Friday, September 03, 2004
Well I've moved house and I am slowly returning to normal life... whew! What a labour! No wonder moving house is one of the Great Stress Events in life. Since I went off-line it seems that SETI@Home might've had a hit! A signal from out in space ~ 1,000 light-years away. Here's a news link...
So it seems to be hype over a repeat found by data-miners in Germany. Little wonder really, since the 1420 MHz frequency used by SETI is decades old for space-transmission. Lasers are far, far better - but what if ET sent us a message instead? Via space-probe, that is...
BBC Alien probes
MSNBC ET should write
The point made by the article referenced is that sending large amounts of data on small, slow probes will probably need less energy than beaming all over the place with radio. This is quite true, even more so because solar-sail propelled probes would have a ZERO energy cost to the sender, except for planetary launch costs. Sent on a solar fry-by to ~ 0.01 AU a solar-sail with a thrust-mass ratio of just 2 would have a peak velocity of ~ 400 km/s. Even faster for gossamer probes with higher ratios - up to 36,000 km/s I have read, tho easier to aim for just 3,600 km/s.
Just imagine countless message-probes sent out like dandelion seeds...
Posted at 12:56 pm by Adam
Tuesday, August 10, 2004
I am about 3 weeks behind for Uni and I'm moving house, hence this is a farewell before a hiatus. Sorry to all my fans... all three of you... (just kidding, I hope)
Some cool links...
KSC's Apollo Program page
That one links to lots of information on Apollo, including PDFs of old press releases.
Cool mission to Mercury, but SLOW! Don't you wish NASA had nuke stages for pushing probes around quickly???
Mercury Meeting 2001
Seemingly an old link, but our knowledge hasn't changed much since Mercury is still years away via probe. Thirty Years since Mariner X. Thirty. More than that since Apollo...
Man Conquers Space
The Way we should've conquered Space, according to Wernher von Braun and Chesley Bonestell c. 1952-54. Now a movie, made by an Aussie... cool.
So long for now. Back ~ two weeks or so. Assignments due 27/29th August and Moving c. 25-29 th. Yikes!
Posted at 3:08 pm by Adam
Sunday, August 08, 2004
Occasionally the mundane is interesting, like my subject CSC1401... beginning with C, as the textbook puts it. Cool stuff - now I have all these groovy software tools for writing code... ;-)
Crimson Editor is one such tool - old hat to all you hackers, but new to me. Let's you write code like you were writing Word documents, but numbers lines and checks syntax for you too. I guess once all the pleasures of C have been explored I will have to graduate to C++, which apparently has a free compiler available. But there are other free compilers out there too for all sorts of languages.
Posted at 3:54 pm by Adam
Thursday, August 05, 2004
20 July, 1969... Neil Armstrong and Buzz Aldrin touched down in the Sea of Tranquility on the Moon. And they had a reasonable expectation that their visit would not be their last. However 35 years later, Neil and Buzz and the rest of us aren't any closer to re-visiting their first Base Camp on that dusty plain.
What was once only a dream, became a reality, and yet is now a mere memory - why?
A hint can be found in how they did it - Apollo/Saturn. Cost a lot to develop and then NASA abandoned it, yet it never had a failure. In fact, aside from Apollo XIII in 1970, the system had fewer malfunctions than the Space Shuttle. But NASA had to give it away to sell a "cheaper" manned program to Nixon - or else there was going to be NO manned program, and maybe not much of an unmanned one either.
Nixon wanted to end the whole mad Moon-rush and redeploy the resources for all sorts of things. Hence no Apollo 18 or 19, though the equipment had all been built and was ready to go. Skylab survived by being too close to completion.
Another point is that the Shuttle got sold partly because of it fit in with the USAF's needs - something the purely civilian Apollo-Saturn could never do because it wasn't an aerospace plane. The USAF loved aerospace planes - the X-15 had been flying for years, the Dyna-Soar program had come close to fruition and they were actively researching lifting-bodies - and a huge manned vehicle just didn't suit. The Gemini program suited them better - it used their Titan rockets and was the basis of their Manned Orbital Laboratory. Apollo-Saturn stank too much of NASA.
