SpaceX Falcon 9/Dragon CRS SpX-1 MISSION GENERAL DISCUSSION

[QuantumG]

You keep acting like you've read this insurance policy. You haven't have you?

I hope it works out for them, but the check hasn't been written yet.

[beancounter]

You keep acting like you've read this insurance policy. You haven't have you?

I hope it works out for them, but the check hasn't been written yet.

Source?

[Kabloona]

You keep acting like you've read this insurance policy. You haven't have you?

I hope it works out for them, but the check hasn't been written yet.

No, I haven't read it, I'm just reading between the lines. If Orbcomm says publicly that their insurance policy covers the loss, I don't see any reason to doubt them, and I don't see any reason why they wouldn't have insured against a low orbit that SpaceX told them was a possible outcome.

I'm not claiming any special knowledge, just trying to explain to marsman why it's not necessarily inconsistent for Orbcomm to (a) get paid for a loss under their insurance policy and (b) publicly claim some degree of mission success.

[Comga]

The obvious (in hindsight) fallback activity for the upper stage, once it failed propellent limits to clear the ISS, would have been to circularize Orbcomm at the insertion orbit apogee. Still below the ISS, still suboptimal, but much longer duration test phase. It's Orbcomm's perigee that will drive quick orbit decay here.

launch vehicles don't make those type decisions.

I wanted to go back to this and ask Jim to explain some of the details.

Let's assume that the second burn of the second stage was to happen around the 330 km apogee of the insertion orbit. We have been told that there was a known decision point for igniting the second stage.  Insufficient LOX or RP1 meant no second burn. 

Why was it not possible to make a different decision, such as starting that second burn but terminating it with a new apogee below the altitude of the ISS?  That seems like a simple branch between two predefined values.   

[cleonard]

I'm sure that the insurance contract has some precise language as to when the insurance company would pay.  I don't know, but I am very confident that Orbcomm will be getting a large insurance payment. 

It may be part of the reason that Orbcomm didn't try to boost the sat up some to get more than a few days out of it before reentry.

Orbcomm really needed the  sat at the proper altitude in order to do it's testing.  At lower altitudes the footprint is smaller and the effective power reaching the ground has a higher intensity. 

[MP99]

I don't know what insurance company would write a policy where both of the other parties involved claim success - SpaceX delivered the payload to an agreed upon orbit and Orbcomm got their engineering data on their "prototype" - but the insurance company still pays out.

Seems very fishy to me. 

The insurance company, and the law, doesn't give a rat's behind what the insured party says publicly in their press releases. The insurance company wrote a policy to reimburse them for certain cases, calculated the odds of those cases, and charged Orbcomm a premium priced accordingly. Since one of the insured events occurred (OG2 not reaching the higher orbit) they'll have to pay out. That's how the insurance business works.

Orbcomm got their satellite into a low orbit, turned it on, ran some tests on it, and verified it worked. So they wrote a press release worded as positively as they could. That's how public relations works. They want to reassure their investors and customers. They can say anything they want in public, and it has nothing to do with the terms of their insurance contract.

I agree it seems quite possible the policy states the payout for various conditions, no second burn being an obvious one. If it's nailed down in the contract, it wouldn't matter about press releases.

cheers, Martin

[cosmicvoid]

Let's assume that the second burn of the second stage was to happen around the 330 km apogee of the insertion orbit. We have been told that there was a known decision point for igniting the second stage.  Insufficient LOX or RP1 meant no second burn. 

Why was it not possible to make a different decision, such as starting that second burn but terminating it with a new apogee below the altitude of the ISS?  That seems like a simple branch between two predefined values.   

Does the second stage even have the instrumentation to know its altitude, and when to cut off the partial burn?

[cordor]

You keep acting like you've read this insurance policy. You haven't have you?

I hope it works out for them, but the check hasn't been written yet.

They will write the cheque when you have 17 more satellites ready to launch. on top of that, they will charge higher insurance fee  on every secondary payload on f9.

[mlindner]

Let's assume that the second burn of the second stage was to happen around the 330 km apogee of the insertion orbit. We have been told that there was a known decision point for igniting the second stage.  Insufficient LOX or RP1 meant no second burn. 

Why was it not possible to make a different decision, such as starting that second burn but terminating it with a new apogee below the altitude of the ISS?  That seems like a simple branch between two predefined values.   

