Cygnus Arrival At ISS Delayed Further
Cygnus Rendezvous Delayed Until 28 September
“This morning, Orbital and NASA together decided to postpone the approach, rendezvous, grapple and berthing operations of the Cygnus cargo logistics spacecraft with the International Space Station until after the upcoming Soyuz crew operations are complete. The Soyuz crew is due to arrive at the ISS very late on Wednesday, September 25. The earliest possible date for the next Cygnus approach and rendezvous with the ISS would be Saturday, September 28. An exact schedule will be determined following the successful completion of Soyuz operations.”
Assuming that the real problem has been described this sounds like a basic data processing problem. It should have been picked up on the ground. (The format on the magnetic tape being different to the program’s data division which is in turn differs from the documentation.)
The Cygnus may have been developed using their own ISS simulator but a real remote control should have been used during integration.
I don’t disagree, but another way of looking at the situation is that on their first attempt they reached the vicinity of the ISS with only one small problem out of the many thousands of problems that might have developed, and they caught it before it did any damage or compromised the mission, the station, or any lives. So, I see it as another major milestone having been passed in our civilian conquest of space. Congratulations to Orbital and NASA, and all the people who have worked long and hard to make this happen.
It’s very easy to say “should have been picked up on the ground”. Space history is littered with failures that “should have been caught” – nicked wires, faulty hatches, upside down gyros, stuck valves, damaged tiles, etc, etc, etc. The truth of the matter is that with the thousands of different of unique components that go into these vehicles the question is not one of nothing failing, but rather catastrophic vs. non-catastrophic failures. Fortunately for Orbital, this appears to have been non-catastrophic, much like Dragon’s stuck valves.
@Spaceman the list you gave are assembly/manufacturing faults, Unless an assembly fault has been got around using software, or a weird procedure, this was a design fault.
Finding the problem before it killed someone was a major success for the rigorous flight testing of the spacecraft. Proof beyond reasonable doubt of why the testing is needed and that testing is cheaper than not doing it. The cure needs applying to all future Cygnus.
The CCDev and Orion spacecraft need checking to see if they have similar problems. Hopefully they can be cured before Christmas. Those vehicles shall be facing equally rigorous inflight testing.
Tough crowd. Must be Monday morning.
Assembly and manufacturing faults can also be labeled design faults. You can always make the claim that if it were designed better, you wouldn’t have had the assembly or manufacturing fault.
Agreed, And some things, like the degree of thermal expansion and/or contraction of a component under actual flight conditions, can not be tested with certainty on the ground; they can only be approximated based on theory and experience. When you combine hundreds, or sometimes thousands, of situations like that found in a spacecraft and its LV the odds pile up against you pretty quickly. They must have done one hell of a lot of testing to end up with just this one significant fault. The software is so closely integrated with and interdependent with the hardware that you can’t test it either separately or with any more certainty.
It reminds me of the internal combustion engines in our cars — if you knew nothing about them, and read the description of how and why they work, you wouldn’t hesitate to say, no way; that’s never going to work! And yet cars do run, rockets do fly, and spacecraft do get to their destinations intact. If you reach the end of your trip with a little oil leak or one software “data format mismatch” the trip is still regarded as a success.
Every problem is always one that “should have been caught”– in hindsight. Hindsight is very clear that way. Once you know the problem, it’s so easy to say that you should have seen it.
Space-X also had a glitch that delayed docking, as you remember. That’s why we do test flights, to find the problems. http://www.popularmechanics…
https://www.scientificameri…
–a quick check of the internet, by the way, shows 1.2 million hits for Space-X Dragon docking, and 0.1 million hits for Space-X Dragon berthing. So, looks like the purported distinction is not catching on.
Mag tape? Data Division? COBOL? Those were the days.
Maybe that was the problem. NASA used a PIC S9 COMP SYNC and Orbital used Java.
The headline is incorrect – the Cygnus is berthed, like Dragon, and does not dock with ISS.
Berthing is a complex type of docking involving using the arm.
