SpaceX Falcon Heavy Discussion (Thread 6)

[Jim]

Or can we do better, something we can use to convince the misguided scientist putting his faith in government statisticians?

Who and what government statisticians?

[AbuSimbel]

I don't think Doug Ellison is capable of talking about anything SpaceX related objectively. He's quick to pull the trigger whenever he finds the opportunity to criticize SpaceX, sometime sacrificing in-depth research of what he's saying when something confirms his already negative opinion of the company.
That's especially true when talking about Falcon performance figures: I remember him trying to pass the narrative that SpaceX has greatly increased the price of Falcon 9, failing to account for inflation and for the fact that, even with recovery, today's Falcon 9 has a payload capacity greater than 2010 F9 expendable. I politely told him and his answer was to quickly block me on Twitter.
Also if something is unclear and he has to make an estimate, he always assumes the worst for SpaceX, never giving them the benefit of the doubt. 
Definitely not a reasonable guy when it comes to SpaceX.

[Hominans Kosmos]

Or can we do better, something we can use to convince the misguided scientist putting his faith in government statisticians?

Who and what government statisticians?

You're right. I've misspoken, no statisticians on staff https://elvperf.ksc.nasa.gov/Pages/Contacts.aspx

[Svetoslav]

I don't think Doug Ellison is capable of talking about anything SpaceX related objectively. He's quick to pull the trigger whenever he finds the opportunity to criticize SpaceX, sometime sacrificing in-depth research of what he's saying when something confirms his already negative opinion of the company.
That's especially true when talking about Falcon performance figures: I remember him trying to pass the narrative that SpaceX has greatly increased the price of Falcon 9, failing to account for inflation and for the fact that, even with recovery, today's Falcon 9 has a payload capacity greater than 2010 F9 expendable. I politely told him and his answer was to quickly block me on Twitter.
Also if something is unclear and he has to make an estimate, he always assumes the worst for SpaceX, never giving them the benefit of the doubt. 
Definitely not a reasonable guy when it comes to SpaceX.

I'm also blocked by Doug Ellison, and thus, forever banned from UMSF. Can someone point out what this tweet is about, as I'm not worthy enough to read it?

[Lar]

UMSF?

[Svetoslav]

UMSF?

Unmanned spaceflight forum. Sorry, didn't have to bring personal issues on this board. Still... can anyone say what the discussion on Twitter is about, as some of us can't read it?

[JoerTex]

Please use private communication for the reply.

This is a SpaceX forum.

[Svetoslav]

Never mind, I found a way to read the discussion.

Do I get it right? Falcon Heavy doesn't have an efficient upper stage and that's why the rocket is inferior to other expendable rockets when it comes to interplanetary missions?

[octavo]

Never mind, I found a way to read the discussion.

Do I get it right? Falcon Heavy doesn't have an efficient upper stage and that's why the rocket is inferior to other expendable rockets when it comes to interplanetary missions?

Yep.

[guckyfan]

Never mind, I found a way to read the discussion.

Do I get it right? Falcon Heavy doesn't have an efficient upper stage and that's why the rocket is inferior to other expendable rockets when it comes to interplanetary missions?

Yep.

But that disadvantage makes FH inferior to Delta 4 Heavy only beyond Mars. Plus it can be at least partly remedied by giving the payload an additional kickstage, taking advantage of the higher payload capacity to lower energetic trajectories. Despite the upper stage FH is still an incredibly powerful launch vehicle even for high energy trajectories.

[Svetoslav]

That's exactly what I wanted to ask. If Falcon Heavy is all about putting 60ish tons in LEO, what would prevent adding a cryo upper stage?

[Hominans Kosmos]

Never mind, I found a way to read the discussion.

Do I get it right? Falcon Heavy doesn't have an efficient upper stage and that's why the rocket is inferior to other expendable rockets when it comes to interplanetary missions?

Yep.

