Minimal Manned Mars Mission - 2*Briz = doable! + a NEA

[DBowman]

1 hour ago, tater said:

Found a cool gif

Cool indeed.

I'd originally wanted to use a shadow shield, but some reading said 'no, it's anisotrophic', so I had to plan for a 'water sarcophagus'. Today I read some study for 'Plymouth Rock' dual Orion asteroid mission and it said the solar maximum cut Cosmic Gamma Ray Background by a factor of 2 or 3 (nice), I guess the sun cranks up it's magnetic fields and/or the increased 'wind' interacts with heavy nuclei. Obviously increases the likely hood and severity of solar proton events (ugly). It's all swings and roundabouts.

[Nibb31]

8 hours ago, AngelLestat said:

-Remember the skylon discussion about if it has economic sense to have those launch cost?  
Well ESA did a big economic study and it was proved that it has economic sense.

The report was paid for by ESA but led by REL. They're not going to say that it isn't possible.

Do you have a link to that report? I was unable to find it, so I really can't comment on it. However, I did find a 2011 report, which was technical but not very detailed on the economics. I do know that the figures that have been produced in the past make absolutely no sense.

Unfortunately, for plenty of political reasons, I don't see ESA funding a UK company without the UK government spending a lot more money ESA, which they aren't prepared to do. ESA funds projects proportionally to the participation of each country, which is why most ESA money goes to France, Germany, and Italy.

Arianespace is in charge of launcher development and the UK or BAe Systems isn't part of it.

Quote

-Remember when I predict a big increase in launch demand with cheap satts made with modern production lines with new business cases, and you said that was impossible because I did not knew nothing on how those projects are managed..  Half year later.. constellations boom news over all the place.  

We are pretty much at the same stage we were 6 months ago, except that SpaceX has gone quiet about its constellation plans.

Quote

-Remember when I predict Airships and quadrotors transporting cargo and you said that quadrotors never will get FAA approval and that airships (if they appear) they will have a very small niche?

Well many drones already have faa approval for those works and airship production start in 4 or 5 different companies and europe is already creating the logistic for this kind of vehicles.

I don't remember saying much about quadrotors. I said that oversized blimps would remain a niche for oversized cargo, like the An225 or Skycrane helicopter. I haven't seen that being contradicted. 

Quote

-When I said that venus was easier and a better case, and almost one year after NASA made the concept mission and said that it will be easier than a trip to mars..

Oooh ! So NASA is ok when they agree with you? I thought they always screw up...  NASA is not a monolithic entity. It is many people working in many labs throughout many centers. NASA didn't make a concept mission. Someone at NASA did. There are all sorts of people at NASA working on all sorts of stuff and trying to attract attention to get funding.

Anyway, I haven't seen NASA switching their Mars plans to Venus plans.

This is getting personal and off topic. So I'll leave it here.

Edited February 9, 2016 by Nibb31

[tater]

Cosmic radiation is pretty much something you just have to live with as a "cost of business." Clearly solar protons are more complex than LOS from the sun, even during flare events, but in the latter case it's closer to a LOS thing than not. Honestly, if you have enough water/supplies to make a shelter that is direction-agnostic, why not?

[fredinno]

6 hours ago, tater said:

Cosmic radiation is pretty much something you just have to live with as a "cost of business." Clearly solar protons are more complex than LOS from the sun, even during flare events, but in the latter case it's closer to a LOS thing than not. Honestly, if you have enough water/supplies to make a shelter that is direction-agnostic, why not?

Those supplies will decline over time, so if a solar flare happens on the way back....

[DBowman]

1 hour ago, fredinno said:

Those supplies will decline over time, so if a solar flare happens on the way back....

Water + food is converted by the astronaut into urine + '(semi)solid waste', the amount of 'shielding water' does not decrease - it just gets converted to a form that's not good for much else. Actually the body creates some water from metabolising food with oxygen, essentially hydrogen from sugars gets attached to oxygen liberating energy and creating water - but I guess the hydrogen is what we want for the shield effect anyway.

