Author Topic: Why do todays largest rockets have similar payload mass to LEO capacity?  (Read 15233 times)

Offline TakeOff

  • Full Member
  • ***
  • Posts: 392
  • Liked: 85
  • Likes Given: 115
Atlas V, Delta IV, Ariane 5, Proton, Mitsubishi H-IIB all can launch between 19 and 23 tons to LEO. Why are they so similar in this respect?

Is it because there isn't much demand for larger launches? Maybe it is enough for any reasonable spy satellite, or communication satellite to GEO? Or are there design reasons which dictate that costs increases more rapidly beyond that launch capability?
« Last Edit: 07/28/2014 04:32 am by TakeOff »

Offline Pipcard

  • Full Member
  • ****
  • Posts: 622
  • Liked: 275
  • Likes Given: 130
I'm guessing that it's like what you said; it's just the demand for spysats and geostationary comsats that drives payload capacity. Other, larger payloads won't launch frequently enough. This is why I like the Mars For Less proposal, because it doesn't require the development of super-heavy launch vehicles and the maintenance of their infrastructure.

edit: I've changed my mind. Mars for Less would have required complex EVA assembly for the ERV as well as the Hab (though the propulsion stages would only require relatively simple dockings), so it would be better to use a heavier launch vehicle to launch something in one piece.

Also, the H-IIB's (which was designed to lift the HTV and its cargo) primary contractor is Mitsubishi, not Hitachi.
« Last Edit: 10/25/2015 05:14 am by Pipcard »

Offline edkyle99

  • Expert
  • Senior Member
  • *****
  • Posts: 15391
    • Space Launch Report
  • Liked: 8566
  • Likes Given: 1356
Atlas V, Delta IV, Ariane 5, Proton, Hitacchi H-IIB all can launch between 19 and 23 tons to LEO. Why are they so similar in this respect?

Is it because there isn't much demand for larger launches? Maybe it is enough for any reasonable spy satellite, or communication satellite to GEO? Or are there design reasons which dictate that costs increases more rapidly beyond that launch capability?
I think that today it is geosynchronous satellites, both commercial and defense types, that play a dominant role in determining the capability of launch vehicles.  That said, it is worth mentioning that both Proton and H-IIB were originally built for non-GEO work.  H-IIB has so far only launched HTV missions to ISS.  Proton, after derivation from a massive never-realized ICBM concept, was developed to launch Zond spacecraft (planned to be manned, but never attained) around the Moon.  Today, of course, Proton and Ariane 5 share the bulk of the world's commercial GTO work while Atlas V and Delta IV are doing mostly the government work for which they were designed.  Only a fraction of that work is to LEO.

 - Ed Kyle   
« Last Edit: 07/28/2014 02:49 am by edkyle99 »

Offline TakeOff

  • Full Member
  • ***
  • Posts: 392
  • Liked: 85
  • Likes Given: 115
Also, the H-IIB's (which was designed to lift the HTV and its cargo) primary contractor is Mitsubishi, not Hitachi.
Hehe, of course. I mix those famous Japanese brand names. I've edited it now. Never hear much about their rockets.

Offline Patchouli

  • Senior Member
  • *****
  • Posts: 4490
  • Liked: 253
  • Likes Given: 457
Atlas V, Delta IV, Ariane 5, Proton, Hitacchi H-IIB all can launch between 19 and 23 tons to LEO. Why are they so similar in this respect?

Is it because there isn't much demand for larger launches? Maybe it is enough for any reasonable spy satellite, or communication satellite to GEO? Or are there design reasons which dictate that costs increases more rapidly beyond that launch capability?
I think that today it is geosynchronous satellites, both commercial and defense types, that play a dominant role in determining the capability of launch vehicles.  That said, it is worth mentioning that both Proton and H-IIB were originally built for non-GEO work.  H-IIB has so far only launched HTV missions to ISS.  Proton, after derivation from a massive never-realized ICBM concept, was developed to launch Zond spacecraft (planned to be manned, but never attained) around the Moon.  Today, of course, Proton and Ariane 5 share the bulk of the world's commercial GTO work while Atlas V and Delta IV are doing mostly the government work for which they were designed.  Only a fraction of that work is to LEO.

 - Ed Kyle   

On the US side the EELVs were built to replace the Titian IV and Shuttle which had similar payload sizes.

I wonder how much effect LV size has had on the mass of commercial satellites and will Falcon Heavy cause the creation of a new class of heavier and more powerful comsats.
Some applications like satellite Internet seem to be limited in capacity by the size of the antenna , and the power of the transmitters.
More spot beams and more power means higher data rates for customers.
Then there's other markets such as 4K and 8K HDTV which need higher data.
Yes you can use better compression but going too high of compression introduces artifacts which can defeat the entire purpose of the higher resolution.
« Last Edit: 07/28/2014 05:04 pm by Patchouli »

Offline pippin

  • Regular
  • Senior Member
  • *****
  • Posts: 2575
  • Liked: 312
  • Likes Given: 45
Nobody will build payloads for only a single LV.
And I don't think you really want much bigger power for Internet data. For that, you need a LEO constellation anyway so you don't need as much power.
Also SEP supports a downsizing trend.

