LIVE: SpaceX Dragon CRS-1 (SpX-1) (EOM) Unberthing, Entry, Splashdown

[yg1968]

This sounds like another investigation to me?    Is it possible this failure will be out of the bounds of the contract, and result in loss of payment from NASA?
 

No, not worthy of an investigation and far from contract breach.

Just to add to what Jim said, we already know what will happen. According to the SFN article linked above:

It wasn't a severe impact in terms of the temperature increase," said Byerly, who added the power snafu would not affect any contractual payments to SpaceX. According to Suffredini, although temperatures exceeded preset tolerances for some samples, researchers believe the temperature limits were conservative. "We're working our way through this, and we may limit the cold stowage coming home [on the next flight]," Suffredini said.

[Go4TLI]

I've heard for some time SpaceX was not pursuing rad-hardened avionics.  Why they did this is beyond me.  It's farily common practice and knowledge to do this. 

[oldAtlas_Eguy]

I've heard for some time SpaceX was not pursuing rad-hardened avionics.  Why they did this is beyond me.  It's farily common practice and knowledge to do this. 

The problem with rad hard computers is that it is only a mitigation against radition induced failures. The basic item here is that rad hardened means less likly that an upset event will cause permanent damage, not that the computer won't have to reset.

DragonRider will have a set of 4 computers for a dual failure scenario. Two computers fail still leaving a working system.

This event sounds like the radition event could have caused some sort of permananent damage making the computer unable to sync back up to the other computers. This is the real concern not the fact the the computer suffered an event which cannot be prevented anyways.

[Robotbeat]

...
My guess, as one who only observes spacecraft computer and software efforts from the sidelines, is that they will improve their system's ability to reboot and resynch.  Sort of what NASA is doing with their smartphone cubesat.  They put in a watchdog circuit that reboots it if it stops transmitting.  It's millions or billions of dollars cheaper than building a rad-hard Android cell phone.

+1.

The most straightforward solution is not always the best one. If you choose RAD-hard electronics, it means you miss out on the continual advancements of the modern electronics industry and are instead tied to the legacy military RAD-hard electronics cycle, which is usually much further behind.

Because they have three computers, I don't see what the big deal is about losing one on an early mission. When you have a system in place to deal with failure gracefully, people shouldn't get their underwear in a bundle when a failure does occur. Adding another string is probably just as good or better than having a single string of rad-hard electronics.

Is it true that Dragon has higher computing requirements than many other such spacecraft? I heard that Dragon has a lot of built-in smarts, and perhaps that has influenced the decision about whether or not to use RAD-Hard electronics, since RAD-Hard electronics is usually a few generations behind conventional electronics (besides being more expensive and produced in smaller volumes).

[neilh]

I've heard for some time SpaceX was not pursuing rad-hardened avionics.  Why they did this is beyond me.  It's farily common practice and knowledge to do this. 

Do rad-hard components exist that meet SpaceX's computational requirements?

[Go4TLI]

I've heard for some time SpaceX was not pursuing rad-hardened avionics.  Why they did this is beyond me.  It's farily common practice and knowledge to do this. 

Do rad-hard components exist that meet SpaceX's computational requirements?

I can't answer that question intelligently because I do not know what Dragon's computational requirements entail. 

However, l would rekon that it is less than what is required for ISS or what was required for the orbiter. 

[Robotbeat]

I've heard for some time SpaceX was not pursuing rad-hardened avionics.  Why they did this is beyond me.  It's farily common practice and knowledge to do this. 

Do rad-hard components exist that meet SpaceX's computational requirements?

I can't answer that question intelligently because I do not know what Dragon's computational requirements entail. 

However, l would rekon that it is less than what is required for ISS or what was required for the orbiter. 

Why would you make that assumption? SpaceX has made much of Dragon's supposed smarts.

[mlindner]

I've heard for some time SpaceX was not pursuing rad-hardened avionics.  Why they did this is beyond me.  It's farily common practice and knowledge to do this. 

Do rad-hard components exist that meet SpaceX's computational requirements?

Well I know they fly multiple full linux systems and they code in C++. C++ has some inherent inefficiencies in it. Also if you have increased computational capability you can also spend more of that time detecting and looking for errors.

Regarding common practice, from what I've heard the industry is moving less toward rad-hardened and more to rad-tolerance. As computers get faster and the transistor size gets smaller, radiation effects become more and more possible. So detecting them and repairing/restarting becomes much more needed. I've heard that conventional electronics is even getting some "rad-hardening" added as well because even terrestrial radiation is starting to become important to detect and fix for.

[mmeijeri]

C++ has some inherent inefficiencies in it.

Say what???

[Go4TLI]

I've heard for some time SpaceX was not pursuing rad-hardened avionics.  Why they did this is beyond me.  It's farily common practice and knowledge to do this. 

Do rad-hard components exist that meet SpaceX's computational requirements?

I can't answer that question intelligently because I do not know what Dragon's computational requirements entail. 

However, l would rekon that it is less than what is required for ISS or what was required for the orbiter. 

Why would you make that assumption? SpaceX has made much of Dragon's supposed smarts.

Simply because it is not as complicated a vehicle.  Isn't that supposed to be part of the point?

[mlindner]

C++ has some inherent inefficiencies in it.

Say what???

I should have clarified.
C++ programmers have developed common programming paradigms that often introduce inefficiency by rapid creation and destruction of objects when they could have reused objects. It's not that the language itself has inefficiency, it just lends itself to inefficiency easily based on how its commonly used.
But this is off topic so lets not get started on a programming language argument/discussion here.

[mmeijeri]

I should have clarified.
C++ programmers have developed common programming paradigms that often introduce inefficiency by rapid creation and destruction of objects when they could have reused objects. It's not that the language itself has inefficiency, it just lends itself to inefficiency easily based on how its commonly used.