Does anyone have any good info re Oxygen & Nitrogen storage mass and volume for pressure vs cryo? I thought I'd sourced info where pressure O₂ tank would be 0.4 the mass of contained O₂, but the 1967 Bellcom Venus flyby says 2.5 the mass contained (0.1 for cryo but higher volume). This flyby has both mass and volume issues.

Another O₂ storage option I found is Hydrogen Peroxide, a 1965 paper describes a system to decompose concentrated H₂O₂ to provide H₂O for drinking and O₂ for breathing. To provide O₂ for 500 days you'd need 978 kg (765 litre) of H₂O₂ to provide all the O₂ and about 100 litres 'excess' water. This is about the same mass as my 'maybe too light' water+(O₂+tank ) estimate, but way less volume (and pressure risk). This is not a scheme with flight heritage but:

• on the plus side it's so simple; no pressure or cryo, practically anything catalyses the decomposition so you could imagine MacGyvering something in an Apollo 13 situation. At 5C it's apparently pretty stable.
• on the minus side; practically anything catalyses the decomposition and if you don't 'treat it right with respect' it's pretty dangerous (explosive decomposition, hot steam, etc). Although it's room temperature storable it's pretty bio-nasty if you managed to spill/leak it onto/into yourself.

I kind of like this one since it's low tankage, near STP, and simple - but I want to know I'm comparing to realistic pressure and cryo options and am having trouble finding good info.

[PB666]

On 12/9/2015 at 3:33 AM, YNM said:

The idea of using trash as extra propellant is... Novel I suppose ? No more costly mid-course corrections (with engines and propellant)... Imagine not needing to have any RCS on the craft... Reentry might be a bit rough though, but Soyuz does them nicely even if deliberately disrupted. Maybe launching the trashes with some springs would help !

For those who wonder "where's lander ?" the OP have stated it will only be a flyby for "tourists" or so. I mean... We did flyby first for Moon no ? So why not on Mars ?

 

Yeah, need to take a leak stick your thing into a minature airlock and relieve, toilet gets flushed into space accelerated by fermented sewer gases. Think of what space would be like in say a couple 1000 years.

"Captain the ship appears to have been abandoned ". . . . . .squak comes over the comm "Coprolites! [bleep bleep] kills every time, right through the hibernation chamber"

[PB666]

5 hours ago, DBowman said:

Water + food is converted by the astronaut into urine + '(semi)solid waste', the amount of 'shielding water' does not decrease - it just gets converted to a form that's not good for much else. Actually the body creates some water from metabolising food with oxygen, essentially hydrogen from sugars gets attached to oxygen liberating energy and creating water - but I guess the hydrogen is what we want for the shield effect anyway.

Does anyone have any good info re Oxygen & Nitrogen storage mass and volume for pressure vs cryo? I thought I'd sourced info where pressure O₂ tank would be 0.4 the mass of contained O₂, but the 1967 Bellcom Venus flyby says 2.5 the mass contained (0.1 for cryo but higher volume). This flyby has both mass and volume issues.

Another O₂ storage option I found is Hydrogen Peroxide, a 1965 paper describes a system to decompose concentrated H₂O₂ to provide H₂O for drinking and O₂ for breathing. To provide O₂ for 500 days you'd need 978 kg (765 litre) of H₂O₂ to provide all the O₂ and about 100 litres 'excess' water. This is about the same mass as my 'maybe too light' water+(O₂+tank ) estimate, but way less volume (and pressure risk). This is not a scheme with flight heritage but:

• on the plus side it's so simple; no pressure or cryo, practically anything catalyses the decomposition so you could imagine MacGyvering something in an Apollo 13 situation. At 5C it's apparently pretty stable.
• on the minus side; practically anything catalyses the decomposition and if you don't 'treat it right with respect' it's pretty dangerous (explosive decomposition, hot steam, etc). Although it's room temperature storable it's pretty bio-nasty if you managed to spill/leak it onto/into yourself.

I kind of like this one since it's low tankage, near STP, and simple - but I want to know I'm comparing to realistic pressure and cryo options and am having trouble finding good info.

