The Space Show, hosted by David Livingston at www.TheSpaceShow.com, will have the following guests this week:
1. Tuesday, May 26, 2015, 7-8:30 PM PDT (May 27, 2-3:30 GMT)
DR. MATTHEW MOYNIHAN visits on the Polywell and fusion.
Dr. Matthew Moynihan has been advocating for fusion research since 2006. He holds a PhD, MS and BS in Chemical Engineering from the University of Rochesters' Laboratory for Laser Energetics. His research was on target manufacturing for the National Ignition F [...]
First came the trees. In the town of Salamanca, Spain, the photographer noticed how distinctive a grove of oak trees looked after being pruned. Next came the galaxy. The photographer stayed up until 2 am, waiting until the Milky Way Galaxy rose above the level of a majestic looking oak. From this carefully chosen perspective, dust lanes in the galaxy appear to be natural continuations to branches of the tree.
Last came the light. A flashlight was used on the far side of the tree to project a [...]
I was talking with my parents tonight and realized that a good topic for a Sunday post would be to introduce my mom’s company’s new website: Mentoring Our Own. My mom’s company is about teaching and mentoring new homeschooling parents, and helping them learn how to teach their children at home. She’s been running this and other related home-education businesses for the past decade and a half.
My brother-in-law (who is a great graphics artist) made my mom this avatar for her website:If you’re interested in homeschooling, but not sure where to start, you might want to check out her website and blog.
What's that rising from the clouds? The space shuttle. Sometimes, if you looked out the window of an airplane at just the right place and time, you could have seen something very unusual -- a space shuttle launching to orbit. Images of the rising shuttle and its plume became widely circulated over the web shortly after Endeavour's final launch in 2011 May. The above image was taken from a shuttle training aircraft by NASA and is not copyrighted.
Taken well above the clouds, the image can be [...]
One of the ideas I had been thinking of blogging about was the thought of augmenting EGT asteroid deflection with in-situ derived propellants. The gravitation attraction force is usually the bottleneck in how fast you can do an asteroid deflection, but in some situations the propellant load might matter too.
What options are there for ISRU propellants in this case?
If the asteroid is a carbonaceous chondrite, water might be your best bet. There are some promising SEP technologies, like the ELF thrusters being developed by MSNW that can operate efficiently with water as the propellant. The challenge is that water is only present in some asteroids, might not be super easy to extract, and might require enough infrastructure to not be worth it on net.
The other big option is asteroid regolith. This could be charged up and run in a similar manner to an electrospray engine, or if it the dust is magnetically susceptible, it could be accelerated by something similar to a coil gun, mass driver, or linear accelerator. One of my employees used to work at a LASP lab running a dusty plasma accelerator. Basically they’d charge up small particles of dust, put them in a crazy electric field, and accelerate them to ~100km/s to smash into other dust particles to study micrometeorite formation processes.
What are some of the considerations for such an idea?
You are probably going to be very power limited. This both impacts what you can do as far as propellant extraction, and also limits the exhaust velocity/Isp that is optimal for an asteroidal ISRU-fed propulsion system. Just as ion engine systems operating in gravity wells typically tend to optimize to a lower Isp/higher thrust, the optimal deflection per unit time likely won’t come from the highest theoretical Isp.
On the other hand, the lower the exhaust velocity, the more material you have to handle to produce the “propellant”. So the optimal exhaust velocity is likely somewhere in the middle.
Also, if you’re extracting water, that’s likely more energy intensive than dust.
Without running the detailed numbers, my guess is you’d want a dust “electrospray” engine with an Isp in the 100-1000s range to optimize the balance between thrust per unit power and required extraction capabilities. For instance a 500s Isp is maybe 25% of the Isp of the Xenon Hall Effect Thrusters they’re thinking of using for ARM. That would imply getting somewhere between 16x the thrust per unit time as running the same amount of power through the HET.You’d need 16x the propellant mass flow rate, but if you’re gathering hundreds of tonnes of regolith, rock, and boulders, I would think that wouldn’t be that hard to get say ~125tonnes of regolith. One nice thing is that some of this material can be gathered while landing to gather the additional mass for the enhanced gravity tractor.
Tests on Mars have confirmed success of a repair to the autonomous focusing capability of the Chemistry and Camera (ChemCam) instrument on NASA's Curiosity Mars rover.
