Author Topic: IAC 2017 -- ITS v0.2  (Read 41390 times)

Offline DJPledger

  • Full Member
  • ***
  • Posts: 306
  • Liked: 81
  • Likes Given: 1887
Re: IAC 2017 -- ITS v0.2
« Reply #100 on: 06/07/2017 08:04 AM »
Future versions of the ITS system larger than the one announced at IAC2016 will need a larger version of Raptor to keep the engine nos. of 42 on booster and 9 on ship. 42 engines on a booster is already pushing it and I just can't imagine a rocket with ~100 FFSC engines on the bottom of it. Just far too many highly stressed parts to go wrong. Also EM likes the no. 42. SpaceX will have the funds to dev. a larger version of Raptor once the initial ITS system is in service and their sat. constellation is bringing in revenue.

Once you have the design for ITS closed out just scale it up for future larger versions.

Offline rakaydos

  • Full Member
  • **
  • Posts: 203
  • Liked: 72
  • Likes Given: 2
Re: IAC 2017 -- ITS v0.2
« Reply #101 on: 06/08/2017 07:05 AM »
Future versions of the ITS system larger than the one announced at IAC2016 will need a larger version of Raptor to keep the engine nos. of 42 on booster and 9 on ship. 42 engines on a booster is already pushing it and I just can't imagine a rocket with ~100 FFSC engines on the bottom of it. Just far too many highly stressed parts to go wrong. Also EM likes the no. 42. SpaceX will have the funds to dev. a larger version of Raptor once the initial ITS system is in service and their sat. constellation is bringing in revenue.

Once you have the design for ITS closed out just scale it up for future larger versions.
42 engines isnt THAT much.

It's only about 2 of these strapped together:
« Last Edit: 06/08/2017 07:07 AM by rakaydos »

Offline Ictogan

  • Member
  • Posts: 87
  • Germany
  • Liked: 46
  • Likes Given: 36
Re: IAC 2017 -- ITS v0.2
« Reply #102 on: 06/08/2017 07:17 AM »
Future versions of the ITS system larger than the one announced at IAC2016 will need a larger version of Raptor to keep the engine nos. of 42 on booster and 9 on ship. 42 engines on a booster is already pushing it and I just can't imagine a rocket with ~100 FFSC engines on the bottom of it. Just far too many highly stressed parts to go wrong. Also EM likes the no. 42. SpaceX will have the funds to dev. a larger version of Raptor once the initial ITS system is in service and their sat. constellation is bringing in revenue.

Once you have the design for ITS closed out just scale it up for future larger versions.
42 engines isnt THAT much.

It's only about 2 of these strapped together:

Only if you either count single four-chamber engines as four engines or if you count the Verniers. Otherwise there is only one engine per R7/Soyuz first stage/booster.

Offline GWH

Re: IAC 2017 -- ITS v0.2
« Reply #103 on: 06/08/2017 04:07 PM »
Future versions of the ITS system larger than the one announced at IAC2016 will need a larger version of Raptor to keep the engine nos. of 42 on booster and 9 on ship. 42 engines on a booster is already pushing it and I just can't imagine a rocket with ~100 FFSC engines on the bottom of it. Just far too many highly stressed parts to go wrong. Also EM likes the no. 42. SpaceX will have the funds to dev. a larger version of Raptor once the initial ITS system is in service and their sat. constellation is bringing in revenue.

Once you have the design for ITS closed out just scale it up for future larger versions.

I have a really hard time seeing the booster needing to be larger.  Consider 1 booster per pad, 2 flights per week (100 per year) gives a 10 year life of each booster for 1000 flights in that 10 year period, requiring 1 replacement tanker per year.  That would be enough for a total of 33 ITS ships to Mars per synod (2 year period), 63,460mT of propellant in LEO, & 9,900mT cargo.
That would put production frequency of boosters & tankers would be at a very low level, but a strain on producing enough ITS ships, although the intent is 12 Mars trips per lifetime (24 years). Booster use however would be at a pretty ideal point of frequency of use vs life duration.

So the limiting factor here wouldn't be booster and tanker size IMO, but rather the Mars transport size, frequency of crew transfer vehicles and number of uses. In space construction of gigantic in space only transport and shuttle craft to and from surface would probably be much more cost effective then going to a larger booster.