Permanganate, H202 is not stable in high concentrations, better at low concentrations with a stabilizer. We don;'t actually consume that much O2 per day, if you think about it the amount of dry carbon in our food is probably on the order of 100grams a day so for 500 days you need roughly 2x 100,000 grams or 100 kilos of O2, considering its importance not that much in a 10tonne vessel. The bigger problem is getting rid of CO2, if you could seperated from the air you could just dump it into space. CO2 is much less volatile than the other gases, so thats a LiOH less method. Before you suffocate CO2 will get you first, major headaches, cramping, etc.

[fredinno]

20 hours ago, DBowman said:

Water + food is converted by the astronaut into urine + '(semi)solid waste', the amount of 'shielding water' does not decrease - it just gets converted to a form that's not good for much else. Actually the body creates some water from metabolising food with oxygen, essentially hydrogen from sugars gets attached to oxygen liberating energy and creating water - but I guess the hydrogen is what we want for the shield effect anyway.

Does anyone have any good info re Oxygen & Nitrogen storage mass and volume for pressure vs cryo? I thought I'd sourced info where pressure O₂ tank would be 0.4 the mass of contained O₂, but the 1967 Bellcom Venus flyby says 2.5 the mass contained (0.1 for cryo but higher volume). This flyby has both mass and volume issues.

Another O₂ storage option I found is Hydrogen Peroxide, a 1965 paper describes a system to decompose concentrated H₂O₂ to provide H₂O for drinking and O₂ for breathing. To provide O₂ for 500 days you'd need 978 kg (765 litre) of H₂O₂ to provide all the O₂ and about 100 litres 'excess' water. This is about the same mass as my 'maybe too light' water+(O₂+tank ) estimate, but way less volume (and pressure risk). This is not a scheme with flight heritage but:

• on the plus side it's so simple; no pressure or cryo, practically anything catalyses the decomposition so you could imagine MacGyvering something in an Apollo 13 situation. At 5C it's apparently pretty stable.
• on the minus side; practically anything catalyses the decomposition and if you don't 'treat it right with respect' it's pretty dangerous (explosive decomposition, hot steam, etc). Although it's room temperature storable it's pretty bio-nasty if you managed to spill/leak it onto/into yourself.

I kind of like this one since it's low tankage, near STP, and simple - but I want to know I'm comparing to realistic pressure and cryo options and am having trouble finding good info.

H2O2 is a bad idea because it decomposes too quickly.

Also, normally, Urine would be turned into water by recyling (like on the ISS) along with sweat, saving lots of mass. So, it would still increase mass of the craft.

[DBowman]

6 hours ago, fredinno said:

H2O2 is a bad idea because it decomposes too quickly.

Also, normally, Urine would be turned into water by recyling (like on the ISS) along with sweat, saving lots of mass. So, it would still increase mass of the craft.

I found this yesterday Hamilton Standard - Life support concepts and trade offs 1970 old but referenced still by modern NASA docs. They think there are materials that will hold H2O2 with low enough decomposition for periods over a year. For propulsion any decomposition is bad because it consumes deltaV. In a life support context it decomposes into two things you want anyway, though you'd rather it happen on your own schedule.

In my plan so far I'd use forward osmosis to extract about 85% of the water in urine leaving 15% as brine + water in 'solid waste' - about 0.4 kg/day becomes usable only for radiation shielding. H2O2 for oxygen would liberate about 1 kg/day of H2O.

H2O2 is for sure no good for doing a full repressurize (hole, fire, EVA) since it liberates too much heat, since it also make 'too much' water you'd want to have a mix of H2O2 and pressure stored O2. H2O2 is good for solar flare shielding and has very low 'tankage' mass. I think it's worth keeping 'in the mix' for now.

[YNM]

On 02/10/2016 at 10:56 AM, PB666 said:

Yeah, need to take a leak stick your thing into a minature airlock and relieve, toilet gets flushed into space accelerated by fermented sewer gases. Think of what space would be like in say a couple 1000 years.

"Captain the ship appears to have been abandoned ". . . . . .squak comes over the comm "Coprolites! [bleep bleep] kills every time, right through the hibernation chamber"

 

"space is mind-boggingly big ... getting help within 25s is improbabe"

Well, yeah, it's just huge empty space.

