Author Topic: Alternative missions for BFR & MCT  (Read 32300 times)

Offline mickeydj80

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Re: Alternative missions for BFR & MCT
« Reply #60 on: 09/24/2014 09:39 AM »
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No documentary has pulled in as much as a Transformers movie, even two of the highest grossing documentaries of all time, that were about space didn't go anywhere near a 5th of that revenue. This is why I was looking here and checking out all the revenues to compare.

Yeah, but is that because of content, or presentation? And was the distribution/advertising/etc as big?

If you're going to make this work it needs to be multimedia, heavily advertised, lots of spinoffs (apps, games, merchandise, books).. everyone needs to know it's out there.

I agree.  It would definitely need lots of advertising and not just that but people really need to care about it. 
« Last Edit: 01/14/2015 08:48 PM by mickeydj80 »

Offline Lourens

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Re: Alternative missions for BFR & MCT
« Reply #61 on: 09/24/2014 08:21 PM »
Why would exploration missions be more lucrative than comsats? They'd pay the same price for the same rocket. But there are many more comsats than exploration missions, so total revenue would be higher for comsats.

Your basic assumptions miss a major point though: The BFR/MCT system in and of itself allows a MUCH higher flight rate avialable for such "exploration" missions at a much lower price.

That doesn't increase NASA's budget though. They may be able to do more science for the same amount of money, but that doesn't make it more lucrative to SpaceX.

Note also that "industry" thinking along these lines has indicated that IF such a high payload to LEO/GTO/GEO was available that the "standard" comm-sat would become obsolete and that larger, modular platforms in GEO would be much more cost and operationally effective. Meaning there would be far fewer "comm-sat" launches but more "component" launches and maintenance and operations launchs as well. And that in and of itself is "supposed" to lead to more space industrialization AND the R&D and explortation required to support that. In the end (as the "plan" goes at any rate :) ) we're supposed to see the "comm-satellite" market disappear into a general "infratructural" industry base and expansion, exploration, exploitation hugely increase to "keep up" with that expansion.

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The Air Force block buy doesn't include exploration missions, those are GPS satellites, spy satellites and military comsats. Maybe BFR could deploy a bunch of spy satellites into polar SSO in one mission in the same way as I suggested above. And the spy satellites could include much bigger optics.

Ahh but you're "assuming" that nothing really changes given the much greater access granted by the BFR and the like :)

Your argument that the comsat market will morph into a more general space infrastructure actually supports my point that comsats are (and/or will be) more lucrative than exploration missions. And I know that Mars is the Roman god of war, but I don't think that that's enough for the USAF to start launching exploration missions to it, even if they become much cheaper.

So I'm wondering, how much would the fully reusable BFR be able to lift to GEO? I'm thinking that going only to GTO like Ariane 5 won't work too well with more than two satellites to drop off. So instead, I'd think that BFR would launch its second stage including the payloads into an orbit just below GEO, and then just drop off the satellites one by one as it passes the correct orbital slot. After dropping off all payloads, the second stage would deorbit and be reused. Provided of course that it has a useful amount of payload for such a mission...

So, it turns out that this was modelled, I just didn't see it. According to sheltonjr's calculations, it can do about 30 tonnes to GEO fully reusably, if I understand correctly. That's a nice chunk of that space infrastructure, or if the market doesn't develop at the same speed as SpaceX, about 6 current size comsats.

With a projected global market of around 100 comsats per year (270kB PDF), that'd give more than a flight per month, assuming they capture most of the market, and that's without any disruptive changes or price elasticity.

SpaceX would of course also want to have the military market, and the exploration missions. I can see them earning back the development costs and then make a nice profit for Elon to retire to Mars :).

Offline RanulfC

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Re: Alternative missions for BFR & MCT
« Reply #62 on: 09/24/2014 09:06 PM »
That doesn't increase NASA's budget though. They may be able to do more science for the same amount of money, but that doesn't make it more lucrative to SpaceX.

NASA is far from the only exploration/science customer out there though and IF prices come down and accessabilty goes up its pretty clear there WILL be other customers. That's part (a large part) of what the attraction to lowered cost/higher access in the first place.

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Your argument that the comsat market will morph into a more general space infrastructure actually supports my point that comsats are (and/or will be) more lucrative than exploration missions.

Actually not as the "market" itself will move more towards "parts" and possibly people to install and maintain than actual "comm-sats" once things get rolling. And once you begin to have such "infrastructure" in place, (as long as you don't do something silly like try to bypass using such an infrastructure which is pretty much what people assume Musk is aiming to do with BFR/MCT in the first place) it becomes a lot easier to get into position to launch exploration and science missions. And hopefully a lot cheaper which increases the usage and flight rates of the RLVs involved.

