget said:

https://www.space.com/linkspace-reusable-suborbital-rocket-launch-success.html

They did a free flight test. The rocket reached the height of 300 m and then landed back where it started. The flight lasted 50 seconds.

Well done!

Is it me or does it seem that the initial acceleration is rather low?

The rocket also seems to hover for a long time before touching down.

They are still in the testing phase, so it wouldn't surprise me if they kept the initial thrust low and test hover capabilities just because it's additional data and the cost of propellant is lower than the cost of building a new test article because the last one misjudged the landing approach.

[tater]

I linked my launch coverage thread to @Wjolcz's thread, not this (older one), and it's full of updates. Sorry, it's hard to find threads sometimes on this forum.

 

Edited August 15, 2019 by tater