If so, then people are using it badly. And boost and STL implementations nowadays use move constructors etc.

But this is off topic so lets not get started on a programming language argument/discussion here.

Agreed, but I didn't start it. 

[woods170]

This sounds like another investigation to me?    Is it possible this failure will be out of the bounds of the contract, and result in loss of payment from NASA?

No investigation needed. The reason for the loss of power to the freezer and pumps has already been found. Read the SFN article.

[neilh]

I've heard for some time SpaceX was not pursuing rad-hardened avionics.  Why they did this is beyond me.  It's farily common practice and knowledge to do this. 

Do rad-hard components exist that meet SpaceX's computational requirements?

I can't answer that question intelligently because I do not know what Dragon's computational requirements entail. 

However, l would rekon that it is less than what is required for ISS or what was required for the orbiter. 

Why would you make that assumption? SpaceX has made much of Dragon's supposed smarts.

Simply because it is not as complicated a vehicle.  Isn't that supposed to be part of the point?

I'm actually not sure. I could very well be wrong, but some potential complications necessitating computational power, which I don't believe ISS and Shuttle have/had to the same extent as Dragon:
* autonomous navigation for rendezvous and docking
* real-time processing of LIDAR data

Upon further consideration though, Mars Curiosity would be a good counterpoint to the points I raised.

[mlindner]

Thinking about it again and about my group's personal experience with deciding over rad hardened or not. The main issue isn't the speed of the hardware, its the cost of the hardware. Rad hardened parts have the speed of standard parts of a few years ago yet cost several orders of magnitude more than those faster parts.

Personally I want to see SpaceX do it without rad hardened, or come up with ingenious (and risky) ways of doing things without the extreme cost of rad hardening.

[woods170]

Let me take this viewpoint: NASA purchased launch services from SpaceX, and in the process of doing so issued a number of requirements for SpaceX to conform to. Was the use of RAD-hardened computer equipment amongst those requirements?

If NO, then NASA apparently was short-sighted OR NASA expected other means of compensating for the increased radiation-induced malfunctions in-orbit to be sufficient. (Such as flying with added redundancy).

If YES, then SpaceX didn't perform as required OR the radiation environment in-orbit exceeds the requirement levels. IF the former turns out to be correct, one could wonder why NASA signed off on a flight that did not meet requirements.

But, the above is all big IF's.

[mlindner]

Let me take this viewpoint: NASA purchased launch services from SpaceX, and in the process of doing so issued a number of requirements for SpaceX to conform to. Was the use of RAD-hardened computer equipment amongst those requirements?

If NO, then NASA apparently was short-sighted OR NASA expected other means of compensating for the increased radiation-induced malfunctions in-orbit to be sufficient. (Such as flying with added redundancy).

If YES, then SpaceX didn't perform as required OR the radiation environment in-orbit exceeds the requirement levels. IF the former turns out to be correct, one could wonder why NASA signed off on a flight that did not meet requirements.

But, the above is all big IF's.

Obvious answer is no. They wouldn't have allowed them to carry any cargo if they weren't aware of the design. As the contract states NASA has "insight" but not "oversight." They can see the designs.

And NASA wasn't short sighted, they and SpaceX knew SpaceX was taking the risk and SpaceX put in place redundancy to account for it.

You're acting like something actually didn't perform as intended lol... All the redundancy worked properly.

[woods170]

Let me take this viewpoint: NASA purchased launch services from SpaceX, and in the process of doing so issued a number of requirements for SpaceX to conform to. Was the use of RAD-hardened computer equipment amongst those requirements?

If NO, then NASA apparently was short-sighted OR NASA expected other means of compensating for the increased radiation-induced malfunctions in-orbit to be sufficient. (Such as flying with added redundancy).

If YES, then SpaceX didn't perform as required OR the radiation environment in-orbit exceeds the requirement levels. IF the former turns out to be correct, one could wonder why NASA signed off on a flight that did not meet requirements.

But, the above is all big IF's.

Obvious answer is no. They wouldn't have allowed them to carry any cargo if they weren't aware of the design. As the contract states NASA has "insight" but not "oversight." They can see the designs.

And NASA wasn't short sighted, they and SpaceX knew SpaceX was taking the risk and SpaceX put in place redundancy to account for it.

You're acting like something actually didn't perform as intended lol... All the redundancy worked properly.

Correct. Redundancy worked just fine.

[Space Pete]

Correct. Redundancy worked just fine.

This time.

For this flight, only one computer went down, but it would only have needed another one to go down, and Dragon would have been flying with no redundancy, with components susceptible to radiation. If a failure had occurred during departure from the ISS, needless to say the consequences could have been severe.

And lest we forget, this was only a three week mission. Suppose non rad-hardened electronics fly on a six month crewed Dragon mission, during which time they will be exposed to much more radiation? On such a flight all their computers could go down, even if they flew ten of them. This is why I think they'll have to go with rad hardened components eventually.

-----
Edit:

As others have suggested, I wonder whether SpaceX could develop their own tailor-made rad-hardened electronics, using their own internal cost-saving approaches, and thus save on having to buy them in from outside? Heck, if they succeeded, they could even create a side-business selling cheap rad-hardened electronics to the rest of the space industry.

[Jim]

As others have suggested, I wonder whether SpaceX could develop their own tailor-made rad-hardened electronics, using their own internal cost-saving approaches, and thus save on having to buy them in from outside? Heck, if they succeeded, they could even create a side-business selling cheap rad-hardened electronics to the rest of the space industry.

Chance is doubtful to nil.  That is done at the chip level.  It is not a turnkey capability.