Author Topic: Should ITS have a smaller prototype to ease development?  (Read 11923 times)

Online Rei

  • Full Member
  • ****
  • Posts: 467
  • Iceland
  • Liked: 170
  • Likes Given: 58
Re: Should ITS have a smaller prototype to ease development?
« Reply #40 on: 02/18/2017 12:50 PM »
Quote
If you get to Mars faster, you just end up having to wait longer to launch back to Earth, and you get back at the same time. Unless you're flying a opposition class mission with a 30-day stay

There is zero stay requirement for ITS, apart from time to offload, reload, and refuel.  ITS is not intended to function as a Martian habitat.  It can fly conjunction and opposition class, with or without Venus assist on opposition.  SpaceX has also put emphasis on non-Mars destinations.  There is additionally a requirement for refurbishment on Earth (they don't give times for it, but they do give a budget - $10M).  All questions of realism of their budget figures directed away from me  ;)
« Last Edit: 02/18/2017 01:07 PM by Rei »

Offline muomega0

  • Full Member
  • ****
  • Posts: 851
  • Liked: 64
  • Likes Given: 1
Re: Should ITS have a smaller prototype to ease development?
« Reply #41 on: 02/18/2017 12:57 PM »
The ITS approach showed the world that if you wanted to colonize Mars, one needs the entire architecture and hardware based on reuse with in space refueling.  Innovations further improve the mass fractions/economics.

ITS highlighted the deep flaws of SLS and Ares: completely expendable with no ability to meet #1 Space Grand Challenge Economic Access to Space in the short term nor 'Colonize' Mars in the long term.

The ITS approach showed the world that a part of NASA controlled by Congress only wants to build and operate decades old expensive rotary phone technology to relive Apollo again.

The ITS showed the shuttle derived folks how to approach the future, and that they too can be a part of a great future.  There is so much to do!

2004 VSE
For future, sustainable exploration programs, NASA requires cost-effective vehicles that may be reused, have systems that could be applied to more than one destination, and are highly reliable and need only small ground crews. NASA plans to invest in a number of new approaches to exploration, such as robotic networks, modular systems, pre-positioned propellants, advanced power and propulsion, and in-space assembly, that could enable these kinds of vehicles  without the VSE: 3 Flaws with just a few words

The ITS is built to the wrong scale, it's a fantasy, etc. crowd simply can't get their heads around the proven fact,
In many cases building a component other than full scale ignores 'scalability'--It works at smaller dimensions and not at larger dimensions.

Note however that SLS then is too small for Mars Colonization for the future, and too big for and expendable to cut costs today.  Between a rock and a hard place.

Reasons to close this thread
- So much concern trolling
- So little that's not been said in other threads.
- So many incorrect statements
- So much lack of understanding of Musk's plans

Reasons to leave this thread open
- It's a place to send the concern trolls so we can keep them out of other threads.

That one's winning, so far.
When you have nothing in defense of your poorly laid out plans other than to support the base and the top 1%, the result has been  http://alternativefacts.com  .  Sadly, to support the base requires actions outside of reason  but there our lines not to cross.
« Last Edit: 03/17/2017 11:32 AM by muomega0 »

Offline envy887

  • Full Member
  • ****
  • Posts: 1497
  • Liked: 642
  • Likes Given: 347
Re: Should ITS have a smaller prototype to ease development?
« Reply #42 on: 02/18/2017 05:45 PM »
Quote
If you get to Mars faster, you just end up having to wait longer to launch back to Earth, and you get back at the same time. Unless you're flying a opposition class mission with a 30-day stay

There is zero stay requirement for ITS, apart from time to offload, reload, and refuel.
It has to wait for a transfer window that's within it's delta-v and other capability limitations. Those aren't clearly defined yet.