Offline JasonAW3

  • Senior Member
  • *****
  • Posts: 2443
  • Claremore, Ok.
  • Liked: 410
  • Likes Given: 14
Atlas V, Delta IV, Ariane 5, Proton, Hitacchi H-IIB all can launch between 19 and 23 tons to LEO. Why are they so similar in this respect?

Is it because there isn't much demand for larger launches? Maybe it is enough for any reasonable spy satellite, or communication satellite to GEO? Or are there design reasons which dictate that costs increases more rapidly beyond that launch capability?
I think that today it is geosynchronous satellites, both commercial and defense types, that play a dominant role in determining the capability of launch vehicles.  That said, it is worth mentioning that both Proton and H-IIB were originally built for non-GEO work.  H-IIB has so far only launched HTV missions to ISS.  Proton, after derivation from a massive never-realized ICBM concept, was developed to launch Zond spacecraft (planned to be manned, but never attained) around the Moon.  Today, of course, Proton and Ariane 5 share the bulk of the world's commercial GTO work while Atlas V and Delta IV are doing mostly the government work for which they were designed.  Only a fraction of that work is to LEO.

 - Ed Kyle   

On the US side the EELVs were built to replace the Titian IV and Shuttle which had similar payload sizes.

I wonder how much effect LV size has had on the mass of commercial satellites and will Falcon Heavy cause the creation of a new class of heavier and more powerful comsats.
Some applications like satellite Internet seem to be limited in capacity by the size of the antenna , and the power of the transmitters.
More spot beams and more power means higher data rates for customers.
Then there's other markets such as 4K and 8K HDTV which need higher data.
Yes you can use better compression but going too high of compression introduces artifacts which can defeat the entire purpose of the higher resolution.

I wouldn't be suprised about bigger Comsats, nor would I be surprised when Bigelow send up the first of his modules from Vandenberg.  (That is, if they'll allow strictly commercial flights from an Air Force base).
My God!  It's full of universes!

Offline edkyle99

  • Expert
  • Senior Member
  • *****
  • Posts: 15391
    • Space Launch Report
  • Liked: 8566
  • Likes Given: 1356
I wonder how much effect LV size has had on the mass of commercial satellites and will Falcon Heavy cause the creation of a new class of heavier and more powerful comsats.
In the "old days", when rockets were less powerful, commercial satellites drove the creation of ever more powerful rockets.  During the 1970s, for example, RCA Global Communications paid for part of the development costs of improved Castor 4 motors so that Delta rockets could lift its new 3-axis stabilized GEO satellites.

That seems to have changed.  Ariane 5, for example, can lift nearly 10 tonnes to GTO, but there haven't been many single-payload GTO launches (the last was in 2009) and none of those seems to have pushed the rocket anywhere near its full capability. 

 - Ed Kyle
« Last Edit: 07/28/2014 08:40 pm by edkyle99 »

Offline baldusi

  • Senior Member
  • *****
  • Posts: 8356
  • Buenos Aires, Argentina
  • Liked: 2539
  • Likes Given: 8273
Falcon Heavy might have a certain impact. But the basic idea is that you have to have at least two price competitive suppliers to get commercial to actually use a feature. For example, how many satellites actually require a 5m fairing? Since Proton-M and Sea Launch have only proven 4m fairing, nobody wants to commit to Ariane 5 exclusively. Also, both are limited to 6.4 tonnes to GTO (or there about). With FH and Ariane 5ME (with its expected 12.5 tonnes to GTO), we might see a certain growth trend.

Offline TakeOff

  • Full Member
  • ***
  • Posts: 392
  • Liked: 85
  • Likes Given: 115
Nobody will build payloads for only a single LV.
That is a very good argument!

I want to illustrate that idea as it inspires me, in terms of that 20 tons to LEO became a standard once, by coincidences pretty much unrelated to today's satellite "needs" and rocket economics. Super powers in a cold war just happened to balance each others to that level. After a while of having prioritized even bigger rockets, the race instead began to get hotter for bigger tanks. Or something like that. You can safely build a 20 tons to LEO satellite, because you have half a dozen competitors to launch it. But if there exists only one 50 tons to LEO launcher, then you need to have some trust in order to invest in a 50 ton satellite.

Offline floss

  • Full Member
  • ****
  • Posts: 549
  • Liked: 33
  • Likes Given: 131
Nobody will build payloads for only a single LV.
That is a very good argument!

I want to illustrate that idea as it inspires me, in terms of that 20 tons to LEO became a standard once, by coincidences pretty much unrelated to today's satellite "needs" and rocket economics. Super powers in a cold war just happened to balance each others to that level. After a while of having prioritized even bigger rockets, the race instead began to get hotter for bigger tanks. Or something like that. You can safely build a 20 tons to LEO satellite, because you have half a dozen competitors to launch it. But if there exists only one 50 tons to LEO launcher, then you need to have some trust in order to invest in a 50 ton satellite.



