Ultimate Steve Posted April 26, 2019 Share Posted April 26, 2019 The third one was built from spare parts and is scheduled to launch on CRS-18 in July, currently. Quote Link to comment Share on other sites More sharing options...
Ultimate Steve Posted April 27, 2019 Share Posted April 27, 2019 https://www.space.com/china-moon-base-10-years.html Quote Link to comment Share on other sites More sharing options...
DDE Posted April 28, 2019 Share Posted April 28, 2019 17 hours ago, Ultimate Steve said: https://www.space.com/china-moon-base-10-years.html Doubt it. China doesn’t rush things like that. Quote China aims to build a scientific research station in the south polar region of the moon and realize manned lunar exploration mission in about ten years, said a senior space official on Wednesday. Zhang Kejian, head of the China National Space Administration... I think we can rule out typical mistake number one: taking the unfounded claims of someone not actually related to the program as gospel. That leaves typical mistake number two: broken telephone. Wouldn’t be the first time the coverage of the Chinese program couldn’t tell manned missions from unmanned missions. Notice the interesting word order in the first paragraph. Now, I don’t speak Chinese, but the Russian term “automated interplanetary station” could confuse quite a few laymen. Silk on the Moon Part 2: Isotope-Heated Boogaloo? Quote Link to comment Share on other sites More sharing options...
tater Posted April 30, 2019 Author Share Posted April 30, 2019 Quote Link to comment Share on other sites More sharing options...
Codraroll Posted April 30, 2019 Share Posted April 30, 2019 On 4/1/2019 at 1:08 AM, insert_name said: what are the odds one of the boosters hits something on the way down Up to 100 %, depending on your definition of "something". Quote Link to comment Share on other sites More sharing options...
Ho Lam Kerman Posted April 30, 2019 Share Posted April 30, 2019 4 hours ago, tater said: Has there ever been a launch without warning like this? Were NOTAMs etc issued? Quote Link to comment Share on other sites More sharing options...
tater Posted April 30, 2019 Author Share Posted April 30, 2019 2 hours ago, Ho Lam Kerman said: Has there ever been a launch without warning like this? Were NOTAMs etc issued? No idea. Quote Link to comment Share on other sites More sharing options...
ThatGuyWithALongUsername Posted April 30, 2019 Share Posted April 30, 2019 4 hours ago, Ho Lam Kerman said: Has there ever been a launch without warning like this? Were NOTAMs etc issued? I think CNSA has done a few of these before, but I could be wrong. I think there was at least one like this last year. Quote Link to comment Share on other sites More sharing options...
tater Posted April 30, 2019 Author Share Posted April 30, 2019 Quote Link to comment Share on other sites More sharing options...
insert_name Posted May 1, 2019 Share Posted May 1, 2019 Wow, this time it wasnt a strap on booster but a whole first stage, and they didnt even bother to issue any kind of notice. Thats horrendous even for the PRC. Quote Link to comment Share on other sites More sharing options...
Ultimate Steve Posted May 6, 2019 Share Posted May 6, 2019 http://www.xinhuanet.com/english/2019-04/03/c_137946434.htm https://space.skyrocket.de/doc_lau/jielong-1.htm China just announced a new rocket, a small four staged solid fuel rocket, 1.2 meters in diameter, 23t at liftoff, and should be able to put 150kg into a sun synchronous orbit. It is designed for the commercial market and is supposed to be reasonably cost competitive, although I don't believe that the price has been released yet. It is designed to be built in just six months, and readied for launch in just 24 hours. It is called Jielong-1, or Smart Dragon 1. The thing is, they appear to be targeting a maiden flight this month. It's a bit of a surprising announcement, this close to the date of a potential test flight. In addition, China appears to be making headway on the Long March 5B, and want to launch their first station module at the end of this year instead of next year. I wouldn't trust this article too much as it mixes up Long March 5B and Smart Dragon 1, but here it is: https://www.forbes.com/sites/jamiecartereurope/2019/03/05/china-hints-at-surprise-space-station-launch-says-its-new-rocket-can-challenge-spacex/#5c4619f23e80 Quote Link to comment Share on other sites More sharing options...
Xd the great Posted May 6, 2019 Share Posted May 6, 2019 1 hour ago, Ultimate Steve said: http://www.xinhuanet.com/english/2019-04/03/c_137946434.htm https://space.skyrocket.de/doc_lau/jielong-1.htm China just announced a new rocket, a small four staged solid fuel rocket, 1.2 meters in diameter, 23t at liftoff, and should be able to put 150kg into a sun synchronous orbit. It is designed for the commercial market and is supposed to be reasonably cost competitive, although I don't believe that the price has been released yet. It is designed to be built in just six months, and readied for launch in just 24 hours. It is called Jielong-1, or Smart Dragon 1. The thing is, they appear to be targeting a maiden flight this month. It's a bit of a surprising announcement, this close to the date of a potential test flight. Somehow feels like a ICBM test... Quote Link to comment Share on other sites More sharing options...
Ho Lam Kerman Posted May 7, 2019 Share Posted May 7, 2019 On 4/30/2019 at 5:48 PM, Codraroll said: Up to 100 %, depending on your definition of "something". No, they could timewarp too fast and end up flying from the planet at 37612 times the speed of light Quote Link to comment Share on other sites More sharing options...
tater Posted May 15, 2019 Author Share Posted May 15, 2019 Quote Link to comment Share on other sites More sharing options...
tater Posted May 17, 2019 Author Share Posted May 17, 2019 Quote Link to comment Share on other sites More sharing options...
tater Posted May 17, 2019 Author Share Posted May 17, 2019 Quote Link to comment Share on other sites More sharing options...
tater Posted May 18, 2019 Author Share Posted May 18, 2019 Most of what goes up... must come down (thanks, rocket equation!): Quote Link to comment Share on other sites More sharing options...
