Author Topic: SpaceX Falcon 9 FT - ORBCOMM-2 - RTF (Return To Flight) DISCUSSION THREAD  (Read 909908 times)

Offline Jcc

  • Full Member
  • ****
  • Posts: 818
  • Liked: 179
  • Likes Given: 77
Perhaps another requirement for RTF is to stop putting shamrocks on the mission patches-- as a sign that they no longer rely on luck.  :o

Offline solartear

  • Member
  • Posts: 99
  • Liked: 13
  • Likes Given: 5
is there a scenario where they'd just mothball the last 1.1?

SpaceX had to keep a v1.0 until they launched 3 of v1.1 before NASA would allow a switch to using v1.1 for the launch. Potentially they could mothball it, but that would be a very expensive and needless throwaway, and would be an additional delay of Jason-3 and others.

Offline PreferToLurk

  • Full Member
  • ***
  • Posts: 308
  • Liked: 141
  • Likes Given: 21
is there a scenario where they'd just mothball the last 1.1?

SpaceX had to keep a v1.0 until they launched 3 of v1.1 before NASA would allow a switch to using v1.1 for the launch. Potentially they could mothball it, but that would be a very expensive and needless throwaway, and would be an additional delay of Jason-3 and others.


Are you sure about that?  I thought they just gambled the contract on the success of V1.1.  What did they do with the old 1.0 core?  I thought that the Jason-3 "uproar" was over the fact that SpaceX didnt have a back up plan.

Online Comga

  • Senior Member
  • *****
  • Posts: 3933
  • Liked: 1242
  • Likes Given: 1057
So...which payload wants to step up and go first? Place your bets.

ISS resupply.

My guess, and it is just that, would be SpaceX launches CRS-8 with enough lead time so that the Dragon does not interfere with the December visit by Orb-4 launched on Atlas-V.  Some time in late October or early November.

Sound reasonable?
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Offline 411rocket

  • Full Member
  • **
  • Posts: 261
  • Retired RCEME w/ tours in Cyprus, Croatia, Bosnia
  • Vancouver Island
  • Liked: 79
  • Likes Given: 115
is there a scenario where they'd just mothball the last 1.1?

SpaceX had to keep a v1.0 until they launched 3 of v1.1 before NASA would allow a switch to using v1.1 for the launch. Potentially they could mothball it, but that would be a very expensive and needless throwaway, and would be an additional delay of Jason-3 and others.

Are you sure about that?  I thought they just gambled the contract on the success of V1.1.  What did they do with the old 1.0 core?  I thought that the Jason-3 "uproar" was over the fact that SpaceX didnt have a back up plan.

If I remember correctly, SpaceX needed to retain the ability, to BUILD another V1.0, until V1.1 successfully flew 3 times. So they did not need to build it, just be prepared to build it, in case of a early V1.1 failure. If you are interested enough to look, there is info & discussion around that timeframe.

Online BrianNH

  • Full Member
  • *
  • Posts: 186
  • Liked: 99
  • Likes Given: 267
With the recent reconfiguration of the ISS, there can now be 2 US/Japanese cargo ships on station at the same time.  This makes scheduling much easier, allowing them to have a Dragon and a Cygnus at the same time, for example.

Edit: 100th post?  I thought I was a lurker.
« Last Edit: 08/03/2015 06:52 PM by BrianNH »

Online notsorandom

  • Full Member
  • ****
  • Posts: 1681
  • Ohio
  • Liked: 373
  • Likes Given: 87
Anyone know how major the changes to the pads and ground support equipment are between the V1.1 and V1.2? If they are not too bad and can be reversed then a V1.2 could fly the RTF and Jason-3 could fly afterwards on it's original rocket. Otherwise NASA will either have to be okay with Jason-3 flying the RTF or flying a bit later on the V1.2. I doubt SpaceX would or could build another v1.1 for the RTF just to satify Jason-3. I am sure SpaceX would like to use that last V1.1 too. They already built it, writing it off basically means that one rocket failure took out two rockets.

