Wish List for Future Outer Planet Missions

brellis · Mar 11, 2007

On many interesting threads in both M&L and SS&A, the discussion keeps leading me to think how we can do it better next time. What's on your 'Wish List' for the next generation of Galileo, Cassini, or NH? Safety in Numbers: I'd like to see more flexibility and a wider range of options, lots of probes being carried by a Mothership of sorts. I pose many of my thoughts as questions to emphasize my lack of professional status in the field of space exploration. If something isn't possible, I'm quite happy to stand (well, technically sit) corrected! <img src="/images/icons/cool.gif" /> From the Planetary Society's Cassini spec page: Launch: October 15, 1997 Venus flyby: April 26, 1998, altitude 284 kilometers (176 miles) Venus flyby: June 24, 1999, altitude 600 kilometers (370 miles) Earth flyby: August 18, 1999, altitude 1,171 kilometers (727 miles) Jupiter flyby: December 30, 2000, altitude 9,723,890 kilometers (6,042,145 miles) Cassini was the size of a school bus. How many kids can squeeze in for the trip? It spent nearly two years inside 1AU. Can a large spacecraft embark on a SMART-1 type of journey and have solar panels charge up some ion thrusters to conserve nuclear energy, and thus have enough juice left over to feed an armada of probes when it arrives at an outer planet? From NASA's Huygens spec page: During probe checkout activities, the probe obtained power from the orbiter via the umbilical cable. After separation, the orbiter continued to supply power to the probe support equipment, but power for the probe itself w <div class="Discussion_UserSignature"> I'm a recovering optimist - things could be better. </div>

qso1 · Mar 12, 2007

All that you have mentioned here is possible IMO. The key is budget. I personally like the idea of multiprobes aboard a larger orbiter or flyby vehicle. I also like the idea of an identical back up set. But NASA has kind of gotten away from backups. Recalling how Mariner 6 and 7 were backing each other up. Mariners 8 and 9 which is a particularly useful example because 8 plunged into the Atlantic IIRC while 9 made history at mars. The Pioneer 10 and 11 missions, the Voyager 1 and 2, the Vikings 1 and 2. Cassini had no backup. Galileo had no backup. Mars Pathfinder had no backup and luckily they were successful. Mars polar lander could have used a backup as could have Mars Observer. But it all boils down to cash. Is the budget enough to cover both a primary and backup craft? These days it appears the answer is no. <div class="Discussion_UserSignature"> My borrowed quote for the time being:There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened. </div>

Boris_Badenov · Mar 12, 2007

All of my wish list probes have nuclear engines. A MITEE powered Pluto probe could fly to Pluto, land in multiple places & return with samples in 12 years. The 550 AU Gravitational Lens Mission could be in place 20 years after launch. A manned round trip to Mars could be done in 150 days. Nuclear is the only way to go. <div class="Discussion_UserSignature"> <div align="center">. </div><div align="center">Never roll in the mud with a pig. You'll both get dirty & the pig likes it.</div> </div>

Aetius · Mar 12, 2007

Everyone rags on the planet because of its name, but Uranus and its satellites are quite interesting. Only a very preliminary reconnaisance has been done by Voyager, and many surprises may await. I feel that it is far too premature to simply conclude that the Uranian system is uninteresting. That's what they used to say about Io and Europa. There could be some amazing discovery, that could change the way we look at our solar system, and it will have to wait in silence until we return. I'd love to see a nuclear-powered probe that could replenish its fuel tanks by extracting fuel from the planet or its moons (an example of In-Situ Resource Utilization, or ISRU). It would be great to have at least a representative sample of Uranian moons studied by an orbiter at relatively close range. I'd also be interested in a sample return mission which could test Helium-3 extraction, and other ISRU equipment.

