bobskythecanadianguy Posted March 2, 2015 Share Posted March 2, 2015 I have a quick question here about the DSCOVR launch. Why is the fairing look so much bigger than the payload? Doesn't that mean wasted mass? Link to comment Share on other sites More sharing options...
Airlock Posted March 2, 2015 Share Posted March 2, 2015 I have a quick question here about the DSCOVR launch. Why is the fairing look so much bigger than the payload? Doesn't that mean wasted mass?http://www.nesdis.noaa.gov/DSCOVR/images/dscovr_payload.jpgThey use a standard fairing size. Easier to mass-produce I presume. Also: Link to comment Share on other sites More sharing options...
Nibb31 Posted March 2, 2015 Share Posted March 2, 2015 I have a quick question here about the DSCOVR launch. Why is the fairing look so much bigger than the payload? Doesn't that mean wasted mass?http://www.nesdis.noaa.gov/DSCOVR/images/dscovr_payload.jpgThey don't use Procedural Fairings in real life. Payload fairings are typically a "one size fits all" affair because they are expensive to develop. Also, there might be secondary payloads below the main payload, support structures, or maybe even a small upper stage. Link to comment Share on other sites More sharing options...
Armchair Rocket Scientist Posted March 2, 2015 Share Posted March 2, 2015 I have a quick question here about the DSCOVR launch. Why is the fairing look so much bigger than the payload? Doesn't that mean wasted mass?A little bit, but my guess is that in the vast majority of cases if the payload is so small that shrinking the fairing would save a noticeable amount of mass, it's also so small that the rocket can put it into the desired orbit with the oversized fairing anyway.Since it costs time and money to design and start manufacturing a smaller fairing, it's probably not financially worth it. Some rockets, like the Atlas V and Delta IV, have different fairing sizes, but they have variations in the launch vehicle with significant variations in payload capacity. This would only be true for the Falcon 9 if the Falcon Heavy ends up getting a modified fairing for bulky payloads. Link to comment Share on other sites More sharing options...
PSOliver Posted March 2, 2015 Share Posted March 2, 2015 Yes it's basically a missile with the bomb taken off and a ferring around a satellite or whatever the payload is. so it goes up pretty fast. also it's a pretty small rocket i think.I'm replying to the guy a few posts above me. Link to comment Share on other sites More sharing options...
Airlock Posted March 2, 2015 Share Posted March 2, 2015 (edited) Here's the full ABS/Eutelsat-1 Mission webcast if anyone missed it. As there is no booster recovery attempt, I won't be updating the OP with this. Overall, it was a standard, boring sat launch. That's good though, more boring = less sudden unplanned kabooms! 14:55 - Liftoff 18:00 - Stage 1 separation 18:46 - Fairing separation - right fairing seemed a bit drunk tonight.23:55 - Great view from inside upper stage LOX tank at second stage engine shutdown. Payload deployment Edited March 2, 2015 by Airlock Link to comment Share on other sites More sharing options...
Albert VDS Posted March 2, 2015 Share Posted March 2, 2015 It's always good to see a flawless launch. Link to comment Share on other sites More sharing options...
Elthy Posted March 2, 2015 Share Posted March 2, 2015 Link to comment Share on other sites More sharing options...
Cirocco Posted March 2, 2015 Share Posted March 2, 2015 We had a few moments to enjoy zero G liquid oxygen tank interior. Very nice, like some magic portal.I swear those shots inside the LOX tank looked so much like a stargate it was scary Link to comment Share on other sites More sharing options...
FishInferno Posted March 2, 2015 Share Posted March 2, 2015 Im not sure if i understood that right: With the upgrade they can also land from missions to high orbits which is now not possible due to payload mass?What does deep cryo oxygen mean? Maybe cooling it way below its boiling point, but i dont know what this would improve...It takes more fuel to deliver a satellite to GSO. Currently, this means that the rocket uses up all of the fuel that would be used to land. Link to comment Share on other sites More sharing options...
Kryten Posted March 2, 2015 Share Posted March 2, 2015 'Deep cryo' refers to subchilling the oxygen to increase the density. Increased oxidiser load without having to increase the size of the tank. Link to comment Share on other sites More sharing options...
Streetwind Posted March 2, 2015 Share Posted March 2, 2015 (edited) Good to see SpaceX managing to actually launch something on the first attempt. That happens so rarely it's worth pointing out I know I know, better safe than sorry - but the ability to launch safely and on time is critical for a lot of their customers, and it's an area where SpaceX is trailing far behind the more established players (particularly ULA and Arianespace). And it creates rolling delays in their chock-full manifest - one missed launch window pushes years worth of launch contracts backwards because there's little to no buffer time in between them. Of course, wheather will always be out of their control, but technical issues need to be gotten on top of.For that reason, executing a flawless launch like this is great to see because it shows that the technology and processes are slowly maturing.Launch cadence is also looking good, with three launches in two months - last year, they managed six in twelve! At this rate they could beat their current yearly record in May already. Edited March 2, 2015 by Streetwind Link to comment Share on other sites More sharing options...
softweir Posted March 2, 2015 Share Posted March 2, 2015 Im not sure if i understood that right: With the upgrade they can also land from missions to high orbits which is now not possible due to payload mass?What does deep cryo oxygen mean? Maybe cooling it way below its boiling point, but i dont know what this would improve...You guessed right - deep-cryo oxygen is liquid oxygen which is much colder than its boiling pooint. It is so very cold that far less of it boils off during launch preparations. This in turn means they can fill the tanks to brimming and be sure they will still be very full at launch - which means they get more dV with no extra hardware. At present they have to allow for a certain percentage of the oxygen boiling off, which means they always launch with partly empty tanks, so less dV and excess weight. Link to comment Share on other sites More sharing options...