This instrument provides information about the chemical composition of targets by zapping them with laser pulses and taking spectrometer readings of the induced sparks. It also takes detailed images through a telescope.
Work by the instrument's team members at Los Alamos National Laboratory in New Mexico and in France ha [...]
Hot, young stars and cosmic pillars of gas and dust seem to crowd into NGC 7822. At the edge of a giant molecular cloud toward the northern constellation Cepheus, the glowing star forming region lies about 3,000 light-years away. Within the nebula, bright edges and dark shapes are highlighted in this colorful skyscape. The image includes data from narrowband filters, mapping emission from atomic oxygen, hydrogen, and sulfur into blue, green, and red hues.
The atomic emission is powered by en [...]
[Disclaimer: My current company and former company have both done work with ULA. In fact, we just started another small IRAD project with ULA. We’ve also done work with SpaceX in the past, but our current work with ULA is a potential bias I wanted to state up front. I’m not being paid by ULA or encouraged to make these points, and I don’t have any super-secret inside knowledge about Vulcan or their inner workings. This is just my opinion, and I feel like I need to share it, even if people will blow me off as being a ULA shill.]
There is a lot of debate swirling around the future of ULA, Vulcan, the RD-180, etc. I had a few quick thoughts I wanted to share that I think don’t get a lot of air-time. While these could be construed as pro-ULA, I’m also on the record as being a fan of real competition, letting SpaceX compete for DoD contracts as soon as possible, and getting rid of the ELC subsidy for ULA. Here’s my thoughts:
While creating incentives to wean ULA off of the RD-180 may make some sense, there is no good reason for doing so in a way that hobbles ULA and makes it impossible for it to compete with SpaceX.
Some will point out that Russia threatened to cut off supply of the RD-180, but the reality is they have no good reason to do so, and really hold very little leverage over the US once SpaceX is certified to fly EELV-class national security payloads. Cutting off the RD-180 only strengthens SpaceX, the one serious competitor to the Russian Soyuz, Proton, and Angara vehicles. No, the RD-180 “supply issues” are entirely a creation of our Congress.
We bought titanium from the USSR during the Cold War, and as mentioned above, Russia has even less leverage on us today with RD-180s and Atlas V than it did then with Titanium supplies.
ULA really does need to downselect to just one launcher family to be competitive. And the only reason it didn’t do so sooner was because without SpaceX being certified for DoD payloads, the DoD required them to keep both EELV families flying for assured access purposes. By ditching over half of their pads, over half of their configurations, etc., they can significantly consolidate their supplier base, and cut down on duplicative capabilities. They would’ve already done this if the DoD had allowed them to previously.
The move to drop Delta-IV is not just a cynical move to try and force our Congress to not be stupid re: the RD-180. And it’s not just that the Delta-IV is less competitive (but you’d think that letting companies shed uncompetitive product lines wouldn’t be such a sore spot with so-called commercial space enthusiasts…). Vulcan is based on the Atlas V and Centaur. If Atlas V were retired, it would be nearly impossible to keep the Atlas V/Centaur supplier base alive long enough to get Vulcan flying. Could you force Vulcan to be more Delta-IV derived so you could force them to shut down their more competitive launcher? Sure. It would just guarantee that Vulcan wouldn’t be as competitive in the marketplace, wouldn’t be as capable, and would be less useful to our military. Could you do it anyway? Sure. And you could stick your hand in the blender and turn it on. There’s no limit to stupid self-defeating things you could do if you put your mind to it. Does anyone else see how ridiculous this line of thinking is though?
The US is served far better by having two healthy and competitive launch service providers than it is with either a ULA or a SpaceX monopoly. It’s also much better served by a healthy SpaceX and ULA w/ Vulcan than it would be with a healthy SpaceX and a ULA that’s only kept alive on life-support from the government. Just as we were all better off with Intel and AMD, Windows and Mac, Apple and Samsung, we’re better off having healthy competition than artificially stifling things in either player’s favor.
I don’t think it’s the government’s job to make ULA successful, but they shouldn’t be telling them what launchers they can build and what engines they can buy either. Make them compete, but let them compete!
The International Space Station Program will take the next step in expanding a robust commercial market in low-Earth orbit when work continues Wednesday, May 27, to prepare the orbiting laboratory for the future arrival of U.S. commercial crew and cargo vehicles. NASA Television will provide live coverage of the activity beginning at 8 a.m. EDT.
