Showing posts from 2010

My 2010 Review

I started this year thinking the Augustine committee had nailed the Moon shut. Considering that I was a proponent of Constellation before the Augustine committee, that's pretty significant. If I go back to that time and see what I was saying to people, most of it was explaining the flexible path as an alternative to sitting on the ground waiting for a booster and a capsule and a lander to be developed by NASA.

I end this year thinking that the Moon isn't nailed shut. SpaceX has demonstrated that making a capsule and booster need not be expensive. Armadillo Aerospace and the other contractor's work on Project M (now Project Morpheus) demonstrated to me that going to the Moon need not be expensive. Tim Pickens and the Rocket City Space Pioneers have successfully restored my faith that the Google Lunar X-Prize will be won. Paul Spudis has actually become a robotic exploration advocate! In a few years time it won't be absurd to suggest that a commercial effort could s…

Soonest Space Solar Power

Space Solar Power has a bad rap, caused predominately by advocates who can't separate the exciting long term vision from the short term facts. In his recent paper, Al Globus has tried to rectify this by investigating what can be done with demonstrated launch vehicles, solar collectors and power beaming (and without on-orbit assembly, manned outposts, lunar materials, etc). His conclusion is that it appears space solar power is now ready for niche markets, such as forward military bases, where the price of power can be as much as $1/kWh.

The low cost launch vehicle of choice is, of course, SpaceX's Falcon 9. High specific power solar collection is achieved using thin-film heliogyros as demonstrated by the Japanese Ikaros satellite. The power beaming technology is infrared laser with custom solar panel receivers, as demonstrated by LaserMotive in their win at the Space Elevator Games last year.

A minor improvement in Globus' architecture is apparent. The mass of the sp…

Non-Rotating Artifical Gravity

If you put a long boom on a satellite, it will align to the "local vertical". This was first demonstrated on the GOES 3 probe in 1978. It works because the forces of gravity and the "centrifugal force" balance at the center of mass.

Today, long life space tethers are available, using existing materials they are light enough for long lengths to be launched on a cheap launch vehicle like SpaceX's Falcon 9. A length of 500 km, with a lifetime of 10 years, would have mass of just 1275 kg. The tether would stretch from the altitude of the International Space Station (~340 km) up past the altitude of the Hubble Space Telescope (~595 km), out to where the polar orbiting satellites do their job (~700 km+). Within equal masses on each end of the tether, a force of 0.1g would be experienced, with no rotation of the structure required.

Of course, this only works while in orbit around a planetary body. Around the Sun, say for generating artificial gravity for a trip…

A New Sputnik Moment?

Stephen Smith has an post over at his blog questioning President Obama's rhetoric that the down tick in the economy is having the same effect today as Sputnik had on the USA in the 50s and 60s. He's not convinced and neither am I, but near the middle he asks an interesting question: What would be the equivalent of a "Sputnik moment" in today's world?

The shock in the US caused by Sputnik was not so much that it was a military threat - although it was - but that it was a significant technical feat achieved by what most of the western world considered a backwater of scientific thought. Today, there are many technologies that are slowly being developed around the world which are primed for a breakthrough. Earlier this year North Korea claimed a fusion power breakthrough which certainly would have been a Sputnik moment if it hadn't turned out to just be a claim about fusion bombs, not fusion power.

This highlights a very important part of the Sputnik formula: …

Apollo 8 Solo

In 1927 Charles Lindbergh flew non-stop from Long Island to Paris. He was catapulted to instant fame by doing so and won the Orteig Prize. He didn't have a co-pilot. He didn't have an army of engineers monitoring his plane or a flight surgeon monitoring his heart rate, it was just him and his trusty single-engine monoplane, the Spirit of St. Louis. His achievement is heralded today as kick-starting the commercial aviation industry and opening up the skies to the everyman.

But what of space? Could a modern Lindbergh fly an impossible journey and change the way we look at spaceflight forever? I think it can be done, and for cheaper than you might imagine.

In 1968 the first humans left the vicinity of Earth, flew 6 days and nearly a million miles to the Moon and back. Their mission not only was the first, it also proved the feasibility of the missions to follow. Apollo 8 would have been much easier to achieve had they only wanted to swing-by the Moon, and still a significan…

I Guess "It's Not Junk" Is Just Too Visionary

Last week I attended a different kind of space conference. It was populated with very intelligent people who are active in doing "real" space, working payloads to get them accepted to fly on government vehicles - often up to the International Space Station - or as free flying satellites. I recorded 17 videos of the event, which I found enthralling, but I'm weird like that.

