SpaceX Falcon 9 v1.1 - Jason 3 - SLC-4E Vandenberg - Jan 17, 2016 - DISCUSSION

[Johnnyhinbos]

Very true - which begs the question... So what's up with that tent??

[Coastal Ron]

Unless I'm awfully mistaken, the situation with regards to RTLS is now quite different from even last week.  RTLS has now been demonstrated, and more to the point has been demonstrated to be absurdly precise.  And I believe that alone deals with most of the objections there may have been to having the Jason booster attempt RTLS.

EDIT: Even more so with that slide-over maneuver they showed at the cape, keeping the free impact location out to sea until the landing burn starts properly.

All that would be relevant if the rocket for Jason-3 was the same as what was used for Orbcomm, but it isn't.  Remember Jason-3 is using the last of the old V1.1 stages, which does not have 33% more power, strengthened legs, and potentially other improvements that affect landing.

I would be surprised if they did a RTLS using this older, less powerful stage.  I'm hoping the do try a barge landing, but we don't know what other improvements this stage doesn't have that would factor into the decision.

[abaddon]

Maybe the Jason S1 doesn't have the stiction valve fix, because NASA cares more about mission success than booster core recovery?
Maybe SpaceX doesn't really care to recover a 1.1 core?  They are going to be swimming in cores next year.
Maybe SpaceX still wants to prove out a barge landing?  They are going to need barge landings.  But it would seem like SES-9 is going to require a barge landing, unless it is fully expendable...

None of these seem very likely to me.  Maybe they're just going to move the tent off post-haste and we'll see an RTLS attempt on the launch .

[cscott]

My money is on a barge landing, because that's the thing they haven't proven they can do yet.  They've had plenty of time to fix the sticking valve and get a change order approved by NASA, and they'll certainly be running the latest avionics control code on the stage (NASA doesn't care what runs after s1 sep).  They thought it worthwhile to try v1.1 S1 recovery before; I think they'll try it again, "because they can" and because the test is effectively free.  Why not try it and see if there's anything you can learn?

[abaddon]

I'm more being the devil's advocate here, because I don't really have a strong feeling one way or another...

They've had plenty of time to fix the sticking valve and get a change order approved by NASA

This is a mission that was supposed to launch on a 1.0 quite some time ago.  If NASA requested SpaceX only fix the RTF issue, wouldn't they respect that?  I have no evidence to suggest this, of course.

and they'll certainly be running the latest avionics control code on the stage (NASA doesn't care what runs after s1 sep)

Agreed

They thought it worthwhile to try v1.1 S1 recovery before

Of course they did, that was all they had at the time!  What else were they going to try and recover?

I think they'll try it again, "because they can" and because the test is effectively free.  Why not try it and see if there's anything you can learn?

I am not sure how "free" a barge landing attempt is, particularly if it goes sideways and damages the barge.  I think an RTLS is much more "free" and should be possible on this flight, barring regulatory issues.  I'd think the regulatory issues would be easier to overcome with the successful landing at the Cape; I imagine Vandenberg might be actually eager to demonstrate the second successful landing of an orbital boost stage on their base.

Maybe they want to work out any remaining bugs in barge landing before attempting to land the SES-9 core that I am assuming will require a barge landing (if possible).

I'm slightly leaning to them RTLS if possible, barge landing second.  Will be interesting to see what happens.

[JamesH]

My money is on a barge landing, because that's the thing they haven't proven they can do yet.  They've had plenty of time to fix the sticking valve and get a change order approved by NASA, and they'll certainly be running the latest avionics control code on the stage (NASA doesn't care what runs after s1 sep).  They thought it worthwhile to try v1.1 S1 recovery before; I think they'll try it again, "because they can" and because the test is effectively free.  Why not try it and see if there's anything you can learn?

Test not really free, but worthwhile nevertheless. They haven't stuck a barge landing yet, and they will want to recover as many stages as possible so they can tear them down for examination. Just tearing down one is not a particularly statistically valid option.