Online Eagandale4114

  • Full Member
  • *
  • Posts: 168
  • Liked: 173
  • Likes Given: 284
This isn't going up on RTF but NASA recently posted a few new pics of IDA -2.

https://blogs.nasa.gov/commercialcrew/2015/07/30/cst-100-docking-system-tested-with-ida-2/

Online gongora

  • Global Moderator
  • Senior Member
  • *****
  • Posts: 2116
  • US
  • Liked: 1469
  • Likes Given: 1039
Anyone know how major the changes to the pads and ground support equipment are between the V1.1 and V1.2? If they are not too bad and can be reversed then a V1.2 could fly the RTF and Jason-3 could fly afterwards on it's original rocket. Otherwise NASA will either have to be okay with Jason-3 flying the RTF or flying a bit later on the V1.2. I doubt SpaceX would or could build another v1.1 for the RTF just to satify Jason-3. I am sure SpaceX would like to use that last V1.1 too. They already built it, writing it off basically means that one rocket failure took out two rockets.

Jason-3 will most likely fly on the last v1.1 from Vandenberg.  Whatever is flying from Florida (which will most likely be the first flight) will go on v1.2.  There is no conflict between the two.

Offline Lars-J

  • Senior Member
  • *****
  • Posts: 3470
  • California
  • Liked: 2700
  • Likes Given: 1729
Anyone know how major the changes to the pads and ground support equipment are between the V1.1 and V1.2? If they are not too bad and can be reversed then a V1.2 could fly the RTF and Jason-3 could fly afterwards on it's original rocket. Otherwise NASA will either have to be okay with Jason-3 flying the RTF or flying a bit later on the V1.2. I doubt SpaceX would or could build another v1.1 for the RTF just to satify Jason-3. I am sure SpaceX would like to use that last V1.1 too. They already built it, writing it off basically means that one rocket failure took out two rockets.

The pad difference should be minimal or none. Possible exceptions being 1) additional equipment to chill RP-1 (for v1.2) and 2) modifications to the transporter/erector for a stretched upper stage. (if it is stretched) But the transporter/erector appears to be modular, so they should be able to extend or switch out the top part fairly easily.
« Last Edit: 08/04/2015 01:56 AM by Lars-J »

Offline Lee Jay

  • Elite Veteran
  • Global Moderator
  • Senior Member
  • *****
  • Posts: 6645
  • Liked: 914
  • Likes Given: 137
This isn't going up on RTF but NASA recently posted a few new pics of IDA -2.

This sooooooo reminds me of this scene, specifically, 2:09 in.

https://www.youtube.com/watch?v=Et4sMJP9FmM?t=2m8s

Offline CameronD

  • Full Member
  • ****
  • Posts: 1244
  • Melbourne, Australia
    • Norton Consultants
  • Liked: 397
  • Likes Given: 301
The pad difference should be minimal or none. Possible exceptions being 1) additional equipment to chill RP-1 (for v1.2).

Apologies if I've missed something somewhere.. but what benefit does chilling RP-1 bring and what sort of temperatures are we talking about here?
With sufficient thrust, pigs fly just fine - however, this is not necessarily a good idea. It is hard to be sure where they are
going to land, and it could be dangerous sitting under them as they fly overhead.

Offline Lee Jay

  • Elite Veteran
  • Global Moderator
  • Senior Member
  • *****
  • Posts: 6645
  • Liked: 914
  • Likes Given: 137
The pad difference should be minimal or none. Possible exceptions being 1) additional equipment to chill RP-1 (for v1.2).

Apologies if I've missed something somewhere.. but what benefit does chilling RP-1 bring and what sort of temperatures are we talking about here?


Densification - you get more of it in the same volume.

Offline CameronD

  • Full Member
  • ****
  • Posts: 1244
  • Melbourne, Australia
    • Norton Consultants
  • Liked: 397
  • Likes Given: 301
The pad difference should be minimal or none. Possible exceptions being 1) additional equipment to chill RP-1 (for v1.2).

Apologies if I've missed something somewhere.. but what benefit does chilling RP-1 bring and what sort of temperatures are we talking about here?


Densification - you get more of it in the same volume.

Thanks for the clarification.  I would not have thought it was worth it for such a small gain, but I guess every little bit counts when aiming for max performance.
« Last Edit: 08/04/2015 03:47 AM by CameronD »
With sufficient thrust, pigs fly just fine - however, this is not necessarily a good idea. It is hard to be sure where they are
going to land, and it could be dangerous sitting under them as they fly overhead.