Online RonM

  • Full Member
  • ****
  • Posts: 1893
  • Atlanta, Georgia USA
  • Liked: 823
  • Likes Given: 654
Re: Should ITS have a smaller prototype to ease development?
« Reply #43 on: 02/18/2017 06:03 PM »
A typical mid-L/D Mars lander with 40mt payload has the dimensions 30m x 10m.

ITS has the dimensions 50m x 12m. Only ~1/3 of that volume is available for the payload, so it's questionable whether SpaceX can land much more volume on Mars than a typical 40mt lander from NASA. DRM 5.0 needs 2 40mt landers.

Making ITS smaller in terms of volume might not be an option if SpaceX plans to sells Mars flights to NASA.

So about 1,800 m3 of volume for payload, at CRS payload densities that is over 200 tonnes, SpaceX say that they will land 100 tonnes (maybe more later).
The IAC presentation says up to 450 tonnes landed. Nominally 300.

DRM 5.0 requires two landers totaling 80 tonnes to the surface. A scaled down ITS capable of landing 100 tonnes would make a great first generation ship. So about 1/3 mass of the full scale ITS.

While the first generation ships are setting up the base and preparing for colonization, the full scaled ITS could be developed.

At 1/3 mass, the first generation ships would be cheaper and not overtax Pad 39A. A full scale ITS is going to take a new pad or a rebuilt 39A, either one an expensive project.

Offline Pipcard

  • Full Member
  • ***
  • Posts: 362
  • Liked: 66
  • Likes Given: 88
Re: Should ITS have a smaller prototype to ease development?
« Reply #44 on: 02/18/2017 06:41 PM »
ITS highlighted the deep flaws of SLS and Ares: completely expendable with no ability to meet #1 Space Grand Challenge Economic Access to Space in the short term nor 'Colonize' Mars in the long term.

Do you know why Ares was designed as an expendable vehicle in the first place?

I'm saying this yet again: before SpaceX started designing the MCT/ITS, almost no one thought that there was going to be enough demand to make development of reusable super-heavy lift launch vehicles worthwhile.
« Last Edit: 02/18/2017 06:50 PM by Pipcard »

Offline Robotbeat

  • Senior Member
  • *****
  • Posts: 25677
  • Minnesota
  • Liked: 5803
  • Likes Given: 4314
Re: Should ITS have a smaller prototype to ease development?
« Reply #45 on: 02/18/2017 06:42 PM »
Quote
If you get to Mars faster, you just end up having to wait longer to launch back to Earth, and you get back at the same time. Unless you're flying a opposition class mission with a 30-day stay

There is zero stay requirement for ITS, apart from time to offload, reload, and refuel.  ITS is not intended to function as a Martian habitat. ...
That's not true. Musk explicitly said the crew would stay in the ITS while on the surface.
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 envy887

  • Full Member
  • ****
  • Posts: 1497
  • Liked: 642
  • Likes Given: 347
Re: Should ITS have a smaller prototype to ease development?
« Reply #46 on: 02/18/2017 07:33 PM »
ITS highlighted the deep flaws of SLS and Ares: completely expendable with no ability to meet #1 Space Grand Challenge Economic Access to Space in the short term nor 'Colonize' Mars in the long term.

Do you know why Ares was designed as an expendable vehicle in the first place?

I'm saying this yet again: before SpaceX started designing the MCT/ITS, almost no one thought that there was going to be enough demand to make development of reusable super-heavy lift launch vehicles worthwhile.

More because Ares HAD to be Shuttle-derived but without the only economically reusable part of the Shuttle. And being Shuttle-derived it was stuck with an inefficient architecture that made the performance hit from reuse prohibitive.

A prototype ITS flying on reusable Falcon Heavy boosters could attack the problem from the opposite end the Shuttle did: return the easy part (the boosters) and expend the orbiter if necessary. It wouldn't have to fly a lot to learn a great amount, and it could make some money while doing testing after the primary mission, like Falcon boosters do.

