The latest Carnival of Space is now available at the Space Disco site, where Dave Mosher has put together a helpful slideshow of entries handsomely illustrated and linked to the originals. With seven new blogs coming online at Discovery Space, we’ll doubtless be seeing contributions from many of these fine writers, people such as Ray Villard, Chris Lintott and Mosher himself. I’m particularly looking forward to Jennifer Ouellette’s Twisted Physics blog, which this week offers a backgrounder on tachyons.
In terms of our usual beat, deep space from the outer planets into interstellar space, I’ll send you to David S.F. Portree’s Altair VI site, where the author has gone to considerable trouble to present the results of a study by Science Applications, Inc. (SAI) on the possibilities of futuristic missions to Titan. This material was originally presented in 1983 at a NASA workshop and offers a view of what should still be a viable game plan: To seed the clouds of Titan with floating laboratories to study the chemical evolution occurring in its atmosphere, with an eye toward examining life’s building blocks.
Image: A blimp hovers explores Titan’s lower atmosphere. Credit: American Blimp Corporation/NASA.
The SAI concept involved an orbiter that would provide the necessary radio relay between systems in the atmosphere and on the surface of Titan and scientists on Earth. It’s fascinating to contrast what we did with the Huygens probe with what SAI came up with 25 years ago, including a ‘penetrator’ probe that would collect surface data for return to the orbiter. And how about these exotic systems:
SAI’s most novel and picturesque Titan exploration systems were its large and small buoyant stations. Delivered into Titan’s atmosphere by the flyby bus, these probes would be based on the Galileo Jupiter atmosphere probe design. The small stations, packed into aeroshells the same size as the Galileo probe (1.25 meters), would be balloons. The large station, packed into an aeroshell twice as large, would be either a large balloon or a powered blimp. Small buoyant stations would operate between 100 and 10 kilometers above Titan, while large buoyant stations would operate between 10 kilometers of altitude and Titan’s surface.
Getting such missions to Saturn using Space Shuttle boosts to Earth orbit imposed severe limitations upon the planners, but assuming a future capability of on-orbit assembly and refueling allowed the full spectrum of concepts to be explored, including a complex mission design with 28 experiments and no need for planetary gravity assists. It’s fascinating to read through these ideas, and frustrating to realize how much the cost estimates have changed in the years since. But we can certainly envision blimps like these being put to use in a variety of exploratory settings — Venus also comes to mind, as do all the outer planets — as we refine robotic systems for environments beyond the reach of manned missions.
Hi Paul;
Thanks for providing this article.
There is a whimsical nature to the idea of deploying blimps at other planets and moons within our solar system. In some ways, blimps are the simplest of aircraft and it is interesting that our first form of flight was not an advanced form of rocket or fancy stealth-plane, but rather a brief flight hot air balloon ride about a couple of centuries ago.
A really interesting idea involves that notion of deploying balloons or blimps within any atmospheres of planets and moons around our nearby stellar neighbors within the next 50 or 60 years. I can imagine that fusion rocket powered craft in the form of relatively small probes could be sent out in droves to all of the star systems within a 12 LY radius for a massive robotic exploration effort.
These probes might have a final payload of about any where from 10 metric tons to 100 metric tons and have a single fusion rocket stage that has a fueled weight to final payload dry weight to mass ratio of 10/1. With super- optimized fusion rockets with an Isp of above 2,500,000, these craft could reach their target systems this very century. In cases where it was desired to reach a terminal velocity of say 0.3 C or greater, additional stages could be included. Electrodynamic breaking and steering could be accomplished by field effect reaction mechanisms interacting with the ambient interstellar magnetic field and/or interstellar plasma.
Fusion fuel is cheap and ubiquitous on Earth and throughout our solar system. With craft journey times less than the time between the launch of Voyager 1 and today, there would be no need to plan crew compatibility and other human factors considerations to be worked out. As we developed antimatter rockets, high gamma factor beam sails, new concepts for ISR craft, and hopefully, eventually warp drive, zpf powered craft, and God willing, wormholes travel and an assortment of other equally exotic transport systems, we could then effectively send manned missions through the Galaxy and hopefully beyond.
Thanks;
Jim
just wondering what kind of buoyancy you could expect from a gas (He?) at the temperatures of Titan’s atmosphere.
One thing about Titan is that only a small amount of lifting surface is needed to get airborned at moderate speeds – perhaps a slightly negative-buoyancy airship is a better option, so that it’s not swept through the air so easily by the vagaries of the winds.
He is much lighter than Titan’s nitrogen et. al. atmospheric gasses, but the added payload weight from Earth of He would not be a rational solution. Just use Tit’s atmosphere and heat the gas with an RTG or nuclear battery. Hot ‘air’ baloon.
Titan’s atmosphere is similar in density to Earth’s, so He balloons would have about the same performance there. The real problem is keeping the payload warm. Nuclear power sources (RPGs) could do the job and the residual heat would both keep the electronics running and heat the He.