Armchair Rocket Scientist Posted March 2, 2015 Share Posted March 2, 2015 Question regarding GTO launches: would it be viable to build a cheap, pressure-fed upper stage to perform the burn to GTO, and have the second stage stay in LEO? Link to comment Share on other sites More sharing options...
Ralathon Posted March 2, 2015 Share Posted March 2, 2015 Question regarding GTO launches: would it be viable to build a cheap, pressure-fed upper stage to perform the burn to GTO, and have the second stage stay in LEO?Not really. GTO is pretty expensive on the dV budget. You need 2.4km/s to get into a GTO from LEO and then another 1.5km/s for circularization. It is cheaper to hit the moon than it is to get in GEO. So you really need a beefy stage to do it.Why would it matter anyway? What's the benefit to keeping the second stage in LEO? Link to comment Share on other sites More sharing options...
magnemoe Posted March 2, 2015 Share Posted March 2, 2015 Not really. GTO is pretty expensive on the dV budget. You need 2.4km/s to get into a GTO from LEO and then another 1.5km/s for circularization. It is cheaper to hit the moon than it is to get in GEO. So you really need a beefy stage to do it.Why would it matter anyway? What's the benefit to keeping the second stage in LEO?Had been more relevant with an 3rd stage to save weight doing the last part, falcon 9 have low carry weight to GTO compared to LEO because its just two stages and the upper stage is heavy and an overkill. Link to comment Share on other sites More sharing options...
Ralathon Posted March 2, 2015 Share Posted March 2, 2015 Had been more relevant with an 3rd stage to save weight doing the last part, falcon 9 have low carry weight to GTO compared to LEO because its just two stages and the upper stage is heavy and an overkill.Yea, a small 3d stage for the circularization burn would've been better for the payload fraction. But I guess the extra development time and complexity wasn't worth it. Link to comment Share on other sites More sharing options...
StrandedonEarth Posted March 2, 2015 Share Posted March 2, 2015 I agree, after the delays in the last few launches (not always SpaceX' fault) it's nice to see them put one on the pad and launch it with no extra mucking about Link to comment Share on other sites More sharing options...
Airlock Posted March 3, 2015 Share Posted March 3, 2015 Now we can get hyped for the Crew Dragon pad abort test. Tentative date is set for the 13th I believe. Garrett Reisman said Dragon 2 was already at the cape last Friday. Link to comment Share on other sites More sharing options...
bigdad84 Posted March 3, 2015 Share Posted March 3, 2015 So, according to The Verge the Falcon 9 did a "soft landing".... They must be wrong.... Right?http://www.theverge.com/2015/3/1/8130017/spacex-falcon-9-rocket-launch-successful Link to comment Share on other sites More sharing options...
RocketPilot573 Posted March 3, 2015 Share Posted March 3, 2015 So, according to The Verge the Falcon 9 did a "soft landing".... They must be wrong.... Right?http://www.theverge.com/2015/3/1/8130017/spacex-falcon-9-rocket-launch-successfulDefiantly wrong. If they had enough fuel for a soft landing then they would have tried the barge landing (and put legs on it in the first place). Link to comment Share on other sites More sharing options...
Streetwind Posted March 3, 2015 Share Posted March 3, 2015 They probably did go for an as-controlled-as-possible reentry with the first stage anyway. They also did this with the AsiaSat missions last August. No legs on the stage, not enough fuel to soft-land, but enough to put the stage on a controlled trajectory and gather data as it descended. Both AsiaSat first stage cores came down fully intact IIRC, but obviously didn't survive their terminal velocity encounter with the ocean surface. Link to comment Share on other sites More sharing options...
magnemoe Posted March 3, 2015 Share Posted March 3, 2015 They probably did go for an as-controlled-as-possible reentry with the first stage anyway. They also did this with the AsiaSat missions last August. No legs on the stage, not enough fuel to soft-land, but enough to put the stage on a controlled trajectory and gather data as it descended. Both AsiaSat first stage cores came down fully intact IIRC, but obviously didn't survive their terminal velocity encounter with the ocean surface.Not enough fuel left for boost back as I understand, they might do stability and controll testing during the ballistic flight. It might also be an eiter an older first stage or one without the RCS and other systems needed in addition to the legs. Link to comment Share on other sites More sharing options...
bigdad84 Posted March 4, 2015 Share Posted March 4, 2015 Not enough fuel left for boost back as I understand, they might do stability and controll testing during the ballistic flight. It might also be an eiter an older first stage or one without the RCS and other systems needed in addition to the legs.I really wish SpaceX would tell us all this kind of info. It's super interesting. Link to comment Share on other sites More sharing options...
Aethon Posted March 5, 2015 Author Share Posted March 5, 2015 https://www.youtube.com/watch?v=IBxud6KGcxEThree second Launch Abort System Motor test.http://www.nasa.gov/larc/orions-launch-abort-system-motor-exceeds-expectations/index.html#.VPjjvvnF-YcNASA TV to cover live SLS booster test, Wednesday March 11.http://www.nasa.gov/press/2015/march/nasa-television-to-air-major-sls-booster-test-firing-events-media-invited/index.html#.VPjlfPnF-Yd Link to comment Share on other sites More sharing options...
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