Author Topic: Economics of RTLS?  (Read 12723 times)

Offline IainMcClatchie

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Economics of RTLS?
« on: 07/23/2016 01:22 am »
According to some speculation here:

Falcon 9 RTLS can send 12 tonnes into ISS orbit.
Falcon 9 Barge landing can sent 17 tonnes into ISS orbit.

That's a huge improvement for the work of sending the barge out and back.  And they own the barge asset regardless of what they do with it.  How much can the barge trip possibly cost?  A couple million $?  Given that the launch costs >$70m, that's peanuts.

So why RTLS?  Why wouldn't NASA just fill the trunk with 5 tonnes of extra stuff for the ISS?  Surely there must be lots of NASA folks with stuff they'd like to bolt on to the ISS exterior if only they could get it there.  Among other things, you could put 3 BEAM modules in the trunk and have quite a bit of spare payload.  If there were propellant tanks in the trunk, and if you had Dragon on the right ISS port, you could reboost the entire ISS.

RTLS make sense to me in the context of development.  Their first stage recovery was on land, and I can see how it would make a bigger, more stable target.

RTLS also makes sense in the context of radical reuse.  But you have to get A LOT of reuse, and shave the launch prep overhead way, way down to overcome a 41% advantage in payload.

Any ideas?

Offline Jim

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Re: Economics of RTLS?
« Reply #1 on: 07/23/2016 01:30 am »

So why RTLS?  Why wouldn't NASA just fill the trunk with 5 tonnes of extra stuff for the ISS?  Surely there must be lots of NASA folks with stuff they'd like to bolt on to the ISS exterior if only they could get it there.  Among other things, you could put 3 BEAM modules in the trunk and have quite a bit of spare payload.  If there were propellant tanks in the trunk, and if you had Dragon on the right ISS port, you could reboost the entire ISS.



NASA doesn't have the money for 5 tonnes of extra stuff for the ISS.  It isnt the cost of getting it there, it is the cost buying and building the "extra stuff".    Anyways, there are no places for BEAM modules, not to mention, they are not made to be operationally used.  It is just a test module.
And no, the Dragon can't reboost the ISS, its thrusters point in the wrong direction.  And there isn't going to be propellant tanks in the trunkc.
« Last Edit: 07/23/2016 01:32 am by Jim »

Online envy887

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Re: Economics of RTLS?
« Reply #2 on: 07/23/2016 02:23 am »
What Jim said, plus:

Dragon is volumetrically limited, not mass limited. Even if they wanted to put more payload in, there's no room.

Same goes for the trunk, especially since it has to be unloaded remotely. Can't exactly squeeze stuff in there.

RTLS is only 30% lower payload than expendable, per Musk. Barber landing is 15% lower. For the coming upgrades, that's 16t RTLS and 19t to a barge landing.

Offline Kabloona

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Re: Economics of RTLS?
« Reply #3 on: 07/23/2016 03:21 pm »
Barber landing is 15% lower.

Don't get Elon mad again. It's a "drone ship," not a barber.  ;)

Online Johnnyhinbos

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Economics of RTLS?
« Reply #4 on: 07/23/2016 03:47 pm »
If you look at the Office of the Inspector General's audit of CRS post CRS-7 and Antares failure, one fault pointed at NASA was their failure to fully utilize the trunk. There was a table with percent utilization used per flight. Though NASA has gotten better manifesting more recent flights, they still are under utilizing it.

Look at page 17:

https://oig.nasa.gov/audits/reports/FY16/IG-16-025.pdf
« Last Edit: 07/23/2016 03:50 pm by Johnnyhinbos »
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Offline GWH

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Re: Economics of RTLS?
« Reply #5 on: 07/23/2016 03:53 pm »
This article is a good summary of some of the challenges to date in maximizing mass given the limited volume:
http://www.parabolicarc.com/2016/07/11/upmass/

Offline kch

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Re: Economics of RTLS?
« Reply #6 on: 07/23/2016 04:39 pm »
Barber landing is 15% lower.

Don't get Elon mad again. It's a "drone ship," not a barber.  ;)

Hmmm -- wonder if a red-and-white-spiral-striped pole would help those marginal landings succeed?  Just might be the thing that shaves the day ... ;D

Offline IainMcClatchie

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Re: Economics of RTLS?
« Reply #7 on: 07/23/2016 08:53 pm »
Johnny,

Thank you for the pointer to the NASA audit report.  That was enlightening.

