SpaceX Falcon Heavy Discussion (Thread 6)

[envy887]

Based on the final orbit, this launch could have lifted roughly 7500 kg to GTO-1800 with 3-core recovery and a large center core boost-back. Block 5 improvements will allow it to do that with 3-core RTLS, or more payload, IMO.

What would you estimate the mass it could have lifted to a direct GSO injection, the process (if not the trajectory) for which was tested?  And for ASDS center core recovery, how much to GSO for an FH made up of Block 5's?

Less than 5000 kg, in either case, I would imagine...

A block 5 with a hotter center core landing (no or less boostback) should put around 4000 kg direct to GSO. That is a lot, but I don't think that's enough for the EELV requirement which is more like 6500 kg. That would likely require expending the center.

[NWade]

Matching payloads was difficult for Ariane because they always need a big and a smaller payload. With the capacity of FH SpaceX could probably match any two payloads almost freely. The obstacle is the fairing size. Also Elon Musk has said he does not want two customer payloads depend on each other.

 
One more issue to think about: You're unlikely to be injecting two GEO payloads to the same orbit, so fit that into the delta-V calcs, required number of 2nd stage burns, time that your payloads spend without their arrays deployed,  etc etc. Seems like it gets messy really quickly, in addition to the other factors previously mentioned.
 
Finally, the appeal is even more dubious once you factor in that the market is seeing a noticeable price drop with FH even *without* ride-sharing to GEO.
 
--Noel
 

[guckyfan]

Matching payloads was difficult for Ariane because they always need a big and a smaller payload. With the capacity of FH SpaceX could probably match any two payloads almost freely. The obstacle is the fairing size. Also Elon Musk has said he does not want two customer payloads depend on each other.

 
One more issue to think about: You're unlikely to be injecting two GEO payloads to the same orbit, so fit that into the delta-V calcs, required number of 2nd stage burns, time that your payloads spend without their arrays deployed,  etc etc. Seems like it gets messy really quickly, in addition to the other factors previously mentioned.
 
Finally, the appeal is even more dubious once you factor in that the market is seeing a noticeable price drop with FH even *without* ride-sharing to GEO.
 
--Noel
 

In GTO satellites will drift quite fast to their orbital position.

[envy887]

Matching payloads was difficult for Ariane because they always need a big and a smaller payload. With the capacity of FH SpaceX could probably match any two payloads almost freely. The obstacle is the fairing size. Also Elon Musk has said he does not want two customer payloads depend on each other.

 
One more issue to think about: You're unlikely to be injecting two GEO payloads to the same orbit, so fit that into the delta-V calcs, required number of 2nd stage burns, time that your payloads spend without their arrays deployed,  etc etc. Seems like it gets messy really quickly, in addition to the other factors previously mentioned.
 
Finally, the appeal is even more dubious once you factor in that the market is seeing a noticeable price drop with FH even *without* ride-sharing to GEO.
 
--Noel
 

In GTO satellites will drift quite fast to their orbital position.

Even in GEO they will drift pretty fast with trivial delta-v.

[Nomadd]

Matching payloads was difficult for Ariane because they always need a big and a smaller payload. With the capacity of FH SpaceX could probably match any two payloads almost freely. The obstacle is the fairing size. Also Elon Musk has said he does not want two customer payloads depend on each other.

 
One more issue to think about: You're unlikely to be injecting two GEO payloads to the same orbit, so fit that into the delta-V calcs, required number of 2nd stage burns, time that your payloads spend without their arrays deployed,  etc etc. Seems like it gets messy really quickly, in addition to the other factors previously mentioned.
 
Finally, the appeal is even more dubious once you factor in that the market is seeing a noticeable price drop with FH even *without* ride-sharing to GEO.
 
--Noel
 

GEO satellites are all in the same orbit. You don't need a 2nd stage to change positions.

[virnin]

As for lunar trajectories, can FH send a Dragon 2 directly to the Moon?

And before anyone asks, can also land on the moon using convenient lithobraking maneuvers.

 

"Lithobraking"

We need to add that new term to the NSF online space terminology dictionary.

Where is that thing these days anyhow?

Did you mean this thread?

http://forum.nasaspaceflight.com/index.php?topic=39450

[Paul451]

Aside:

SF author David Brin is hosting an informal FH-inspired flash-fiction contest on his blog: https://davidbrin.blogspot.com.au/2018/02/what-happens-to-starman-and-red.html

100 word limit. Subject: aliens or future humans misinterpreting Tesla/Starman.

