Launch News SpaceX Falcon 9 F4 CRS SpX-1 Updates

[Urwumpe]

I disagree with his methodology though; it doesn't make any distinction between say, a lower than intended orbit and a pad explosion. Partially met goals and secondary payload failures are why we have labels such as "partial success" or "partial failure". Considering that the payload onboard F9 with the most monetary value (and indeed, a good deal more monetary value than the Orbcomm satellite) was inserted to a nominal orbit and is continuing on with its mission, this F9 flight definitely shouldn't be considered a total failure.

Thats right, but then he only counts the launches, not the missions. The launch was a failure since not all objectives of the launch vehicle had been achieved. Yes, it is a coarse way to see it, but he is only consequent there.

 

[Cosmic Penguin]

There was some discussion of it on the NASASpaceflight, where it was quite controversial as I understand it. Ed Kyle stated that he's labelled other launches that reached lower than intended or incorrect orbits as failures (including one shuttle flight).

I disagree with his methodology though; it doesn't make any distinction between say, a lower than intended orbit and a pad explosion. Partially met goals and secondary payload failures are why we have labels such as "partial success" or "partial failure". Considering that the payload onboard F9 with the most monetary value (and indeed, a good deal more monetary value than the Orbcomm satellite) was inserted to a nominal orbit and is continuing on with its mission, this F9 flight definitely shouldn't be considered a total failure.

As a "launch statistics record keeper" at Wikipedia, I think the numerous kinds of launch failures can be best described by this method by Johnathan McDowell, an astrophysicist who keeps an amazing database of every known launch into orbit and into space:

Launch Vehicle Statistics
--------------------------

The practice, of which I and others have long been guilty, of evaluating launch
vehicle reliability based on a simple pass/fail value for each launch is rather a
blunt instrument, as the recent Falcon 9 launch shows.

I have revised my launch tables (http://planet4589.org/space/lvdb/)
to include an attempt at reasonably objective fractional success values for marginal cases.
For pass/fail purposes I consider a score of 0.75 or less to be a failure; one could argue for
lowering that boundary a little bit.

For launches with a single payload, or multiple equal-priority payloads, I give:
- full success 1.00
- orbit usable but not nominal 0.75
- orbit but not a usable one 0.40
- payload failed to separate 0.25 (even if good orbit)
- orbit not reached 0.00 (or reentry after circa 1 orbit)

For missions with primary (P) and secondary (S) payloads, a rough scaling
to give the P 3 times the weight of S -
- full success 1.00
- S off-nominal orbit 0.95
- S unusable orbit 0.85
- S failed to sep 0.75
- P off-nominal orbit 0.55
- P unusable orbit 0.30
- P failed to separate 0.10

There's still some subjectivity here, and I've allowed myself to assign intermediate values,
e.g. when an orbit is only slightly off-nominal. Now obviously scores of 0.40 or less
are going to mean an unhappy customer, but I think it's still worth distinguishing from complete
failure to orbit a it usually indicates a vehicle which is 'close' to working in contrast
to some vehicles which never make it beyond first or second stage burn (I'm looking at you,
North Korea...). For Earth escape missions stranded in LEO, I've kept a 0 (complete failure) score.

Here are the proposed scores assigned so far that differ from 0.0 and 1.0:
0.25 96-061 Pegasus
0.40 63-021 Thor Agena; 67-032 Proton; 76-062,76-088, 80-031, 86-075,90-055 Molniya, 78-119, 95-052 Kosmos,
84-120, 04-052 Tsiklon, 91-051 Pegasus, 95-U01 Mu-3S-II, 96-048 CZ-3, 80-043 Atlas,
99-017, 99-023 Titan, 99-024 Delta 3, 06-006, 08-011, 11-045, 12-044 Proton/Briz, 11-005 Rokot
0.45 04-050 Delta 4H (primary payload medium-bad orbit, secondary failed to orbit)
0.50 01-029 Ariane 5/V142
0.75 97-057 PSLV, 97-066 Ariane 502, 07-027 Atlas V/NROL-30, 09-029 Soyuz/Meridian
0.80 00-048 Delta 3, 01-015 GSLV (somewhat off-nominal orbit)
0.85 12-054 Falcon 9 (primary perfect, secondary unusable)