Nope. Docking, by NASA definition, requires that the chaser actively propel itsself into position. In berthing, the chaser gets to a predefined point, goes passive, is grappled, and is put in place by the station arm. The total operation may be more complex than docking, but it is much simpler for the chaser.
The ports that the Dragon and Cyngus use have Common Berthing Mechanism, which I don’t think supports docking. The advantage of using CBMs, as opposed to the APAS on station, is that larger objects can be passed through it.
Just because the ISS is not surrounded by salt water does not mean that NASA can change the definition of docking.
dock: to tie up at a dock, esp. in order to load or unload passengers or cargo; synonyms:moor, berth
Wrong context and incorrectly designated as synonyms. From a free internet dictionary?
Wrong, NASA can change the definition of docking as it relates to spaceflight and has made different than the nautical definition. So, no salt water or any water required
Sounds like an argument about how to say Tomato….
Uh…that is “toe-mah-toe”
Wrote mine before reading your post. I did not mean to copy your good sense of humor lol
Termater or tormator lololol
Actually, in space, docking came first, and then berthing (using the arm and station control) was developed, started, and named by the Russians, not NASA. They felt it was a lot safer than docking, which involves a considerable minimum amount of kinetic energy being imparted to a station by the docking craft, and therefore requires absolute aiming precision. Berthing, by comparison, is slow and steady, with a much lesser chance of doing any damage to a station, and you can stop, correct, or even reverse at any point in the procedure, whereas with docking a single wrongly aimed approach can damage either or both ports. There have also been cases of incomplete docking (before ISS, between spacecraft), which could not be used because there was no air seal, and had to be forcefully disconnected with short thrusts, much like getting your car out again when you’re stuck in snow (not good for any of the hardware).
Both terms were taken directly from Maritime terminology, and the distinction is as simple as who is in control of the joining — the approaching craft (docking) or the craft being approached and joined to (berthing), which in space are generally the spacecraft and station respectively.
As Geoff and others have noted here and elsewhere, the distinction between docking and berthing is often not made, even by professional reporters and representatives, probably because it’s simply not understood.
Question – It seems that crew capsules are always “docked”, not “berthed”. Are crew always “docked” as opposed to “berthed” because that way they can do it without anybody in the station (mothership) if needed?
As I understand it, that’s a factor, but the #1 issue is the approaching spacecraft itself. The Russians are happy to let their TMAs dock on a Russian portion of the ISS, but don’t allow anybody else’s spacecraft to do so, insisting that all others be berthed, on any port. As for non-Russian ports, I don’t think anybody else currently has certified dockable spacecraft, do they? I suspect that this will be a point of contention in the future. When the US had the Shuttle, it’s much larger mass, and subsequent ability to do damage to the station was a (claimed) controlling factor, which makes sense.
Although there is politics and national pride in this issue, docking really is more of a risk than berthing. Personally, except for emergencies, I’d make it a requirement for every incoming craft to be berthed, independent of being crewed and/or what approach control mechanism it uses.
Please note that this is what I learned from various NASA documents, but I can’t say what behind the scenes “arrangements” there might be. When it comes to safety, the Russians have long been inconsistent, rigid in some things and sloppy in others, but they seem to always get their way. I am most certainly not an expert in this; I was familiar with the berthing vs. docking from working on military contracts, but not spacecraft.
Huh? What about ATV docking to the Russian segment?
The point about contention is baseless and unfounded and you did not learn it from NASA documents because they do not reflect what you said. Manned spacecraft will dock because they have to be able to undock in an emergency. They don’t want to have rely on an berthing system or help from personnel onboard the station.
That’ll make it interesting once the Crewed Dragon starts to bring astronauts. Of course I suppost they can still perform some berthing-like process for coming in. But for departures, especially in emergencies, the astronauts should be allowed to just undock and pull away from the Station, under the Dragon’s own power (with no help from an arm, thankyouverymuch).
