Author Topic: SpaceX Falcon 9 v1.1 - Dragon - CRS-4/SpX-4 - Sept 20, 2014 - DISCUSSION THREAD  (Read 316201 times)

Offline bilbo

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I've converted this into a discussion thread, given most of it is now. I'll set up an update thread tomorrow.

Very unlikely to be September 19, by the way.

Oh and Nadreck, no official reason given and no official confirmation (but that's what I'm being told. When I know more - past the rumors - I'll use that too).
I dont know, according to this tweet they are still go for the 19th
https://twitter.com/Leone_SN/status/506828054203990016

Care to elaborate why you feel it wont make the 19th? or is that restricted to L2 for now?

Offline Norm38

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The reason of it discussed somewhere in the forum earlier is a core swapping between Asiasat and CRS - as I remember.

If that's true, then they'd need another static fire.  Or was it swapped long ago?

We've had two statements from SpaceX.  Don't have references handy, but they were:

"The next landing will be on a barge"

"We're done with water landings"

That could mean that CRS-4 will have no recovery effort at all, and the barge landing will wait.
Speculation:  That's an opportunity to test the grid fins alone to control roll, absent the legs.  To better gauge their effect, etc...

Offline Kabloona

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I dont know, according to this tweet they are still go for the 19th
https://twitter.com/Leone_SN/status/506828054203990016


NET= No Earlier Than (the 19th). Which is not the same as "still go for the 19th." All it means is that SpaceX doesn't have a new date yet, but according to Chris it will likely be later than the 19th.

Offline su27k

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The reason of it discussed somewhere in the forum earlier is a core swapping between Asiasat and CRS - as I remember.

If that's true, then they'd need another static fire.  Or was it swapped long ago?

A SpaceX employee mentioned the swap months ago.

Quote
We've had two statements from SpaceX.  Don't have references handy, but they were:

"The next landing will be on a barge"

"We're done with water landings"

Those are not SpaceX statements, I think they are tweets from Rand Simberg, which happened to be wrong. SpaceX statement is http://www.spacex.com/news/2014/07/22/spacex-soft-lands-falcon-9-rocket-first-stage, which makes it clear CRS-4 is landing in water.

Offline darkenfast

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While they are slowly getting better, at launching rockets in quick succession, I don't think they are going to try and launch a CRS mission within less than two weeks from the Asiasat-6.  It's not worth the risk.
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Offline IslandPlaya

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While they are slowly getting better, at launching rockets in quick succession, I don't think they are going to try and launch a CRS mission within less than two weeks from the Asiasat-6.  It's not worth the risk.
I don't think the < two weeks possibility would increase risk.
SpaceX can or can't do a launch within that time-frame.
They wouldn't "cut corners" to make it so...
I hope.

Offline mikelepage

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Maybe there is nothing left to learn by putting the legs on, until they are ready for a hard-surface landing?

IIRC they needed the landing legs to control rotational rates - ie they act as "fins" on the way down as well as supports during landing (that was why the very first water landing attempt failed).  It will be interesting if their guidance systems have developed to the point that they can pull off a soft water landing without legs.

Offline TrevorMonty

The reason of it discussed somewhere in the forum earlier is a core swapping between Asiasat and CRS - as I remember.

If that's true, then they'd need another static fire.  Or was it swapped long ago?

A SpaceX employee mentioned the swap months ago.

Quote
We've had two statements from SpaceX.  Don't have references handy, but they were:

"The next landing will be on a barge"

"We're done with water landings"

Those are not SpaceX statements, I think they are tweets from Rand Simberg, which happened to be wrong. SpaceX statement is http://www.spacex.com/news/2014/07/22/spacex-soft-lands-falcon-9-rocket-first-stage, which makes it clear CRS-4 is landing in water.

Flight13 is CRS-4.  So the decision to not attempt a landing was made a while back.
Flight14  was meant to be Orbcom but that seems to have moved to next year.
Flight15 is CRS-5. Unless Orbcom is back on then we will have to wait till December for a landing.

The best we can hope for from CRS-4, besides a successful launch, is better video footage of the water landing.


Offline saliva_sweet

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Ben Cooper is saying CRS-4 will be "around Sept 28 at the earliest".
http://www.launchphotography.com/Delta_4_Atlas_5_Falcon_9_Launch_Viewing.html

Offline Prober

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Ben Cooper is saying CRS-4 will be "around Sept 28 at the earliest".
http://www.launchphotography.com/Delta_4_Atlas_5_Falcon_9_Launch_Viewing.html

This is just like what happened last year with scheduled CRS launches.

The pressures must be building within NASA atm.   See the two scheduled EVA's on the ISS are waiting on the new Batteries to be brought up by CRS-4.   ::)
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Offline Chris Bergin

I've converted this into a discussion thread, given most of it is now. I'll set up an update thread tomorrow.

Very unlikely to be September 19, by the way.

Oh and Nadreck, no official reason given and no official confirmation (but that's what I'm being told. When I know more - past the rumors - I'll use that too).
I dont know, according to this tweet they are still go for the 19th
https://twitter.com/Leone_SN/status/506828054203990016

Care to elaborate why you feel it wont make the 19th? or is that restricted to L2 for now?

Only what we're hearing. Nothing official. Technically, the above is more official, as that's a NET, but yeah it will be incredibly tight and to the point we believe it will be later.

When we know, you'll know! :)
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Offline Targeteer

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http://www.jpl.nasa.gov/news/news.php?release=2014-298

September 04, 2014

NASA's ISS-RapidScat wind-watching scatterometer, which is scheduled to launch to the International Space Station no earlier than Sept. 19, will be the first science payload to be robotically assembled in space since the space station itself. This image shows the instrument assembly on the left, shrouded in white. On the right is Rapid-Scat's nadir adapter, a very sophisticated bracket that points the scatterometer toward Earth so that it can record the direction and speed of ocean winds. The two pieces are stowed in the unpressurized trunk of a SpaceX Dragon cargo spacecraft at Cape Canaveral Air Force Station in Florida.