Does the second stage even have the instrumentation to know its altitude, and when to cut off the partial burn?

Through first hand contacts the dragon flies with a Linux operating system and is written in C++. They also have similar computers spread around the launch vehicle. So yes they have plenty of computing power to know their altitude. The decision to not reboost was decided by the rocket, from my understanding SpaceX doesn't actually do any commanding anywhere between some seconds before launch and after solar array deployment.
They stated themselves that the rocket recomputed its flight path/burn times itself after the loss of the engine.

[woods170]

Let's assume that the second burn of the second stage was to happen around the 330 km apogee of the insertion orbit. We have been told that there was a known decision point for igniting the second stage.  Insufficient LOX or RP1 meant no second burn. 

Why was it not possible to make a different decision, such as starting that second burn but terminating it with a new apogee below the altitude of the ISS?  That seems like a simple branch between two predefined values.   

Does the second stage even have the instrumentation to know its altitude, and when to cut off the partial burn?

Through first hand contacts the dragon flies with a Linux operating system and is written in C++. They also have similar computers spread around the launch vehicle. So yes they have plenty of computing power to know their altitude. The decision to not reboost was decided by the rocket, from my understanding SpaceX doesn't actually do any commanding anywhere between some seconds before launch and after solar array deployment.
They stated themselves that the rocket recomputed its flight path/burn times itself after the loss of the engine.

Welcome to the forum. Interesting post. I wonder what Jim thinks of this.

[ugordan]

Of course the stage knows its state vector, it's got IMU data to propagate and I believe GPS overlay as well. IMU data accuracy will tend to degrade over longer periods of time, but only minutes into flight it should still be very accurate. Doesn't take all that much computing power to do that.

[Jim]

Let's assume that the second burn of the second stage was to happen around the 330 km apogee of the insertion orbit. We have been told that there was a known decision point for igniting the second stage.  Insufficient LOX or RP1 meant no second burn. 

Why was it not possible to make a different decision, such as starting that second burn but terminating it with a new apogee below the altitude of the ISS?  That seems like a simple branch between two predefined values.   

Does the second stage even have the instrumentation to know its altitude, and when to cut off the partial burn?

Through first hand contacts the dragon flies with a Linux operating system and is written in C++. They also have similar computers spread around the launch vehicle. So yes they have plenty of computing power to know their altitude. The decision to not reboost was decided by the rocket, from my understanding SpaceX doesn't actually do any commanding anywhere between some seconds before launch and after solar array deployment.
They stated themselves that the rocket recomputed its flight path/burn times itself after the loss of the engine.

Welcome to the forum. Interesting post. I wonder what Jim thinks of this.

The Falcon and Dragon are independent.  Solar array deployment is after separation.  Falcon is autonomous

[meekGee]

The Falcon and Dragon are independent.  Solar array deployment is after separation.  Falcon is autonomous

Why would that matter?

The second stage might be carrying something other than Dragon...  and even with Dragon, it has to do the subsequent burns after letting released Dragon..    Doesn't that imply it can figure out where it is?  Or are you saying it is flying open loop?

Regarding batteries, the time between first burn and a hypothetical circularization burn is about 45 minutes.  Are you saying the stage can't survive that long?

As for autonomy, clearly it was capable of figuring out a series of tests and deciding not to fire, so it appears it already did at least some decision making

[Jim]

The Falcon and Dragon are independent.  Solar array deployment is after separation.  Falcon is autonomous

Why would that matter?

The second stage might be carrying something other than Dragon...  and even with Dragon, it has to do the subsequent burns after letting released Dragon..    Doesn't that imply it can figure out where it is?  Or are you saying it is flying open loop?

Regarding batteries, the time between first burn and a hypothetical circularization burn is about 45 minutes.  Are you saying the stage can't survive that long?

As for autonomy, clearly it was capable of figuring out a series of tests and deciding not to fire, so it appears it already did at least some decision making

No, I was just providing some clarification to: "SpaceX doesn't actually do any commanding anywhere between some seconds before launch and after solar array deployment".

[dunderwood]

I believe woods170 was concurring, Jim.  He's stating that not only is Falcon 9 autonomous through launch and payload release, but that even Dragon is autonomous through (at least) solar array deployment.

[FinalFrontier]

So now there is a PFIB. Wonder what they will find.

I still think this was probably a manufacturing issue unique to this engine. But it remains to be seen.