I haven't done a throrough scrub of the database, particularly the older launches - let me know
what you think. Note that I don't count PAM and IUS payloads on Shuttle as part of the launch vehicle.
There's a whole other discussion to be had about measuring each stage instead of the LV
as a whole, and measuring upper stage and apogee motor reliability - but that is not this discussion:
the question of integrated launch vehicle reliability comes up often enough to be worth doing better.

 

[DBD]

Safety Limits

I was wondering if there are any safety limits allowed below the 99% figure. Is it merely the danger to the ISS that forced the dumping of the OrbComm sat? Are other scenerios possible where a 95% safety rating or lower is acceptable?

 

[T.Neo]

Thats right, but then he only counts the launches, not the missions. The launch was a failure since not all objectives of the launch vehicle had been achieved. Yes, it is a coarse way to see it, but he is only consequent there.

I did not intend to count missions as anything more than something contingent on the success of a launch.

My entire point was that there's a difference between failing to completely achieve your objectives, failing completely to achieve any your objectives, and failing to achieve some of your objectives. In my opinion, a launch with a $130M and a $15M payload, that fails to deliver the $15M payload, should be considered differently to a launch that fails when the second stage engine decides it wants to meet Poseidon for dinner.

Some objectives were met, others were not. It isn't about denying failure, just recognising the difference between partial failure and total failure.

If we were to continue to think within the terms of such simplicity, one might consider a hypothetical Delta IV launch of a $500 million DOD payload a failure simply because a tertiary cubesat payload failed to seperate. It makes no sense whatsoever.

As a "launch statistics record keeper" at Wikipedia, I think the numerous kinds of launch failures can be best described by this method by Johnathan McDowell, an astrophysicist who keeps an amazing database of every known launch into orbit and into space:

That is an interesting system; I have not yet read through all of it, but I do not really understand the relevance of whether a failure is caused by, for example, a seperation failure. It's relevant from an LV point of view in terms of determining what has caused the failure, but I'm failing to see how it makes much of a difference to the payload customer. Regardless of how well everything has been inserted into orbit, you may as well have not delivered the payload at all if a seperation failure occurs.

 

[RGClark]

Good point. I discuss a suggestion to upgrade the Merlin to another thrust level to reduce the number of engines on the Falcon 9 here:

Re: On the lasting importance of the SpaceX accomplishment.
http://exoscientist.blogspot.com/2012/10/re-on-lasting-importance-of-spacex.html

Elon Musk recently mentioned the possibility of creating a large new rocket engine several times the thrust of the Merlin 1:

SpaceX aims big with massive new rocket.
By: ZACH ROSENBERG WASHINGTON DC
http://www.flightglobal.com/news/articles/spacex-aims-big-with-massive-new-rocket-377687/

The natural guess is that he's referring to the Merlin 2, proposed as a 1.5+ million pound thrust, kerolox engine. And this article mentions that Gwynne Shotwell mentioned producing such an engine in an April interview.
The problem with this theory though is that Elon says it will not be RP-1 fueled. Then it could be hydrogen fueled or hypergolic fueled. For the hydrogen fueled case, you would need a quite large number of engines to make a heavy lift vehicle without using SRB's.
For the hypergolic case, these are quite toxic, and while you might use them for small engines and propellant tanks for RCS thrusters and a LES, it is more problematical for the large tanks you need on a HLV first stage.


Bob Clark

 

[mojoey]

Maybe the Merlin II is the SpaceX response to the NASA reboot of the F-1 design.

 

[Urwumpe]

For the hydrogen fueled case, you would need a quite large number of engines to make a heavy lift vehicle without using SRB's.

