Author Topic: ITS as a LEO/VLEO Constellation deployer  (Read 1059 times)

Offline Robotbeat

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ITS as a LEO/VLEO Constellation deployer
« on: 03/15/2017 02:20 AM »
SpaceX wants to deploy 12000 satellites, about 2400 per year. At 80 per launch, that's 30 FH launches. That's a lot! A whole bunch of cores and a whole bunch of down range landings. A lot of folding legs, 30 new upper stages, 30 new deployers and maybe fairings (if they haven't solved that, and if they have, recovering them is significant work, too).

I think they'd like to transition to using ITS to deploy the satellites. I'm thinking of giant PPOD type deployers mounted when the unpressurized payload section is. I'm thinking 240 birds per launch, giving you performance margin and a lot of on-board delta-V for inclination changes. Speaking of, because BFS is a lifting body, it could do efficient inclination changes, making it feasible for, say, a Florida launch to actually deploy some birds up to over 75-80 degrees inclination. Maybe even multiple inclinations per launch.

That'd make it easier to get by with fewer launches. All in all, they may be able to do just 10 launches per year for their absolutely mind-bogglingly huge constellation. And no new deployers, fairings, or upper stages. All those things RTLS. And the booster itself flies back to the launch mount, making its recovery even easier. It could quickly be used for other purposes, like lofting Mars payloads.

This is one thing ITS is actually surprisingly useful for besides Mars.
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Offline guckyfan

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Re: ITS as a LEO/VLEO Constellation deployer
« Reply #1 on: 03/15/2017 07:20 AM »
Are you suggesting to dip BFS into the atmosphere to do inclination changes? That is how I read your post.

Offline JamesH65

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Re: ITS as a LEO/VLEO Constellation deployer
« Reply #2 on: 03/15/2017 10:07 AM »
Why bother with the ITS? Would it be easier to build an upper stage dispenser launch by the ITS booster? Give it some engines so it can do inclination changes, and perhaps enough fuel to actually do a powered return? Rather like the original second stage return video SpaceX did some years ago, but larger. Much larger.

An in orbit delivery system.

I have no idea whether the fuel maths works out though.


Offline Robotbeat

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Re: ITS as a LEO/VLEO Constellation deployer
« Reply #3 on: 03/15/2017 10:43 AM »
Why bother with a new vehicle when you can use a BFS with few modifications? Heck, with cleverness you can use a stock spaceship with custom equipment in the unpressurized section. There's a huge door there already.
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 Robotbeat

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Re: ITS as a LEO/VLEO Constellation deployer
« Reply #4 on: 03/15/2017 10:44 AM »
Are you suggesting to dip BFS into the atmosphere to do inclination changes? That is how I read your post.
Yes. For the VLEO satellites in particular, the altitude is very low, still.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

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Offline Robotbeat

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Re: ITS as a LEO/VLEO Constellation deployer
« Reply #5 on: 03/15/2017 11:48 AM »
I think X-37b might be able to do those kind of inclination changes, too. BFS should be able to do a similar thing. I have no idea why the USAF wants the x37b for, but ITS should be able to do the same job. Except not very stealthy (if that's what they're looking for).

Anyway, yeah, it should open the trade space a little further. Large amounts of on-board propellant AND the ability to generate significant lift.
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 jsgirald

Re: ITS as a LEO/VLEO Constellation deployer
« Reply #6 on: 03/15/2017 12:00 PM »
I think X-37b might be able to do those kind of inclination changes, too. BFS should be able to do a similar thing. I have no idea why the USAF wants the x37b for, but ITS should be able to do the same job. Except not very stealthy (if that's what they're looking for).

Anyway, yeah, it should open the trade space a little further. Large amounts of on-board propellant AND the ability to generate significant lift.

Interesting idea, a couple questions:
1) How low is that VLEO thing?

2) I gather a series of dip/reboost maneuvers, right?

