SpaceX FH : Falcon Heavy Demo : Feb 6, 2018 : Discussion Thread 2

[spacenut]

If NASA just purchased launches and services, and didn't spend $1 billion a year on a rocket that is going to be obsolete when it is fully functional, then we would probably already have Dragon II with powered landings.  NASA spends a lot of money developing something to then scrap it and no use it, like aerospike engines, J2X, Saturn V, Saturn IB, and didn't they give some money for the DCX and the Star Clipper, both never fully developed and would have been reusable.  They seemed to think powered landings by rockets were "to hard".  Yet SpaceX did it in less than 10 years. 

Maybe it is time for NASA to get out of the launch business and design spacecraft like NautilusX and have SpaceX, ULA, Blue Origin, and international partners launch the parts to assemble it.  NASA should design the parts by enlisting multiple contractors and having them all designed to fit existing rockets (or Vulcan and New Glenn since they are coming soon) and do in Space Assembly.  Nautilus could be designed to be moon centric, or Mars Centric depending on the modules attached.  NASA could do a public-private partnership to get this done like they did with launch services.  I believe this would be money better spent. 

[deruch]

Are there any videos that clearly show the 1-3-1 sequence in the landing burn? Every video I've seen looks like it could be single, whereas the entry burn's 1-3-1 sequence was clearly visible. I know it happened due to how much shorter the landing burn was, but what clues am I missing in the videos?

Discussed in this thread: https://forum.nasaspaceflight.com/index.php?topic=44839.0

Here are 2 screen caps from the SpaceX launch video during the landing portion.  It's a bit hard to see because the camera has trouble tracking.  But if you set the video to 0.25x speed and start at T+07:49, you'll clearly see that there is a very short period of 3-engine burn in the middle there. 

[tvg98]

The performance numbers in this database are not accurate. In process of being fixed. Even if they were, a fully expendable Falcon Heavy, which far exceeds the performance of a Delta IV Heavy, is $150M, compared to over $400M for Delta IV Heavy.

https://twitter.com/elonmusk/status/963076231921938432

So we now have an actual price for an expendable Falcon Heavy.

[abaddon]

Some interesting further statements in that thread:

David Legangneux
Just under $400M for Delta IV Heavy, not over. The cost of the Parker Solar Probe launch is $389.1M (contract announced in 2015).

Elon Musk
‏That was three years ago, before ULA cancelled all medium versions of Delta IV. Future missions have all Delta fixed costs piled on, so their cost is now $600M+ for missions contracted for launch after 2020. Nutty high.

Looking forward to seeing those updated performance numbers...

[Nomadd]

The performance numbers in this database are not accurate. In process of being fixed. Even if they were, a fully expendable Falcon Heavy, which far exceeds the performance of a Delta IV Heavy, is $150M, compared to over $400M for Delta IV Heavy.

https://twitter.com/elonmusk/status/963076231921938432

So we now have an actual price for an expendable Falcon Heavy.

Atlas 551 is listed at $153 million. The performance numbers were inaccurate and Doug Ellison's conclusion was wrong.

[clongton]

I do. The answer is old age.

Some people age gracefully, with a fully functional brain capable of adapting to change, right until the very end.
But other people, when going old, experience something that is best described as "mindset lock".
I've seen it happen to several people, not the least of which was my own farther-in-law. When it happens you can argue all you want but the person in question will not change its opinion, no matter what evidence to the contrary is presented.

God I hope that doesn't happen to me. When I finally enter the big recycle bin at the age of 102, I want to have learned at least 2 new things that very day.

[Svetoslav]

On the other side, Buzz Aldrin went to the pad and watched the liftoff of Falcon Heavy.

[raketa]

Stretching S2, will increase the payload to LEO and maybe all 3 boosters could do RTLS. Center S1 will deal with ~1.6km/s instead of ~2.6km/s. Easier to recover.
I think SpaceX discover, that rocket could be almost SSO, just need little bit push at the beginning, that what S1 do and it is better under 2Km/s to do MECO, higher speed make an S1 recovery difficult.

[woods170]

Oh now this is interesting with regards to fairing 2.0:

https://twitter.com/elonmusk/status/963095860060934144

[ugordan]

https://twitter.com/elonmusk/status/963107229523038211

Elon Musk
‏Compte certifié @elonmusk
16 minil y a 16 minutes
En réponse à @kerrbones @nextspaceflight

Not enough ignition fluid to light the outer two engines after several three engine relights. Fix is pretty obvious.

The centre core landing failure was caused by the fact that the need for ignition fluids (TEA/TEB) increases after several engine relights. They are adding more storage to fix the issue.

So, basically, the side cores had as much of a chance to result in 2 high speed lawn darts as the center core?

[rpapo]

On the other side, Buzz Aldrin went to the pad and watched the liftoff of Falcon Heavy.

In spite of being in Bezos' camp.  Good for him.

[rsdavis9]

https://twitter.com/elonmusk/status/963107229523038211

Elon Musk
‏Compte certifié @elonmusk
16 minil y a 16 minutes
En réponse à @kerrbones @nextspaceflight

Not enough ignition fluid to light the outer two engines after several three engine relights. Fix is pretty obvious.

The centre core landing failure was caused by the fact that the need for ignition fluids (TEA/TEB) increases after several engine relights. They are adding more storage to fix the issue.

So, basically, the side cores had as much of a chance to result in 2 high speed lawn darts as the center core?

so were all 3 stages with all 3 burns 1-3-1 ?
I think so?

EDIT: I just rewatched launch and side boosters do 1-3-1 for landing burn. Haven't checked boost back or reentry.(yet?)