brellis · Mar 13, 2007

hi aetius Thanks for your post. I'm going to save the Uranus jokes for Free Space <img src="/images/icons/wink.gif" /> I just cruised through some web pages devoted to Uranus, and I learned that Spring is on the way! From the Wiki Article on Uranus One of the most distinctive features of Uranus is its axial tilt of ninety-eight degrees. Consequently, for part of its orbit one pole faces the Sun continually while the other pole faces away. At the other side of Uranus orbit the orientation of the poles towards the Sun is reversed. This gives each pole 42 years of continuous sunlight, followed by 42 years of darkness. Between these two extremes of its orbit, particularly at the equinoxes, the Sun rises and sets around the equator normally. Uranus will reach its next equinox around December 2007, and not again until 2049. aetius: I feel that it is far too premature to simply conclude that the Uranian system is uninteresting. That's what they used to say about Io and Europa. There could be some amazing discovery, that could change the way we look at our solar system, and it will have to wait in silence until we return. It may be a matter of exposure, so to speak. While Cassini traveled to Saturn, Galileo was getting everyone excited about the Jovian system. Now, while NH heads out to Pluto, Cassini is putting Saturn in the Limelight. When will we begin to unlock the mysteries of Miranda and the Uranus system, Triton and the Neptune system? Based on our detailed observations of the Jupiter and Saturn systems, can we find indications of similar characteristics on the moons of Uranus or Neptune from a space-based instrument like Spitzer or Hubble? Imagine if we could catch a whiff of a geyser feeding the rings of Uranus (wow, that sounds way too muc <div class="Discussion_UserSignature"> I'm a recovering optimist - things could be better. </div>

brellis · Mar 13, 2007

hi Boris Glad we're not talking about Slurm or No Frills Potted Meat Products <img src="/images/icons/crazy.gif" /> (see vogon's Slurm thread in Free Space - no link provided, on purpose. Approach vogon's food threads with caution) I admit to being a weee little bit nervous when Cassini, with its nuclear canister, came whizzing by earth at an astounding rate, 720 miles off the surface. Glad they had their imperial-to-metric conversions correct on that one. I like the H-3 fusion -- it sounds completely harmless. That said, nuclear is in fact the only way for a craft to survive a long time in the cold outer reaches of the solar system. But for No Frills Potted Nuclear Fusion? MITEE sounds very promising indeed. How tough is it to have it both ways? Is it too cumbersome for a craft to have Solar Panels, ion Propulsion, and a zesty can of MITEE? With MITEE, is power so abundant that the sun is no longer even necessary? Will Time Warner include MITEE in their cable package? Now THERE's something for the Wish List! <div class="Discussion_UserSignature"> I'm a recovering optimist - things could be better. </div>

no_way · Mar 13, 2007

<blockquote>In reply to:<hr />Cassini had no backup. Galileo had no backup. Mars Pathfinder had no backup and luckily they were successful. Mars polar lander could have used a backup as could have Mars Observer. <hr /></blockquote> MERs seem to be a strong counterpoint here.

3488 · Mar 13, 2007

The MERs do not disprove the values of back up missions. With the MERs we have been able to sample two very different areas on Mars with two very different histories. The Uranus system is certainly not uninteresting. Cryovolcanism appears to play a big part here with the moons. We have seen only detailed images of one hemisphere of all of the major moons. Also Uranus itself is undergoing an equinox in December of this year & weird weather is brewing up. Follow up orbiter missions to both Uranus & Neptune would be very desirable indeed. Really Galileo / Cassini type orbiters for ALL four of the giant planets, with perhaps New Horizons type orbiters for the KBOs Eris, Pluto, Sedna, Quaoar, etc would be good too. I am still trying to get a dedicated Io mission!!! Andrew Brown. <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

centsworth_II · Mar 13, 2007

"Mars polar lander could have used a backup..." MPL did have a backup, and if it had flown at the same time as MPL it could very well have been lost due to the same problem as MPL. It will now fly as the Phoenix mission this summer. <div class="Discussion_UserSignature"> </div>

j05h · Mar 13, 2007

> What's on your 'Wish List' for the next generation of Galileo, Cassini, or NH? A Europa orbiter/lander mission is #1 for Outer Planets research, IMHO. Europa is right after Mars on my space science list (above cosmology, extra solar planets, SETI, etc). The orbiter would include cameras, spectrometry and nuke-powered radar, able to image down to whatever rocky core is under that ice. The lander (prefer rover like MSL) would at least be able to sample various ices on the surface, ideally it would be dropped in a region that includes both the reddish-ice "tiger lines" and some rafting ice blocks. The reddish material that erupts along these rupture lines is strongly indicative of life, as it is degraded carbonaceous material. A simple, direct sample should give a yes/no to extraterrestrial life. The complicated part is getting the instruments to that ice. <img src="/images/icons/wink.gif" /> If we're talking about a kitchen-sink mission, include an ice-burrowing submarine to try getting down to Europa's ocean. Josh <div class="Discussion_UserSignature"> <div align="center">We need a first generation of pioneers. </div> </div>

saurc · Mar 13, 2007

Referring to the Europa mission, is it well established that Europa does, indeed have an ocean under it's crust? And what about Enceladus? Does it have an ice crust and an ocean underneath as well?