 

[DBowman]

I worked up a pretty complete mass & power budget for a 500 day Venus & Mars flyby (paper) using data from current NASA Advanced Life Support Baseline Values and Assumptions Document (NASA BVA) and a 1967 Apollo Applications Manned Venus flyby paper (paper from nasaspaceflight.com).

Radiation shielding sarcophagus style storm shelter is from remaining food and accumulated 'bio waste', it should provide near NASA mandated levels of protection from Solar events though I'd be inclined to spend buffer mass on H₂O to be sure (paper). Excluding solar events the astronaut will get about an 833 msv radiation dose - this is below the NASA lifetime does for the 'worst case' 25 year old female astronaut (they'd 'happily' send an old man 4 times before he hit his limit - paper).

I chose a 0.7 atm normal O₂ partial pressure cabin atmosphere; with budget for 3 full re-pressurizes (post fire or EVA) and leakage. The O₂ and N₂ are pressure stored for simplicity. CO₂ removal is via a ISS style (but half mass) CDRA, or I could consume all the mass buffer by switching to LiOH for more simplicity and more radiation shielding.

Water is mainly from vapor H₂O and forward osmosis urine recovery (HTIWater.com). I've included budget for clothing, fecal 'handling', food packaging, communication equipment, power for communication bandwidth, etc - see below.

Then I used that mass estimate to design mission around Russian current hardware - no current USA tech can make a viable mission. Soyuz and Proton Briz M (non-cryogenic upper stage) can get the job done going by data from astronautix.com. Some of the mission payload mass and volume won't fit on a Soyuz launch so I put 1800 kg of it in an 'InterPlanetary Module', it has a docking adapter for the Soyuz capsule. The Briz upper stages need to be able to dock to each other to create a two stage Flyby Injection Stack:

• 1 Proton + Briz M + IPM - the Briz is under-fueled by the mass of the IPM
• 1 Proton + Briz M - this Briz is fully fueled
• the two Briz dock to form the Flyby Injection Stack
• Soyuz launch, the capsule docks to the FIS
• 4.3 km/s 'eyeball out' injection burn, probably in at least two 'kicks'. Ideally while in an elliptical and abort-able orbit final 'go' checks can be done on any IPM elements (radiators, extra deployed solar array, any internal hook ups, any boot-able elements, etc).
• about 70 m/s tweak is required while en-route by Soyuz engine
• a very fast & hot Soyuz re-entry is made - I've budgeted mass for more ablation material based on the NASA Venus flyby plan
• imagine the problem of Soyuz H₂O₂ for it's turbos and RCS decomposing is 'solved' somehow

This mission profile works deltaV wise with a 350 kg mass buffer. If you allocate:

• 045 MUSD for IPM and Briz 'stacking' hardware (just a guess)
• 210 MUSD TASS Proton launch cost estimates x 2 (link)
• 188 MUSD NASA cost for Soyuz 'hire' (link)
• 050 MUSD for 'the rest' (just a guess)

then the whole thing comes in at 500 MUSD.

Mass budget details:

1. 7200 kg Soyuz Capsule
2. -700 kg propellant - we don't need all it's propellant
3. 0491 kg O₂ 
4. 0179 kg O₂ tank-age
5. 0044 kg N₂
6. 0020 kg N₂ tank-age
7. 0098 kg CDRA CO₂ removal
8. 0057 kg Forward Osmosis 'driver' solution (concentrated sports drink)
9. 0355 kg packaged dehydrated food (near 50kg is packaging - maybe could be used for fecal after)
10. 0028 kg Apollo style 'kitchen'
11. 0104 kg Hygiene & fecal treatment supplies
12. 0016 kg Medical and tool kit
13. 0032 kg exercise equipment
14. 0040 kg clothes ( 16 monthly changes ... )
15. 0010 kg emergency O2 masks
16. 0195 kg additional ablation material (NASA Venus, this will be a hotter entry, but Soyuz is smaller - needs numerical simulation to get a better number)
17. 0080 kg light weight radiator cooling for 4 kW thermal rejection
18. 0050 kg communication equipment, 3 kW power required
19. 0711 kg solar arrays etc for additional 3 kW communication power
20. 9010 kg Total - 'regular Soyuz' + 1800 kg
21. 0600 kg additional 'structure' mass for IPM & a Briz to Briz stage-able docking adapter
22. 0350 kg additional 'buffer' mass