Offline Lar

  • Fan boy at large
  • Global Moderator
  • Senior Member
  • *****
  • Posts: 7439
  • Saw Gemini live on TV
  • A large LEGO storage facility ... in Michigan
  • Liked: 4331
  • Likes Given: 2933
Re: Should ITS have a smaller prototype to ease development?
« Reply #47 on: 02/18/2017 08:57 PM »

Note however that SLS then is too small for Mars Colonization for the future, and too big for and expendable to cut costs today.  Between a rock and a hard place.
show yout work.... i thimk it is just right.
Quote
Reasons to close this thread
- So much concern trolling
- So little that's not been said in other threads.
- So many incorrect statements
- So much lack of understanding of Musk's plans

Reasons to leave this thread open
- It's a place to send the concern trolls so we can keep them out of other threads.

That one's winning, so far.
When you have nothing in defense of your poorly laid out plans other than to support the base and the top 1%, the result has been  http://alternativefacts.com  .  Sadly, to support the base requires actions outside of reason  but their our lines not to cross.
you just described SLS... poorly laid out plans redux...
"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk
"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

Offline envy887

  • Full Member
  • ****
  • Posts: 1497
  • Liked: 642
  • Likes Given: 347
Re: Should ITS have a smaller prototype to ease development?
« Reply #48 on: 02/18/2017 10:00 PM »

Note however that SLS then is too small for Mars Colonization for the future, and too big for and expendable to cut costs today.  Between a rock and a hard place.
show yout work.... i thimk it is just right.
Quote
Reasons to close this thread
- So much concern trolling
- So little that's not been said in other threads.
- So many incorrect statements
- So much lack of understanding of Musk's plans

Reasons to leave this thread open
- It's a place to send the concern trolls so we can keep them out of other threads.

That one's winning, so far.
When you have nothing in defense of your poorly laid out plans other than to support the base and the top 1%, the result has been  http://alternativefacts.com  .  Sadly, to support the base requires actions outside of reason  but their our lines not to cross.
you just described SLS... poorly laid out plans redux...

Still a little groggy, Lar? :D

Offline Lar

  • Fan boy at large
  • Global Moderator
  • Senior Member
  • *****
  • Posts: 7439
  • Saw Gemini live on TV
  • A large LEGO storage facility ... in Michigan
  • Liked: 4331
  • Likes Given: 2933
Re: Should ITS have a smaller prototype to ease development?
« Reply #49 on: 02/18/2017 10:15 PM »
much more alert...
"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk
"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

Online Rei

  • Full Member
  • ****
  • Posts: 467
  • Iceland
  • Liked: 170
  • Likes Given: 58
Re: Should ITS have a smaller prototype to ease development?
« Reply #50 on: 02/19/2017 12:04 AM »
Quote
If you get to Mars faster, you just end up having to wait longer to launch back to Earth, and you get back at the same time. Unless you're flying a opposition class mission with a 30-day stay

There is zero stay requirement for ITS, apart from time to offload, reload, and refuel.  ITS is not intended to function as a Martian habitat. ...
That's not true. Musk explicitly said the crew would stay in the ITS while on the surface.

Is that so?  I need to watch the presentation again then, my understanding was that the idea was for ITS to function as cargo / people delivery, not surface habitation.

Ed: Just rewatched it; I saw nothing about using ITS as a habitat.  Quite to the contrary, it was explicitly stated that they're seeking to avoid having ITS vehicles collect and sit around on the surface of Mars.

