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1
The S2 doesn't have solar panels and very limited batteries so it's self life is very limited -parking it someone and coming back to sort it out later is not an option.

Hypothetically, if a secret expensive payload failed to separate from an F9 S2 for any reason, would SpaceX or the nameless government customer likely proceed to deorbit the second stage anyway destroying all possibility of salvaging the mission or would they just let it orbit for awhile to see if something could be done?

Does SpaceX have the capability of leaving the S2 in orbit and deciding at some future time to deorbit it?

Would it be pretty clear that nothing could be done soon after the event or would that be a difficult call until the problem had been worked for awhile?

Not to mention that LOX would boil off and that RP1 could cool below its pour point without active thermal management.
2
Space Science Coverage / Re: General SETI Thread
« Last post by Welsh Dragon on Today at 07:55 AM »
<snip>. Water may be one of the most dangerous poisonous liquids in the universe but hey we're made of it so that's what we think life is composed of. </snip>
Oxygen is the poison, not water.
3
Thinking about how many of which vehicle gets built first, in the early days, what will happen if a BFS Crew version bound for Mars gets launched to its parking orbit, only for the first tanker launch to explode, destroying the pad and the launch vehicle?

Would the BFS have sufficient fuel to return from its parking orbit and land back on earth? Presumably following such a launch failure, a lengthy investigation will ground any further BFR "rescue" launches, even if a second pad and ship are available to try and retrieve the crew.
If the craft is fully fuelled, and then goes into an eliptical parking orbit from LEO, it only needs a very small amount of fuel to lower the perigee and aerobrake into capture.

This is basically precisely what it does for Mars. However, if it's starting out in LEO with a full fuel load, and burning for a transfer orbit, it's going to have a significant amount of fuel remaining, enough to reenter without much issue at all.

To clarify, maybe my use of the term "parking orbit" was incorrect. What I was trying to say is assume the crew BFS has reached LEO, and is now waiting for the tankers to refuel it. If the first tanker blows up, thus leaving the ship unable to refuel, does it have enough margin left to return to earth and do a propulsive landing, or is the crew stuck up there until they can be rescued?

And if so, could a Crew Dragon be used to rescue them if further refuelling is indefinitely delayed by the accident?
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A 30-40t topup of EUS in LEO would give SLS 1B equivalent of block 2 performance.  If ULA are already doing DL then all NASA needs to do is upgrade EUS to flight proven systems and pay for fuel launch. NB topups are not limited to 30-40t, more fuel more capability.

 TDM paper also reported on HIAD, a commercial interests wanted to speed things up and possibly include Mid Air Recovery. No company mentioned but its good bet that commercial interest is ULA.
5

Wrong. COTS carries much more valuable things than Tang, t-shirts and toilet paper. It has carried science experiments, BEAM, IDAs etc. Yes, it wasn't certified for the highest risk category payloads, but ignoring the actual expensive hardware that has flown is wrong.


and was proven wrong with the lost IDA

Funny how you are very selective in what you consider "proven".

You dismiss COTS as "proof" for a new (and more cost-efficient) way of doing things, despite the fact that COTS has been a resounding success via the follow-on programs CRS-1 and CRS-2.

On the other hand you consider a single lost high-value item as "proof" that COTS should be for high-risk tolerance missions (in your words: Tang, T-shirts and toilet paper) only.

You completely disregard that several other high-value items have been successfully launched on COTS vehicles. You also completely disregard that NASA apparantly has no problem with flying such high-value items on COTS vehicles.
And finally you disregard that NASA has extended the use of the COTS vehicle with a very significant number of follow-on missions (CRS-2), a good number of which will fly high-value items.

Like it or not Jim, but your logic with regards to dismissing COTS as suited for flying high-value items is flawed IMO. The single biggest piece of evidence to support my opinion on this is that NASA flew IDA-2 on the very same vehicle as IDA-1, despite the loss. So what you call "proof" in reality isn't. Otherwise NASA would have flown the next IDA on a different cargo vehicle (HTV).
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Thinking about how many of which vehicle gets built first, in the early days, what will happen if a BFS Crew version bound for Mars gets launched to its parking orbit, only for the first tanker launch to explode, destroying the pad and the launch vehicle?

Would the BFS have sufficient fuel to return from its parking orbit and land back on earth? Presumably following such a launch failure, a lengthy investigation will ground any further BFR "rescue" launches, even if a second pad and ship are available to try and retrieve the crew.
If the craft is fully fuelled, and then goes into an eliptical parking orbit from LEO, it only needs a very small amount of fuel to lower the perigee and aerobrake into capture.

This is basically precisely what it does for Mars. However, if it's starting out in LEO with a full fuel load, and burning for a transfer orbit, it's going to have a significant amount of fuel remaining, enough to reenter without much issue at all.

7
The S2 doesn't have solar panels and very limited batteries so it's self life is very limited -parking it somewhere and coming back to sort it out later is not an option.

Hypothetically, if a secret expensive payload failed to separate from an F9 S2 for any reason, would SpaceX or the nameless government customer likely proceed to deorbit the second stage anyway destroying all possibility of salvaging the mission or would they just let it orbit for awhile to see if something could be done?

Does SpaceX have the capability of leaving the S2 in orbit and deciding at some future time to deorbit it?

Would it be pretty clear that nothing could be done soon after the event or would that be a difficult call until the problem had been worked for awhile?
8

When there are no winning arguments about the launch vehicle, the goal posts move to 'more interesting missions.'

It was never about the launch vehicles, it was always about the missions.  It has been the fan boys that have made about the launch vehicles, first it was shuttle, then it was Direct and now it is Falcon 9.

NROL, Juno, MSL, STSS Demo, X-37, MRO, SBIRS, etc are all more interesting than F9 comsat launch.


Tell that to the owners of comsats. Those are generally very interested in the launch of their comsats but couldn't care less about a random X-37 launch.

Whether or not a mission is interesting is a matter of personal opinion. And Jim just tried to generalize your personal opinion with his "It was never about the launch vehicles, it was always about the missions" remark.

Based on Jim's comment above we now understand that he finds the highlighted missions more interesting than comsat launches. Fine, that is his personal opinion and he is entitled to have on.

Personally I find all orbital launches equally interesting, because I don't look at WHAT is being launched but at the outcome of the launch.
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Spaceflight Entertainment and Hobbies / Re: Star Trek Discovery
« Last post by Star One on Today at 06:22 AM »
I can handle one or two mirror episodes per season... but if the rest of this season is in the mirror universe I'm going to stop watching.

Best you turn off now then because the few remaining episodes are all MU as far as I am aware.
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I think the real question is, do they have to cease work/evacuate 39A for launch operations at LC-41?
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