Payload to orbit if all US main launchers launched simultaneously

[john smith 19]

NASA appears to have a horror of multiple launch missions. A pathological fear that some half fueled payload will be stuck in space due to launch mishap, delayed pad refurbishment or whatever.

So I wondered what would happen if you side stepped that problem by using all major US launchers to carry parts of a mission into LEO, possibly with one of them as backup to the most critical parts.

I don't really think that scheduling a group of launches to happen on the same day is that advanced but I don't know where else to put it.  Some are part of the EELV programme, some COTS, all with different mfgs.

According to the relevant Wikipedia entries doing this would give a Delta IV Heavy with 27569Kg, an Atlas V with either 20520Kg (potential) or 18814Kg (flown), an F9 at 13150Kg and an Antares II with 5000Kg.

So that's a total of 64533Kg proven capability or 66239Kg with the top end DIV H.

That is capability available now in the US, with a launch date of 24-36months from the money on the table.

Spacex seem keen on shortening the turnaround time on their pad to <24 hours, but I've no information on the others. I get the impression 1 month is nearer the mark.

My question is twofold. 1) IRL are there any impediments that I'm unaware of (apart from a large bag of money  ) to doing this and if so how difficult would they be to overcome and 2) Once you know this what sort of missions could be enabled by it?

This should not be viewed as a competitor to SLS. Currently for anything over 53 mt SLS would be the only option, or FH if the payload were less than 53 mt. But this is about  LV's available now.

I'll note that Atlas in the 401 variant is close to (already?) crew rated but not at 18814Kg  payload level. F9 is likewise crew rated pending crewed Dragon. I'll also note that (in principle) payloads on EELV's have common payload attach fittings and could be interchanged, payload mass limits permitting.

I'll also note that the empty mass for Saturn V "Earth Departure Stage" (SIVb) was about 10 000Kg and a human being needs about 5Kg of air, water and food (mostly water TBH) a day, so an Antares could carry enough supplies for a 1000 days for 1 person, so even this LV (in the right architecture) could have its uses.

[Lee Jay]

It takes a couple of days to reconfigure the range for a new flight from the same location.  So, that means one location at a time for a launch, separated by a couple days to the next reuse of the same location.  Then you're going to need to worry about launch windows all to the same plane and then rendezvous from the inevitably different phase angles, and the propellant and control that will take, plus the ability of the earlier payloads to loiter while they wait.

[savuporo]

My question is twofold. 1) IRL are there any impediments that I'm unaware of (apart from a large bag of money  ) to doing this and if so how difficult would they be to overcome and 2) Once you know this what sort of missions could be enabled by it?

It would require a massive campaign of AR&D to be useful for anything. If cooperative, every launched element will need to be a full autonomous spacecraft with GN&C, power , attitude and propulsion etc. If uncooperative, you need a fairly involved "tug" element to get the full stack together. Depending on how things are configured, you may need to transfer propellants, either storable and/or cryo.

All these technologies are relatively low maturity in US, so nobody is going to pay for 60 ton payload that relies on all that.

[edkyle99]

NASA appears to have a horror of multiple launch missions. A pathological fear that some half fueled payload will be stuck in space due to launch mishap, delayed pad refurbishment or whatever.

ISS?  How many launches over how many years to build, fuel, supply, and crew that multiple launch mission?  There were twelve launches to ISS alone just this year.

Which brings up another point - why only U.S. launches?  Throw in Proton, Ariane 5, H-2B, Zenit, and maybe others and the mass to orbit grows in a hurry.

The launch range reconfiguration restriction could be nullified with appropriate funding.  Back in the day, rockets flew from the Cape within hours of each other, sometimes on the same day.

 - Ed Kyle

[john smith 19]

It takes a couple of days to reconfigure the range for a new flight from the same location.  So, that means one location at a time for a launch, separated by a couple days to the next reuse of the same location.  Then you're going to need to worry about launch windows all to the same plane and then rendezvous from the inevitably different phase angles, and the propellant and control that will take, plus the ability of the earlier payloads to loiter while they wait.