j05h · Mar 13, 2007

> Referring to the Europa mission, is it well established that Europa does, indeed have an ocean under it's crust? And what about Enceladus? Does it have an ice crust and an ocean underneath as well? A pretty strong case has been made for Europa having an ice shell over a world-ocean with a rocky core (and chocolate center). There is some play on the extent and thickness of each layer, but Ganymede, Callisto, Enceladus and other moons seem to share it's basic layout. Europa is closer than Saturnian or other gas giants, it's huge (planet sized) and has a compelling amount of research behind sending a mission there. I'd like to see landers for Enceladus and others as well, but think Europa should be first. For all these moons, there is either a "slush layer" or liquid ocean under the ice. http://www.space.com/scienceastronomy/solarsystem/europa_ocean_000824.html http://www.space.com/scienceastronomy/solarsystem/europa_icecrust_011113.html <div class="Discussion_UserSignature"> <div align="center">We need a first generation of pioneers. </div> </div>

brellis · Mar 13, 2007

With so many attractive destinations for dedicated orbiters, landers and rovers, wouldn't it be cost-effective to load to a large ship with lots of options? How many "better, cheaper" landers can be squeezed onto a Cassini-style bus? Can a mother ship combine the size of Cassini with the speed of New Horizons and the durability of Voyager, and release a coordinated set of probes and orbiters during a Jupiter flyby, and do the same thing at Saturn and beyond? There are big risks at launch and orbit insertion. If a big mother ship is destroyed at launch with lots of eggs in one basket, that would be terrible. However, if the "eggs" themselves are relatively less expensive, have lots of backups, interchangeable aspects, etc., that risk would be alleviated. Additionally, if the mothership drops a bunch of probes on a less-risky flyby of a Giant Planet, that part of the risk is reduced. A mother ship with open options for release of orbiters/probes could attempt a release at Jupiter. Evaluation of that performance can point to certain adjustments as it releases another set when it flies past Saturn. Still more refinement can give us a well-informed chance to release a set at Neptune/Uranus. Something like that. <div class="Discussion_UserSignature"> I'm a recovering optimist - things could be better. </div>

solarspot · Mar 13, 2007

If reffering to deep-space missions (I'm personally itching for a deticated asteroid hunting infrared telescope) I think I would send an orbiter to Uranus and an identical orbiter to Neptune (NEP? Could RTG's power sufficently-large hall effect thrusters?) I would also send Orbiters designed to carry moderately large landers to both Jupiter's Europa and Saturn's Titon (landers would be different due to Europa having no atmosphere for areobreaking, but could the orbiters that carry the landers be themselves similar?) And after all that, I'd want a deticated mission to study the intersteller medium and possibly do some moderate deep-space astronomy...

j05h · Mar 13, 2007

MOdularity and cost are important, but there are important differences between Cassini, New Horizons and others. NH is getting to it's destinations so quickly precisely because it doesn't need to enter orbit. Dropping a probe off at Jupiter or Saturn at NH's speeds is going to require an incredible amount of braking thrust, whether rocket or aerobraking. I'd prefer something along the lines of the nuclear powered JIMO proposal. It would be a massive, nuclear-electric probe that would be able to individually orbit each of the 3 icy Jovian moons, while dispensing landers and remote sensing. Of course, it got cancelled with ISS & VSE pressures. Nuclear-powered robots dedicated to each of the gas giants (with moons) makes more sense than trying to cram all sorts of different spacecraft together on a Grand Tour. Cassini carried one drop probe - Huygens. NEAP (SpaceDev's original, unflown project) would have carried 2-4 drop canisters. Orbiter-Lander combos are a great idea, dropping them off at escape velocity seems unfeasible. ESA's Venus Express is based on Mars Express, same bus, mostly the same instruments. It did learn lessons from Mars Express, but they were incorporated on the ground in the new instruments. The problem with stacking many landers on a singular Grand Tour is that they are horribly out of date by the time they deploy. Even Cassini's "high end" digital camera is a 20 year old design. Josh <div class="Discussion_UserSignature"> <div align="center">We need a first generation of pioneers. </div> </div>