Wrong. The primary reasons why using hydrogen/oxygen as propellant combination for a first stage is not popular are costs and external efficiency.

A hydrogen/oxygen rocket has its peak performance in external efficiency at about 4300 m/s, while kerosene/oxygen rockets peak already at 3300 m/s. This means that a kerosene fueled rocket can be even better in giving the payload kinetic energy for the early phases of flight under certain circumstances. *

Otherwise, there is nothing that prevents hydrogen/oxygen rocket engines to be used for HLVs. See Delta IV H as example. This is not using any other propellants than hydrogen and oxygen at all.

* Explained in brief. External efficiency means, how much of the energy of the rocket engine is used for increasing the kinetic energy of the rocket. It is maximal, when the velocity relative to the reference frame is equal to the exhaust velocity (kinetic energy of the exhaust relative to the reference is zero than, all energy accelerated the rocket). When you get past this point, you again eject more energy with the exhaust. If you are at twice the exhaust velocity, you actually start reducing the kinetic energy of your rocket: The propellant that you consume and eject as exhaust contains more kinetic energy after leaving your rocket (in the reference frame), as your rocket gained by burning it.

This does not mean: You can't reach velocities that are higher than two times the exhaust velocity. You can. But you need to get much more energy during the more effective phases (= need more thrust) than if you would be using better propellants. Thus, a rocket with a lower exhaust velocity as first stage (and thus lower ISP, as you know) can really exploit this phenomena to be more effective than a rocket with only high-ISP engines - but not always.

 

[RGClark]

...
Otherwise, there is nothing that prevents hydrogen/oxygen rocket engines to be used for HLVs. See Delta IV H as example. This is not using any other propellants than hydrogen and oxygen at all.

By HLV I suppose I should have been more clear. Perhaps super heavy lift vehicle would have been more accurate, i.e., in the 100+ mT range. I assume that's what he is referring to since he mentions a quite large core stage and Shotwell also discussed the super heavy lift option. Plus, they will already have a 50+ mT launcher in the Falcon Heavy so presumably he means something more powerful than that.


Bob Clark

---------- Post added at 11:16 AM ---------- Previous post was at 11:12 AM ----------

Maybe the Merlin II is the SpaceX response to the NASA reboot of the F-1 design.

That would be the natural guess. But it's odd he says it will not be RP-1 fueled. Perhaps it could use methane or other hydrocarbon, but that would be rather misleading to say it would not be RP-1 fueled.


Bob Clark

 

[Urwumpe]

By HLV I suppose I should have been more clear. Perhaps super heavy lift vehicle would have been more accurate, i.e., in the 100+ mT range. I assume that's what he is referring to since he mentions a quite large core stage and Shotwell also discussed the super heavy lift option. Plus, they will already have a 50+ mT launcher in the Falcon Heavy so presumably he means something more powerful than that.


Bob Clark

Again: There is nothing, NOTHING (Sgt Schultz voice) that prevents you from using hydrogen/oxygen rocket engines there. If you want to build a single chamber 50 MN LH2/LO2 rocket engine, that is only an engineering challenge, but not impossible by physics or chemistry.

The only reason why most hydrogen/oxygen rocket engines today are fairly low-thrust and second stage engines has other reasons. They are simply better at altitude, more affected by ambient pressure than engines with lower ISP (but thats a tiny difference), more expensive by the more complicated metallurgy and propulsion system engineering, and require a certain amount of aerospace industry and experience in your economy before you can try building them. It is not that easy to prevent the formation of metalhydrides in the hot parts of your engine, or get the manufacturing accuracy to get hydrogen gas tight seals.

But once you have mastered the first such engines, the next engines are simpler.

 

[RGClark]

Again: There is nothing, NOTHING (Sgt Schultz voice) that prevents you from using hydrogen/oxygen rocket engines there. If you want to build a single chamber 50 MN LH2/LO2 rocket engine, that is only an engineering challenge, but not impossible by physics or chemistry.