Volume of a Soyuz is 8.3 m³. NASA BAV doc has 5.1 m³ as 'tolerable', 9.91 m³ as 'performance', and 18.41 m³ as 'optimal'. Some internal volume is going to be consumed by 'stuff' that won't fit in the IPM, It seems likely we could hit the 'tolerable' range of free volume. My feeling is that with multiple people you'd need more volume per person than for a solo mission, but I've not come across any data for solo missions.

Edited March 7, 2016 by DBowman
corrected a cost error - forgot 1 proton lanch

[DBowman]

I think the NASA BVA doc kg/kW power system doesn't make sense for the transit legs - at least for a flyby. They must include batteries and/or regenerative fuel cells - perhaps assuming that the transit vehicle will be in a low orbit at 'the destination' and require eclipse handling. For my application the vehicle will be in sun all the way except for the brief Mars occultation. This shows TRL 9 (e.g. JUNO) PV only systems at 15-40 kg/kW (at Mars distance) vs BVA 237 kg/kW.

I planned 3 kW additional power => 711 kg - 28% of the non Soyuz mass - looks like I could take back 590 kg.

Also 46 kg of food packaging and 74 kg of faecal  disposal bags seems like a missed opportunity. Rather than collect food packaging trash we should be able to package food in faecal disposal bags and then use them, take back 40 kg.

I think this brings the mass buffer/contingency/margin up to 980 kg. The top remaining contributors to non Soyuz mass are:

• 35% O2 (+ it's tankage) 670 kg (maybe time to look at PEM electrolysis per @AngelLestat)
• 16% food
• 10% additional ablator
• 06% additional PV
• 05% CDRA

re the costs I'm not sure why a Proton launch is 105 MUSD and a Soyuz 188 MUSD - but that's what NASA will be paying for Soyuz. I've seen 'space tourists' priced as low as 25 MUSD - so maybe there is up to 100 MUSD excess cost budgeted.

If only there was a small light one man reentry vehicle that was flyable one could use something lighter (and more voluminous) than a Soyuz.

 

[fredinno]

4 hours ago, DBowman said:

I think the NASA BVA doc kg/kW power system doesn't make sense for the transit legs - at least for a flyby. They must include batteries and/or regenerative fuel cells - perhaps assuming that the transit vehicle will be in a low orbit at 'the destination' and require eclipse handling. For my application the vehicle will be in sun all the way except for the brief Mars occultation. This shows TRL 9 (e.g. JUNO) PV only systems at 15-40 kg/kW (at Mars distance) vs BVA 237 kg/kW.

I planned 3 kW additional power => 711 kg - 28% of the non Soyuz mass - looks like I could take back 590 kg.

Also 46 kg of food packaging and 74 kg of faecal  disposal bags seems like a missed opportunity. Rather than collect food packaging trash we should be able to package food in faecal disposal bags and then use them, take back 40 kg.

I think this brings the mass buffer/contingency/margin up to 980 kg. The top remaining contributors to non Soyuz mass are:

• 35% O2 (+ it's tankage) 670 kg (maybe time to look at PEM electrolysis per @AngelLestat)
• 16% food
• 10% additional ablator
• 06% additional PV
• 05% CDRA

re the costs I'm not sure why a Proton launch is 105 MUSD and a Soyuz 188 MUSD - but that's what NASA will be paying for Soyuz. I've seen 'space tourists' priced as low as 25 MUSD - so maybe there is up to 100 MUSD excess cost budgeted.

If only there was a small light one man reentry vehicle that was flyable one could use something lighter (and more voluminous) than a Soyuz.

 

This proposal was a bad idea anyways since you need a LOT more living space than this gives to prevent the crew from going crazy. A realistic one would use a inflatable module + soyuz+ SLS Block I.