Online Kabloona

  • Senior Member
  • *****
  • Posts: 4027
  • Velocitas Eradico
  • Fortress of Solitude
  • Liked: 2205
  • Likes Given: 446
The pad difference should be minimal or none. Possible exceptions being 1) additional equipment to chill RP-1 (for v1.2).

Apologies if I've missed something somewhere.. but what benefit does chilling RP-1 bring and what sort of temperatures are we talking about here?

More discussion of LOX/RP-1 densification here:

http://forum.nasaspaceflight.com/index.php?topic=36815.msg1347675#msg1347675
http://forum.nasaspaceflight.com/index.php?topic=36815.msg1348002#msg1348002
« Last Edit: 08/04/2015 04:07 AM by Kabloona »

Online DanseMacabre

The pad difference should be minimal or none. Possible exceptions being 1) additional equipment to chill RP-1 (for v1.2).

Apologies if I've missed something somewhere.. but what benefit does chilling RP-1 bring and what sort of temperatures are we talking about here?




Densification - you get more of it in the same volume.

Thanks for the clarification.  I would not have thought it was worth it for such a small gain, but I guess every little bit counts when aiming for max performance.

NASA study on it with respect to being used in X-33 here: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20100035154.pdf
« Last Edit: 08/04/2015 07:44 PM by DanseMacabre »

Offline CameronD

  • Full Member
  • ****
  • Posts: 1244
  • Melbourne, Australia
    • Norton Consultants
  • Liked: 397
  • Likes Given: 301
NASA study on it with respect to being used in X-33 here: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20100035154.pdf

Thanks for the link.  It makes for interesting reading, but, unfortunately, is referring to LOX/LH2 and is not relevant in the slightest to densification of RP-1 (which is a completely different animal).. :)
With sufficient thrust, pigs fly just fine - however, this is not necessarily a good idea. It is hard to be sure where they are
going to land, and it could be dangerous sitting under them as they fly overhead.

Online notsorandom

  • Full Member
  • ****
  • Posts: 1681
  • Ohio
  • Liked: 373
  • Likes Given: 87
Anyone know how major the changes to the pads and ground support equipment are between the V1.1 and V1.2? If they are not too bad and can be reversed then a V1.2 could fly the RTF and Jason-3 could fly afterwards on it's original rocket. Otherwise NASA will either have to be okay with Jason-3 flying the RTF or flying a bit later on the V1.2. I doubt SpaceX would or could build another v1.1 for the RTF just to satify Jason-3. I am sure SpaceX would like to use that last V1.1 too. They already built it, writing it off basically means that one rocket failure took out two rockets.

Jason-3 will most likely fly on the last v1.1 from Vandenberg.  Whatever is flying from Florida (which will most likely be the first flight) will go on v1.2.  There is no conflict between the two.
Yes of course, forgot that Jason-3 was going out of Vandenberg. That also means that SpaceX hasn't made any irreversible changes to the pad there even though they have been testing with the former reusable test rocket.

Offline Greg Hullender

  • Member
  • Posts: 48
  • Seattle
    • Rocket Stack Rank
  • Liked: 54
  • Likes Given: 62
Thanks for the clarification.  I would not have thought it was worth it for such a small gain, but I guess every little bit counts when aiming for max performance.

Reading  Kabloona's links, it looks like there's a 10% gain from chilling the liquid oxygen and a 5% gain from the RP-1. Theyre also stretching the RP-1 tank.

Online Kabloona

  • Senior Member
  • *****
  • Posts: 4027
  • Velocitas Eradico
  • Fortress of Solitude
  • Liked: 2205
  • Likes Given: 446
Thanks for the clarification.  I would not have thought it was worth it for such a small gain, but I guess every little bit counts when aiming for max performance.

Reading  Kabloona's links, it looks like there's a 10% gain from chilling the liquid oxygen and a 5% gain from the RP-1. Theyre also stretching the RP-1 tank.

Just to be clear, we don't really know the actual % gain that SpaceX will shoot for in the RP-1 density. All we know is that Gwynne said they would "slightly" chill the RP-1, which implies something less than the 5% gain mentioned by Green Shrike, which I believe is a theoretical maximum. So the word "slightly" suggests something less than that.
« Last Edit: 08/04/2015 03:03 PM by Kabloona »

Tags: