Author Topic: Delta-IV Heavy payload capacity  (Read 1753 times)

Offline ncb1397

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Delta-IV Heavy payload capacity
« on: 04/13/2017 05:16 PM »
So, I heard on here that there was a Falcon Heavy performance upgrade and so I finally got around to looking at the SpaceX website for the full details. Something else caught my eye that I thought was weird. Delta IV Heavy LEO performance is listed as 22,560 kg which is actually beat by Proton M.

http://www.spacex.com/falcon-heavy

So, I head over to wikipedia to check, and it lists Proton M at 23 mT which is the same as what is listed on the SpaceX website. Wikipedia lists Delta IV Heavy at 28,790 kg which is 6,230 kg higher than what is listed on SpaceX's website. More importantly, ULAlaunch.com lists 28,370 kg:

http://www.ulalaunch.com/products_deltaiv.aspx

Does SpaceX know something we don't? Is this using a different orbital altitude as a standard for "LEO"? Still 6,230 kg is a massive difference for a slight difference in orbital specifications. SpaceX's website listed Falcon 9 performance at ~28 mT but that was revised down to ~23 mt at one point. Is this just another example of information on the SpaceX website being wrong?

Offline Dante80

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Re: Delta-IV Heavy payload capacity
« Reply #1 on: 04/13/2017 05:53 PM »
ULA lists LEO numbers as 200km circular x 28.7. SpaceX does it for an inclination of 28.5, while not listing altitude (I think I saw 185km circular somewhere in the past).

The higher (28.790kg) wikipedia number also comes from ULA (its from the D IV data sheet, page 34).

Pre-RS68A, DIV H might have had something closer to what SpaceX lists. Certainly not now though. No idea how or why SpaceX came up with that number on their website.

ps: The Proton M number is for 180 km circular x 51.5 from Baikonur
« Last Edit: 04/13/2017 06:06 PM by Dante80 »

Offline envy887

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Re: Delta-IV Heavy payload capacity
« Reply #2 on: 04/13/2017 06:36 PM »
The RS-86 DIVH (2012 and earlier) had a capability of 22,980 kg to ISS.  With RS-68A the payload to ISS went up to 25,980 kg and the payload to 200 km x 28.5 deg LEO is 28,370 kg.

Ed lists several references for these numbers: http://www.spacelaunchreport.com/delta4.html

Offline RonJohn63

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Re: Delta-IV Heavy payload capacity
« Reply #3 on: 04/17/2017 04:44 AM »
So, I heard on here that there was a Falcon Heavy performance upgrade and so I finally got around to looking at the SpaceX website for the full details. Something else caught my eye that I thought was weird. Delta IV Heavy LEO performance is listed as 22,560 kg which is actually beat by Proton M.

http://www.spacex.com/falcon-heavy

So, I head over to wikipedia to check, and it lists Proton M at 23 mT which is the same as what is listed on the SpaceX website.

The spacex web page you cited says (as of 16-Apr-2017) "the ability to lift into orbit over 54 metric tons".

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Does SpaceX know something we don't? Is this using a different orbital altitude as a standard for "LEO"? Still 6,230 kg is a massive difference for a slight difference in orbital specifications. SpaceX's website listed Falcon 9 performance at ~28 mT but that was revised down to ~23 mt at one point. Is this just another example of information on the SpaceX website being wrong?

If you actually mean the Falcon 9 (Full Thrust?) at http://www.spacex.com/falcon9 then the reduced payload might be related to the amount of fuel needed for landing on the drone ship.

Offline envy887

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Re: Delta-IV Heavy payload capacity
« Reply #4 on: 04/17/2017 01:30 PM »
So, I heard on here that there was a Falcon Heavy performance upgrade and so I finally got around to looking at the SpaceX website for the full details. Something else caught my eye that I thought was weird. Delta IV Heavy LEO performance is listed as 22,560 kg which is actually beat by Proton M.

http://www.spacex.com/falcon-heavy

So, I head over to wikipedia to check, and it lists Proton M at 23 mT which is the same as what is listed on the SpaceX website.

The spacex web page you cited says (as of 16-Apr-2017) "the ability to lift into orbit over 54 metric tons".

That's completely unrelated to what it says about Delta IV Heavy.

But that's an interesting point of itself; the text on the FH page hasn't been updated to match the specs listed further down. It's still technically true (63.8 tonnes is "over 54" tonnes) but annoyingly inconsistent.

Offline RonJohn63

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Re: Delta-IV Heavy payload capacity
« Reply #5 on: 04/17/2017 01:45 PM »
So, I heard on here that there was a Falcon Heavy performance upgrade and so I finally got around to looking at the SpaceX website for the full details. Something else caught my eye that I thought was weird. Delta IV Heavy LEO performance is listed as 22,560 kg which is actually beat by Proton M.

http://www.spacex.com/falcon-heavy

So, I head over to wikipedia to check, and it lists Proton M at 23 mT which is the same as what is listed on the SpaceX website.

The spacex web page you cited says (as of 16-Apr-2017) "the ability to lift into orbit over 54 metric tons".

That's completely unrelated to what it says about Delta IV Heavy.

I didn't mention the DIVH at all.

Instead, I was referring to your comment about the FH launching 23MT.   You probably meant http://www.spacex.com/falcon9

Quote
But that's an interesting point of itself; the text on the FH page hasn't been updated to match the specs listed further down. It's still technically true (63.8 tonnes is "over 54" tonnes) but annoyingly inconsistent.

As I wrote before, it probably has to do with reusable vs. expendable first stage.

Offline envy887

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Re: Delta-IV Heavy payload capacity
« Reply #6 on: 04/17/2017 02:02 PM »
I didn't mention the DIVH at all.

This thread is about DIVH.

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Instead, I was referring to your comment about the FH launching 23MT.   You probably meant http://www.spacex.com/falcon9

It wasn't my comment. And it definitely wasn't a reference to F9. There is a comparison of various heavy lifters at the bottom of http://www.spacex.com/falcon-heavy and Proton M is listed at 23 tonnes. More than DIVH, which is no longer true.

Quote
Quote
But that's an interesting point of itself; the text on the FH page hasn't been updated to match the specs listed further down. It's still technically true (63.8 tonnes is "over 54" tonnes) but annoyingly inconsistent.

As I wrote before, it probably has to do with reusable vs. expendable first stage.

It's much more likely that it simply wasn't updated with the last FH capability revision. That's probably also the explanation for the old DIVH numbers.

Offline RonJohn63

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Re: Delta-IV Heavy payload capacity
« Reply #7 on: 04/17/2017 02:18 PM »
There is a comparison of various heavy lifters at the bottom of http://www.spacex.com/falcon-heavy and Proton M is listed at 23 tonnes. More than DIVH, which is no longer true.

OK, I see that now.  (Didn't scroll down far enough before.)

Offline RedLineTrain

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Re: Delta-IV Heavy payload capacity
« Reply #8 on: 04/17/2017 03:38 PM »
So, I heard on here that there was a Falcon Heavy performance upgrade and so I finally got around to looking at the SpaceX website for the full details. Something else caught my eye that I thought was weird. Delta IV Heavy LEO performance is listed as 22,560 kg which is actually beat by Proton M.

http://www.spacex.com/falcon-heavy

So, I head over to wikipedia to check, and it lists Proton M at 23 mT which is the same as what is listed on the SpaceX website. Wikipedia lists Delta IV Heavy at 28,790 kg which is 6,230 kg higher than what is listed on SpaceX's website. More importantly, ULAlaunch.com lists 28,370 kg:

http://www.ulalaunch.com/products_deltaiv.aspx

Does SpaceX know something we don't? Is this using a different orbital altitude as a standard for "LEO"? Still 6,230 kg is a massive difference for a slight difference in orbital specifications. SpaceX's website listed Falcon 9 performance at ~28 mT but that was revised down to ~23 mt at one point. Is this just another example of information on the SpaceX website being wrong?

I think that's just an error on SpaceX's part.  Musk quoted the 28 ton figure in his Mars speech.  See page 27 of the slides.

http://www.spacex.com/sites/spacex/files/mars_presentation.pdf

Offline smfarmer11

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Re: Delta-IV Heavy payload capacity
« Reply #9 on: 04/20/2017 05:02 PM »
Its also not technically wrong, and it makes the FH payload look even more amazing. While not like they're deliberately posting that number to make them look better just maybe not changing it.

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