I'm aware that most of them launch off their own separate pads, which seemed to take quite a bit of abuse during launch and hence need physical repair and cleanup. However I'm surprised it takes so long to set up for another launch on the range as a whole. 

It would require a massive campaign of AR&D to be useful for anything. If cooperative, every launched element will need to be a full autonomous spacecraft with GN&C, power , attitude and propulsion etc. If uncooperative, you need a fairly involved "tug" element to get the full stack together. Depending on how things are configured, you may need to transfer propellants, either storable and/or cryo.

All these technologies are relatively low maturity in US, so nobody is going to pay for 60 ton payload that relies on all that.

Well those are certainly a couple of options. But "uncooperative" comes in several more flavors. An obvious option would be to develop one payload with all of that stuff and the others to carry a beacon and docking package. Note that both COTS winners for the cargo contract to the ISS use automated docking and rendezvous systems already.

I think a substantial part of the question would hinge on how tight an orbital "bubble" the various LV's could place a payload in before separation. The tighter the bubble the lower the delta v needed by any residual system.

Storable transfer has been demonstrated although no one else seems to have done cryo yet. Propellant settling has been demonstrated to need less than 10 micro g of acceleration.

Note also that 12000lb of thrust was enough to deliver the final delta v to get a 245000lb vehicle (the Shuttle) to and from final orbit. Each delta v being about 100m/s. That's 2x the mass of the whole that these could deliver to LEO working together.

[savuporo]

Note that both COTS winners for the cargo contract to the ISS use automated docking and rendezvous systems already

Neither of them docks, both are berthed.

[Patchouli]

It would require a massive campaign of AR&D to be useful for anything. If cooperative, every launched element will need to be a full autonomous spacecraft with GN&C, power , attitude and propulsion etc. If uncooperative, you need a fairly involved "tug" element to get the full stack together. Depending on how things are configured, you may need to transfer propellants, either storable and/or cryo.

All these technologies are relatively low maturity in US, so nobody is going to pay for 60 ton payload that relies on all that.

I think the technology for autonomous spacecraft is mature enough I'd have no issues having it be part of a mission architecture.

On a Mars mission I'd trust it a lot more then I would the present state of development in tightly closed loop life support.

Though what's more important to me then the payload all at once is what kind of payload can be orbited over the course of six months using existing launch vehicles.

[john smith 19]

ISS?  How many launches over how many years to build, fuel, supply, and crew that multiple launch mission?  There were twelve launches to ISS alone just this year.

A fair point but ISS is very much an outlier where NASA is concerned. It's not going anywhere and it's not a stage that's expected to take a payload anywhere.

Which brings up another point - why only U.S. launches?  Throw in Proton, Ariane 5, H-2B, Zenit, and maybe others and the mass to orbit grows in a hurry.

True. Ariane certainly, although I'm not sure what the H-2B launch record has been like.
As for US launchers only the answer is ITAR, and the ensuing row by the Legislature of foreign launchers.

The launch range reconfiguration restriction could be nullified with appropriate funding.  Back in the day, rockets flew from the Cape within hours of each other, sometimes on the same day.

That is useful to know. In an era when automation is relatively cheap to do it's surprised me that the time needed between launches should go up. 

Note that both COTS winners for the cargo contract to the ISS use automated docking and rendezvous systems already

Neither of them docks, both are berthed.

Which would mean that one of the payloads would need a berthing arm. However I note that at least Draon appears to have the necessary hardware to "dock" rather than "berth."

I think the technology for autonomous spacecraft is mature enough I'd have no issues having it be part of a mission architecture.

Agreed. I also think the amount of development needed can be minimized with care

On a Mars mission I'd trust it a lot more then I would the present state of development in tightly closed loop life support.

Yes. Progress seems to be being made there but it's almost as slow as cryogenic propellant transfer

Though what's more important to me then the payload all at once is what kind of payload can be orbited over the course of six months using existing launch vehicles.

These are existing vehicles. 

The problems with the serial approach include propellant boil off, risk of impact, depletion of consumables (the IVF concept proposed for Centaur and it's developments is not SOP and may not be transferrable to non cry systems ) and the need for a higher orbit and consequent loss of payload.