Fuel for orbital maneovering would be a good market for a 50 ton to LEO launcher but with todays market conditions 10 to 15 tons of fuel in GEO would be far more valuable seeing as a multi billion transfer vehicle need not be developed.

Offline Kryten

  • Full Member
  • ****
  • Posts: 735
  • Liked: 426
  • Likes Given: 33
You can safely build a 20 tons to LEO satellite, because you have half a dozen competitors to launch it. But if there exists only one 50 tons to LEO launcher, then you need to have some trust in order to invest in a 50 ton satellite.
Except nobody is building 20 tons satellites, with the sole exception of the NRO (larger recon sats) and the Russian government (space station modules); and neither would be willing to use a competing launcher.

Offline QuantumG

  • Senior Member
  • *****
  • Posts: 9238
  • Australia
  • Liked: 4477
  • Likes Given: 1108
20 ton to LEO != 20 ton satellite.
Human spaceflight is basically just LARPing now.

Offline breadfan

  • Member
  • Posts: 25
  • Liked: 7
  • Likes Given: 31
20 ton to LEO != 20 ton satellite.
Why is this the case? I always thought the payload to LEO number was the maximum mass that could be put in LEO, and therefore an upper limit on satellite mass?

Offline QuantumG

  • Senior Member
  • *****
  • Posts: 9238
  • Australia
  • Liked: 4477
  • Likes Given: 1108
20 ton to LEO != 20 ton satellite.
Why is this the case? I always thought the payload to LEO number was the maximum mass that could be put in LEO, and therefore an upper limit on satellite mass?

Theoretically, but the orbit chosen for the metric is essentially arbitrary. Most satellites are not going to a LEO orbit at all.
Human spaceflight is basically just LARPing now.

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 37440
  • Cape Canaveral Spaceport
  • Liked: 21450
  • Likes Given: 428
Here is a short synopsis of launcher development in terms of GTO capability.  LEO capability is a fallout of GTO (for these cases).

1980’s

Shuttle – 65klb to LEO  5-10Klb to GSO 15’ dia x 60’ payload bay.   
Ariane -  2 Delta/Atlas class to GTO  4m fairing


Post Challenger

Titan IV  -   5-10Klb to GSO 15’ dia x 40’ usable fairing.
Ariane  4 – 2 spacecraft totaling 4.5-9.5klb to GTO  4m fairing
Atlas II –  6.2-8.0klb to GTO  4m fairing


Late 1990’s

Atlas III – 8.9-8.9klb to GTO  4m fairing
Delta III – 8.4klb to GTO  4m fairing
Ariane 5 - 2 spacecraft totaling 13.6-23.1klb to GTO  5m fairing

2000’s

Atlas V – 10.5-19.2klb to GTO  4m or 5m fairing
Delta IV – 8.4-28.6klb to GTO  4m or 5m fairing


Spacecraft growth has been the driver.

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 37440
  • Cape Canaveral Spaceport
  • Liked: 21450
  • Likes Given: 428
Atlas II, IIAS, III were all driven by commercial requirements.
The intermediate EELV's, the ones with solids, were driven by commercial requirements.  The DOD did not have requirements in those performance ranges.    DOD requirements were for small, medium and heavy EELV's, which equated to Delta II, Atlas II and Titan IV.  The deletion of the small vehicle was to reduce the number of configurations (upper stages) to save money and was done by eliminating the PKM on GPS and performing direct insertion.  When the legacy spacecraft programs of the 1980's were at the end of their production runs, the replacement programs took advantage of commercial comsat buses and integral perigee boost systems.  This allowed the use of the intermediate EELV's and reduced the need for the heavy EELV's. 

Offline floss

  • Full Member
  • ****
  • Posts: 549
  • Liked: 33
  • Likes Given: 131
Thought Titan IV was built to launch shuttle class payloads that were banned from the shuttle hence the short lift time of that rocket .

Damn pity that NASA did not use Titan for the construction of the ISS it would have saved a fortune.

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 37440
  • Cape Canaveral Spaceport
  • Liked: 21450
  • Likes Given: 428
Thought Titan IV was built to launch shuttle class payloads that were banned from the shuttle hence the short lift time of that rocket .


It was developed before Challenger.  A production run of 41 vehicles from 1989 to 2005 is not defined as a short lifetime.

Offline floss

  • Full Member
  • ****
  • Posts: 549
  • Liked: 33
  • Likes Given: 131
Thought Titan IV was built to launch shuttle class payloads that were banned from the shuttle hence the short lift time of that rocket .


It was developed before Challenger.  A production run of 41 vehicles from 1989 to 2005 is not defined as a short lifetime.

Compared to Delta or Atlas  .

PS. says a lot about how much fait the US military had in Shuttle .

Tags:
 

Advertisement NovaTech
Advertisement Northrop Grumman
Advertisement
Advertisement Margaritaville Beach Resort South Padre Island
Advertisement Brady Kenniston
Advertisement NextSpaceflight
Advertisement Nathan Barker Photography
0