The best talk (in my opinion) was given by Dr Alice Gorman of Flinders University (Australia) about achieving an international agreement on Space Heritage. The presentation was aimed at preserving historic sites related to human spaceflight so that future generations have some physical connection with the past. This is something we do well in Australia, with "heritage listing" enforced by law. Of course, there's not that many sites that one might consider space heritage in Australia, a few radio telescopes that were used during Apollo - one that has already been heritage listed - but…

The Space Industry

Here's a great video by Bob Stover, Tim Walters and Todd Halvorson.. one of the best I've seen.

Thoughts on a SpaceX Lunar Architecture

It's no secret that the SpaceX Dragon capsule has a very impressive heat shield believed to be capable of direct lunar return. Official statements from SpaceX that they intend to add deployable landing gear and leverage the thrusters in order to land on land in the future prompts an obvious suggestion: if it can land on Earth, could it land on the Moon too?

The Dragon capsule has thus far been launched on the Falcon 9 booster, and although that booster is able to put 2473kg into lunar transfer orbit, after using the Draco thusters on the Dragon to enter low lunar orbit the total mass would be under 1876kg.. this seems a bit light for a crewed configuration, especially when you consider that only 1422kg of it could be returned to Earth. And that's just lunar orbit.

We need a bigger rocket, and the official SpaceX plan right now is called the Falcon 9 Heavy. One should not be confused by the name, the F9H is not "heavy lift" in the sense often used by space advocate…

Revolutionary Thinking in Nuclear Rockets

A few months ago I started talking to Jim Dewar about his latest book, which I reviewed in August. My suggestion to him was that he needs to write a better introduction that assumes the technical knowledge of rocketry but not the nuclear industry. He took on the task and recruited a number of people to serve as reviewers, myself included. So far, it hasn't been published anywhere, but he's given me a copy and invited me to publish it here.

To avoid confusion, I've put it on my website:

A Technical and Economic Introduction to Nuclear Rockets

It's long but divided into sections, and I think Dewar has done a great job, so check it out.

Jim tells me he would like to hear feedback.

Affordable Deep Space Exploration

For too long the aspirations of NASA have not matched the budget allocated. Building the International Space Station has been a decade long effort, now finally reaching completion, and until just recently the plan was to splash it into the ocean before moving on to "the next thing". For a while, that was a return of humans to the Moon, but the recognition that the necessary budget would not be forthcoming has pushed that goal so far into the future that it doesn't even make much sense to talk about it anymore.

Today, the focus is on making a new heavy lift vehicle, finishing a big heavy capsule to go on it, and considering the possible missions that could be done with that hardware should it ever be finished. At the same time, technology development and commercialization of ISS resupply promise to free up some existing budget dollars to pay for the lunar landers and prepare for the next next thing: Mars.

This has prompted many to ask: what if we didn't need heav…

Mining The Moon: Closing The Business Case

I recently read Platinum Moon by Bill White, in just 4 days, it's just that much of a page-turner. Clark Lindsey has written an extensive review, which is mostly positive but has this little dig at the end:

A kilogram of pure platinum today sells for something like $53,000/kg. On the Moon even rich PGM ore would have have to be extensively refined to get anywhere close to that purity. A kilogram of raw ore would be worth a tiny fraction of that.

Until there are fully reusable vehicles flying frequently enough to LEO to bring costs there down to the low hundreds of dollars per kg, it's difficult to see how space mining can even begin to be viable.
My first reaction is to suggest that obviously high purity enrichment of platinum should be done on the Moon, and only "pure platinum" returned to the Earth - but I should first point out that Platinum Moon made the realistic argument that lunar platinum would be worth a lot more than market value in the form of commemorati…

Some Retrospective Space Policy

It's been a while since I said anything about space policy. This is primarily because the whole ball of wax can be summarized as, well, a big fat mess. As many of you are likely aware, I was an avid viewer of the Augustine committee when it was on, all 37+ hours of it, and still think they did a fantastic job with what they had to work with.

However, in retrospect, I think Norm Augustine hit the nail on the head when he started talking about "blue plate" options vs the alternatives that stuck within the existing NASA budget. I bet if they had to do it all over again they would have changed the balance to include more of the affordable options and less of the blue plate options.

Perhaps they could have worked out the completion dates and total prices of the various components of Constellation program under the "restricted" budget (aka, the "real" budget) including the options of splashing the ISS in 2015 and without. As Augustine himself said "…

Engineering An Asteroid Close Approach

I've been posting lately about the threat large asteroids pose to Earth, human missions to smaller asteroids, and the opportunities that will exist in the next few decades to do so. Up until this point, my analysis has been mostly for my own education and amusement, but I'd like to make a suggestion now which I haven't seen published in the literature or seriously discussed in either NASA working groups or even in the space advocacy community.

I'd like to suggest that we need not wait for an appropriate asteroid to come within range of Earth and plan human missions around just those opportunities - we can engineer a perfect close approach.