Launching the whole mission on 1 day, spread across multiple launchers lowers the loiter time on orbit for all of these things to occur. Using existing LVs allows the architecture to leverage the safety characteristics of the LV's. Within 1 day all parts are on orbits and I would expect all parts to be joined ready to leave orbit within the week.
 

[Jim]

That is useful to know. In an era when automation is relatively cheap to do it's surprised me that the time needed between launches should go up.

It is an issue of limited shared resources, where automatic has little use.   The range is manned for 5/40 with overtime and creative shifting used to cover other hours.  The range operator is like a launch team, where the same team works all the launches. There has to be a break between ops.  Additionally, there are items like tracking cameras that would have be moved to cover different launch pads.  voice channels have to reconfigured and verified between different control centers.  Roadblocks have to be moved around. 

There is more, will need some time to think.

[john smith 19]

That is useful to know. In an era when automation is relatively cheap to do it's surprised me that the time needed between launches should go up.

It is an issue of limited shared resources, where automatic has little use.   The range is manned for 5/40 with overtime and creative shifting used to cover other hours.  The range operator is like a launch team, where the same team works all the launches. There has to be a break between ops.  Additionally, there are items like tracking cameras that would have be moved to cover different launch pads.  voice channels have to reconfigured and verified between different control centers.  Roadblocks have to be moved around. 

There is more, will need some time to think.

These were exactly the issues I was wondering about. 

I was wondering how many  separate ranges there are that could operate at the same time. My instinct is Wallops Island for Antares II and whatever the resources are at Kennedy Space Centre / Cape Canaveral Air Station, but I'm not sure how that's split up. Is that 2 or 3 ranges?

Note that in my OP I did not specify when these launches would take place. My goal was to get then all to LEO in as short a time as possible. From my PoV it the best for the range is 10-4 weekdays (weather permitting) I'd be fine with that.

I'm guessing but do you know if the Delta IV /Atlas vehicles interface to the range in roughly the same way? I mean that it would be easier switching from covering a Delta IV Heavy to an Atlas V launch than say Delta IV Heavy to F9?

So far it's looking like you'd need additional tracking cameras to avoid the delay of moving them around, faster  voice and data channel re-configuration processes and an extra supply of roadblocks (and staff to man them?)

None of which sounds too difficult if you want to put a minimum of 64 1/2 mt into LEO at the same time.

[edkyle99]

ISS?  How many launches over how many years to build, fuel, supply, and crew that multiple launch mission?  There were twelve launches to ISS alone just this year.

A fair point but ISS is very much an outlier where NASA is concerned. It's not going anywhere and it's not a stage that's expected to take a payload anywhere.

Planning a LEO rendezvous mission that requires a big launch surge in a short period of time creates more opportunity for mission failure.  If one flight falters, the whole mission is lost.

If the mission is designed for gradual buildup, over many months (or even years), and for long-duration on-orbit propellant storage, flight failures can be tolerated.  (ISS is still there, despite the loss of Shuttle access for two years and despite an unprecedented Progress launch failure.)  An extra plus would be that no new launch pads or extra launch range expenditure would be required to support the surge.

I see ISS as a valuable (unparalleled actually) teacher when it comes to LEO buildup missions.  We know, for example, that the flight pace needed for ISS is possible, not just technically but financially and politically.  Why not plan to use similar techniques for beyond LEO?

For ISS and other purposes, probably 70-90 tonnes of storable hypergolic propellant is routinely orbited every year.  The stuff lasts for years and years - even decades - in orbit, and that is not a theory, it is proven daily by hundreds of operating satellites . 

... I'm not sure what the H-2B launch record has been like.
As for US launchers only the answer is ITAR, and the ensuing row by the Legislature of foreign launchers.

H-2B has four launches and no failures since 2009.  Smaller H-2A has flown 22 times with one failure since 2001. 