Where did you see something stating that ITS would be used as a habitat?
« Last Edit: 02/19/2017 01:49 AM by Rei »

Offline redliox

  • Full Member
  • ****
  • Posts: 1563
  • Arizona USA
  • Liked: 281
  • Likes Given: 52
Re: Should ITS have a smaller prototype to ease development?
« Reply #51 on: 02/19/2017 03:15 AM »
Interesting mix of responses so far in this thread.  In addition to the voice of Lars-slayer-of-Trolls I notice 3 opinions come up regularly from differing people:

1) Make a smaller ITS for quicker development
2) Make full-scale ITS to avoid complicating development
3) Potential use of ITS as a Martian habitat

The first two are actually equal in merit; a smaller ship might be easier to build, but scaling it up later might generate development problems.  One lesson the STS/shuttle taught us: implementing (significant) vehicle improvements are nearly impossible to do while on a budget, which NASA is likely to be tight on for the foreseeable future.  In the case of the SLS, especially if competition from Blue Origin and SpaceX emerge, it may advance no further than block 1B or forced to settle for a maximum liftoff mass less than the 130 mt intended for 2.  My personal opinion on the matter of a mini-ITS: miniaturize the spaceship/payload component but fly the booster itself at full-scale; that way SpaceX has the workhorse at full strength.

Using the ITS spaceship as a habitat is an interesting thought.  Drawing on Mars Direct for comparison, it's meant to be more like a giant ERV rather than a Hab.  However, especially at full scale, the spaceship may as well be a luxury yacht given it's bigger than the total module volume of the ISS.  All the same, it's a ship not a hotel.

These questions ought to be given to Elon Musk directly if possible.  ITS is his baby, and I'm sure his engineers are trying to prepare its delivery.
"Let the trails lead where they may, I will follow."
-Tigatron

Offline TomH

  • Full Member
  • ****
  • Posts: 1827
  • CA
  • Liked: 586
  • Likes Given: 178
Re: Should ITS have a smaller prototype to ease development?
« Reply #52 on: 02/19/2017 03:53 AM »
IF SpaceX did start with a smaller prototype, them segue to the full sized ITS, how feasible would it be for them then to sell the prototype to NASA for use in Lunar exploration?

Offline Space Ghost 1962

  • Full Member
  • ****
  • Posts: 1954
  • Whatcha gonna do when the Ghost zaps you?
  • Liked: 1667
  • Likes Given: 1157
Re: Should ITS have a smaller prototype to ease development?
« Reply #53 on: 02/19/2017 04:45 AM »
Give it up already. No HSF craft ever had a "mini me", no one ever will.  ::)

Online guckyfan

  • Senior Member
  • *****
  • Posts: 5842
  • Germany
  • Liked: 1430
  • Likes Given: 1136
Re: Should ITS have a smaller prototype to ease development?
« Reply #54 on: 02/19/2017 04:51 AM »
Where did you see something stating that ITS would be used as a habitat?

Elon Musk had said this before. It makes all kind of sense too. We must always differentiate between the long term intended use, that is return after refuelling and specific mission requirements. The first crew arrives and there is no other habitat than the ITS at that time. ITS is plenty big for a crew of 12 to 18. There is likely also no fuel for an immediate return of the ITS.

So they get there, live in the ITS until they have set up fuel ISRU and possibly a habitat. Later missions would arrive and there is a habitat waiting for them and fuel in the tanks. They disembark, unload cargo and the ship goes back. Will they even have a ship on standby? I doubt it.

Offline GWH

IF SpaceX did start with a smaller prototype, them segue to the full sized ITS, how feasible would it be for them then to sell the prototype to NASA for use in Lunar exploration?

Prototype as an F9/FH upper stage coupled with LEO refueling I thinkthat would be very effective and fill in a need that could only be met by one other player (ULA + xues).  Dragon can act as a crew lander.

I think there is a very crucial definition that needs to be made on the mini ITS in this discussion . Which is whether it is an extension on existing systems(New US only, no crew inside) to test tech and prove out feasibility vs a partial scale version of the whole system.

Online Rei

  • Full Member
  • ****
  • Posts: 467
  • Iceland
  • Liked: 170
  • Likes Given: 58
Re: Should ITS have a smaller prototype to ease development?
« Reply #56 on: 02/19/2017 11:31 AM »
Where did you see something stating that ITS would be used as a habitat?