[cscott]

I actually agree with abaddon that they'd prefer RTLS to barge.  My money is on the barge because my understanding is that the flight profile is too costly for RTLS (and supporting this assumption, an ASDS was readied posthaste and positioned on the west coast).  I'd be happy to be proven wrong.

[Robotbeat]

Maybe the Jason S1 doesn't have the stiction valve fix, because NASA cares more about mission success than booster core recovery?...

Valve stiction sounds like something that you'd REALLY want to fix for main mission success, too.

[Lars-J]

Part of the issue with RTLS is that the landing pad at LC4 is very close to other infrastructure. Not only the SpaceX facilities, but the rocket will also have to cross the Amtrak railroad tracks before reaching the pad. So SpaceX may themselves not feel comfortable with doing it (even if VAFB allows it) until they have nailed some more landings.

[abaddon]

Valve stiction sounds like something that you'd REALLY want to fix for main mission success, too.

From what I understand, it has zero impact on the primary mission, as the conditions that caused the stiction to occur are well outside the envelope required.

[te_atl]

All that would be relevant if the rocket for Jason-3 was the same as what was used for Orbcomm, but it isn't.  Remember Jason-3 is using the last of the old V1.1 stages, which does not have 33% more power, strengthened legs, and potentially other improvements that affect landing.

Granted it doesn't have more power, but is it a given it doesn't have the stronger legs?  Couldn't they be swapped out?  I was under the impression it was the legs that were altered, not the attach points.

[kevin-rf]

Does the SpaceX Vandenberg pad for Jason 3 require doglegs to get around the oil rigs? If so, it may further complicate the return to Vandenberg.   

[1]

Very true - which begs the question... So what's up with that tent??

Well, either there's a rocket in there, or space-x is just really happy to see their new landing pad.

[cscott]

Theory was they just needed a place to work on another rocket (F9dev2 for pad abort?) while the main hanger was occupied with Jason-3.  Are you confirming that theory?

[AJW]

Every year the SpX Vandy team does have a holiday party, but it is usually at someone's house...

[Kabloona]

Does the SpaceX Vandenberg pad for Jason 3 require doglegs to get around the oil rigs? If so, it may further complicate the return to Vandenberg.

It does require a dogleg going uphill to avoid the islands.

[Star One]

Part of the issue with RTLS is that the landing pad at LC4 is very close to other infrastructure. Not only the SpaceX facilities, but the rocket will also have to cross the Amtrak railroad tracks before reaching the pad. So SpaceX may themselves not feel comfortable with doing it (even if VAFB allows it) until they have nailed some more landings.

Especially with a now outdated booster.

[Antilope7724]

Near the launch track along the Western Test Range, out of Vandenberg, are the environmentally sensitive Channel Islands of California.

One of the lesser islands is San Nicolas Island. It is controlled by the United States Navy, has had Redstone missiles launched from there in the 1960's and currently has a launch pad for military research rockets. The area is used for weapons training and testing.

There was also one underwater nuclear test further south of there in the 1950's, 500 miles (800 km) south west of San Diego.

https://en.wikipedia.org/wiki/Operation_Wigwam

So, landing a Falcon 9 1st stage there should be trivial from an environmental impact standpoint. The island is mostly solid rock with little vegetation. Seems like a perfect place for a Landing Zone.

Looking at one of the island maps on the San Nicolas Is Wikipedia page, there is an area on the western tip of the island labelled, "inert missile impact area" near a "Weapons Test Area". At the opposite end of the island is an area labelled, "cruise missile  soft landing area". Nearby is a 10,000 ft paved runway.

https://en.wikipedia.org/wiki/San_Nicolas_Island#/media/File:San_Nicholas_Island_California_military_facilities.png

https://en.wikipedia.org/wiki/San_Nicolas_Island

[cscott]

There was talk of this, but that was before the ASDS.  Since the focus shifted to ASDS I haven't heard anything about landing on a channel island.

[AJW]

After posting this over two years ago, I've looked for signs that this might happen, but haven't seen any, just rumors.

http://forum.nasaspaceflight.com/index.php?topic=32757.msg1092558#msg1092558