I don’t know about the CST-100 or Dreamchaser, whether they would have the full docking capability — and the permission to do so. (They’d better!)
I’m not interested in arguing about it, Charlie. I indicated that I wasn’t an expert on this, but I stand by my statement that berthing and docking are not the same thing. The ATV is an exception to standard ISS procedures and the “Automated” part of the name says things pretty clearly.
At the ISS — to the best of my knowledge — only the Progress capsules and the ATVs are currently docked; everything else is berthed, on either PMA-2 or PMA-3 (PMA-1 is not accessible). This is insisted on by the Russians, who were the first to propose and implement the berthing of spacecraft at a space station.
As I understand it, there are plans to upgrade the two currently accessible docking adapters on the ISS in the next couple of years. A newer “International Docking Adapter” (IDA) will be attached to each of PMA-2 and PMA-3 (currently, the Russian docking mechanism is different from others). This will (supposedly) change the “rules” and plans are being made to use more unmanned docking (as opposed to berthing) spacecraft types for the ISS.
As for emergency crew escape from an unmanned station, I’m not familiar with the design, but I would suspect that the procedure for “disconnecting” in an emergency is unrelated whether the escape spacecraft and ISS were docked or berthed, but I am not at all familiar with the details of what goes on.
A newer international docking adaptor” Will the Chinese be using this new docking adaptor or is that another can of worms?? ??
Spacecraft returning to Earth have various descent methods available, they can come down by thrust, or by parachute, or they can glide in. However regardless of the method used we refer to all of them as “landing” and no one seems to have a problem understanding what we are talking about.
For some reason however we can’t use docking as a generic term anymore otherwise everyone will get confused?
And what is the correct terminology after Cygnus is connected to ISS, is it docked or is it berthed? Will we be able to say “Currently there are four spacecraft docked at ISS”, or will we have to say “Currently there are three spacecraft docked to ISS and one spacecraft that is berthed”. Sure does get wordy.
Whatever rules NASA managers want to impose in their meetings is fine with me, but I think that journalists, writing to a wider audience, should have more leeway and should be able to use the more widely understood term docking if they want to, especially in their headlines.
Sweet Christ on a bicycle, are we really still arguing about this? Can’t we all just agree that, regardless of whether the term that was used was correct or not, we all knew what he was talking about anyway?
we have so many more things to nitpick on NASA Watch such as the public affairs office not dotting the many Is in their press releases. 😉
This nitpicking is very educational!
Thankyou very much!
sounds like we need a space fishing rod, magnet equipped with motorized winding. Astronauts would probably enjoy going satellite and space craft fishing while on EVA.
A telescoping rod might work, sort of like the old motorized antennas on cars.
A fishing line however would only work if the spacecraft, like a fish, was constantly pulling away from the station so that there would be constant tension in the line. That would use up a lot of propellant, all of it pointed towards the station which would not be very desirable.
In theory if the spacecraft stayed below ISS the difference in speed might provide enough tension, but then that would also make it harder for the astronauts to “catch” the spacecraft as it passes below.
That being said, if they could figure out a way to reel in a spacecraft with a line, that might be safer than the current method where the visiting spacecraft has to maneuver within about thirty feet of the station, which is always inherently risky.
I’m sure the physics of the material could be worked out, some sufficiently stretchy nano material, and who knows perhaps a propellent filled tether ball with retro thrusters to control speed and attitude once captured.
Is there any limitation on how long the Cygnus can loiter prior to berthing? Technically berthing and docking are synonyms. IIRC, the name “berthing” was arbitrarily chosen to designate RMS grapple and CBM mating because it suggests the process by which tug boats would tie onto a large ship and maneuver it into the dock.
Actually, the term berthing derives from attaching to a berth, as opposed to a dock (docking). In marine terms, a berth is a designated attachment point or space on or in a vessel (a ship) where another vessel (a boat) can be attached. The terms ship and boat are distinct; ships can carry (berth) boats (like life boats on a cruise ship, or tugs boats moving a large ship), but not the other way around (the terms cruise boat and life ship don’t exist). On ISS you have Pressurized Mating Adapters (PMAs) attached to “berthing ports.” A spacecraft can be berthed to a berthing port, but only if a PMA is attached to a berthing port can a spacecraft dock to it. Location is also a factor, since docking ports need to be able to absorb more stress.