Elon Musk had said this before. It makes all kind of sense too. We must always differentiate between the long term intended use, that is return after refuelling and specific mission requirements. The first crew arrives and there is no other habitat than the ITS at that time. ITS is plenty big for a crew of 12 to 18. There is likely also no fuel for an immediate return of the ITS.

So they get there, live in the ITS until they have set up fuel ISRU and possibly a habitat. Later missions would arrive and there is a habitat waiting for them and fuel in the tanks. They disembark, unload cargo and the ship goes back. Will they even have a ship on standby? I doubt it.

I'm trying to find anywhere that he actually said that.  Do you perchance have a link?  What I have is:

https://www.youtube.com/watch?v=H7Uyfqi_TE8?t=801

Re, local propellant production: "Again, if we didn't do this, it would have at least a half order of magnitude increase in the cost of a trip, so 500% increase in the cost of a trip. And it would be pretty absurd to try to build a city on Mars if your spaceships just kept on staying on Mars and not going back to Earth. You would have this, like, massive graveyard of ships.  You would have to, like, do something with them. So it really wouldn't make sense to leave your spaceships on Mars, you really want to build a propellant plant on Mars and send the ships back."

To be fair, this could be interpreted through the lens of "eventually".  There still is the question of what to do in the beginning - whether a propellant plant and tanks would be delivered by Red Dragon, or whether you have to have one ITS sitting around acting as a refuelling tank, with its payload being a propellant plant.  But that describes only a very small number of ships, and still says nothing about using ITS ships as habitats.  I know Zubrin at the very least hasn't interpreted Musk's statements as meaning using the spaceships as habitats - he published an editorial criticizing Musk for that purpose:

http://www.thenewatlantis.com/publications/colonizing-mars

Quote
7. The sending of a large habitat on a roundtrip from Earth to Mars and back. This, too, is a very bad idea, because the habitat will get to be used only one way, once every four years. If we are building a Mars base or colonizing Mars, any large habitat sent to the planetís surface should stay there so the colonists can use it for living quarters. Going to great expense to send a habitat to Mars only to return it to Earth empty makes no sense. Mars needs houses.

And honestly, they'd make pretty poor long-term habitats.  The design does not call for any sort of heavy radiation shielding (clear from their mass figures, but also their design drawings), and it's surely not rated to bear such added regolith loads - nor would it  be easy to dump regolith over such a thing.

But, if he's said some other things elsewhere, I'd be very curious to hear them.  :)

Online guckyfan

  • Senior Member
  • *****
  • Posts: 5842
  • Germany
  • Liked: 1430
  • Likes Given: 1136
Re: Should ITS have a smaller prototype to ease development?
« Reply #57 on: 02/19/2017 01:06 PM »
Sorry I don't collect sources, maybe I should. But he definitely said this, earlier, not in his IAC presentation.

Again, this is not a contradiction to his goal of returning the ships to earth for reuse.

Re radiaton, true that an ITS is not the best possible solution for that. They could use barrels or water bags to produce some barrier, if they think it is needed. Piling regolith on top is not a solution with ITS:

Offline DigitalMan

  • Full Member
  • ***
  • Posts: 388
  • Liked: 39
  • Likes Given: 1
Re: Should ITS have a smaller prototype to ease development?
« Reply #58 on: 02/19/2017 02:09 PM »
Where did you see something stating that ITS would be used as a habitat?

Elon Musk had said this before. It makes all kind of sense too. We must always differentiate between the long term intended use, that is return after refuelling and specific mission requirements. The first crew arrives and there is no other habitat than the ITS at that time. ITS is plenty big for a crew of 12 to 18. There is likely also no fuel for an immediate return of the ITS.

So they get there, live in the ITS until they have set up fuel ISRU and possibly a habitat. Later missions would arrive and there is a habitat waiting for them and fuel in the tanks. They disembark, unload cargo and the ship goes back. Will they even have a ship on standby? I doubt it.