So Neil and Buzz and all the rest never got to go back. A shame IMHO. A few more Apollo Moon-shots into the 1970s would have made for a greater impetus in the 1980s. But maybe Voyage is right - all the spectacular unmanned achievements of the 1970s/80s been passed-up to pay for it.
Posted at 11:56 am by Adam
I found since last entry that my estimates for dv around Mars are really ultra-sensitive to Mars' orbital position. Hence the propellant mass quoted is potentially off the mark. When Mars is at aphelion the dv is about ~ 1 km/s lower than if Mars was at perihelion. Early September 1986 would find Mars at aphelion, but where would Venus be for the sling-by from the novel? Working on it currently. Transfer time is ~ 384 days, meaning a launch in August 1985.
BTW The mission flight-plan from Voyage is an Opposition Class Hohmann transfer. Usually the dip past Venus is on the way back from Mars to reduce the re-entry velocity at Earth. But it works the other way too, it seems.
And I am wondering about the propellant choice - UDMH/N2O4 is very space friendly, but there are other options for fuels and oxidisers out there. Liquid oxygen is the very definition of cryogenic, but keeping it liquified doesn't take a lot of equipment or power, especially if the tank was wrapped in reflective insulation, for example. A mix of RP-1 and LOX has a decent amount of kick, an Isp ~ 353s, but LOX and UDMH can get ~ 363s, which is cool. Definitely better than the N2O4/UDMH mix of Apollo. The mix is a lot denser (0.97 vs 0.28 gm/cc) than the LH2/LOX used in the Saturn IV-B, so if we assume the tanks are lighter, but the cooling system makes up the difference, then the Interplanetary Maneuver Stage (IMS - another TLA) can mass ~ 13.5 tons like the Saturn IV-B + IU combination.
Propellants that have been tried in real rockets can all be found here...
Interesting mix is LH2/LF2 - hydrogen and fluorine - which would have a highly toxic exhaust, hydrofluoric acid! Yikes! Glad the rocket makers settled on LH2/LOX for high performance - only exhaust is steam.
Posted at 11:41 am by Adam
Wednesday, August 04, 2004
John London's report on cheap access to LEO is 10 years old and I re-read with interest his conclusions. Important points...
Make a cheap orbital booster a national goal
Streamlined management of development
Loosening of Gov't regulation compliance - best practice NOT exacting compliance
Small development budget
Pressure-fed or simple pump-fed LOX-hydrocrabon boosters - preferably RP-1 (refined kerosine)
Retire the Space Shuttle's solid boosters - simple liquid propellant boosters are safer, better and tie in to the above point
better yet... retire the Shuttle - its multi-billion budget, even without launching a Shuttle is a terrible drain. Redeploy the resources for something cheaper, better and more frequent
Build a Space Station by the end of the 1990s... oh well, almost there... so manned, on-orbit operations aren't tied to the Shuttle
Build a simple, dedicated crew transporter - perhaps based on *gasp* Soyuz
So as you can see there's a lot missed by Gov't, but taken up by Musk and his kin in the private Space Access movement. And will quasi-private efforts get a Soyuz around the Moon before Big Gov't by 2008? Imagine that...
Posted at 3:54 pm by Adam
Tuesday, August 03, 2004
Here's more on the plan to send Soyuz around the Moon...
Soyuz to the Moon
The attached Gallery illustrates what a Block D upper-stage looks like quite well and indicates that the Russian Moon Program might have a pay-oof yet...
Posted at 12:10 pm by Adam
Monday, August 02, 2004
Price to Orbit II... revision
Lt.Col. John R. London III wrote for the USAF the book length study of space costs and space cost reduction, LEO On the Cheap, which is available for free from here:
LEO On the Cheap
The author released it for general distribution because his message is vitally important - Space costs too much chiefly because it is done at the extreme edge of technical ability, and the launch vehicle and satellite makers like it that way.