« Last Edit: 06/08/2017 05:57 PM by GWH »

Online Robotbeat

  • Senior Member
  • *****
  • Posts: 26602
  • Minnesota
  • Liked: 6476
  • Likes Given: 4700
Re: IAC 2017 -- ITS v0.2
« Reply #104 on: 06/08/2017 05:02 PM »
They could just build a bigger spaceship (that can still be orbited in one piece) and require more refueling flights.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline matthewkantar

  • Full Member
  • ****
  • Posts: 636
  • Liked: 399
  • Likes Given: 390
Re: IAC 2017 -- ITS v0.2
« Reply #105 on: 06/08/2017 05:57 PM »
9,900 metric tons, so half of the capacity of one modern container ship.

Matthew

Edit: more like a quarter of the capacity.
« Last Edit: 06/08/2017 06:03 PM by matthewkantar »

Offline JasonAW3

  • Senior Member
  • *****
  • Posts: 2399
  • Claremore, Ok.
  • Liked: 371
  • Likes Given: 10
Re: IAC 2017 -- ITS v0.2
« Reply #106 on: 06/08/2017 10:02 PM »
9,900 metric tons, so half of the capacity of one modern container ship.

Matthew

Edit: more like a quarter of the capacity.

Personally, I rather liked the picture someone did a year or so ago, of rockets on their sides being loaded with conex containers. 

That's sort of how I envision the cargo variant to be loaded anyway.
My God!  It's full of universes!

Online Robotbeat

  • Senior Member
  • *****
  • Posts: 26602
  • Minnesota
  • Liked: 6476
  • Likes Given: 4700
Re: IAC 2017 -- ITS v0.2
« Reply #107 on: 06/09/2017 12:56 AM »
I susp XY they'd still use something like the standard aluminum containers used for air freight.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline ChrisWilson68

  • Senior Member
  • *****
  • Posts: 3493
  • Sunnyvale, CA
  • Liked: 2042
  • Likes Given: 2378
Re: IAC 2017 -- ITS v0.2
« Reply #108 on: 06/09/2017 04:03 AM »
Exactly. A full on cargo cargo version won't look much different than a passenger ITS. A big cargo bay that replaces the pressurized crew section, and you're done.
Umm, remember the McDonnell Douglas Delta Clipper SSTO proposal?  Like the ITS ship, it was supposed to do a nose-first (or broad-side) entry, followed by rotation and tail-first landing.  As a result, it needed the payload sandwiched between the two propellant tanks for cg control.   Similarly, the ITS ship shows "densely packed cargo" in between the tanks and the loosely filled passenger area.  It has to do the rotation maneuver with full payload at Mars, and nearly empty back at Earth, so cg control is very crucial.

I think that the ITS upper passenger volume is not usable during entry; likely all passengers will be strapped into seats at the very bottom of the passenger volume, and all luggage will be moved out of the upper area too; any room dividers or bathroom fixtures up top will be very lightweight too. 

So for the cargo version, most of that upper cargo volume will also be limited to extremely lightweight items or empty space.

 see http://www.astronautix.com/d/deltaclipper.html

That only applies to downmass cargo.  Cargo being taken from the surface of Earth to orbit (i.e. 99% of all commercial space business today) has no CG issues.

Offline oldAtlas_Eguy

  • Senior Member
  • *****
  • Posts: 2919
  • Florida
  • Liked: 1237
  • Likes Given: 85
Re: IAC 2017 -- ITS v0.2
« Reply #109 on: 06/09/2017 04:47 PM »
There is actually a thread that discussed all of the pro and con arguments about standardized containers for use not only with ITS but also touched on usage on any LV.

http://forum.nasaspaceflight.com/index.php?topic=40454.0

The general consensus is that packing the containers to a standard CG and moment arm characterization and to a certain weight category allowed for a load and go without any new analysis work with regard to the LV's flight control and aerodynamics of flight.

This was identified as the superior reason for standardized containerizing payloads to greatly reduce costs, flexibility and increased flight rates. Even when the standardized containers added some parasitic weight, up to 10% or more, to the payload. This was because the cost of launch was so low that any additional manpower for handling or analyzing a custom payload swamped the costs of launch of $/kg. Making it far cheaper to stuff it into a container even if it added 20% to the weight than to try to handle it as a custom payload which ended as more than doubling the $/kg for the payload.

Online DAZ

  • Full Member
  • *
  • Posts: 111
  • Everett WA
  • Liked: 74
  • Likes Given: 1
Re: IAC 2017 -- ITS v0.2
« Reply #110 on: 06/09/2017 09:49 PM »
Exactly. A full on cargo cargo version won't look much different than a passenger ITS. A big cargo bay that replaces the pressurized crew section, and you're done.
Umm, remember the McDonnell Douglas Delta Clipper SSTO proposal?  Like the ITS ship, it was supposed to do a nose-first (or broad-side) entry, followed by rotation and tail-first landing.  As a result, it needed the payload sandwiched between the two propellant tanks for cg control.   Similarly, the ITS ship shows "densely packed cargo" in between the tanks and the loosely filled passenger area.  It has to do the rotation maneuver with full payload at Mars, and nearly empty back at Earth, so cg control is very crucial.