Scotius Posted May 18, 2019 Share Posted May 18, 2019 What exploded? Was it fuel leftover in the first stage, or did it hit something combustible on the ground? Quote Link to comment Share on other sites More sharing options...
tater Posted May 18, 2019 Author Share Posted May 18, 2019 8 hours ago, Scotius said: What exploded? Was it fuel leftover in the first stage, or did it hit something combustible on the ground? They usually do that. I assume it's the remaining hypergolics. Quote Link to comment Share on other sites More sharing options...
MinimumSky5 Posted May 18, 2019 Share Posted May 18, 2019 11 hours ago, Scotius said: What exploded? Was it fuel leftover in the first stage, or did it hit something combustible on the ground? All liquid rockets leave a small amount of fuel in discarded stages, to prevent the engines undergoing RUD's when the turbines start sucking air. Quote Link to comment Share on other sites More sharing options...
Ho Lam Kerman Posted May 19, 2019 Share Posted May 19, 2019 Why would the engine go RUD when the turbine starts sucking air? I imagine it's due to pressure of some sort but I can't imagine why. And I think there was that Falcon 9 landing attempt where they ran out of fuel just moments before touchdown and the Merlins didn't RUD. Btw that really needs to be a feature on KSP... Engine RUD when your tank is bone-dry, just to bug all the people who do stock super efficient rockets with 0.1m/s of ∆v left in the stage after mission completion. Quote Link to comment Share on other sites More sharing options...
MinimumSky5 Posted May 19, 2019 Share Posted May 19, 2019 10 minutes ago, Ho Lam Kerman said: Why would the engine go RUD when the turbine starts sucking air? I imagine it's due to pressure of some sort but I can't imagine why. And I think there was that Falcon 9 landing attempt where they ran out of fuel just moments before touchdown and the Merlins didn't RUD. If the turbine starts pulling in air, then it will rapidly start to overspeed, and will very likely fly to pieces, or the bearings will overheat. When SpaceX (or any rocket company) says that the stage is out of fuel, what the mean is that a sensor at the very bottom of the tank, where the fuel pipe is, has detected a lack of fuel and shut the engine down. There is still fuel left in the plumbing and often the tank as well, its just not safe to continue using it. Quote Link to comment Share on other sites More sharing options...
Ho Lam Kerman Posted May 19, 2019 Share Posted May 19, 2019 And... that's why I'm the Resident Orbital Mechanic and @MinimumSky5 is the Sr. Spacecraft Engineer. Well, you learn stuff every day. I guess this is it. Quote Link to comment Share on other sites More sharing options...
wumpus Posted May 20, 2019 Share Posted May 20, 2019 16 hours ago, MinimumSky5 said: If the turbine starts pulling in air, then it will rapidly start to overspeed, and will very likely fly to pieces, or the bearings will overheat. When SpaceX (or any rocket company) says that the stage is out of fuel, what the mean is that a sensor at the very bottom of the tank, where the fuel pipe is, has detected a lack of fuel and shut the engine down. There is still fuel left in the plumbing and often the tank as well, its just not safe to continue using it. Except that it won't start pulling air. It is far more likely to start pulling helium (or other "filler" gas), which presumably wouldn't compress the same and probably wouldn't pull at the right velocity and could presumably still overspeed. Of course, this assumes that there is enough propellant (whichever one) being pulled to power the turbopumps. Most turbopumps (exceptions include expander types (RL-10), electric (Rutherford engine), and old fashioned hydrogen peroxide (V-2)) use the same fuel contained in the propellant, so they will quickly stop being driven when the fuel runs out. If you overspeed before there isn't enough fuel to drive the propellant, your turbine still flies apart, tearing lots of holes in the middle of a formerly controlled explosion. If you don't, then it just stops spinning. Quote Link to comment Share on other sites More sharing options...
StrandedonEarth Posted May 20, 2019 Share Posted May 20, 2019 32 minutes ago, wumpus said: Except that it won't start pulling air. It is far more likely to start pulling helium (or other "filler" gas), which presumably wouldn't compress the same and probably wouldn't pull at the right velocity and could presumably still overspeed. Of course, this assumes that there is enough propellant (whichever one) being pulled to power the turbopumps. Most turbopumps (exceptions include expander types (RL-10), electric (Rutherford engine), and old fashioned hydrogen peroxide (V-2)) use the same fuel contained in the propellant, so they will quickly stop being driven when the fuel runs out. Well, given that most engines use a small fraction of propellants to drive the pump compared to the volume being pumped, the compressor would run out first before the preburner loses pressure. And if the compressor sucks anything but liquid, it will overspeed and rapidly dis-assemble. The Rutherford might be an interesting case as electric motors are self-governing, but might still exceed maximum safe RPM. And with Raptors being full-flow, I'm not sure what would happen then. Probably still not a safe thing to have happen. An interesting engineering challenge to ensure that a turbopump spins down when completely out of propellants, instead of flying apart. If it was easy, it would have been done already. There may be other considerations, like vibration, balance, or resonance at play. Easier to just not let it run dry. As an aside, the Shuttle was grounded for awhile when the ECO (engine cut-off sensors) in the LH2 tank were acting up. There was also one Shuttle mission when a LH2 leak caused the ECO sensors to command MECO a little earlier than usual. But it should be safe to run a pressure-fed engine, like on the LEM, to complete depletion, AFAI can guess Quote Link to comment Share on other sites More sharing options...
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