[DBowman]

12 hours ago, fredinno said:

This proposal was a bad idea anyways since you need a LOT more living space than this gives to prevent the crew from going crazy. A realistic one would use a inflatable module + soyuz+ SLS Block I.

More volume is always better and new heavy lift would help a lot (and cheaper hopefully). However I'm not shooting for the best flyby, I'm shooting for something flyable with current vehicles - I'll sure take advantage of newer launchers and vehicles as they become available.

Soyuz (8.3 m³) has more than the NASA tolerable rating (5.1 m³) and almost their performance rating (9.91 m³). A lot of the 'cargo' would have to be in the interplanetary module - which is kind of playing the role of the inflatable - but smaller. I really should do a detailed look at volume but feel like the Soyuz Orbital Module would end up pretty clear - which at 5 m³ is 'almost tolerable' on it's own. Without the heavy lift the inflatables and even a half vol Cygnus is just too massive, maybe if the reduced PV mass panned out and I could 'do something about O₂' it might free up enough mass margin to use a half size (one segment) Cygnus - but that would for sure take the mass margins back to 0.

[fredinno]

1 hour ago, DBowman said:

More volume is always better and new heavy lift would help a lot (and cheaper hopefully). However I'm not shooting for the best flyby, I'm shooting for something flyable with current vehicles - I'll sure take advantage of newer launchers and vehicles as they become available.

Soyuz (8.3 m³) has more than the NASA tolerable rating (5.1 m³) and almost their performance rating (9.91 m³). A lot of the 'cargo' would have to be in the interplanetary module - which is kind of playing the role of the inflatable - but smaller. I really should do a detailed look at volume but feel like the Soyuz Orbital Module would end up pretty clear - which at 5 m³ is 'almost tolerable' on it's own. Without the heavy lift the inflatables and even a half vol Cygnus is just too massive, maybe if the reduced PV mass panned out and I could 'do something about O₂' it might free up enough mass margin to use a half size (one segment) Cygnus - but that would for sure take the mass margins back to 0.

How big is the interplanetary module?

[DBowman]

22 minutes ago, fredinno said:

How big is the interplanetary module?

So far I was thinking mounts for extra PV, extra thermal control, O2 & tanks, and some minimal pressurized cargo space (since it's natural to use the docking port, maybe at most make it storm shelter sized. Really all I'm using the Soyuz for is 'getting someone up' and reentry - maybe it's worth just ditching the 3 ton Service Module prior to Mars injection and use a Cygnus as starting point for the IPM? I'll have to try the math to see if the reduced propellant in the Briz from larger IPM is balance by the reduced 'transfer payload'. 

 

[fredinno]

35 minutes ago, DBowman said:

So far I was thinking mounts for extra PV, extra thermal control, O2 & tanks, and some minimal pressurized cargo space (since it's natural to use the docking port, maybe at most make it storm shelter sized. Really all I'm using the Soyuz for is 'getting someone up' and reentry - maybe it's worth just ditching the 3 ton Service Module prior to Mars injection and use a Cygnus as starting point for the IPM? I'll have to try the math to see if the reduced propellant in the Briz from larger IPM is balance by the reduced 'transfer payload'. 

 

You need the SM for changes in mid-course trajectory tho.

[DBowman]

57 minutes ago, fredinno said:

You need the SM for changes in mid-course trajectory tho.

Cygnus has it's own SM (and 3.5 kW of power @ Earth) - it might be enough for the 70 m/s fly by tweak (and 'Earth approach' tweak buffer). I'm having trouble finding out how much propellant it has though, enough to do GEO circularization of big sats at least.

Edited March 11, 2016 by DBowman

[fredinno]

16 hours ago, DBowman said:

Cygnus has it's own SM (and 3.5 kW of power @ Earth) - it might be enough for the 70 m/s fly by tweak (and 'Earth approach' tweak buffer). I'm having trouble finding out how much propellant it has though, enough to do GEO circularization of big sats at least.

Removing the Soyuz SM also exposes the heat shield, which was something those in Apollo 13 wanted to prevent since that leaves a whole new level of risk.