Boris_Badenov · Mar 13, 2007

I'd prefer something along the lines of the nuclear powered JIMO proposal. It would be a massive A MITEE engine with 6,300lb thrust weighs in at only 300lb. What kind of a probe could you design around that engine? From the article; A new approach for a near-term compact, ultralight nuclear thermal propulsion engine, termed MITEE (MIniature ReacTor EnginE) is described. MITEE enables a wide range of new and unique planetary science missions that are not possible with chemical rockets. With U-235 nuclear fuel and hydrogen propellant the baseline MITEE engine achieves a specific impulse of ~1000 seconds, a thrust of 28,000 newtons, and a total mass of only 140 kilograms, including reactor, controls, and turbo-pump. Using higher performance nuclear fuels like U-233, engine mass can be reduced to as little as 80 kilograms. Using MITEE, V additions of 20 km/sec for missions to outer planets are possible compared to only 10 km/sec for H 2 /O 2 engines. The much greater V with MITEE enables much faster trips to the outer planets, e.g., 2 years to Jupiter, 3 years to Saturn, and 5 years to Pluto, without needing multiple planetary gravity assists. Moreover, MITEE can utilize in-situ resources to further extend mission V. One example of a very attractive, unique mission enabled by MITEE is the exploration of a possible subsurface ocean on Europa and the return of samples to Earth. Using MITEE, a spacecraft would land on Europa after a 2-year trip from Earth orbit and deploy a small nuclear heated probe that would melt down through its ice sheet. The probe would then convert to a submersible and travel through the ocean collecting samples. After a few months, the probe would melt its way back up to the MITEE lander, which would have replenished its hydrogen propellant by melting and electrolyzing Europa surface ice. The s <div class="Discussion_UserSignature"> <div align="center">. </div><div align="center">Never roll in the mud with a pig. You'll both get dirty & the pig likes it.</div> </div>

Boris_Badenov · Mar 13, 2007

How about these designs; The performance capabilities and technology features of ultra compact nuclear thermal rockets based on very high power density (30 Megawatts per liter) fuel elements are described. Nuclear rockets appear particularly attractive for carrying out missions to investigate or intercept near-Earth objects (NEOs) that potentially could impact on the Earth. Many of these NEO threats, whether asteroids or comets, have extremely high closing velocities, i.e., tens of kilometers per second relative to the Earth. Nuclear rockets using hydrogen propellant enable flight velocities 2 to 3 times those achievable with chemical rockets, allowing interaction with a potential NEO threat at a much shorter time, and at much greater range. Two versions of an ultra compact nuclear rocket based on very high heat transfer rates are described: the PBR (Particle Bed Reactor), which has undergone substantial hardware development effort, and MITEE (MIniature ReacTor EnginE) which is a design derivative of the PBR. Nominal performance capabilities for the PBR are: thermal power 1000 MW thrust 45,000 lbsf, and weight 500 kg. For MITEE, nominal capabilities are: thermal power 100 MW; thrust 4500 lbsf, and weight 50 kg.Development of operational PBR/MITEE systems would enable spacecraft launched from LEO (low-Earth orbit) to investigate intercept NEO's at a range of 100 million kilometers in times of 30 days. High-Performance Ultra-light Nuclear Rockets for Near-Earth Objects Interaction Missions <div class="Discussion_UserSignature"> <div align="center">. </div><div align="center">Never roll in the mud with a pig. You'll both get dirty & the pig likes it.</div> </div>

brellis · Mar 13, 2007

hi J05H Dropping a probe off at Jupiter or Saturn at NH's speeds is going to require an incredible amount of braking thrust, whether rocket or aerobraking. This is probably a silly question to ask, but what if a mother ship launches probes behind it as it approaches a target? Would conservation of motion make the mother ship go a bit faster, and simultaneously get the launched sub-craft heading towards their destination slowly enough to get captured into orbit? <div class="Discussion_UserSignature"> I'm a recovering optimist - things could be better. </div>