[AC in NC]

https://twitter.com/elonmusk/status/963107229523038211

Elon Musk
‏Compte certifié @elonmusk
16 minil y a 16 minutes
En réponse à @kerrbones @nextspaceflight

Not enough ignition fluid to light the outer two engines after several three engine relights. Fix is pretty obvious.

Anyone have shareable insight into how much TEA/TEB is loaded, typically used, and extra can be loaded with the current design?  Even within an order of magnitude if the specifics is too much proprietary information.

[John Alan]

It MAY be as simple as someone did not get the memo and thinking core was only doing a reentry and landing burn... only put that much in the lighter bottles... 

I said MAY and really it's not important... what's done is done...
The boosters acted like they did three of the three engine relights too...
My GUESS is the bottles are already big enough... just MY opinion on subtopic... 

[speedevil]

The boosters acted like they did three of the three engine relights too...
My GUESS is the bottles are already big enough... just MY opinion on subtopic... 

Is it clear that all of the engines of the centre core were lit on takeoff?

[mike robel]

* A flight to Mars is more difficult than Musk or anyone else thinks
* His plans are laughable
* The biggest problem on long flights is radiation. Astronauts are going to get fried
* The long time in 0 gravity is difficult, astronauts will not be able to walk once on Mars
* Musk does not advance space flight, he just distracts from other things
* NASA should not get hypnotized by people like Elon Musk, new satellites for communication, weather and climate science are more important than helping Elon with his Mars mission.

Well, let's take a look at this.  This is just my opinion, because without facts and numbers, that is all anyone has.  There are a few facts strewn below.   And some of what I think are facts might be wrong.  Some things I say are probably assumptions but I have not labeled them.

 
1.  I think Ander's is partly right here.  Falcon Heavy was more difficult than Musk thought it would be.  I think flying to the moon was more difficult than anyone thought it would be.  That both succeeded doesn't mean they weren't hard.  I think, without any data, that Musk is too optimistic, but on the other hand, he want from concept to take off and landing of FH in less time than NASA has gone from concept to ... um ... even the SLS equivalent of the Saturn V 500F vehicle sitting on the pad with the Mobile Pad.

2.  I think Ander's is partly right here.  Musk's plans are grandiose, but probably not laughable.  They will almost certainly take longer and cost more than Musk thinks.  Moving to a spacecraft that can hold a 100 people while not having yet flown one that holds any might not the best course of action to follow.  Perhaps an extensive unmanned precursor mission series landing 10 - 20 highly capable rovers at several sights for initial surveys in conjunction with mass stationary probes strewn over the planet to narrow down a sight for a 10 man spacecraft with supplies for two years to establish a precursor outpost of a series of 3 or 4 outposts every two years to choose a final site.

3. I think Anders is right on this issue.   Radiation is indeed a big problem.  I have searched in vain for a finding from a spacecraft bound for Mars reporting how much radiation was encountered along the way.  If the radiation is above current guidelines, than how will we mitigate or avoid the exposure.  I admit, my google-fu is weak and I probably have just not found it or used the right terms.  Is it easier to protect a small craft or a large craft?  Without hard data, we can't make a judgement.

4.  Again, I think Ander's is partly right.  We know gravity is a problem when astronauts return from the ISS and it took "a while" for Scott to recover, but he had people to help him.  Common sense says it should be easier to adapt to Mars gravity than Earth's after a long trip, but we don't know.  Again, that would seem to call for a smaller crew and smaller, less expensive ship to test rather than risk a lot of people and a lot of money.  Perhaps we need to have Starship Troopers' style space suits with mechanical amplification of human muscle power and load bearing.

5.  I think Anders is wrong on this one.  Demonstrating powered supersonic hypersonic reentry and precision landings advances space flight.  It seems this approach should allow bigger payloads to Mars and landings within near walking distance of an outpost.  Current satellites are pushing the limits of parachute entry.  I did not think the landing system used by last lander would work -- too complicated by half.  The Boeing IMIS lander was supposed to use a combination of parachutes and powered hypersonic reentry and we knew much less about the Martian Atmosphere today.

6.  I think Ander's is wrong on this one and  NASA is hypnotized by their past and is not organizationally capable, like many old organizations like the US Army, of easily adapting to and adopting new concepts or perhaps even critical self-examination.  Two examples of this trend are the LOR mission mode, poor design in the Apollo Block 1 hatch,  and poor decision making for Challenger and Columbia.

I do not claim to be a rocket scientist.  I'm just a fan boy (and love the spectacle of a rocket launch --- and landing) and a retired Army officer who knows a little about the value of reconnaissance and about sustaining people in austere environments where someone wants to hurt you.  At least on Mars, NOONE will be trying to kill you.  Mars just doesn't care if it does.

Let the debate begin

[John Alan]

The boosters acted like they did three of the three engine relights too...
My GUESS is the bottles are already big enough... just MY opinion on subtopic... 

Is it clear that all of the engines of the centre core were lit on takeoff?

Based on looking some of the zoomed in "fire and fury" just at liftoff pics posted all over in here...
My opinion... all 27 were lit before hold downs released... 

[Rocket Science]

On the other side, Buzz Aldrin went to the pad and watched the liftoff of Falcon Heavy.

In spite of being in Bezos' camp.  Good for him.

Buzz will pitch a tent in anyone's camp....

[TheFallen]

The Tesla is permanently connected to the second stage, yes? No separation of it?

Correct. That's why its orbit will become unpredictable as time goes by... due to venting that may come from the upper stage (among other factors) as the duo makes their way around the Sun

[cscott]

https://twitter.com/elonmusk/status/963145162397396992
@elonmusk:
Found the source of the problem. The NASA database has the Falcon Block 1 performance. Version currently in production and set to fly in a few months is Block 5. SpaceX GNC team is submitting updated numbers.