[DBowman]

Just now, fredinno said:

Removing the Soyuz SM also exposes the heat shield

good point!

I had found some Cygnus(3 segment) + SM data:

• 7492 kg launch mass
• 828 kg propellant N2H4/MON-3 isp 315 - 328 => deltaV 360 m/s @ launch mass
• 3513 kg cargo (depends on the launcher that's lifting)

[DBowman]

It's been a while since I worked on this but I saw today NASA Has No Plans To Buy More Soyuz Seats ( NASA has no plans to buy more Soyuz seats, and it may be too late anyway ). TLDNR is that NASA seems to be relying on USA commercial launchers by 2019 and look like not paying to make sure there are Soyuz 'in the pipeline' 'just in case'.

Having no fall back seems like a bad idea, especially given that relying on the Russians at all must have seemed like a fall back position. It's quite possible that NASA will front some money to keep the pipeline alive 'just in case', even if they don't Roscosmos may 'bet' on a USA commercial delay allowing them to 'put a premium' on a Soyuz launch and have a 'spares' in the pipeline.

If one side plays safe or the other gambles and USA commercial has no delays then there could be a 'surplus' Soyuz in 2020... (semi built, excess parts / sub-assemblies etc)

[Emperor of the Titan Squid]

I know that it ruins the whole minimalism thing, but I want to note that some orbital construction isn't a complete disadvantage, since we have learned so much about it from. The ISS.

[DBowman]

On 10/18/2016 at 10:17 AM, Emperor of the Titan Squid said:

I know that it ruins the whole minimalism thing, but I want to note that some orbital construction isn't a complete disadvantage, since we have learned so much about it from. The ISS.

I've nothing against orbital construction if it's necessary. For sure remote controlled docking assembly would be required. Crewed assembly just seems like it's likely to spiral up costs and complexity.

I downloaded Proton Launch System Mission Planner's Guide section 1. & section 2. Just from skimming it I can see:

1. references I'd used quoting 23 ton to LEO are wrong since the 'payload' / 4^th stage has to contribute about 420 m/s to circularize.
2. though it's 45 N they launch to minimum 51 degree inclination (avoid China? or other downrange 'exclusion zones')
3. they have 2 pads so could launch two Protons in 'quick succession'
4. they can launch off a single pad minimum 25 days apart 

I've just started playing with RO so did a mass mockup using some 'real' parts. Briz stacks on Briz+InterPlanetary module and Soyuz docks with the other end of the IPM:

I've left out some structure mass for 'stacking' etc but already you can see that with Briz fuel removed to account for circularizing (one with the interplanetary module and one without) it's 300 m/s short of the 4,300+70 minimally required. If I shed 1,700 kg of IPM it would have near 4,500 m/s - I cannot see being able to reduce mass enough.

Adding another Briz for another 110 M USD, time, and complexity buys +3 ton @ 4500 m/s or brings m/s up to 5,000 - given that I cannot see how to avoid it it opens up more options on trajectory, mass, and duration. 

 

Edited October 31, 2016 by DBowman

[DBowman]

I think I have a 'flight plan' that makes sense using the components; Soyuz, Inter Planetary Module, IPM lifting Briz, & 2 x naked Briz.

I didn't really like 'dock stacking' 4 components (5 if you count the IPM+Briz that launches as a unit - it never need to un-dock), plus just using one Briz engine at a time means you start with 0.3 m/s² thrust, but clustering them sounds like a bad and complicated idea. I think this plan works though:

1. Day 0: Launch a Proton with IPM + Briz. IPM can power the Briz past it's 11 hour limit
2. Day 0': Launch Proton with Naked Briz. (Not sure how close in time the pads can launch...)
3. Day 0'+ <11 hours: Rendezvous and dock stack top of Naked Briz to bottom of IPM's Briz. IPM powers both Briz.
4. Day 0'+: Briz stack does 5 Pe kicks to total 3150 m/s into a marshaling orbit, acceleration ranges from 0.5 to 1.7 m/s². It stages a toroidal tank & a Briz core.
5. IPM is now in an about 13 day highly eccentric orbit with Ap somewhat further than the Moon, about 40 m/s from Earth escape. Allowing some idle kick orbits, shakedown time etc and call it a week until the final kick, followed by plenty of time for remote system checks. The Proton pads will be ready for use 8 days before the second IPM Pe pass on Day 33.
6. Day 31: Launch Soyuz. Launch is into the plane of the IPM marshaling orbit.
7. Day 31': Launch Proton with Naked Briz (into same plane)
8. Day 31'+ <11 hours: Rendezvous and nose to nose dock, Soyuz powers the Briz.
9. Day 33 IPM Pe - 8h40m: Soyuz + Briz does 2 Pe kicks starting at 0.8 m/s² to total 1700 m/s2 and stages the toroidal tanks. The burns and time is chosen so Soyuz and IPM reach their common Pe together, the Soyuz will zero out relative velocity with the Briz's remaining 1400 m/s at 2.25 m/s² followed by dumping the Briz core and tuning with Soyuz main engines. Soyuz is now committed to the 14 day marshaling orbit with:
   1. an assured records for furthest, fastest, ... human
   2. a fall back / bail out to re-entry burn of only a few m/s
10. Day 33': Soyuz closes and docks nose to nose with the IPM. 13 days before the last Earth Pe for system checks & 'rigging for deep space running'.
11. Day 46: Earth Pe - Burn or bail - Soyuz+IPM+Briz can either:
    1. retrograde burn the Briz to get into a 4 hour orbit from where the Soyuz can re-enter with a -35 m/s burn
    2. prograde burn the Briz for a Trans Venus & Mars Injection

the good:

1. the three 'legs' each have only one docking
2. max 2 components 'dock stacked'
3. inanimate stuff takes the most time / kicks to the marshaling orbit
4. the Pe kicks give natural places to pause and troubleshoot / reassure
5. the crew is docked to final configuration and almost escaped within 48 hours of launch
6. it can use the Soyuz main engine as much as it likes for tuning and maneuvering since the stage will 'expire' when it's H₂O₂ goes 'off'.
7. there are a few bail / fail safe points  

the bad:

1. The crew has to have 14 days life support in the Soyuz on launch.
2. the plane matching and Soyuz to IPM rendezvous are unforgiving
3. the Briz main engines do not throttle so:
   1. rendezvous relies on Soyuz IPM capability
   2. any in transit maneuver burns would have to use either Briz rcs or coarse by main and tweak with rcs
4.  

[DBowman]

I got PLAD's Flyby Finder for RSS to look for actual E-V-M-Es - so far I've been going with the Inspiration Mars plan on 'faith'.Here you can see the Braking dV. I'm using it as indicator of re-entry velocity - which I'd like to minimize. The middle lower ones also have lowest start dV 3700-3900 m/s. From poking at a few trajectories on the upper edge of the lower part it looks like the hole in the plot is the trajectories that go through Mars, so I guess you can tune the flight to pass very close to Mars surface! I saw a couple at 140 km - yikes.

On the worrying side all of these have high negative inclinations (e.g. -58 degrees). PLAD's tool gives you a prograde and normal to plug into an equatorial reference orbiter via MechJeb/Precise node; one example was -1,956 prograde and -9,983 normal for like -10 km/s wha? it wants a 'backward' orbit? - I got a bad feeling...

Cranked up RO, I had a Baikonur 51 degree reference probe. I roughed in an equatorial reference maneuver node within a week or so of the right time using PLAD's numbers and got a Venus close approach at more or less the expected time as a sanity check. The trajectory looked very inclined  My Baikonur reference was just in a random plane though, by launching at the right time you can get it where ever you want so I dragged the longitude of ascension node around using hyper edit until Baikonur reference orbit crossed the EVEM injection maneuver node pretty close! and the right direction! The bog standard Proton launch is almost a perfect match. According to their mission planing doc launching into the departure plane would cost about 500 kg in forgone payload. I have to assume that is 'really' more Briz propellant used, but on the upside the found trajectories are sub 4,000 m/s and I'd been budgeting 4,300 up to 5,000 - maybe the 'cheap' two Briz option will work.