j05h · Mar 13, 2007

> This is probably a silly question to ask, but what if a mother ship launches probes behind it as it approaches a target? Would conservation of motion make the mother ship go a bit faster, and simultaneously get the launched sub-craft heading towards their destination slowly enough to get captured into orbit? No such thing as a silly question. Ejecting the probe out the rear is only going to slow it down minimally, if at all. New Horizons is already at solar escape velocity, it's vastly faster than a craft designed for aerobraking. J <div class="Discussion_UserSignature"> <div align="center">We need a first generation of pioneers. </div> </div>

brellis · Mar 13, 2007

hi J05H, thanks for your informative posts. I'm beginning to see the reasoning behind the New Frontiers slogan of "medium class" spacecraft. So much for the "nuclear family"! <img src="/images/icons/crazy.gif" /> That said, I'm going to try to keep the "family" scenario together here: A big mother ship is cruising at a nice easy pace toward the outer planets. As it approaches Jupiter, it actually "launches" behind it 2 Jupiter orbiters that will also serve as longlasting comm relay devices for the entire outer-planet "family" of spacecraft, and 2 dedicated lander/orbiters for Europa and Io. The mother ship puts enough juice into this "launch" to slow down the ejected craft enough for capture into their desired orbits. Perhaps it could have some kind of super-titanium arms that serve as "launch" pads and simultaneously conserve the momentum gained from the "liftoff" of the ejected craft. The mother ship would perform the same procedure at other Giant Planets lined up in some kind of optimal formation for its trajectory. For that matter, what if the "launch" sends the mother ship off at a considerable angle to its previous trajectory, like a "switch back" on a hiking trail? It could throw itself into a lazier path to its next destination, for easier orbital insertion. It would make the trip take longer, but everyone knows your travel takes a little more time when you use mass transportation! <div class="Discussion_UserSignature"> I'm a recovering optimist - things could be better. </div>

alokmohan · Mar 14, 2007

New horizom reminds me of IO.

j05h · Mar 14, 2007

Brellis - nuclear engines (like JIMO) and dedicated platforms (one "mothership" per gas giant) would solve the problems with your scenario. Imagine when your mothership gets to Neptune and has a camera that is 20-30 years old. With faster (nuclear & modular) motherships, you can build and fly them more often with improvements. You can imagine whatever you want, but there are some tech and basic physics issues. You aren't going to get a 'switchback" effect from throwing a relatively small probe from the ship, it'll be more like a bump. Medium-class probes do make a lot of sense. I still want to see something nuke-powered, someday. j <div class="Discussion_UserSignature"> <div align="center">We need a first generation of pioneers. </div> </div>

brellis · Mar 14, 2007

hey J05H thanks for easing me out of my mother ship dream, lol. it's just difficult to let go of the idea of some big sexy mama throwing probes like little rose petals as she leads us on our path of discovery! <div class="Discussion_UserSignature"> I'm a recovering optimist - things could be better. </div>

qso1 · Mar 16, 2007

no_way: MERs seem to be a strong counterpoint here. Me: Very true. Thats the reason I didn't mention them. I'd like to think that one reason they were so successful was because they backed each other up as did the ones I did mention. I'd also like to think mission planners rethought the idea of single probes to Mars or anywhere else and because they were able to do the MERs for significantly less cost, they were able to do two in effect, for the price of half a Cassini. Fortunately Cassini has been wildly successful as well despite no backup and a long seven year journey to Saturn. But just imagine if Cassini had failed short of Saturn and Titan. Or if just one MER had failed to land on mars. The press and public would surely have lambasted NASA for shortsightedness. <div class="Discussion_UserSignature"> My borrowed quote for the time being:There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened. </div>

qso1 · Mar 16, 2007

brellis: How many "better, cheaper" landers can be squeezed onto a Cassini-style bus? Me: The problem here is cost of current launchers. Cassini was launched by the second or third most expensive booster in our fleet, a Titan-IV rocket (Don't recall off hand the cost of Delta-IV heavy or Atlas V). But in the future, if private industry succeeds in cost effectively opening the door to LEO, it may well become less expensive to launch probes to their destinations in which case, it becomes more practical to develop carrier craft for such probes. In addition to that, microminiaturization of electronic components and advances in computing power will make fleets of probes more practical. <div class="Discussion_UserSignature"> My borrowed quote for the time being:There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened. </div>

Wish List for Future Outer Planet Missions

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