The only reason why most hydrogen/oxygen rocket engines today are fairly low-thrust and second stage engines has other reasons. They are simply better at altitude, more affected by ambient pressure than engines with lower ISP (but thats a tiny difference), more expensive by the more complicated metallurgy and propulsion system engineering, and require a certain amount of aerospace industry and experience in your economy before you can try building them. It is not that easy to prevent the formation of metalhydrides in the hot parts of your engine, or get the manufacturing accuracy to get hydrogen gas tight seals.
But once you have mastered the first such engines, the next engines are simpler.

It is not impossible, but is highly non-trivial. It's something no other space program has done before, and SpaceX has not been known to expand the envelope in regards to technology, just in their business case.
Even just matching the RS-68 engine would be a highly non-trivial endeavor and that would require using 15 of them in a multi-core vehicle.


Bob Clark

 

[Urwumpe]

It is not impossible, but is highly non-trivial. It's something no other space program has done before, and SpaceX has not been known to expand the envelope in regards to technology, just in their business case.
Even just matching the RS-68 engine would be a highly non-trivial endeavor and that would require using 15 of them in a multi-core vehicle.


Bob Clark

yes, but that is their problem. If they manage to make a rocket engine run on Ammonia/Etylene + LOX, they have done so.

 

[T.Neo]

Rambly and poorly put-together blog post regarding hydrolox engines on first stages here.

Obviously you will need a large amount of engines on the first stage, if the thrust level of the engines in question requires a large number of engines. There is nothing intrinsic about hydrolox engines that limits their thrust.

Of course noone has created a 50MN hydrolox engine. There's no reason to do so. And while making an engine similar to the RS-68 would introduce many new issues (issues not yet dealt with by SpaceX), developing a kerolox engine of comparable thrust would also be challenging.

And there is no reason to do so. SpaceX has the Merlin 1. It exists. It works. And they are improving on it. They need to get into healthy launch operations and sustain themselves with contracts with NASA and commercial customers. Why would they waste money and personnel on a larger engine?

Sure, it would be useful for an HLV... but there is no market for an HLV. Not even from NASA (they're simply told by Congress to develop and utilize SLS). Maybe an HLV would be viable under Mr Musk's fantastic 'people emigrating to Mars for $500 000' scenario, but the division between this scenario of massive space transport industry and today's reality- where SpaceX needs an in on the real launch market in order to survive, should be very evident.

 

[Kyle]

Guys, I hate to be that one annoying member who's not a mod that tells everyone to stay on topic but.. stay on topic, this is an update thread

NTV schedule up for undocking.
October 28, Sunday
7 a.m. – SpaceX/Dragon CRS-1 Unberthing and Release Coverage (Unberthing begins at 7:55 a.m. ET, release scheduled at 9:10 a.m. ET – JSC (All Channels)

 

[orb]

NASASpaceflight: Dragon enjoying ISS stay, despite minor issues – Falcon 9 investigation begins:

SpaceX’s Dragon spacecraft is behaving well – bar a couple of minor issues – during its berthed phase of the CRS-1 (SpX-1) mission, as it closes in on its departure at the end of the month. The unberthing will be conducted by the Space Station Remote Manipulator System (SSRMS), which translated away from the Dragon to allow for an inspection this week.

{...}

 

[N_Molson]

bar a couple of minor issues

Still from NASASpaceflight :

Dragon experienced a Single Event Effect (SEE) on the Trunk Remote Input/Output (RIO) Unit String B as ISS passed over the South Atlantic Anomaly. The team power cycled and re-synched the RIO string and recovered the unit.”

After the evaluation, ground teams in Hawthorne, California (MCC-X) worked on troubleshooting the “SpX Network Switch B” which went down during the week.

“There are two fully redundant Network Switches which are up and running nominally,” added the notes. “Teams will attempt a reboot of the switch and if that doesn’t work, will reflash the switch from the flight computer.”

