I asked this question on unmannedspaceflight.com about 4 years ago

The problem is of course the shortage of 238 Pu so perhaps we could blend or cut 238 Pu with 241 Am, this is an unknown alloy with unknown properties.

241 Am gives off much more gamma rays then 238 Pu and this requires much more shielding at a cost to spacecraft weight budgets so my alternative idea was a RTG with an 241 Am core and a cladding of 238 Pu! This would shield the 241 Am gamma rays and the 238 Pu would add to the mission design power loss curves do to decay of both.

(A)(1) would 241Am and 238Pu chemically bond or form alloys at their interfaces in the cladding scenario?(galvanic erosion)And do we know 241 Am and 238 Pu Anodic index?

(A)(2) How would 238 Pu react to gamma ray loads from the 241 Am?

(A)(3) the core could be a blend of 241 Am and 238 Pu with 238 Pu cladding to reduce gamma ray and  compatibility at the cladding interface.

International cooperation, (B)(1) the EU separates its spent nuclear fuel while the US does not, so the supply of 241Am could come from them.(B)(2)We in the US  have reestablished 238 Pu production and we could share both.(B)(3) we have abandoned our Stirling RTG effort while the EU/ESA are contemplating doing such an effort, we could also join efforts here to.

Utilize 2 SLS launches that attempt to synergize the upper stages and payloads with a distributed launch of propellant by a second SLS.

One or both SLS launches might be dual manifested with a secondary cargo or just 1 vehicle.

If 1 SLS is lofting just fuel this opens up the possibility of payloads on the second SLS, This would mean a 70 Mt in LEO which is equivalent to two (2) Vulcan ACES upper stages at 35 MT each on the first launch on a SLS and perhaps Vulcan launched refueling vehicles.

The Austin Powers Robonaut anthropoid/Rodent caregiver onboard interplanetary flight precursor mission

Based on an idea posted to Lori Garver’s NASA Facebook page in 2010

Robonaut is equipped with heated chest pads to simulate Mammalian nurture and breast-feeding for an interplanetary uncrewed precursor mission.The Protocol is that rodents and small anthropoids are nurtured in zero gee with a Robonaut programmed with software that allows for a range of laboratory animal husbandry skills with some remote input from humans back on Earth

These skills and the test flight allow for knowledge gained for future robotic medical care for human astronauts and for future animal husbandry for human astronaut consumption in 1/6th and 1/3rd gee.

Early research in anthropology/sociology used a metal doll with a furry carpet attached to test behavior of rhesus monkeys who were nurtured by this mechanical doll and this who were raised without any nurturing

The dark side of robonaught programmed behavior

Another post on Lori Garvers former Facebook page around April first was the proposed “Mars Vivisection Lander” This would require a robonaught with the proper software for sacrificing specimens and collecting tissues  possibly examine them photography under microscopy and freezing specimens in 1/6th and 1/3rd gee.

(A) (1)SBIR study of behavior of a range of noble gases as ullage with a range of chemical propellants;at end of mission of the chemical burn does some noble gasses miscible with LH2, LO2 or LCh4  give molar mass to the chemical burn thrust?

(A)(2) Do some Nobel ullage gases form harmful ice blockage threats to chemical propellants? Does the range of the triple point of Noble gasses to the range of chemical cryogenic chemical propellants  make for some better or poorer choices between ullage and ion propellant? An example on an earlier post is Xenon ullage gas and liquid Hydrogen.

(A)(3)We propose that these studies look at two issues,(a) noble ullage gases in ion systems with a short duration chemical burn mission design with a subsequent re purposed of that stage as the ion powered vehicle and (b) noble gasses as ullage/ion propellent together with the possibility of chemical stage refueling and a long term Chemical storage and refueling

In an earlier post we suggested mission designs that incorporate orbital missions about 2 or more planets in order to combine both budgetary limits with Decadal survey desires.This idea was inspired by the Okutso Cassini end of mission paper that demonstrates that Titan flybys can send Saturn orbiting spacecraft to Jupiter and Uranus

Earlier post;  https://yellowdragonblog.com/2015/11/16/a-multiple-planet-armsep-derived-mission-design-architecture-part-2/

Such a mission that combines multiple decadal survey requirements would have to be a flagship mission in costs.Here we propose yet another alternative inspired by the suggestion from NASA HQ that the next flagship to the outer planets could be two spacecraft.We propose that 1 spacecraft be an orbital mission around Uranus and the other would be a flyby of Neptune followed by a Centaur and  interstellar probe.

