Author Topic: Space Access '12 Live Blog  (Read 16608 times)

Offline simonbp

Space Access '12 Live Blog
« on: 04/09/2012 02:20 AM »
I'll try livebloging Space Access again this year, agenda below:

http://www.space-access.org/updates/sa12info.html

Anyone else going?

Offline QuantumG

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Re: Space Access '12 Live Blog
« Reply #1 on: 04/09/2012 02:28 AM »
Thanks!
Jeff Bezos has billions to spend on rockets and can go at whatever pace he likes! Wow! What pace is he going at? Well... have you heard of Zeno's paradox?

Offline simonbp

Re: Space Access '12 Live Blog
« Reply #2 on: 04/12/2012 03:40 PM »
I'm here and set up, everything should start soon; Henry Spencer is up first.

Offline simonbp

Re: Space Access '12 Live Blog
« Reply #3 on: 04/12/2012 05:03 PM »
Beyond Chemical Rockets, Henry Spencer

Fuel fraction of 40% = Easy
Fuel fraction of 90% = Hard
Fuel fraction of 96% = Very Hard, but done by Titan III first stage

Even in space, low thrust has costs. Going from LEO to escape takes 3 km/s high-thrust, but 8 km/s with low thrust. So, got to have high Isp, but thrust cannot be too low.

Best chemical rocket ever: 542 s, fluorine/lithium/hydrogen triprop system. Not much better than LH2/LOX.

Solar Sail: 9 N of thrust per km2 at 1 AU. Sail can make their own Lagrage points; e.g. park over the North Pole.

Mag Sail: Uses solar wind drag. Can be combined from with a plasma generator. Physics very complex, and not well characterized.

Space Fountain circulating pellet stream, as a ground-to-space power transfer.

If you want high Isp _and_ thrust, you need a lot of power, and that means mass. Electric thrusters are generally about 50% efficient. Optimum Isp for fuel/power mass is always around a few thousand seconds.

Ultimate power source is a small black hole; problem is step 1.

Efficiently ionizing gas is hard, and that's most of the inefficiency in ion thrusters. All-electric comm sats are the new fad.

Electrothermal thrusters (arcjets) have potential, because it's easier to lower their Isp (and thus dv/power). But, poorly developed so far.

Chemical rockets aren't bad if you refuel early and often. You could deliver many thousands of tons LOX/RP1 to LEO for the cost of the first nuclear rocket.

Outer solar system need advanced (not solid-core fission) nuclear propulsion.
« Last Edit: 04/12/2012 05:04 PM by simonbp »

Offline MP99

Re: Space Access '12 Live Blog
« Reply #4 on: 04/12/2012 05:17 PM »
Great, thanks. Can see this being a go-to thread for the next couple of days.

cheers, Martin
« Last Edit: 04/12/2012 05:17 PM by MP99 »

Offline simonbp

Re: Space Access '12 Live Blog
« Reply #5 on: 04/12/2012 05:22 PM »
Keith Henson (L5 Society), $100 a kg to GEO with Beamed Energy Propulsion

Laser propulsion using space-based solar-powered lasers. Hydrogen combustion to 25 km and Mach 5, and then space-based lasers after that. First laser-powered stage circularizes in LEO, and second goes to GEO. 500 Falcon Heavy launches to build giant solar powered laser (at $10/W).

Offline simonbp

Re: Space Access '12 Live Blog
« Reply #6 on: 04/12/2012 05:40 PM »
Students for the Exploration and Development of Space, Sara Meschberger

Largest student-run space-focused organization. Lots being done; any you reading this that are undergrads or in high school, get involved!

Offline Jason1701

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Re: Space Access '12 Live Blog
« Reply #7 on: 04/12/2012 06:08 PM »
500 Falcon Heavy launches to build giant solar powered laser.

+500

Offline simonbp

Re: Space Access '12 Live Blog
« Reply #8 on: 04/12/2012 06:30 PM »
Liftport, Frank Smith and Ben Sitnnet

Carbon nanotubes haven't quite gone as fast as hoped. Lunar L1-surface space tether. Counterweight on a tether most of the way back to Earth. Capacity of 48 kg on initial tether. Zylon the best material option at the moment. Also looking at a "lunar lawn dart" to embed anchor in the lunar surface. Solar-powered electric climbers at 5 m/s (11 mph). Use the first small tether to build it up to many tethers. Is actually stable to the eccentricity of the Moon's orbit (apparently).

ASU Lunabotics kickstarter ends Sunday.

Online Robotbeat

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Re: Space Access '12 Live Blog
« Reply #9 on: 04/12/2012 06:36 PM »
Earth is a pretty difficult place to build a tether. Barely possible with significant advancements in carbon nanotubes. Other places are much more amenable to the concept, including Mars, the Moon, and asteroids. Plus there are rotovators.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline simonbp

Re: Space Access '12 Live Blog
« Reply #10 on: 04/12/2012 06:38 PM »
That's why they were shooting for it; it can be launched on a single FH using existing tether materials.

Online Robotbeat

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Re: Space Access '12 Live Blog
« Reply #11 on: 04/12/2012 06:41 PM »
That's why they were shooting for it; it can be launched on a single FH using existing tether materials.
Yes, very encouraging. (Also would be neat if deployed to study Phobos on an early manned orbital mission of Mars.)