If I understand correctly, NASA let two commercial resupply contracts.
Orbital: 8 missions, 18.6 tonnes up, 18.6 tonnes trash, $1.9B, $102,000/kg
SpaceX: 12 missions, 35.4 tonnes up, X tonnes down, $1.6B, $45,000/kg

Is there some reason Orbital gets paid over 2x more per amount of upmass?

Offline skybum

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Re: Economics of RTLS?
« Reply #8 on: 07/23/2016 09:01 pm »
And no, the Dragon can't reboost the ISS, its thrusters point in the wrong direction.  And there isn't going to be propellant tanks in the trunkc.

Out of curiosity: why not? Is there anything preventing the trunk from carrying a propellant tank + a thruster that *isn't* pointed in the wrong direction?

Offline joek

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Re: Economics of RTLS?
« Reply #9 on: 07/23/2016 09:08 pm »
Is there some reason Orbital gets paid over 2x more per amount of upmass?

Orbital was a late COTS replacement for RpK (terminated for non-performance).  Orbital had to build something fairly quickly with less funding, and which was profitable at low launch rates.  The difference in pricing is the quid-pro-quo.

edit: and what whitelancer64 said more concisely.  Difference in price represents difference in cost.
« Last Edit: 07/23/2016 10:43 pm by joek »

Offline whitelancer64

Re: Economics of RTLS?
« Reply #10 on: 07/23/2016 09:16 pm »
Johnny,

Thank you for the pointer to the NASA audit report.  That was enlightening.

If I understand correctly, NASA let two commercial resupply contracts.
Orbital: 8 missions, 18.6 tonnes up, 18.6 tonnes trash, $1.9B, $102,000/kg
SpaceX: 12 missions, 35.4 tonnes up, X tonnes down, $1.6B, $45,000/kg

Is there some reason Orbital gets paid over 2x more per amount of upmass?

They don't. They get paid the amount they bid for the resupply services.
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Online Ronsmytheiii

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Re: Economics of RTLS?
« Reply #11 on: 07/24/2016 08:29 am »
What Jim said, plus:

Dragon is volumetrically limited, not mass limited. Even if they wanted to put more payload in, there's no room.

Same goes for the trunk, especially since it has to be unloaded remotely. Can't exactly squeeze stuff in there.

RTLS is only 30% lower payload than expendable, per Musk. Barber landing is 15% lower. For the coming upgrades, that's 16t RTLS and 19t to a barge landing.

On the other hand, 15% for a GEO mission is value that they traded for reusability. Even without any extra payloads, the satellite lifted could have extra energy to get to its slot quicker (meaning revenue sooner, or an extended life once in place). Some vendors value this above all else, and may go to Arianespace/ILS (or even ULA) regardless of reduced launch prices for Falcon 9.

« Last Edit: 07/24/2016 08:29 am by Ronsmytheiii »

Offline AncientU

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Re: Economics of RTLS?
« Reply #12 on: 07/24/2016 12:42 pm »
What Jim said, plus:

Dragon is volumetrically limited, not mass limited. Even if they wanted to put more payload in, there's no room.

Same goes for the trunk, especially since it has to be unloaded remotely. Can't exactly squeeze stuff in there.

RTLS is only 30% lower payload than expendable, per Musk. Barber landing is 15% lower. For the coming upgrades, that's 16t RTLS and 19t to a barge landing.

On the other hand, 15% for a GEO mission is value that they traded for reusability. Even without any extra payloads, the satellite lifted could have extra energy to get to its slot quicker (meaning revenue sooner, or an extended life once in place). Some vendors value this above all else, and may go to Arianespace/ILS (or even ULA) regardless of reduced launch prices for Falcon 9.

And they are entitled to do that.  FH would serve this hypothetical customer well, and RTLS is how FH conops will be born. (At least for the boosters.)
« Last Edit: 07/24/2016 12:48 pm by AncientU »
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Online kevinof

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Re: Economics of RTLS?
« Reply #13 on: 07/24/2016 12:47 pm »
And no, the Dragon can't reboost the ISS, its thrusters point in the wrong direction.  And there isn't going to be propellant tanks in the trunkc.

Out of curiosity: why not? Is there anything preventing the trunk from carrying a propellant tank + a thruster that *isn't* pointed in the wrong direction?

There is nothing to stop space x doing this but as far as we know they have no plans and they (as far as we know) have not been asked to.

It would require significant work and time and these are two things space x have little of these days.

Offline mfck

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Re: Economics of RTLS?
« Reply #14 on: 07/24/2016 12:57 pm »


And no, the Dragon can't reboost the ISS, its thrusters point in the wrong direction.  And there isn't going to be propellant tanks in the trunkc.