SpX ground specialists successfully executed a reboot of the Network Switch B, which recovered the Network Switch B without issue.

 

[RGClark]

Guys, I hate to be that one annoying member who's not a mod that tells everyone to stay on topic but.. stay on topic, this is an update thread

I moved this discussion to the thread "Should SpaceX create a larger engine to reduce the number of engines of the Falcon 9?"

Bob Clark

 

[orb]

spacexchannel:

 

[orb]

Florida Today:

• SpaceX's Dragon capsule scheduled to return to Earth on Sunday:

  NASA today confirmed that SpaceX’s Dragon capsule will depart the International Space Station on Sunday morning.
  
  Station mission managers gave a unanimous “go” for those operations to proceed even though the Dragon may be without one of its three flight computers.
  
  Flight computer “B” automatically reset itself and is healthy but no longer in sync with the other two, reported NASA TV commentator Kyle Herring.
  
  Engineers are discussing whether to attempt to re-sync that computer or leave the system as it is. Flight rules only require the use of two computers.
  
  {...}
  
  Current schedules anticipate the crew pulling the Dragon from its docking port with a robotic arm at 7:55 a.m. Sunday, then releasing the spacecraft at 9:07 a.m.
  
  A deorbit burn would be expected about six hours later, leading to a splashdown in the southern Pacific Ocean.
  
  {...}

  
  
• SpaceX Dragon OK'd to come home

Spaceflight Now:

• Blood, urine among 'priceless' cargo in Dragon
  
  
• Dragon return cargo

 

[orb]

NASA News Release:
MEDIA ADVISORY : M12-207
NASA TV to Air Live Coverage of Dragon Space Station Departure Sunday

Oct. 26, 2012

HOUSTON -- NASA Television will provide live coverage of the release and departure of SpaceX's Dragon spacecraft from the International Space Station on Sunday, Oct. 28. Coverage will begin at 6 a.m. CDT and conclude approximately three hours later after Dragon has left the vicinity of the orbiting laboratory.

Space station Expedition 33 Commander Sunita Williams and Flight Engineer Akihiko Hoshide will be at the controls of the space station's robotic arm as they back Dragon away from the complex. Dragon is scheduled to be released by the crew at 8:26 a.m. and will conduct its first departure burn one minute later.

The Dragon capsule has been attached to the station's Harmony module since Oct. 10. The spacecraft delivered 882 pounds of cargo, including 260 pounds of crew supplies, 390 pounds of scientific research, 225 pounds of hardware and several pounds of other supplies. This included critical materials to support 166 scientific investigations planned for the station's crew, including 63 new investigations.

Dragon will return 1,673 pounds of cargo, including 163 pounds of crew supplies, 866 pounds of scientific research, and 518 pounds of vehicle hardware and other hardware. Not since the space shuttle has NASA and its international partners been able to return considerable amounts of research and samples for analysis.

There will be no live NASA TV coverage of Dragon's reentry and splashdown, which are scheduled for Sunday afternoon. Mission updates and images of splashdown will be provided when they become available on the SpaceX and NASA websites. To join the conversation on Twitter, follow the hashtags #CRS1 and #Dragon.

{...}



SpaceX via Twitter:

#Dragon expected home from the space station Sunday at approx. 12:20PM PT. Safe travels!

Discovery News: NASA to SpaceX: Bring Our Astronauts' Urine Home

NewScientist: SpaceX poised to bring back blood and cucumber plants

SPACE.com: SpaceX's Dragon Capsule to Leave Space Station Sunday

Parabolic Arc: NASA to Air Dragon Departure from Station on Sunday

 

[Kyle]

Dragon has been released from the station.

---------- Post added at 01:40 PM ---------- Previous post was at 01:34 PM ----------

Yawing around, awesome view of the complex.

---------- Post added at 01:44 PM ---------- Previous post was at 01:40 PM ----------

Suni Williams - "Congradulations Hawthorne and thank you for her".

Splashdown time scheduled for 3:20pm EDT.