Space elevators are a pretty difficult goal, but the idea is a sound one, if the technical requirements can be reduced (say, by putting it on the Moon). The drive towards higher strength/mass materials will have benefits all over the place, and the effort can also take advantage of R&D used for other applications.
« Last Edit: 04/12/2012 06:41 PM by Robotbeat »
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline simonbp

Re: Space Access '12 Live Blog
« Reply #12 on: 04/12/2012 07:11 PM »
John Schilling, "Halfway to Anywhere, Part II: Groundwork For Going Beyond LEO"

Once you get to LEO, 4-6 km/s gets you anywhere in the inner solar system. Lunar landers (and vehicle like them) are pretty darn similar in requirements and technology.

Satellites are so expensive partially because they have to spring from an Atlas fully formed. Having a few technicians on-orbit to commission satellites would be a major improvement.

Modified density Isp: Performance = Isp * (density)^(1/6). LOX/LH2 only slightly better than LOX/CH4. LOX/CH4 and NTO/MMH almost the same.

RL-10 best engine, but so expensivye. Only need a few 0.1g's to get to impulsive transfers. Pump-fed best just to get as much Isp as possible. Long life, lots of starts. GOX/GH2 or GOX/GCH4 great for RCS.

How to fit a large (empty) tank in a small vehicle is a real problem. Ditto for a large aerocapture heatshield.

Really want a system that has both chemical and electric propulsion. Room some economic trades on solar panel quality vs. cost.

Mars is the transition point where nuclear starts to make sense, within that, it doesn't. Startrackers are too expensive. MLI is great but too fragile for human or robot touch labor. Active thermal control has some great advantages.

Path 1: do lots of small deep-space missions; learn from process

Path 2: LEO operations base; cost as much as developing an RLV; is transportation infrastructure that a government can support

Material selection for storables is horrible; no polymers, limited number of metals. Makes CH4 more attractive.
« Last Edit: 04/12/2012 07:14 PM by simonbp »

Offline simonbp

Re: Space Access '12 Live Blog
« Reply #13 on: 04/12/2012 07:32 PM »
Commercial Spaceflight Federation, Alex Saltman, Executive Director

Chamber of Commerce for space companies. Mike Lopez-Alegria is the recently-hired President of CSF. Mix of small and large companies. Goal is make launches boringly common, but it's what you're doing that's interesting. Suborbital is really important to that making that happen. About 75% on winning people on the Hill over to commercial spaceflight.

Offline simonbp

Re: Space Access '12 Live Blog
« Reply #14 on: 04/12/2012 09:21 PM »
David Hoerr, "The Rocket Company, 10 Years After"

Whole strategy was global fleets of many RLVs. As soon as it gets feasible, start working on "insanely big projects" to force a move beyond communication sats. Big projects drive down cost and engage public.

As Napoleon said, "If you want to take Vienna, take Vienna".

Offline simonbp

Re: Space Access '12 Live Blog
« Reply #15 on: 04/12/2012 09:41 PM »
Ed Wright of Citizens In Space, on "Citizen Science: 'Pump Priming' For Suborbital"

Suborbital at the moment is about joyrides for rich guys. Really talking up "citizen science" as a potential market. Acquired 10 Lynx flights from Xcor for initial flight campaign.

Offline simonbp

Re: Space Access '12 Live Blog
« Reply #16 on: 04/12/2012 10:09 PM »
Bruce Pittman, NASA Ames, "Barriers And Opportunities For Reusable Launch Vehicles"

RLVs have to have a much higher flight rate than ELVs to be competitive. RLV return on investment exponentially proportial to the number of flights per year. The key to make money on an airline is to fly often and full. Who would be the customer for one Falcon Heavy flight per day? Comm sats are a money maker - for the operators, not launchers. Need a new growth market. A lot more money out there than good ideas. Solution may be an aggregation of many customers (FedEx model) rather than one big customer.

Offline simonbp

Re: Space Access '12 Live Blog
« Reply #17 on: 04/12/2012 10:48 PM »
Space Studies Institute, Gary Hudson

The Great Enterprise, a bold hardware project to lead to space settlement. G-Lab: study vertebrate (lab rat) responses to reduced gravity. E-Lab: Demonstrate balanced life support systems, first on Earth and then in space. G-Lab 20 times more expensive because it's in space. ISS co-orbital core module using SEP. Lots of traffic to ISS, just a tiny delta v away. Could repurpose used ISS visiting vehicles; i.e. if OSC donated a used Cygnus, SSI would give them a massive tax deduction. Starting design phase now, Space Act Agreement in progress, talking to donors. Could be a visiting vehicle to a Bigelow station. Earliest possible launch date 2016, probably later.

Offline simonbp

Re: Space Access '12 Live Blog
« Reply #18 on: 04/12/2012 11:45 PM »
Dallas Bienhoff, "Payload Requirements For A Low Cost Reusable Launch Vehicle"

(Speaking for himself, not his employer.) Payload requirements can drive RLV design. Very different requirements for passengers vs. bulk propellant vs. GEO sats. People are quite profitable at $5 million a seat, but bulk propellant isn't as much.

Offline simonbp

Re: Space Access '12 Live Blog
« Reply #19 on: 04/13/2012 12:04 AM »
Rick Maschek, Sugar Shot To Space

Goal is build a sugar-powered rocket that eventually reaches space. Many tests, slowly making progress. DoubleShot (aiming for 120,000 ft) has been tested once, and blew up.

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