Re:  foreign launchers - U.S. astronauts are launched, and will continue to be launched for years to come, by Russia.  U.S. satellites are orbited by European and Russian rockets.  The Pentagon and NASA both depend on Russian rocket engines (Atlas 5 and Antares), and on a Ukrainian built stage (Antares), etc.  Orion will use a European service module and SLS will use tank panels made in Germany.  That "foreign" bridge was crossed long ago. 

 - Ed Kyle

[Lar]

I don't want ISS to go away in order to support this big campaign, so Ed's point that we have the political will for multiple launches, while true, doesn't necessarily mean we have enough will for the launches needed to sustain ISS PLUS this campaign.

Neat exercise though.

To Jim's point, ranges can have more cameras and can be staffed 24/7 and etc. It just takes bagfuls of money and the NEED. As long as there's another way, there may not be the need. Or not the apparent need.

[Jim]

1.  I was wondering how many  separate ranges there are that could operate at the same time. My instinct is Wallops Island for Antares II and whatever the resources are at Kennedy Space Centre / Cape Canaveral Air Station, but I'm not sure how that's split up. Is that 2 or 3 ranges?

2.  I'm guessing but do you know if the Delta IV /Atlas vehicles interface to the range in roughly the same way? I mean that it would be easier switching from covering a Delta IV Heavy to an Atlas V launch than say Delta IV Heavy to F9?

3.  So far it's looking like you'd need additional tracking cameras to avoid the delay of moving them around, faster  voice and data channel re-configuration processes and an extra supply of roadblocks (and staff to man them?)

1.  2 ranges.  KSC and CCAFS are the Eastern Range (one range).  But depending on the orbit, Wallops may use resources of the Eastern Range.

2.  No, it is pad/vehicle dependent. so no difference.

3.  The issue isn't the supply of physical roadblocks.  It is setting up and clearing out the areas that the roadblocks are to protect.  faster  voice and data channel re-configuration processes are still limited by having to do physical voice checks on on all the channels at all the positions. 

[john smith 19]

Planning a LEO rendezvous mission that requires a big launch surge in a short period of time creates more opportunity for mission failure.  If one flight falters, the whole mission is lost.

I think that depends on mission details. For example is this one of a series? If so buy 2 launchers at a time and build 2 payloads together. If the primary launches without a hitch the backup becomes prime for the next launch. If not clear the pad and launch the backup or re configure the mission. Another option would be to break the payload into "pods" and mounting hardware which add up to multiples of the smallest LV. So Antares II would be good for 1 pod and Delta IV H would be good for say 5 pods.

If the mission is designed for gradual buildup, over many months (or even years), and for long-duration on-orbit propellant storage, flight failures can be tolerated.  (ISS is still there, despite the loss of Shuttle access for two years and despite an unprecedented Progress launch failure.)  An extra plus would be that no new launch pads or extra launch range expenditure would be required to support the surge.

True. But you have 2 problems where NASA is concerned. 1) Once outside of LEO NASA are convinced that LO2/LH2 is the only serious option for large vehicles. 2) Despite 5 decades NASA has flown no actual flights to demonstrate long term (and in this context I mean as little as 1 week) cryo storage.

I see ISS as a valuable (unparalleled actually) teacher when it comes to LEO buildup missions.  We know, for example, that the flight pace needed for ISS is possible, not just technically but financially and politically.  Why not plan to use similar techniques for beyond LEO?

I'd agree.

For ISS and other purposes, probably 70-90 tonnes of storable hypergolic propellant is routinely orbited every year.  The stuff lasts for years and years - even decades - in orbit, and that is not a theory, it is proven daily by hundreds of operating satellites . 

I did not know it was that much  . Without fuss, without drama. But see problem #1 with this above. 

The trade is tricky. Last time I checked the amines are about 6x the cost of LH2 (never the cheap option  to begin with) OTOH the tank price is about 8.1% per ft^2 of surface area for LH2 tanks  [edit that's 8.1% higher than the surface area price of all other tanks, based on a NASA "Access to Space" study quoted by Rand Simberg]. And of course you have to factor in the LH2 volume versus that of an amine.

H-2B has four launches and no failures since 2009.  Smaller H-2A has flown 22 times with one failure since 2001. 