The Neptune flyby mission would require an RTG powered SEP stage! and that requirement involves a very generous supply of RTG radionuclides and the SLS launch vehicle and an ULA ACES stage.After RSEP shut down the power of the RTG’s should keep the spacecraft alive for decades as suggested here   6-UranusTrajStudy_Hughes_et_al (1) for the interstellar follow on mission that is described here,McNutt et al Acta Astronaut. 68 (2011) 790-8011

Both spacecraft would carry atmosphere probes for Jupiter(flyby) and the target planet for a total of 4 probes The RSEP for the Uranus orbiter mission could make up in maneuverability for the small flyby mass of the moons of Uranus.

Drew Lepage writes about the next windows for flights to Uranus and Neptune here;   http://www.thespacereview.com/article/2787/1

I am unable to see any practical way to enable Okutsu’s dual planetary missions that would involve Uranus and Neptune without SEP stage.

Who really invented multiple planet gravity assist?

http://www.gravityassist.com/

 Drop Tank SEP Reuse (DTSR)

Drop Tank would be pressurized with Xenon or more likely  pressurized with xenon  after cryogenic propellent transfer.Drop Tank needs IVF and a air liquefaction/fractionation unit.

Drop tank needs a solar array and communications and carries a secondary payload such as cubesats

Drop tank itself could be the secondary payload of the primary mission and undock with the primary mission after the primary mission completes its injection.This would require a common berthing mechanism in addition to the robotic arm fuel transfer system.

Cryogenic propellent boil off could be used to ZBO cryogenic Xenon to save space and mass from its tank and the drop tank would need a in space air liquefaction/fractionation system to segregate gases Xenon fro gasses O2 and H2 in order for the IVF engine to work.

ZUEXS   as drop tank

Dr Sperling,

The Proposed Lucy Trojan tour is a spacecraft that incorporates into its mission design journey to both Trojan swarms at L4 and L5 with an earth flyby in between  the L4 and L5 targets, this could be an opportunity for a Enceladus sample return. Hows that you might wonder?

Let’s go back to the first blog article inspired by Otsuka and Strange who proposed Cassini Saturn escape orbits at end of mission Saturn Cassini ballistic end of mission.This idea could allow a Enceladus sample return mission to utilize a Titan flyby   to a Lucy Jupiter Trojan mission after a 9 year flight from Saturn Lucy Jupiter Trojan tour mission .You will note at near end of mission Lucy does an Earth gravity assist on its way to its last Jupiter Trojan asteroid, it’s here we drop off the saturn/Enceladus samples.

Perhaps the inbound spacecraft could perform the Jupiter B plane Aim Point so as to perform the Earth flyby first with a subsequent Lucy Jupiter Trojan tour?The paper by Broucke and Prado possibly describes how a spacecraft returning from the outer solar system could use Jupiter to bring back samples from Saturn, AAS93177JupSB     “JUPITER SWING-BY TRAJECTORIES PASSING NEAR THE EARTH” Or rather I should say they describe a Earth Jupiter Earth trajectory.I would think the proposed Enceladus sample return missions  might incorporate this sort of trajectory in their mission design?

Any Enceladus time of flight to Saturn would be 7 to 8 years and Saturn orbit mission 4 to 5 more.Add in the 9 year time of flight to Jupiter followed by a 9 year Trojan Mission comes out to 29 years.For safety and risk reduction the spacecraft should have on board a space based microscope in case of failure to return the samples to Earth from Enceladus.

Risk reduction would be to keep the Saturn/Enceladus TOF to a minimum.SEP might reduce the 9 year TOF back to Jupiter

The proposed ARM/SEP designs with its 11 tons of Zenon could make for a unique flagship mission.Outbound Jupiter flybys might allow for Jupiter and Saturn atmosphere probes.

EJSJE

SLS launch vehicle

I ARM derived SEP

2 spacecraft with common avionics

3 atmosphere probes with common architecture

1 spacecraft separates for a Uranus and probe mission

The other performs the saturn/jupiter trojan mission

SEP returns to Earth L2

EDIT

A good description of budgetary and mission design is here Future Planetary exploration

Rabbit warmed winter beehives

(A)(1) Rabbits are creatures that tend to nest, The idea here is to encourage nesting over winter in between closed up beehives in a hoopskirt shelter or a greenhouse.Thermal mass heating from large breed rabbits such as belgium’s might make for the better choice in this case and for this purpose.

(A)(2) a carefully planned rabbit system could have some rabbits housed on top of the overwintering beehives.We would need to find a source for a formula for Rabbit mass X BTU.

Raising Livestock and Crops Simultaneously in Unheated Greenhouses

Livestock heated hoophouses

The papers above seem to talk about livestock heated greenhouses so the idea is not new

Golf Course arboretum polyculture

Many of our nations arboretums are under financial stress so the hypothesis I have is that the golf course would subsidize the tree collections and the educational opportunity they offer