[WindyCity]

Just curious if anybody knows what data from the center core would have been gathered had the booster not crashed. I assume that on-board sensors sent back loads of information via telemetry. What differences are there between what was likely obtained by signal transmission and the physical data that was lost?  Do you have an opinion about how important that loss is. Thanks.

[sanman]

This article quotes Musk as saying that Falcon Heavy could be used for crewed missions, including the recently-shelved circumlunar flight, if BFR takes too long:

https://memeburn.com/2018/02/spacex-else-can-expect-2018/

“If that (BFR development) ends up taking longer than expected, then we will return to the idea of sending a Crew Dragon on a Falcon Heavy around the moon, and potentially do other things with crew on Falcon Heavy,” Musk was quoted as saying by Space News.

Well, at least Musk knows how to manage expectations. But are there a suitable repertoire of cutting-edge missions for FH to keep pushing the envelope, if BFR gets bogged down in development hell?

[speedevil]

“If that (BFR development) ends up taking longer than expected, then we will return to the idea of sending a Crew Dragon on a Falcon Heavy around the moon, and potentially do other things with crew on Falcon Heavy,” Musk was quoted as saying by Space News.

Well, at least Musk knows how to manage expectations. But are there a suitable repertoire of cutting-edge missions for FH to keep pushing the envelope, if BFR gets bogged down in development hell?

That depends on who's willing to pay for it.

There are a number of capability demonstrators F* could do, in principle, relatively inexpensively.

Testing propellant transfer between second stages.
Docking payloads as a service - two S2s, demonstrate clamping the payload adaptors together or similar.
Larger fairing.
Metholox second stage.
Metholox third stage - a relightable  stage liftable by one F9 expendable or one FH reusable to LEO, which can dock with a pre-orbited payload.

But while these offer great possibilities, they still need someone to actually buy them - be it for space hotels or to set up a working coke machine on the moon.

[Roy_H]

"Lithobraking"

We need to add that new term to the NSF online space terminology dictionary.

Where is that thing these days anyhow?

Did you mean this thread?

http://forum.nasaspaceflight.com/index.php?topic=39450

That's not the original one, but better than nothing. Thanks 

[John Alan]

Based on what Elon says at about 1:30 point in this video interview and then puff piece.
(Interview was pre-launch... one on one type at 39A pad site... and good questions I thought)

Do you think SpaceX throttles the boosters a lot in the last say 20 seconds to limit transfer loads at no more then the 1/2 million pounds each value Elon mentioned in answering the question?
OR... was he just simplifying the answer in layman's terms?



I guess the root question I am asking for comment and speculation on is...
What do you think the thrust verses time map looks like from launch thru to MECO from the boosters and the core?
 
On add
We know from what was said at the 15:20+ point in this version 2.0 SpaceX launch video...
Boosters throttling late in their burn is required for loads as per the 15:54 start of statement made... 

https://www.youtube.com/watch?v=wbSwFU6tY1c?t=15m20s

[envy887]

Based on what Elon says at about 1:30 point in this video interview and then puff piece.
(Interview was pre-launch... one on one type at 39A pad site... and good questions I thought)

Do you think SpaceX throttles the boosters a lot in the last say 20 seconds to limit transfer loads at no more then the 1/2 million pounds each value Elon mentioned in answering the question?
OR... was he just simplifying the answer in layman's terms?



I guess the root question I am asking for comment and speculation on is...
What do you think the thrust verses time map looks like from launch thru to MECO from the boosters and the core?
 
On add
We know from what was said at the 15:20+ point in this version 2.0 SpaceX launch video...
Boosters throttling late in their burn is required for loads as per the 15:54 start of statement made... 

https://www.youtube.com/watch?v=wbSwFU6tY1c?t=15m20s

The boosters throttle before BECO to keep gee loads within payload constraints. FH could pull up to ~12 gees at BECO if they didn't throttle the boosters. F9 could only pull 5 gees before MECO, that's not a problem there.