Re:  foreign launchers - U.S. astronauts are launched, and will continue to be launched for years to come, by Russia.  U.S. satellites are orbited by European and Russian rockets.  The Pentagon and NASA both depend on Russian rocket engines (Atlas 5 and Antares), and on a Ukrainian built stage (Antares), etc.  Orion will use a European service module and SLS will use tank panels made in Germany.  That "foreign" bridge was crossed long ago. 

I agree, IRL both the Pentagon and NASA have been pragmatic, but it's the political dimension that I was concerned about and in the US that is a significant dimension. A US only launched mission(s) whould be easier to navigate through the Legislature.

I don't want ISS to go away in order to support this big campaign, so Ed's point that we have the political will for multiple launches, while true, doesn't necessarily mean we have enough will for the launches needed to sustain ISS PLUS this campaign.

Nor do I.

Neat exercise though.

Thank you. 

But I'd like to see someone tackle the other question of what to do with this capability, which (essentially) already exists, in the sense of LV's and pads for them to fly from.

To Jim's point, ranges can have more cameras and can be staffed 24/7 and etc. It just takes bagfuls of money and the NEED. As long as there's another way, there may not be the need. Or not the apparent need.

IIRC hardware costs rise linearly but staff costs rise exponentially, so hardware is relatively cheap, but raising headcount is expensive. I think 24/7 coverage is unnecessary provided all the launch windows can be hit in a 9-5 day, which I think is possible.

[edkyle99]

If the mission is designed for gradual buildup, over many months (or even years), and for long-duration on-orbit propellant storage, flight failures can be tolerated.  (ISS is still there, despite the loss of Shuttle access for two years and despite an unprecedented Progress launch failure.)  An extra plus would be that no new launch pads or extra launch range expenditure would be required to support the surge.

True. But you have 2 problems where NASA is concerned. 1) Once outside of LEO NASA are convinced that LO2/LH2 is the only serious option for large vehicles. 2) Despite 5 decades NASA has flown no actual flights to demonstrate long term (and in this context I mean as little as 1 week) cryo storage.

It is hard to beat LH2 for high energy missions, but a large number of NASA's beyond Earth orbit missions were not boosted by hydrogen fueled stages.  Many of the Mars missions (Pathfinder, Spirit, Opportunity, Mars Global Surveyor, Mars Odyssey, and others) were launched by Delta 2 rockets with their hypergolic pressure fed and solid fuel upper stages.  Galileo and Magellan were boosted by IUS solid rocket motors.  The most recent lunar mission, LADEE, went up on an all-solid rocket, with final boosting by LADEE's own on-board storable propellant system.  Orion will use the tried and true hypergolic propellant combination, as likely will any commercial crew spacecraft and as already do the commercial cargo spacecraft.

Cryos are going to boil off from a depot, especially in LEO and especially liquid hydrogen, no matter how good the insulation.  That lost propellant mass is extra mass that must be launched, which obviously will offset some or all of the performance benefit offered by the higher specific impulse of the fuel.  It all makes me wonder why storable hypergolics aren't seriously contemplated for larger scale deep space missions. 

 - Ed Kyle

[john smith 19]

It is hard to beat LH2 for high energy missions, but a large number of NASA's beyond Earth orbit missions were not boosted by hydrogen fueled stages.  Many of the Mars missions (Pathfinder, Spirit, Opportunity, Mars Global Surveyor, Mars Odyssey, and others) were launched by Delta 2 rockets with their hypergolic pressure fed and solid fuel upper stages.  Galileo and Magellan were boosted by IUS solid rocket motors.  The most recent lunar mission, LADEE, went up on an all-solid rocket, with final boosting by LADEE's own on-board storable propellant system.  Orion will use the tried and true hypergolic propellant combination, as likely will any commercial crew spacecraft and as already do the commercial cargo spacecraft.

Interesting point. But how many Delta II upper stages are left? IIRC Antares II is planned to have a hypergolic upper stage but I think this is on the upgrade list at present.