Out of curiosity: why not? Is there anything preventing the trunk from carrying a propellant tank + a thruster that *isn't* pointed in the wrong direction?

There is nothing to stop space x doing this but as far as we know they have no plans and they (as far as we know) have not been asked to.

It would require significant work and time and these are two things space x have little of these days.

If the trunk had a tank and an engine those would be discarded with the trunk, which goes against SpaceX goal of full and rapid reusability. The trunk as it is today is already a compromise to that principle.


Online Herb Schaltegger

Re: Economics of RTLS?
« Reply #15 on: 07/24/2016 01:30 pm »
And no, the Dragon can't reboost the ISS, its thrusters point in the wrong direction.  And there isn't going to be propellant tanks in the trunkc.

Out of curiosity: why not? Is there anything preventing the trunk from carrying a propellant tank + a thruster that *isn't* pointed in the wrong direction?

There is nothing to stop space x doing this but as far as we know they have no plans and they (as far as we know) have not been asked to.

It would require significant work and time and these are two things space x have little of these days.

Even more, it would require Dragon to be berthed to a location that has an axis that passes through or very close to the station center of mass. Operationally it's not worth it. There are other options for reboost - SpaceX's combination of pressurized up- and downmass is more valuable than hypergolic propellants.
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Offline Dave G

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Re: Economics of RTLS?
« Reply #16 on: 07/25/2016 02:48 am »
Falcon 9 RTLS can send 12 tonnes into ISS orbit.
Falcon 9 Barge landing can sent 17 tonnes into ISS orbit.

That's a huge improvement for the work of sending the barge out and back.  And they own the barge asset regardless of what they do with it.  How much can the barge trip possibly cost?  A couple million $?  Given that the launch costs >$70m, that's peanuts.

Assuming minimal costs to reuse a first stage, then FH RTLS may be cheaper than an F9 barge landing.

Elon said the first stage propellant is around $100-200 thousand.  If it costs a couple million $ more to use the barge, then FH RTLS seems cheaper.

Remember, FH can throw 7 tons GTO with all 3 stages RTLS.  That's the entire launch market with RTLS.

So I'll turn the question around: After FH reuse gets working well, why bother with maintaining a barge?

Online Brovane

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Re: Economics of RTLS?
« Reply #17 on: 07/25/2016 03:13 am »
What Jim said, plus:

Dragon is volumetrically limited, not mass limited. Even if they wanted to put more payload in, there's no room.

Same goes for the trunk, especially since it has to be unloaded remotely. Can't exactly squeeze stuff in there.

RTLS is only 30% lower payload than expendable, per Musk. Barber landing is 15% lower. For the coming upgrades, that's 16t RTLS and 19t to a barge landing.

On the other hand, 15% for a GEO mission is value that they traded for reusability. Even without any extra payloads, the satellite lifted could have extra energy to get to its slot quicker (meaning revenue sooner, or an extended life once in place). Some vendors value this above all else, and may go to Arianespace/ILS (or even ULA) regardless of reduced launch prices for Falcon 9.

Would SpaceX say no if a vendor was willing to pay a higher price to use the full performance of a F9 in expendable mode?   

SpaceX has been using extra margin on the last couple of GTO launches to deliver the satellites to Super-synchronous GTO. 




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Offline guckyfan

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Re: Economics of RTLS?
« Reply #18 on: 07/25/2016 04:43 am »
Would SpaceX say no if a vendor was willing to pay a higher price to use the full performance of a F9 in expendable mode?   

My impression is they believe they can launch a Falcon Heavy with 3 core RTLS cheaper than a Falcon 9 expendable. So that is what they will offer once reuse is established as a safe launch. Payloads that will require expending Falcon Heavy are rare. And even then it would mostly be only the central core expended.
 
SpaceX has been using extra margin on the last couple of GTO launches to deliver the satellites to Super-synchronous GTO.

As far as I know on one flight for SES, but that was to make up for a launch delay. The contract was for a launch with a higher -deltaV GTO and they decided to deliver to a better GTO. With the increased performans it seems they now offer GEO -1500m/s as standard to match Arianespace.

Offline darkenfast

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Re: Economics of RTLS?
« Reply #19 on: 07/25/2016 05:33 am »
One correction for the OP: I believe that the barge is leased, not owned by SpaceX.  The original ASDS was returned to it's original configuration and is back in the commercial barge business.  The tugs and support ships are on charter.  I don't believe we know the nature of the contracts, for instance, can a vessel take off on a run for another customer when SpaceX is in a slow period, or do the crews shift around to other vessels of the company, that sort of thing.  The crews and vessels are actually quite small as these thing go.   
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