Exploring the solar system in any large scale demands nuclear rockets, such as those the US and USSR developed and tested in the 1960s-70s. That’s the smart path to a robust space program. Alas, fusion doesn’t exist yet.
Gregory Benford
Greg B, I’m a major East Coast (NH) fan. Agree that nukes are a requirement for solar system exploration. Maybe, just maybe one positive benefit of the oil price rises will be a public re-examination of America’s irrational nuclear phobia. Thank you Jane Fonda et. al. It’s pathetic that since circa 1970 NASA has done nothing to advance NERVA.
The new nuclear battery technology and maybe, just maybe the longshot of Bussard Fusion will pan out.
At 94 K and 1.5 bar Titan’s lower atmosphere is ~4.5 times denser than Earth’s atmosphere – a balloon of nitrogen at Earth temperatures would be a HOT air balloon compared to its environment.
If Greg’s still reading, any particular nuclear propulsion system for solar system exploration? The old NERVA and DUMBO systems struggled to get 1000s Isp, thus weren’t really much better than chemical propulsion for Outer Planet missions. A Gas Core Reactor NTR might get ~ 5000s and that would allow quite a vigorous OutPlanet program, making even manned missions within reach, to Jupiter or Saturn at least. Robert Zubrin’s Nuclear SaltWater Rocket might (a big might) reach 10,000s Isp, opening up the whole of the outer System, perhaps even the near reaches of the Kuiper Belt. The Inner and Outer Oort Cloud would need high-end Nuclear Pulse or Antimatter-triggered Fission/Fusion.
At least Titan has methane so that old SF idea is still feasible – it wouldn’t take much compression to condense the methane into the tanks for refuelling, or a polar mission could refuel straight from the lakes. Dump it into a GCR and a trip back to Earth is easy. Wouldn’t really need to carry any return propellant at all, just enough fission-fuel or whatever (uranium hexafluoride I guess.) Plus a heat-sink at 95 K would mean very high efficiencies for power generation…
http://www.dailygalaxy.com/my_weblog/2008/10/titan-saturns-p.html
October 23, 2008
Titan: Saturn’s Plugged In Moon Host to Electrical Storms
Spanish physicists at the University of Granada and the University of Valencia have used data sent back by the Cassini-Huygens probe from Titan, the largest moon of Saturn. Already unique in that it is the only other body within our solar system that has an atmosphere, researchers also found that it is home to electric storms within its atmosphere.
“In this moon there are clouds with convective movements and therefore there can be static electric fields and stormy conditions,” explains Juan Antonio Morente, from the Department of Applied Physics of the University of Granada. “It significantly increases the chance that organic and prebiotic molecules get formed, according to the theory of Russian biochemist Alexander I. Oparín and Stanley L. Miller’s experiment.”
Oparín and Miller’s experiment was the first to form organic compounds from inorganic compounds using only electric shocks.
In their study of Titan, Morente and his team measured the Schumann resonances, a set of spectrum peaks in the ELF portion of a planet’s or moon’s electromagnetic field. Titan’s electric field was measured using the Mutual Impedance (MIP) sensor aboard the Huygens probe.
“In a stable descent, without rolling, the MIP sensor would have been able to measure the peak tangential component of the electric field”, says Morente, “but unfortunately a strong wind made the probe to roll and the electrodes measured a superposition of such tangential and radial component”.
Despite this setback, and due to the lack of Schumman resonances received back from Huygens, the Spanish research team designed a process to reveal Schumman hidden resonances which allowed them to obtain what they believe is “irrefutable proof” that there is natural electric activity in Titan’s atmosphere.
While such a discovery does not mean we’ll be visiting Titan in the next decade, it does propose some interesting questions for astronomers and scientists alike. This adds another tick next to the “Titan is like Earth” box, and will only continue to provide information as we continue to study it in the near future.
http://www.physorg.com/news143889585.html
Titan Triple Threat
Artist’s image depicting a hot air balloon riding along the winds of Titan, floating over a lake of liquid hydrocarbon. Credit: ESA
by Leslie Mullen
for Astrobiology Magazine
Moffett Field CA (SPX) Nov 07, 2008
A hot air balloon drifts gently in the breeze, gliding over mountain ranges and vast lakes. Thick clouds extend over the entire horizon, threatening rain. The meager light that filters through illuminates one side of the balloon, making it look like a giant question mark in the sky.
This is a vision that floats in the minds of scientists who study Titan, Saturn’s largest moon. The Cassini spacecraft currently traveling around the Saturn system has provided us with our best glimpse yet of Titan, but there is still much to be explored.
Athena Coustenis, an astrophysicist and planetologist with the Paris Observatory, is helping draft a plan to send a hot air balloon to Titan, as well as an orbiting spacecraft and a surface probe. Called TSSM – the Titan and Saturn System Mission – this three-tiered approach to exploration could shed more light on the still-mysterious moon.
Full article here:
http://www.saturndaily.com/reports/Titan_Triple_Threat_999.html