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And I know that Mars is the Roman god of war, but I don't think that that's enough for the USAF to start launching exploration missions to it, even if they become much cheaper.

Actually I highly doubt the Air Force or any military branch will "engage" in exploration at all, however "access" means they HAVE to increase their portion and presence as a consequence of civil presence and the possible "pressence" of others that require monitoring and possible interaction :)

People may recall the concept of "Hot Eagle?" and being able to drop Marines anywhere on the globe in a few hours? Station them in orbit and you're response time drops dramatically and a "specially modified" MCT can problably put quite a bit more than a single platoon on the ground as well :)
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So I'm wondering, how much would the fully reusable BFR be able to lift to GEO? I'm thinking that going only to GTO like Ariane 5 won't work too well with more than two satellites to drop off. So instead, I'd think that BFR would launch its second stage including the payloads into an orbit just below GEO, and then just drop off the satellites one by one as it passes the correct orbital slot. After dropping off all payloads, the second stage would deorbit and be reused. Provided of course that it has a useful amount of payload for such a mission...

So, it turns out that this was modelled, I just didn't see it. According to sheltonjr's calculations, it can do about 30 tonnes to GEO fully reusably, if I understand correctly. That's a nice chunk of that space infrastructure, or if the market doesn't develop at the same speed as SpaceX, about 6 current size comsats.

Probably a bit less than half that if they have to deliver them to different "slots" which they will. Still very nice :)

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With a projected global market of around 100 comsats per year (270kB PDF), that'd give more than a flight per month, assuming they capture most of the market, and that's without any disruptive changes or price elasticity.

SpaceX would of course also want to have the military market, and the exploration missions. I can see them earning back the development costs and then make a nice profit for Elon to retire to Mars :).

Well that IS the plan after all :)

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline GregA

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Re: Alternative missions for BFR & MCT
« Reply #63 on: 09/25/2014 01:03 AM »
I imagine that as they learn the sweet spots of reusability and RTLS, the best points to separate stages etc, that the BFR will be the first design to adjust its staging points (is that the right term?) to be more effective.

For example, we speculate that the centre core of the Falcon Heavy will be too far downrange to RTLS but can't do an orbit - so you need to determine if the best answer is to stage it earlier, land it downrange, or design it to do an orbit and re-enter (all leading to other questions and issues to resolve). If you stage it earlier then you may need a bigger 2nd stage to get the payloads to orbit, and the 2nd stage needs to orbit and re-enter too. The BFR design will be considering some different setups.

So all that said - and with the MCT in the back of my mind - it starts to sound like a 2nd stage could be a more significant "space tugboat", in contrast to what appears to be one of the less important pieces in the launch puzzle.

Probably a bit less than half that [mass] if they have to deliver [multiple payloads] to different "slots" which they will. Still very nice :)

I started to envisage 3 types of 2nd stages - with the MCT version used extensively during launch windows.
1) an MCT integrated version
2) a tugboat version that re-enters when it's done its job.
3) an multi-headed version

I remember as a teenager watching the videos of multi headed ICBMs. One rocket to get into a low orbit, then 20 different mini-rockets heading their own way. Could the BFR launch multiple different payloads in some similar manner?... 9 second stage rockets configured in the same shape as the engines?

(Of course the off-season BFR use may simply be to send slow payloads to Mars and general maintenance and refurb after 10 launches)

Offline ArbitraryConstant

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Re: Alternative missions for BFR & MCT
« Reply #64 on: 09/25/2014 02:43 AM »
No.  It'll be SpaceX's problem to try and pack the BFR full.  But the customer should design to the mission, not the launcher.  And what will bring down launch costs, especially for a reusable launcher, is using the same design to handle a large range of payloads.
Yeah.

The reality is that there's a lot of nations interested in space activities, as we can see from robotic missions and ISS participation. If the budget for a significant manned mission can be brought close to current budgets for robotic missions or other stuff like national Antarctica programs, I think it would be completely reasonable to expect to see manned Moon missions or bases, for example.

Offline Hyperion5

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Re: Alternative missions for BFR & MCT
« Reply #65 on: 10/05/2014 01:49 AM »
No.  It'll be SpaceX's problem to try and pack the BFR full.  But the customer should design to the mission, not the launcher.  And what will bring down launch costs, especially for a reusable launcher, is using the same design to handle a large range of payloads.
Yeah.

The reality is that there's a lot of nations interested in space activities, as we can see from robotic missions and ISS participation. If the budget for a significant manned mission can be brought close to current budgets for robotic missions or other stuff like national Antarctica programs, I think it would be completely reasonable to expect to see manned Moon missions or bases, for example.