But that disadvantage makes FH inferior to Delta 4 Heavy only beyond Mars. Plus it can be at least partly remedied by giving the payload an additional kickstage, taking advantage of the higher payload capacity to lower energetic trajectories. Despite the upper stage FH is still an incredibly powerful launch vehicle even for high energy trajectories.

I'm finding my limited mathematical and programming qualifications make getting that point across over at the FB group difficult.

[Robotbeat]

Never mind, I found a way to read the discussion.

Do I get it right? Falcon Heavy doesn't have an efficient upper stage and that's why the rocket is inferior to other expendable rockets when it comes to interplanetary missions?

Yep.

But that disadvantage makes FH inferior to Delta 4 Heavy only beyond Mars. Plus it can be at least partly remedied by giving the payload an additional kickstage, taking advantage of the higher payload capacity to lower energetic trajectories. Despite the upper stage FH is still an incredibly powerful launch vehicle even for high energy trajectories.

Not even /partially/ mitigated: ENTIRELY mitigated.

Doug was being disingenuous. You would not launch a large payload to such high energy trajectories on any EELV or Falcon without a kick stage. Atlas V with kick stage is cheaper & higher performance than D4H without one (which is partly why New Horizons did just that), and FH plus kick stage beats them both.

[Robotbeat]

That's exactly what I wanted to ask. If Falcon Heavy is all about putting 60ish tons in LEO, what would prevent adding a cryo upper stage?

Simply stretching the upper stage of FH would basically null out any performance difference. And adding a kick stage on top of *that* would allow FH to launch Europa Clipper direct to Jupiter like SLS.

[Ictogan]

That's exactly what I wanted to ask. If Falcon Heavy is all about putting 60ish tons in LEO, what would prevent adding a cryo upper stage?

1. Development costs
2. extreme fineness ratio of the vehicle+GSE incompability if the cryogenic stage would be part of the vehicle stack
3. taking up a large portion of the fairing volume and having to figure out how to fuel it in the fairings if it would be in the fairings

[Jim]

Doug was being disingenuous. You would not launch a large payload to such high energy trajectories on any EELV or Falcon without a kick stage. Atlas V with kick stage is cheaper & higher performance than D4H without one (which is partly why New Horizons did just that), and FH plus kick stage beats them both.

Not true.  Only high speed missions like PNH and PSP need kick stages. Mars, Jupiter and Saturn missions don't and that is where FH falls short.

[dglow]

3. taking up a large portion of the fairing volume and having to figure out how to fuel it in the fairings if it would be in the fairings

I've always wondered about this. (slightly OT, apologies) What is the reason for Atlas V's fairing encapsulating (much of) Centaur?

[Jim]

Simply stretching the upper stage of FH would basically null out any performance difference. And adding a kick stage on top of *that* would allow FH to launch Europa Clipper direct to Jupiter like SLS.

There is no kick stage for Europa Clipper on FH.  "Kick" stages are solid motors which have high thrust.  Solid motors and Falcon are none starters.

There is no stretching of the upperstage.  there is no more F9 development.

Europa Clipper on FH would use gravity assists.

[Jim]

3. taking up a large portion of the fairing volume and having to figure out how to fuel it in the fairings if it would be in the fairings

I've always wondered about this. (slightly OT, apologies) What is the reason for Atlas V's fairing encapsulating (much of) Centaur?

Aeroloads with the big fairing

[Robotbeat]

Doug was being disingenuous. You would not launch a large payload to such high energy trajectories on any EELV or Falcon without a kick stage. Atlas V with kick stage is cheaper & higher performance than D4H without one (which is partly why New Horizons did just that), and FH plus kick stage beats them both.

Not true.  Only high speed missions like PNH and PSP need kick stages. Mars, Jupiter and Saturn missions don't and that is where FH falls short.

He was looking basically exclusively at high energy missions, higher energy than the typical deep space missions which use multiple gravity assists.

To Mars, FH also beats Atlas V handily.