Howard Eisen, the ISS-RapidScat project manager at NASA's Jet Propulsion Laboratory, Pasadena, California, said, "Another mission had the idea of a two-piece payload first, but we beat them to the punch." The RapidScat team designed and built both parts of the science payload in an 18-month-long sprint so as to take advantage of an available berthing space on the space station and a free ride on a resupply mission. The other two-piece payload is still a year and a half from launch.

Each piece of the ISS-RapidScat payload is attached to the space station by a standardized interface called a Flight Releasable Attachment Mechanism, or FRAM. JPL's Stacey Boland, an engineer on the ISS-RapidScat team, explained, "The space station is almost like a Lego system, and a FRAM is a particular type of Lego block. We had to build on two separate Lego blocks because each block can only hold a certain amount of cargo."

Eisen noted, "We are not only robotically assembled, we are robotically installed." When the Dragon spacecraft reaches the station, a robotic arm will grapple it and bring it to its docking port. Using a different end effector -- a mechanical hand -- the arm will first extract the nadir adapter from the trunk and install it on an external site on the Columbus module of the space station. The arm will then pluck the RapidScat instrument assembly from the trunk and attach it to the nadir adapter, completing the installation. Each of the two operations will take about six hours.

NASA monitors Earth's vital signs from land, air and space with a fleet of satellites and ambitious airborne and ground-based observation campaigns. NASA develops new ways to observe and study Earth's interconnected natural systems with long-term data records and computer analysis tools to better see how our planet is changing. The agency shares this unique knowledge with the global community and works with institutions in the United States and around the world that contribute to understanding and protecting our home planet.

For more information about NASA's Earth science activities in 2014, visit:
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Offline woods170

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Here's the full image, showing nice detail on the interior of the Dragon trunk
« Last Edit: 09/05/2014 06:31 am by woods170 »

Offline Steven Pietrobon

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Is that a Remove Before Flight tag stuck behind the crossbeams?
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Offline mvpel

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IIRC they needed the landing legs to control rotational rates - ie they act as "fins" on the way down as well as supports during landing (that was why the very first water landing attempt failed).  It will be interesting if their guidance systems have developed to the point that they can pull off a soft water landing without legs.

That speculation turned out to be unfounded, as illustrated by the OG2 and CRS3 landing videos. They managed the roll through improved GN2 thrusters and additional N2, rather than using the legs, and are developing grid fins for that purpose as shown by the various recent photos F9R-Dev1.
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Offline ugordan

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IIRC they needed the landing legs to control rotational rates - ie they act as "fins" on the way down as well as supports during landing (that was why the very first water landing attempt failed).  It will be interesting if their guidance systems have developed to the point that they can pull off a soft water landing without legs.

That speculation turned out to be unfounded, as illustrated by the OG2 and CRS3 landing videos. They managed the roll through improved GN2 thrusters and additional N2, rather than using the legs, and are developing grid fins for that purpose as shown by the various recent photos F9R-Dev1.

Perhaps, but who's to say that the very fact the legs are attached to a stage doesn't change its aerodynamic properties and so the amount of aero torque it experiences on the way down?

Offline deruch

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IIRC they needed the landing legs to control rotational rates - ie they act as "fins" on the way down as well as supports during landing (that was why the very first water landing attempt failed).  It will be interesting if their guidance systems have developed to the point that they can pull off a soft water landing without legs.

That speculation turned out to be unfounded, as illustrated by the OG2 and CRS3 landing videos. They managed the roll through improved GN2 thrusters and additional N2, rather than using the legs, and are developing grid fins for that purpose as shown by the various recent photos F9R-Dev1.

No.  I believe mike is talking about the anti-spin control offered by the legs when they are in their stowed position, not in the extended position.  i.e. Even though they are not very proud (stick out from) of the cylinder prior to extension, the legs do act as fins providing anti-rotation control during descent.
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Offline Jim

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Here's the full image, showing nice detail on the interior of the Dragon trunk

Another SPIF photo.

Offline Pete

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I've converted this into a discussion thread, given most of it is now. I'll set up an update thread tomorrow.

Very unlikely to be September 19, by the way.

Oh and Nadreck, no official reason given and no official confirmation (but that's what I'm being told. When I know more - past the rumors - I'll use that too).
I dont know, according to this tweet they are still go for the 19th
https://twitter.com/Leone_SN/status/506828054203990016

Care to elaborate why you feel it wont make the 19th? or is that restricted to L2 for now?

Is a pad turnaround time of 19th-7th = 12 days really conceivable yet?
Assuming we sprinkle enough fairy dust on the four-leaf clovers, can the current pad infrastructure theoretically handle two launches 12 days apart?

Offline Jet Black

I've converted this into a discussion thread, given most of it is now. I'll set up an update thread tomorrow.

Very unlikely to be September 19, by the way.

Oh and Nadreck, no official reason given and no official confirmation (but that's what I'm being told. When I know more - past the rumors - I'll use that too).
I dont know, according to this tweet they are still go for the 19th
https://twitter.com/Leone_SN/status/506828054203990016

Care to elaborate why you feel it wont make the 19th? or is that restricted to L2 for now?

Is a pad turnaround time of 19th-7th = 12 days really conceivable yet?
Assuming we sprinkle enough fairy dust on the four-leaf clovers, can the current pad infrastructure theoretically handle two launches 12 days apart?

careful, don't say "Inconceivable" to anyone from SpaceX, lest they quote Inigo Montoya.
For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled. -- Richard Feynman

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