So, sorry to disagree, but technically, the terms are not synonyms.
Berthing is not the same as docking.
Boats are not the same as ships.
A little less posting by you would raise the signal to noise ratio.
A PMA is not needed to dock, a mechanism such as the APAS, which was the docking interface, is needed. The PMA was for the shuttle and was just a standoff for the APAS. Future spacecraft may dock to different docking systems attached to new adapters mated to the CBM’s
Fine, I’ll refrain from posting in future. I started out simply by trying to clarify the difference between berthing and docking; I thought it might help a few people who weren’t clear on the matter.
Just one more comment: I pulled up the list of your NASA Watch comments and they seem to be entirely arguments or attacks on other posters. And today in my email I got three DISQUS notifications that you are now following me. I don’t know who you are charliexmurphy; maybe you do have all the answers, or maybe not. The one thing that I do know is that you’re clearly going out of your way to look for trouble. I’d much rather forego participating from now on than have any more “interactions” with an attitude like yours.
Mr. Whitfield
Your posts are very informative and important to the less informed on this site. Just like no one of consequence you are an excellent thoughtful teacher. If you were to post less, It would be a loss to us all.
Joe Q Public
With no offense meant to Steve, I’m interested in an answer to the substantive question posed here, as well. How long can Cygnus hang out in orbit before it becomes impossible to attach it to ISS (choose your favorite descriptive word for that process).
Will it get more difficult with time? Are there any parts that are aging, as it were, in space that need to be used within a limited time? Battery issues? Fuel supply?
Oh I agree. I have to explain this all the time to people I am a fan of berthing as it is less damaging to the spacecraft. It does require more infrastructure though.
I recall reading on another space news website that the Orbital rendezvous system on Cygnus is based on the MELCO proximity locator system used on the Japanese HTV system , provided by Mitsubishi. That in turn is integrated with a few other systems from contractors in Canada and US and Europe. The rendezvous approach is supposed to be independent of reference points. The workhorse is apparently the Canadian TriDAR system tested on three of the last shuttle flights, which worked well then. So I’m not surprised there are some glitches. The Cygnus itself is of the same structural genetics as the European ATV, the cargo compartment being a modified Multipurpose Logistics Module.
So, the complete Cygnus spacecraft is horizontally integrated ( read: cobbled together like an erector set) from pieces gathered all around the globe that have to play well together .
Advantage SpaceX for its vertical unified integration of Dragon.
The first Dragon had some issues on its first flight to the ISS, vertical unified integration didn’t help there. So your point is unfounded.
Point is founded. Dragon had system integration built in. That is what vertical integration is. Everything native to spacecraft from one maker . Much easier to debug, as SpaceX has shown several times in resolving issues on the fly. As was case in first mission. Keep in mind SpaceX was new to spaceflight. Whereas Cygnus was cobbled together systems from several different suppliers and bolted to an Orbital Sciences spacecraft bus. No less than four different software packages used in the Rendezvous and Approach . Orbital has been using that same STAR spacecraft bus for a very long time , and melded it with components developed for the Dawn deep space probe . Orbital has done spaceflight for 30 years prior. Yes, there were some issues on Dragon’s first , but I still give SpaceX the higher score here for performance and problem solving.
I forget
Was it for docking software testing that grounded Spacex’a first flight to ISS, couple weeks?????
Berthing/docking, docking/berthing. Who really cares, except for those who want to take up all of the comments arguing about nothing. One spacecraft is going to attach to another one.
What I would like to know, is why was the Cygnus even launched, if it had to orbit for days, before rendezvous? Was there something happening on the ground that required an early liftoff? It seems like the craft would have been safer on the ground – less risk of something going wrong.