I think that the ITS upper passenger volume is not usable during entry; likely all passengers will be strapped into seats at the very bottom of the passenger volume, and all luggage will be moved out of the upper area too; any room dividers or bathroom fixtures up top will be very lightweight too. 

So for the cargo version, most of that upper cargo volume will also be limited to extremely lightweight items or empty space.

 see http://www.astronautix.com/d/deltaclipper.html

That only applies to downmass cargo.  Cargo being taken from the surface of Earth to orbit (i.e. 99% of all commercial space business today) has no CG issues.

Iím not so sure about this only applying to down mass cargo.  If you donít take CG and cargo mass into account you could end up with no viable abort situations on an inherently reusable vehicle.  This is kind of the equivalent of a plane taking off with more gross weight than it can land with.  If you are willing to use your reusable vehicle in this manner then so be it.

Offline Lumina

Re: IAC 2017 -- ITS v0.2
« Reply #111 on: 06/17/2017 06:15 AM »
No, it's not. ITS as shown in the early drafts was clearly already lacking radiator surface area even without trying to shed enough heat load for a phase change.
.....

If you are referring to the IAC 2016 version of ITS, what's stopping that design from using most of the backside of the solar panels as radiators?

Offline colbourne

  • Full Member
  • **
  • Posts: 290
  • Liked: 18
  • Likes Given: 5
Re: IAC 2017 -- ITS v0.2
« Reply #112 on: 06/17/2017 07:29 AM »
There is actually a thread that discussed all of the pro and con arguments about standardized containers for use not only with ITS but also touched on usage on any LV.

http://forum.nasaspaceflight.com/index.php?topic=40454.0

The general consensus is that packing the containers to a standard CG and moment arm characterization and to a certain weight category allowed for a load and go without any new analysis work with regard to the LV's flight control and aerodynamics of flight.

This was identified as the superior reason for standardized containerizing payloads to greatly reduce costs, flexibility and increased flight rates. Even when the standardized containers added some parasitic weight, up to 10% or more, to the payload. This was because the cost of launch was so low that any additional manpower for handling or analyzing a custom payload swamped the costs of launch of $/kg. Making it far cheaper to stuff it into a container even if it added 20% to the weight than to try to handle it as a custom payload which ended as more than doubling the $/kg for the payload.
I don't think we need to consider the container as wasted weight. They will be very valuable on Mars as raw materials or  used for construction of the base in their original format.

Online Jcc

  • Full Member
  • ****
  • Posts: 767
  • Liked: 162
  • Likes Given: 64
Re: IAC 2017 -- ITS v0.2
« Reply #113 on: 06/17/2017 04:24 PM »
No, it's not. ITS as shown in the early drafts was clearly already lacking radiator surface area even without trying to shed enough heat load for a phase change.
.....

If you are referring to the IAC 2016 version of ITS, what's stopping that design from using most of the backside of the solar panels as radiators?

The solar panels shown seem to deploy by rolling out from a very compact volume. It is not clear to me how radiators would attach to the back of those, but maybe others would know how to do that.

Offline Nomadd

  • Senior Member
  • *****
  • Posts: 2549
  • Boca Chica, Texas
  • Liked: 3051
  • Likes Given: 211
Re: IAC 2017 -- ITS v0.2
« Reply #114 on: 06/17/2017 04:35 PM »
There is actually a thread that discussed all of the pro and con arguments about standardized containers for use not only with ITS but also touched on usage on any LV.

http://forum.nasaspaceflight.com/index.php?topic=40454.0

The general consensus is that packing the containers to a standard CG and moment arm characterization and to a certain weight category allowed for a load and go without any new analysis work with regard to the LV's flight control and aerodynamics of flight.

This was identified as the superior reason for standardized containerizing payloads to greatly reduce costs, flexibility and increased flight rates. Even when the standardized containers added some parasitic weight, up to 10% or more, to the payload. This was because the cost of launch was so low that any additional manpower for handling or analyzing a custom payload swamped the costs of launch of $/kg. Making it far cheaper to stuff it into a container even if it added 20% to the weight than to try to handle it as a custom payload which ended as more than doubling the $/kg for the payload.
I don't think we need to consider the container as wasted weight. They will be very valuable on Mars as raw materials or  used for construction of the base in their original format.
I' not sure about raw materials, but I could see containers made from dis-assemblable panels that could be used for other structures. Maybe Lego could produce them. Make Lar happy.