Enter Elon Musk who, with the SpaceX team, has taken on board Colonel London's findings and has simplified LEO bound rockets. If SpaceX can reach their goals the price to LEO will drop to ~ $2,200/kg, instead of the ludicrous ~ $40,000 - $10,000/kg currently on offer. And the price to GTO will drop to ~ $4,400/kg or so.
SpaceX is offering 4,200 kg payloads to LEO delivered for ~ $12 million. That's $2,860/kg, but they'll get better at it after a few launches and the price should come down. The main point about their efforts is that the rockets and avionics might not be absolute marvels of engineering perfection - instead they work well enough. Incredible amounts can be spent pushing machinery and designs to their absolute limits because of the continual review and refinement process uses large numbers of staff and resources to achieve the incremental approach to such limits.
A common satellite design mistake is to try to fit the satellite into a specific mass - the cost of space launch means people want to use all the mass budget they're alloted. As a result in the final stages $100,000s are spent refining the design. Larger, cheaper launcher payload options would mean a cheaper design process. Bigger satellites, because of ease of design, are also cheaper satellites. A common satellite frame-work that can be adjusted for several roles - rather than needing total redesign each time - would make for cheaper satellites too.
And rocket design? Advanced, computer controlled rockets pushed to their absolute limit, pushing propellants at high pressure into exhaust chambers with complicated and expensive turbo-pumps, and cooling jackets... well it all adds to costs. Exotic alloys for propellant tanks and refined rocket motors that push the envelope are long labours of (very expensive) engineering love - and simpler, proven designs and components could do the job for a lot less money. No commercial rocket these days needs to push the envelope when there is so much prior experience already paid for.
Posted at 12:53 pm by Adam
Back in the '70s the Space Shuttle was supposed to be the answer to revolutionise space-travel. No more expensive throwaway rockets, but routine, reuseable space-flight cheap enough for all to be involved in some way. In reality NASA over-sold the Shuttle in a valiant attempt to avoid getting the whole manned space program shut down by Richard Nixon. To achieve the hoped for price-tag of $750/kg to LEO (1980$... more like ~ $1,200/kg today) the Shuttle would need to be flying ~ 60 flights to LEO per annum with a full load of ~ 29,500 kg each time.
So why is the Shuttle so damn expensive? For starters the whole ground support system costs $2.8 billion per annum without a single Shuttle lifting off. Developing the Shuttles cost ~ $7.5 billion and building one costs ~ $1.5 billion. Say NASA had their full complement of 5 Shuttles. If they can manage 100 flights each, they then cost ~ $90 million plus those per annum housekeeping costs ($560 million per Shuttle per year), which totals (@ 60 flights/annum) $137 million/flight before we buy fuel. Surprisingly the fuel only costs ~ $1.5 million. Go figure...
So lets call it ~ $138 million to haul our 29,500 kg to LEO. That's still $4,700/kg - I guess NASA expected cheaper operating costs and wrote off the development costs - they expected to be making fleets of Shuttles eventually which would have driven that initial cost down dramatically.
My old favourite from 1979, "The Space-Traveller's Handbook", is set in a fictional 2061 in which all the 1970s dreams have come true - and Shuttle costs a mere ~ $60/kg to fly. About 100,000 people fly on a Shuttle per year, plus who knows how many cargo flights launched via reusable Heavy Lift Vehicles. Hence development costs have long been paid for, mass production has cut costs per Shuttle and ground support costs are spread over LOTS of flights (~ +2,000/annum.) That's how flight costs could be cut down dramatically - LOTS of traffic to LEO and beyond.
The reality is different, very different. In the fiction there are several Space Colonies - all Standford Torus designs - with a space population +100,000. There is a market - if not many space markets - that make Space pay-off for Earth's investment. In our current reality Earth-oriented "services" are the only pay-off. There is NO primary industry in Space, and that's what it really needs. So what can we get in Space and sell back here for $$$ ???
Posted at 1:43 am by Adam
Here's a cool Optics news bite...
Sydney Opera House repro/reduced
...micro-lithography - if it can be sped up - enables all sorts of amazing things to be crafted at micro-scale.
Posted at 12:35 am by Adam