Cryos are going to boil off from a depot, especially in LEO and especially liquid hydrogen, no matter how good the insulation.  That lost propellant mass is extra mass that must be launched, which obviously will offset some or all of the performance benefit offered by the higher specific impulse of the fuel.  It all makes me wonder why storable hypergolics aren't seriously contemplated for larger scale deep space missions. 

LM have done a lot of on IVF for Centaur. Just tapping that boil off and using it to run a small settling thruster (IIRC) cuts the boiloff in half. The biggest win was eliminating the GHe pressurization tanks, which turned out to be the mission ending consumable. The deeper goal was the elimination of all mission shortening problems EG batteries running flat, lack of pressurization etc.

Actually it's not that big a mystery. When NASA do an architecture study and include storables that increases the mass to orbit by a lot.. Plus the fact that AFAIK there are no pump fed storable engines in the US inventory. IIRC the Shuttle OMS got ab out 312secs, the RL10s about 450sec plus? Agena seemed to be the last big one.

NB I still recall a slide of Robert Braun's stating that improved propellant management (reduced boileoff, on orbit transfer) was the #1 way to lower mass to orbit for a Mars mission. On an exponential curve it cut something like 60% off the steepest part of the curve, cutting the mass to orb it for Mars by more than half.  That seemed like a huge sign post to me that this was a technology to work on yet proposals for things like CRYOTE have gone nowhere 

So IRL we have 3 factors 1) No big pump fed storable engines 2) No improvements to existing on orbit cryogenic propellant management. 3) A strong bias for cryogenic propellants.

My pragmatic response. Launch the payload on multiple launches as close together as possible to enable cryo use with minimal boiloff. 

[savuporo]

My pragmatic response. Launch the payload on multiple launches as close together as possible to enable cryo use with minimal boiloff. 

So you can use cryo for earth departure, but for any burns beyond that you are still back to hydrazine - and another set of engines and tanks ?
IMHO the only real chance for maturing long duration cryo stages is if someone builds an engine and a full stage small enough that can be realistically used on planetary probes, like Mars landers and maybe a MAV. Nobody seems to bother.

Centaur centric thinking with ACES, Cryote talks etc are all too big projects to go anywhere.

[edkyle99]

Actually it's not that big a mystery. When NASA do an architecture study and include storables that increases the mass to orbit by a lot.. Plus the fact that AFAIK there are no pump fed storable engines in the US inventory. IIRC the Shuttle OMS got ab out 312secs, the RL10s about 450sec plus? Agena seemed to be the last big one.

AJ10-118K had a 319 sec specific impulse, but that's pressure fed and only 4.45 tonnes thrust.  The Titan 4 second stage LR91-AJ-11 engine was pump fed.  It produced 48 tonnes thrust at 316 sec ISP, but of course was not restartable.  Ariane 5 has Aestus, with its 321 sec ISP and restart ability.  Russia has more modern hypergolic pump fed engines, including some with staged combustion cycles.  They have proven specific impulses of up to 327 seconds. 

What about combining space storable with cryogenics?  Serial launch a mess of storables propellant to a depot/stage.  Then, at the last minute, launch a fully fueled cryogenic stage on the biggest rocket available.  After docking with the storable stage and payload, have the cryogenic stage burn to depletion, then use the storable stage to perform the rest of the departure burn.  Best of both worlds, perhaps.

 - Ed Kyle

[savuporo]

Btw, i looked up what small(ish) LOX/LH2 engines actually have existed.
Ottobrunn 300N came up, RS-52 , anything else ? I mean something on a scale that could fly as a cheap technology demonstrator for long duration cryo stages.
LOX/CH4 obviously has even smaller gene pool of existing designs, but may actually work out to be cheaper as a tech demo.

[notsorandom]

Rockets with LH2 upper stages are not at a great disadvantage when assembling a spacecraft at an L point. The beauty of assembling at a Lagrange point is that the majority of the Delta V for a Trans Mars Injection burn  is delivered before boil off becomes a concern within the first few hours of flight. The drawback to this is that the rocket can't lift nearly the same amount of payload as it can for LEO. If the smallest part of a Mars lander for example is bigger than 50 or so tones not even SLS could get it to L2 in one launch.