Offline oldAtlas_Eguy

  • Senior Member
  • *****
  • Posts: 2919
  • Florida
  • Liked: 1237
  • Likes Given: 85
Re: IAC 2017 -- ITS v0.2
« Reply #115 on: 06/17/2017 07:08 PM »
There is actually a thread that discussed all of the pro and con arguments about standardized containers for use not only with ITS but also touched on usage on any LV.

http://forum.nasaspaceflight.com/index.php?topic=40454.0

The general consensus is that packing the containers to a standard CG and moment arm characterization and to a certain weight category allowed for a load and go without any new analysis work with regard to the LV's flight control and aerodynamics of flight.

This was identified as the superior reason for standardized containerizing payloads to greatly reduce costs, flexibility and increased flight rates. Even when the standardized containers added some parasitic weight, up to 10% or more, to the payload. This was because the cost of launch was so low that any additional manpower for handling or analyzing a custom payload swamped the costs of launch of $/kg. Making it far cheaper to stuff it into a container even if it added 20% to the weight than to try to handle it as a custom payload which ended as more than doubling the $/kg for the payload.
I don't think we need to consider the container as wasted weight. They will be very valuable on Mars as raw materials or  used for construction of the base in their original format.
I' not sure about raw materials, but I could see containers made from dis-assemblable panels that could be used for other structures. Maybe Lego could produce them. Make Lar happy.
See the discussion on standardized containers and the usability of these containers at Mars.
http://forum.nasaspaceflight.com/index.php?topic=40454.0

Also it discusses features that would be extremely useful especially for self contained pressurized containers to minimize supplies offloading, etc at Mars. Using a CBM like port the triangle pie piece shaped containers would be connected to the habitat one at a time creating a complete pie so that if the supplies are organized correctly they are removed as needed by the colonists. Thus the containers also function asd the storage space once at Mars. Once all the containers are empty the result is more habitation space for colonists. Each Pie of containers adds 400m^3 of volume to the colony. There are ~ three layers of containers in each ITS. But not all layers would be pressurized containers.

Offline gongora

  • Global Moderator
  • Full Member
  • *****
  • Posts: 1641
  • US
  • Liked: 1080
  • Likes Given: 861
Re: IAC 2017 -- ITS v0.2
« Reply #116 on: 06/17/2017 08:46 PM »
Quick question...do we have a reputable source actually saying Elon is going to speak at IAC, or is everyone assuming that based on the approximate timing for his update?

Offline oldAtlas_Eguy

  • Senior Member
  • *****
  • Posts: 2919
  • Florida
  • Liked: 1237
  • Likes Given: 85
Re: IAC 2017 -- ITS v0.2
« Reply #117 on: 06/17/2017 11:43 PM »
Quick question...do we have a reputable source actually saying Elon is going to speak at IAC, or is everyone assuming that based on the approximate timing for his update?
The only item that points to the, IAC is the statement that he would have an update in 3 or 4 months which would put it at about the IAC plus it would be 1 year point and a good place to give an update. But no, I don not think there has been any substantial statement saying exactly when or what venue.

Offline russianhalo117

  • Senior Member
  • *****
  • Posts: 3650
  • AR USA / Berlin, DE / Moscow, RF
  • Liked: 655
  • Likes Given: 416
Re: IAC 2017 -- ITS v0.2
« Reply #118 on: 06/17/2017 11:53 PM »
Quick question...do we have a reputable source actually saying Elon is going to speak at IAC, or is everyone assuming that based on the approximate timing for his update?
The only item that points to the, IAC is the statement that he would have an update in 3 or 4 months which would put it at about the IAC plus it would be 1 year point and a good place to give an update. But no, I don not think there has been any substantial statement saying exactly when or what venue.
his name and presentation abstract is not in the latest version of the IAC schedules.
Only unassgined slot is the 0830-0930 Friday slot for Late Breaking News before closing ceremony events later that day.

Offline jpo234

  • Full Member
  • ****
  • Posts: 451
  • Liked: 287
  • Likes Given: 41
Re: IAC 2017 -- ITS v0.2
« Reply #119 on: 07/11/2017 07:29 AM »
https://twitter.com/elonmusk/status/884664723429498880

Quote
Quote
I know some of us sound like a broken record by now, but can we get a real estimate on when the big Mars update will be?
Maybe the upcoming IAC in Adelaide
« Last Edit: 07/11/2017 10:50 AM by jpo234 »

Tags: