TheEpicSquared Posted August 14, 2017 Share Posted August 14, 2017 (edited) Apparently the legs on this mission were reused: "...coming in for a powered landing eight minutes after launch reaching its culmination with a gentle touchdown on four fold-out landing legs that had been recycled from a previous rocket." http://spaceflight101.com/falcon-9-launches-dragon-spx-12-first-stage-landing-success/ Edited August 14, 2017 by TheEpicSquared Quote Link to comment Share on other sites More sharing options...
tater Posted August 14, 2017 Share Posted August 14, 2017 Quote Link to comment Share on other sites More sharing options...
tater Posted August 14, 2017 Share Posted August 14, 2017 Quote Link to comment Share on other sites More sharing options...
CastleKSide Posted August 14, 2017 Share Posted August 14, 2017 Darn it I missed it Quote Link to comment Share on other sites More sharing options...
cubinator Posted August 14, 2017 Share Posted August 14, 2017 I noticed the grid fins were doing a lot more correction during the landing burn than usual. Was it windy, or was the guidance system upgraded to be more precise? I noticed it landed right in the middle of the X whereas sometimes it tends to be a little off. Quote Link to comment Share on other sites More sharing options...
Jaff Posted August 14, 2017 Share Posted August 14, 2017 Separation shots on point! Nice to to see the full first stage cycle! Quote Link to comment Share on other sites More sharing options...
tater Posted August 15, 2017 Share Posted August 15, 2017 Quote Link to comment Share on other sites More sharing options...
CatastrophicFailure Posted August 15, 2017 Share Posted August 15, 2017 (edited) New sponsor: That insanely clean soot line continues to trip me out. Edited August 15, 2017 by CatastrophicFailure Quote Link to comment Share on other sites More sharing options...
Brotoro Posted August 15, 2017 Share Posted August 15, 2017 (edited) 1 hour ago, tater said: Yeah, yeah, SpaceX...very pretty. But if you want to impress me, show me your Bulgariasat landing videos. Edited August 15, 2017 by Brotoro Quote Link to comment Share on other sites More sharing options...
Grand Ship Builder Posted August 15, 2017 Share Posted August 15, 2017 Will SpaceX make more barge ships for the Falcon Heavy boosters, second stage, and possibly Dragon? Quote Link to comment Share on other sites More sharing options...
Hotaru Posted August 15, 2017 Share Posted August 15, 2017 (edited) 31 minutes ago, Grand Ship Builder said: Will SpaceX make more barge ships for the Falcon Heavy boosters, second stage, and possibly Dragon? My understanding is the boosters will always return to the launch site; the second stage basically goes into orbit along with the payload, so if it were to be recovered it could land pretty much anywhere, possibly a once-around flight with a landing back at KSC; the Dragon 2 would've made its propulsive landings on land but now that they've given up on that idea, I believe it's planned to parachute into the ocean like previous capsules. So no, there should be no need for more than one barge per ocean. Edited August 15, 2017 by Hotaru Quote Link to comment Share on other sites More sharing options...
Lukaszenko Posted August 15, 2017 Share Posted August 15, 2017 (edited) I still don't understand exactly what kind of trajectory the rocket flies and how it turns around to the launch site, even after watching the entire video from start to finish. How far down-range does it actually go before turning around? The speed indicator doesn't seem to help. How much delta-v does the boost-back burn actually take up? It's still going thousands of km/h after the burn, but apparently the other way? Edit: I did some rough calculations, and I'm guessing it needs 1-1.5 km/s delta-v. Still, would be nice to get more detailed data regarding the velocity vectors and distance. Edited August 15, 2017 by Lukaszenko Quote Link to comment Share on other sites More sharing options...
Streetwind Posted August 15, 2017 Share Posted August 15, 2017 (edited) 12 hours ago, cubinator said: I noticed the grid fins were doing a lot more correction during the landing burn than usual. Was it windy, or was the guidance system upgraded to be more precise? I noticed it landed right in the middle of the X whereas sometimes it tends to be a little off. From the way the exhaust flame flickered during the landing burn, it was very windy indeed. 50 minutes ago, Lukaszenko said: I still don't understand exactly what kind of trajectory the rocket flies and how it turns around to the launch site, even after watching the entire video from start to finish. How far down-range does it actually go before turning around? The speed indicator doesn't seem to help. How much delta-v does the boost-back burn actually take up? It's still going thousands of km/h after the burn, but apparently the other way? The boostback burn doesn't arrest all velocity. It arrests (and reverses) the horizontal component. The rocket is still moving upwards at a good clip, therefore the speed indicator never reaches zero until the actual landing. They simply let gravity deal with vertical velocity. Here is an infographic showing the principle. As for exact values for altitude and downrange distance, that differes from launch to launch. Overall though, the Falcon 9 flies a steeper trajectory than traditional rockets, and has a larger part of its total dV shifted to the second stage. Both of these things make first stage recovery easier. Edited August 15, 2017 by Streetwind Quote Link to comment Share on other sites More sharing options...