3) How bad would that be in terms of TPS?
"For every expert, there is an equal and opposite expert".

Offline JamesH65

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Re: ITS as a LEO/VLEO Constellation deployer
« Reply #7 on: 03/15/2017 12:55 PM »
Why bother with a new vehicle when you can use a BFS with few modifications? Heck, with cleverness you can use a stock spaceship with custom equipment in the unpressurized section. There's a huge door there already.

Because modifying a huge, specific use case craft for something completely different will, in all likelihood, be more expensive than creating a dedicated system. Its certainly more than 'a few modifications'. You will need some sort of horribly complicated (and automated) conveyor racking inside the ITS to transfer satellites around so they can be bunged out of the door. A door note, that's not intended to be used in space (AFAICT). If you are fitting 240 satellites, the internal storage system is going to be a nightmare within the constraints of the ITS.

Note though, that development on one may well help with development of the other - e.g. the engines, tankage etc.

Offline guckyfan

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Re: ITS as a LEO/VLEO Constellation deployer
« Reply #8 on: 03/15/2017 01:04 PM »
You will need some sort of horribly complicated (and automated) conveyor racking inside the ITS to transfer satellites around so they can be bunged out of the door. A door note, that's not intended to be used in space (AFAICT). If you are fitting 240 satellites, the internal storage system is going to be a nightmare within the constraints of the ITS.

I have suggested before, fill the ITS with shelves and use a small robot that picks them up one by one. Not very complicated. Maybe not very volume efficient if it is really simple but with huge volume available that is not the big problem.

A different launch vehicle may be more efficient long term. But with the efficiency of ITS so much bigger than anything available today that can wait for a while. Competitors will need time to catch up. I think SpaceX can afford to build ITS first and a more competetive vehicle for cislunar space after that.

Online RonM

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Re: ITS as a LEO/VLEO Constellation deployer
« Reply #9 on: 03/15/2017 01:21 PM »
As mentioned in several other threads, a special cargo variant of ITS for cislunar operations might be a good idea. No crew areas and a larger payload door.

Offline Ludus

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Re: ITS as a LEO/VLEO Constellation deployer
« Reply #10 on: 03/15/2017 02:55 PM »
One of the many uses for the Cargo variant ITS spaceship. Odd that SpaceX has never mentioned it. It would make sense for it to be the first and most common ITS ship. Deploying the Constellation. Lifting hab modules. 9 out of 10 trips to support a Mars colony. It seems like they'd build 10 of them for every passenger or tanker ITS ship.

Offline meekGee

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Re: ITS as a LEO/VLEO Constellation deployer
« Reply #11 on: 03/16/2017 02:22 AM »
The logic you use is that ITS can lift many more satellites "to space".

But the dV to do a large inclination change for LEO rivals that of going from earth to LEO....  So the launch effort didn't help them any.

Of course maybe the plan is to do the orbital change is made with a hugely efficient electric drive, or other wizardry, but actually I don't think the plan is to use ITS.

UNLESS there's some desire to do a constellation of much larger satellites, though I can't think of what such an application will be, except maybe from-orbit-forest-fire-fighting or something similar.
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Offline Aussie_Space_Nut

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Re: ITS as a LEO/VLEO Constellation deployer
« Reply #12 on: 03/16/2017 06:46 AM »
I wonder how much it would cost to insure? That is a lot of very expensive satellites. Too many eggs in 1 basket perhaps?

Offline IRobot

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Re: ITS as a LEO/VLEO Constellation deployer
« Reply #13 on: 03/16/2017 08:38 AM »
If SpaceX is doing the whole thing (production and launch), they would probably skip insurance.

Online envy887

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Re: ITS as a LEO/VLEO Constellation deployer
« Reply #14 on: 03/16/2017 12:36 PM »
If SpaceX is doing the whole thing (production and launch), they would probably skip insurance.

Using their ability to mass produce more satellites to make up for any losses.

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