I'm trying to find anywhere that he actually said that.  Do you perchance have a link?  What I have is:

https://www.youtube.com/watch?v=H7Uyfqi_TE8?t=801

Re, local propellant production: "Again, if we didn't do this, it would have at least a half order of magnitude increase in the cost of a trip, so 500% increase in the cost of a trip. And it would be pretty absurd to try to build a city on Mars if your spaceships just kept on staying on Mars and not going back to Earth. You would have this, like, massive graveyard of ships.  You would have to, like, do something with them. So it really wouldn't make sense to leave your spaceships on Mars, you really want to build a propellant plant on Mars and send the ships back."

To be fair, this could be interpreted through the lens of "eventually".  There still is the question of what to do in the beginning - whether a propellant plant and tanks would be delivered by Red Dragon, or whether you have to have one ITS sitting around acting as a refuelling tank, with its payload being a propellant plant.  But that describes only a very small number of ships, and still says nothing about using ITS ships as habitats.  I know Zubrin at the very least hasn't interpreted Musk's statements as meaning using the spaceships as habitats - he published an editorial criticizing Musk for that purpose:

http://www.thenewatlantis.com/publications/colonizing-mars

Quote
7. The sending of a large habitat on a roundtrip from Earth to Mars and back. This, too, is a very bad idea, because the habitat will get to be used only one way, once every four years. If we are building a Mars base or colonizing Mars, any large habitat sent to the planetís surface should stay there so the colonists can use it for living quarters. Going to great expense to send a habitat to Mars only to return it to Earth empty makes no sense. Mars needs houses.

And honestly, they'd make pretty poor long-term habitats.  The design does not call for any sort of heavy radiation shielding (clear from their mass figures, but also their design drawings), and it's surely not rated to bear such added regolith loads - nor would it  be easy to dump regolith over such a thing.

But, if he's said some other things elsewhere, I'd be very curious to hear them.  :)

My recollection is he said it afterwards I think in the 2nd Q+A from Reddit.  He definitely said it, also that the 2nd landing with crew would complete the propellant plant.

Offline gin455res

  • Member
  • Full Member
  • **
  • Posts: 299
  • uk
  • Liked: 5
  • Likes Given: 16
Re: Should ITS have a smaller prototype to ease development?
« Reply #59 on: 02/19/2017 07:25 PM »
Interesting mix of responses so far in this thread.  In addition to the voice of Lars-slayer-of-Trolls I notice 3 opinions come up regularly from differing people:

1) Make a smaller ITS for quicker development
2) Make full-scale ITS to avoid complicating development
3) Potential use of ITS as a Martian habitat

The first two are actually equal in merit; a smaller ship might be easier to build, but scaling it up later might generate development problems.  One lesson the STS/shuttle taught us: implementing (significant) vehicle improvements are nearly impossible to do while on a budget, which NASA is likely to be tight on for the foreseeable future.  In the case of the SLS, especially if competition from Blue Origin and SpaceX emerge, it may advance no further than block 1B or forced to settle for a maximum liftoff mass less than the 130 mt intended for 2.  My personal opinion on the matter of a mini-ITS: miniaturize the spaceship/payload component but fly the booster itself at full-scale; that way SpaceX has the workhorse at full strength.

Using the ITS spaceship as a habitat is an interesting thought.  Drawing on Mars Direct for comparison, it's meant to be more like a giant ERV rather than a Hab.  However, especially at full scale, the spaceship may as well be a luxury yacht given it's bigger than the total module volume of the ISS.  All the same, it's a ship not a hotel.

These questions ought to be given to Elon Musk directly if possible.  ITS is his baby, and I'm sure his engineers are trying to prepare its delivery.

How about a merlin-based booster (ITS-lite) with 42 Merlins on the bottom?
« Last Edit: 02/19/2017 07:26 PM by gin455res »