Only problem I see with that is the MCT lander's design really won't be optimized for the Moon, AC.  I believe Sheltonjr calculated that a possible MCT lander would only be able to put 8 mt of payload down on our lunar neighbor.  Perhaps a better role for it would be to fly people over to the reusable landers in Polar orbit?  The MCT after all will be designed much better for landing and ascending from Mars compared to the Moon. 

Online guckyfan

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Re: Alternative missions for BFR & MCT
« Reply #66 on: 10/05/2014 08:38 AM »
Only problem I see with that is the MCT lander's design really won't be optimized for the Moon, AC.  I believe Sheltonjr calculated that a possible MCT lander would only be able to put 8 mt of payload down on our lunar neighbor.  Perhaps a better role for it would be to fly people over to the reusable landers in Polar orbit?  The MCT after all will be designed much better for landing and ascending from Mars compared to the Moon.

Correct, but why would you think 8 t to the moon and 2 t back is bad? It is a perfect amount for station resupply and crew exchange runs, better than anything presently for the ISS.

For initial station building that capacity can be increased. I have suggested to refuel the MCT plus a tanker in LEO and send them both on the same trajectory to the moon. After TLI the tanker transfers its remaining fuel to the MCT and returns to earth on a free or almost free return trajectory and lands back on earth. The MCT continues to the moon with a much larger cargo capacity. I cannot calculate by how much such a maneuver will increase the payload capacity but it will be a lot, I am sure. Enough to transport large station modules to lunar surface.

Note that I don't suggest any infrastructure in lunar orbit or L-points which greatly complicate any mission and increases cost IMO.

Offline Nilof

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Re: Alternative missions for BFR & MCT
« Reply #67 on: 10/05/2014 10:04 AM »
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So I'm wondering, how much would the fully reusable BFR be able to lift to GEO? I'm thinking that going only to GTO like Ariane 5 won't work too well with more than two satellites to drop off. So instead, I'd think that BFR would launch its second stage including the payloads into an orbit just below GEO, and then just drop off the satellites one by one as it passes the correct orbital slot. After dropping off all payloads, the second stage would deorbit and be reused. Provided of course that it has a useful amount of payload for such a mission...

So, it turns out that this was modelled, I just didn't see it. According to sheltonjr's calculations, it can do about 30 tonnes to GEO fully reusably, if I understand correctly. That's a nice chunk of that space infrastructure, or if the market doesn't develop at the same speed as SpaceX, about 6 current size comsats.

Probably a bit less than half that if they have to deliver them to different "slots" which they will. Still very nice :)

Different slots doesn't affect payload to GTO though. If the satellites still do the circularization themselves they can perform phasing maneuvers essentially for free, by splitting up the circularization into several burns.
« Last Edit: 10/05/2014 10:06 AM by Nilof »
For a variable Isp spacecraft running at constant power and constant acceleration, the mass ratio is linear in delta-v.   Δv = ve0(MR-1). Or equivalently: Δv = vef PMF. Also, this is energy-optimal for a fixed delta-v and mass ratio.

Offline enkarha

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Re: Alternative missions for BFR & MCT
« Reply #68 on: 10/06/2014 06:07 PM »
Now back on topic!  Out of curiosity, does anyone know if a ~300 t to LEO methalox monster would have the capacity to put an orbiter around Pluto?  I've always wondered if that was within the realm of possibility. 

Yes.

But the question you should ask is "How long would it take to get there?" The problem with taking a New Horizons-like trajectory to Pluto is that the spacecraft's velocity vector is almost perpendicular to Pluto's heliocentric velocity vector. So, the magnitude of the delta v to stop is enormous (from memory, it's close to 10 km/s for NH). To get around that with standard rockets, you really need to approach Pluto on a non-escape trajectory, bound heliocentric orbit with an aphelion at Pluto. That's great, but it would take around 70 years to reach Pluto. Not so great.

Non-chemical rockets are the real answer, and a nuclear reactor-ion engine system is the most plausible Pluto orbiter that could reach the destination before everyone on the mission team dies of old age. But nuclear-electric is a whole different can of worms to a super-large rocket.

Actually, it's probably more like 35 years to Pluto,( the period is 70 years, but we're only doing half the orbit to transfer). If we are going the Hohmann route, at Pluto it would need around 4 km/s to match pluto's orbit. So with 300 tons in orbit, with a stage that was 96% prop, 2 tons could conceivably be brought to Pluto transfer, which would leave ~500 kg of dry mass in Pluto orbit. It really shows how bad even 380s is for those really high delta-v maneuvers. This is all first order approximations, without gravity assist. With gravity assist you could put a lot more at Pluto, and I'll try those calculations later.
Let me see what spring is like on Jupiter and Mars ♪

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