KSK Posted August 15, 2017 Share Posted August 15, 2017 1 hour ago, Lukaszenko said: I still don't understand exactly what kind of trajectory the rocket flies and how it turns around to the launch site, even after watching the entire video from start to finish. How far down-range does it actually go before turning around? The speed indicator doesn't seem to help. How much delta-v does the boost-back burn actually take up? It's still going thousands of km/h after the burn, but apparently the other way? Edit: I did some rough calculations, and I'm guessing it needs 1-1.5 km/s delta-v. Still, would be nice to get more detailed data regarding the velocity vectors and distance. I assume that the velocity we see is the total velocity, i.e. the vector sum of F9's horizontal and vertical velocity. So a lot of the velocity after the burn will still be vertical velocity. Similarly the boostback burn only affects horizontal velocity (I presume), to arrest and possibly slightly reverse that velocity. From the video, speed at MECO is 5877 km/hour or 1.63 Km/s. I'm not sure how much delta-V the boostback burn does impart but I think your estimate is probably a bit high. A 1.5 km/s burn would be nearly enough to stop the whole stage dead in mid air! Quote Link to comment Share on other sites More sharing options...
Just Jim Posted August 15, 2017 Share Posted August 15, 2017 22 minutes ago, Streetwind said: Here is an infographic showing the principle. Thank you... this is exactly what I was wondering about. Quote Link to comment Share on other sites More sharing options...
Nibb31 Posted August 15, 2017 Share Posted August 15, 2017 (edited) 1 hour ago, Lukaszenko said: I still don't understand exactly what kind of trajectory the rocket flies and how it turns around to the launch site, even after watching the entire video from start to finish. How far down-range does it actually go before turning around? As you can see, it doesn't simply burn retrograde. It reverts the horizontal vector but maintains the vertical component. Edited August 15, 2017 by Nibb31 Quote Link to comment Share on other sites More sharing options...
Lukaszenko Posted August 15, 2017 Share Posted August 15, 2017 48 minutes ago, KSK said: From the video, speed at MECO is 5877 km/hour or 1.63 Km/s. I'm not sure how much delta-V the boostback burn does impart but I think your estimate is probably a bit high. A 1.5 km/s burn would be nearly enough to stop the whole stage dead in mid air! I crudely timed how fast the altitude was changing, which gave me the vertical component. From this I figured out the horizontal (~1.1 km/s). In order to kill the horizontal and then hope to make it back, I guessed ~1.5 km/s would suffice. Quote Link to comment Share on other sites More sharing options...
Damien_The_Unbeliever Posted August 15, 2017 Share Posted August 15, 2017 (edited) On 14/08/2017 at 5:38 PM, Racescort666 said: Just divide by 3.6 nbd. I was going to make a joke about metric being easy to use but decided against it. Last I checked, hours weren't part of metric. The use of hours is what makes the conversion awkward, not the use of km. Edited August 15, 2017 by Damien_The_Unbeliever Quote Link to comment Share on other sites More sharing options...
sevenperforce Posted August 15, 2017 Share Posted August 15, 2017 (edited) 1 hour ago, Damien_The_Unbeliever said: Last I checked, hours weren't part of metric. The use of hours is what makes the conversion awkward, not the use of km. But still, divide by 3.6. There are 3600 seconds in an hour and 1000 meters in a km, so there are 3.6 km/hr in a single m/s. Edited August 15, 2017 by sevenperforce Quote Link to comment Share on other sites More sharing options...
sevenperforce Posted August 15, 2017 Share Posted August 15, 2017 At T+2:28, MECO, altitude is 61.1 km. At T+2:32, staging, altitude is 65.2 km. Thus, the average vertical component of velocity is 1.025 km/s. Since staging velocity is about 1.63 km/s, this means the horizontal component of velocity is roughly 1.27 km/s. However, Cape Canaveral is comoving underneath at a nice steady clip of 409 m/s, meaning that the Falcon 9 first stage only needs to kill about 860 m/s of downrange velocity to essentially "stop". 16 hours ago, Hotaru said: My understanding is the boosters will always return to the launch site; the second stage basically goes into orbit along with the payload, so if it were to be recovered it could land pretty much anywhere, possibly a once-around flight with a landing back at KSC; the Dragon 2 would've made its propulsive landings on land but now that they've given up on that idea, I believe it's planned to parachute into the ocean like previous capsules. So no, there should be no need for more than one barge per ocean. In certain cases, there may be a need for both boosters to land on an ASDS. In such cases, the core will be going so fast that it will almost certainly be expended. So they will probably need one more ASDS for the Atlantic. I don't anticipate another one for the Pacific. Quote Link to comment Share on other sites More sharing options...
Lukaszenko Posted August 16, 2017 Share Posted August 16, 2017 10 hours ago, sevenperforce said: ....this means the horizontal component of velocity is roughly 1.27 km/s. However, Cape Canaveral is comoving underneath at a nice steady clip of 409 m/s, meaning that the Falcon 9 first stage only needs to kill about 860 m/s of downrange velocity to essentially "stop". You lost me...how/ why is the cape moving slower than the rocket? Quote Link to comment Share on other sites More sharing options...
Elthy Posted August 16, 2017 Share Posted August 16, 2017 Maybe he is counting in the rotation of earth. But afaik the speeds shown in the stream are relative to ground, since they start from zero. Quote Link to comment Share on other sites More sharing options...
michal.don Posted August 16, 2017 Share Posted August 16, 2017 If anybody is awake and has time, the docking to the ISS is coming pretty soon here: Quote Link to comment Share on other sites More sharing options...
tater Posted August 16, 2017 Share Posted August 16, 2017 Quote Link to comment Share on other sites More sharing options...
tater Posted August 16, 2017 Share Posted August 16, 2017 Quote Link to comment Share on other sites More sharing options...
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