[AbuSimbel]

And we now have official word about Falcon Heavy's price if expendable: 150 million$; as well as clarification about its performance as listed on NASA's database* that would put it behind Delta IV H for High energy missions.

elonmusk: @doug_ellison @dsfpspacefl1ght 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


*reference: https://elvperf.ksc.nasa.gov/  and the tweet by Doug Ellison that brought it to our attention https://twitter.com/doug_ellison/status/959604957283368961 

[AbuSimbel]

Also, as I remember our own Robotbeat pointing out regarding FH 2nd stage lower ISP vs. D4H

elonmusk: @doug_ellison @dsfpspacefl1ght Both exhaust velocity (Isp) and mass ratio drive the rocket equation. Also thrust/mass matters a lot for Oberth effect. Delta upper stage Isp is good, but mass ratio and thrust are not.

https://twitter.com/elonmusk/status/963087975004319746

[rakaydos]

https://twitter.com/elonmusk/status/963094533830426624

"Side boosters landing on droneships & center expended is only ~10% performance penalty vs fully expended. Cost is only slightly higher than an expended F9, so around $95M."

5 mil over a baseline falcon heavy? perhaps they arnt as sure about core recovery as I thought.

[M.E.T.]

Did people read the rest of that twitter conversation? This struck me as particularly interesting:

https://twitter.com/DJSnM/status/963094625375240192

"For full recovery to make sense over single stick expendable needs each booster to be reused multiple times. I’m also curious as to whether SpaceX would consider stretching Stage 2 if there was a market that made sense."

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

"Under consideration. We’ve already stretched the upper stage once. Easiest part of the rocket to change. Fairing 2, flying soon, also has a slightly larger diameter. Could make fairing much longer if need be & will if BFR takes longer than expected."

[WH2OPaddler]

I am curious about how people feel as regards Elon's comment that he is no longer considering the manned mission around the moon, and that he would only do so if problems arose during development of the BFR/BFS. Thing is, problems WILL arise. Schedules WILL slip. And for those reasons, I think not going to the moon as soon as is feasible is a mistake.

As is well known in this group, the SLS is consuming an enormous amount of money. And as bad as that is, it's money being spent on a system that will likely never fly more than twice a year. Still, SLS is well regarded in Congress, where all those taxpayer dollars come from. Dollars that I believe can be better spent doing things like designing/building the infrastructure - habitats, power stations, mining and manufacturing facilities, bio-structures to grow crops, etc., etc - that Elon Musk and anyone else will need once the BFR/BFS is flying to either the moon or Mars. What's needed is a way to redirect the SLS billions so that it can be better spent elsewhere.

The recent test launch of FH garnered world wide attention, and rightly so. But it has not altered the view of a sufficient number of Congressmen and women as regards SLS. What would is a space spectacular. A feat that would hold the world's attention, not for a day or two, but for an entire week. That headline grabbing effort is sending people around the moon. No single mission in the foreseeable future has the potential to more thoroughly grab the attention of every [taxpaying] citizen in the US. For SpaceX, it could begin an entirely new movement: "Take me, too!"

In many L2 discussions, writers decry the fact that the non-space following public has no idea about how much SLS has and is costing, and how much less the Falcon 9 and FH launch vehicles are in comparison to the competition. But send people around the moon on a journey that will last a week or more, and any person with a cell phone will hear about the tens of billions of dollars presently being wasted on a system that has no future.

The work to make Dragon round-the-moon ready have to take place regardless of launch vehicle. And while I'm sure there are readers here who know in-depth how the launch vehicle certification requirements differ between paying tourists and paid astronauts, I cannot see that NASA could prohibit their launch (though I'll admit... I could be wrong).

I believe Elon should move to launch people to the moon because, if for no other reason, a) doing so will create a tsunami of taxpayer outrage that will put an end to SLS, and b) if properly directed, the money now being spent on SLS could be used to design and build the multitudinous pieces of infrastructure necessary to allow people to live and work on both the moon and Mars.

The longer SLS lives, the longer it will be before boots disturb the dusty surfaces of the moon or Mars.

Ad astra.   

[gongora]

The work to make Dragon round-the-moon ready have to take place regardless of launch vehicle.

No.  If the mission is done with BFR then Dragon wouldn't be involved at all.

[speedevil]

The work to make Dragon round-the-moon ready have to take place regardless of launch vehicle.

No.  If the mission is done with BFR then Dragon wouldn't be involved at all.

BFR can - if refuelled in LEO - get some 20 tons to and back from the moon.
Approximately equal to the whole payload of the Apollo program.
(not counting the mass of the vehicles)

https://forum.nasaspaceflight.com/index.php?topic=41682.40 - more advanced schemes can do over a hundred tons a launch, with some complexity.

FH - in comparison would need another vehicle to handle TLI and lunar return, or a vastly upgraded dragon 2 capsule.
BFR needs nothing.