[Comga]

Let's assume that the second burn of the second stage was to happen around the 330 km apogee of the insertion orbit. We have been told that there was a known decision point for igniting the second stage.  Insufficient LOX or RP1 meant no second burn. 

Why was it not possible to make a different decision, such as starting that second burn but terminating it with a new apogee below the altitude of the ISS?  That seems like a simple branch between two predefined values.   

Through first hand contacts the dragon flies with a Linux operating system and is written in C++. They also have similar computers spread around the launch vehicle. So yes they have plenty of computing power to know their altitude. The decision to not reboost was decided by the rocket, from my understanding SpaceX doesn't actually do any commanding anywhere between some seconds before launch and after solar array deployment.

Falcon is autonomous

Yes, I remember you explaining that the rocket too is autonomous, but could you please address my original question?  Given all the processing power and state knowledge, could the Falcon rocket control system have autonomously made the choice, in addition to between firing vs not firing, between one burn duration or delta V and another?  Could it have decided that, not meeting the criteria for a safe full burn to do a pre-programmed, safe, reduced burn?

PS Welcone, mlindner!
edit: fixed quotes and spelling

[baldusi]

You keep acting like you've read this insurance policy. You haven't have you?

I hope it works out for them, but the check hasn't been written yet.

They will write the cheque when you have 17 more satellites ready to launch. on top of that, they will charge higher insurance fee  on every secondary payload on f9.

This was a very particular mission with very particular requirements for the secondary. Not only did the secondary required a second burn (which is not usual for cubesats, for example), but they had some very specific condition for executing the second burn (the 99% success probability requirement). Normal ride of secondaries is to "same" orbit (for SSO or GTO). And even if it does require a second (or third) burn, only when you have the ISS in the same orbital plane you're going to have such an issue. If this hadn't been an ISS primary mission, the secondaries would have been put, at the very least, in a usable orbit.
The actuarial calculations for insurance require to take all the risks for a particular mission. We're talking here about millions of dollars of insurance, which usually allow for some very specific calculations of risks. The fact that NASA and FAA require those risk calculation and probably have forwarded them to the insurance company, would probably lower the cost of the insurance.

[Jim]

Yes, I remember you explaining that the rocket too is autonomous, but could you please address my original question?  Given all the processing power and state knowledge, could the Falcon rocket control system have autonomously made the choice, in addition to between firing vs not firing, between one burn duration or delta V and another?  Could it have decided that, not meeting the criteria for a safe full burn to do a pre-programmed, safe, reduced burn?

The problem is not whether the launch vehicle has the computational capability.  The issue is can all the potential outcomes be determined and analyzed prelaunch to allow the vehicle to make the choice. 

Launch vehicle burn durations are calculate preflight basic on nominal values for engine performance and stage loading.  The vehicle doesn't compute realtime ISP and thrust and use it to predict future burn durations.
During flight, the burn time isn't used for control but actually delta V as measured. 

[meekGee]

Yes, I remember you explaining that the rocket too is autonomous, but could you please address my original question?  Given all the processing power and state knowledge, could the Falcon rocket control system have autonomously made the choice, in addition to between firing vs not firing, between one burn duration or delta V and another?  Could it have decided that, not meeting the criteria for a safe full burn to do a pre-programmed, safe, reduced burn?

The problem is not whether the launch vehicle has the computational capability.  The issue is can all the potential outcomes be determined and analyzed prelaunch to allow the vehicle to make the choice. 

Launch vehicle burn durations are calculate preflight basic on nominal values for engine performance and stage loading.  The vehicle doesn't compute realtime ISP and thrust and use it to predict future burn durations.
During flight, the burn time isn't used for control but actually delta V as measured. 

Which makes perfect sense for a generic second burn, since nobody is going to trust the stage to do ISS-related risk assessments in real time without human oversight.   

But, Joffen's proposal (from so long ago) was to make the contingency burn a circularization of the orbit to the apogee of the post-release orbit, as a can't-lose maneuver.  This orbit can be pre-approved without knowing the exact starting situation, since a circle is a circle is a circle.

Anyway, what's done is done, and the situations in which this is useful are rare - only secondaries that can either lift themselves later, or can derive some value from lingering longer in a too-low orbit.

From what has been said in the forum, I gather that it would have been possible from a capability point of view, but basically nobody bothered, and probably justifiably so.