Next year, at the start of June, the asteroid 2009 BD will pass within the orbit of the Moon. Even though it is not a rare occurrence, few opportunities such as this have been identified, and realistically, no-one is going to be ready to send a human mission to an asteroid for years to come.

It seems a shame to let this close app…

Rusty Schweickart Explains The Asteroid Threat

I don't think he's given a better lecture than this.

Rock Envy

With the exception of Hayabusa, all asteroid missions to-date have been to targets bigger than 1 km in "spherical radius".

DateEncounterAsteroidRadius (km)Spacecraft1991Flyby951 Gaspra6.1Galileo1993Flyby243 Ida15.7Galileo1999Flyby9969 Braille~1Deep Space 12000Flyby2685 Masursky~8Cassini2001Landing433 Eros8.42NEAR Shoemaker2002Flyby5535 Annefrank2.4Stardust2005Sample
Return25143 Itokawa0.165Hayabusa2006Flyby132524 APL~1.1New Horizons2008Flyby2867 Šteins~2.8Rosetta2010Flyby21 Lutetia95.8Rosetta
This has led a number of people to express dismay that all the asteroids which have been identified for human exploration missions have significantly smaller estimated sizes.

DateAsteroidRadius (m)20162008 HU4~520171991 VG~4520192008 EA9~620202007 UN12~420251999 AO10~3520262008 JL24~2.520282006 RH120~2.520292000 SG344~22.5
Notice that the scale has changed from km to m. Of course, exactly why these rocks are small is most probably what makes them optimal for a human mission. Their close…

Early vs Late Human Missions To Deep Space

Anyone who has enjoyed my recreational attempts at designing a human mission to a near-Earth asteroid should check out the newly released mission to an asteroid by a team at Lockheed Martin*. The report ends with these important words:

The Plymouth Rock study shows that the first visits to asteroids can be easier and earlier than we have previously thought. The United States does not need to wait for more advanced technologies or develop expensive dedicated deep space vehicles. We can explore the asteroids within a decade, using spacecraft already being developed and tested.
This is a reasonable statement which I agree with. As far back as Apollo the question of "are we ready?" has been asked, and despite the success of Apollo it is still being asked. I have tried to make the argument that a Dragon capsule would be sufficient for a bare-bones mission to an asteroid, assuming some modifications to life support systems, dual use of propellant and supplies as radiation shiel…

Smacking Asteroids For Resources

Video by Eric Brueton

Summer studies of space settlements by Gerard O'Neill and NASA in the 70s and again in the early 90s both determined that significant amounts of mass is required for passive radiation shielding. Although structurally, most designs call for refined steel, it has been suggested that mass for the shielding could just be raw lunar regolith, left-over slag from future on-orbit industrial processing, or obtained from the asteroids. The asteroids are seen as preferable as, in terms of delta-v, they are most easily available. The typical argument is that a long duration mission to rendezvous with a near-Earth asteroid or comet (collectively, near earth objects, or NEOs) could skip a lot of launches from deep gravity wells, either digging into the NEO or
dismantling and processing it to make a nearby structure, or both.

The wrinkle, however, is in that "long duration" part. In terms of delta-v, there are NEOs which are easier to hit than the Moon, but al…

Prospector's Skymap

There have been over 535,000 asteroids discovered to date and they're all different. Some 7,121 of them are known to cross the orbit of the Earth and so are referred to as the near-Earth asteroids. If you're interested in flying a robotic mission to an asteroid, you need some idea of how much delta-v your spacecraft is going to need. I've written on this before. However, if you're interested in flying humans to an asteroid, you also need to know how long the round trip is likely to be.To answer this, one needs to know both how far away the asteroid is at closest approach to Earth, and for how many days it will remain that close. To the interested public, finding this information out using the available NASA tools is a slow process, and understanding what you've discovered is difficult without good visualization. Introducing the Prospector's Skymap, a tool for visualizing Earth-centric plots of asteroid trajectories over the next 20 years, in 3d. Included i…

Mission To Asteroid Using SpaceX Hardware - NASA's Target

As a target of study, NASA has identified the asteroid 1999AO10 as the 2025 destination for human exploration. We've heard that NASA plans to build a giant heavy lift vehicle to make the trip, but is it really necessary?

I previously described a human asteroid mission, but I assumed the logical choice of asteroid with the lowest known delta-v (and included analysis for the second lowest too), but for some reason this isn't as interesting to NASA, so let's consider how one might do the trip to their preferred target, using existing SpaceX hardware.

The reference numbers are: Earth departure stage 3291m/s, and storable propellant 3939m/s of total delta-v. We could improve this by carefully measuring the boiloff of LOX in Falcon 9 upper stages and analyzing the required insulation to do the arrival rendezvous using non-storable propellants, but I don't really have that information handy, so I'll just go with the storables.

Like last time, we'll use the Dragon …