NASA is in the process of reconfiguring the station to create primary and back up docking ports for U.S. commercial crew spacecraft currently in deve [...]
NASA's Curiosity Mars rover climbed a hill Thursday to approach an alternative site for investigating a geological boundary, after a comparable site proved hard to reach.
The drive of about 72 feet (22 meters) up slopes as steep as 21 degrees brought Curiosity close to a target area where two distinctive types of bedrock meet. The rover science team wants to examine an outcrop that contains the contact between the pale rock unit the mission analyzed lower on Mount Sharp and a darker, bedded r [...]
I’ve enabled the use of comment and author avatars. I wanted a way of helping people tell which posts were mine and which were those of the other bloggers, as there’s been occasional confusion. I wasn’t able to figure out how to splice in the code to display our avatars next to each post title, but it’s a start.
I added a bio block at the bottom of each post (when you click on the individual post), serving the above mentioned function of making it clear which of us wrote which post.
I added a profile picture/avatar that’s recent enough to show me with my beard (and all the grey hair I’ve earned between two space startups and four little boys).
I also installed a plugin that lets me add footnotes to my blog posts.1
The footnotes appear if you mouseover the footnote number, or you can see them in the footer if you go to the specific post. I can’t figure out how to show them above the author bio, but really, I mostly just wanted them as mouseover text.
Hopefully this should enable a slight decrease in my abuse of parenthetical and nested parenthetical statements, and slightly increase my use of witty sarcasm.
I still need to find a header picture that works and doesn’t suck, so the default one will stay for a bit longer.
In the dusty sky toward the constellation Taurus and the Orion Arm of our Milky Way Galaxy, this broad mosaic follows dark and faint reflection nebulae along the region's fertile molecular cloud. The six degree wide field of view starts with long dark nebula LDN 1495 stretching from the lower left, and extends beyond the (upside down) bird-like visage of the Baby Eagle Nebula, LBN 777, at lower right.
Small bluish reflection nebulae surround scattered fainter Taurus stars, sights often skipp [...]
Astronomers using NASA's Hubble Space Telescope have uncovered surprising new clues about a hefty, rapidly aging star whose behavior has never been seen before in our Milky Way galaxy. In fact, the star is so weird that astronomers have nicknamed it "Nasty 1," a play on its catalogue name of NaSt1. The star may represent a brief transitory stage in the evolution of extremely massive stars.
First discovered several decades ago, Nasty 1 was identified as a Wolf-Rayet star, a rapidly evolving st [...]
A remote galaxy shining with the light of more than 300 trillion suns has been discovered using data from NASA's Wide-field Infrared Survey Explorer (WISE). The galaxy is the most luminous galaxy found to date and belongs to a new class of objects recently discovered by WISE -- extremely luminous infrared galaxies, or ELIRGs.
"We are looking at a very intense phase of galaxy evolution," said Chao-Wei Tsai of NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, lead author of a new [...]
SpaceX’s Dragon cargo craft splashed down in the Pacific Ocean at 12:42 p.m. EDT, about 155 miles southwest of Long Beach, California, marking the end of the company’s sixth contracted cargo resupply mission to the International Space Station.
The spacecraft is returning more than 3,100 pounds of NASA cargo and science samples from the International Space Station. A boat will take the Dragon spacecraft to a port near Los Angeles, where some cargo will be removed and returned to NASA withi [...]
The SpaceX Dragon cargo spacecraft was released from the International Space Station’s robotic arm at 7:04 a.m. EDT.
The capsule will begin a series of departure burns and maneuvers to move beyond the 656-foot (200-meter) “keep out sphere” around the station and begin its return trip to Earth. The capsule is currently scheduled to splashdown in the Pacific Ocean at 12:42 p.m., about 155 miles southwest of Long Beach, California. [...]
The previously linked-to EGT paper had a great introduction to the concept of using a gravity tractor for deflecting potentially hazardous asteroids. In all gravity tractor concepts you’re using the mutual gravitational attraction between the spacecraft and the asteroid itself as a way of transferring thrust from the spacecraft’s thrusters into the asteroid itself. You can do this using an in-line tractor orientation, where you cant the spacecraft engines outwards at an angle sufficient to avoid plume impingement on the asteroid, and you eat the cosine losses on the thrusters.
Or you can place the spacecraft into a halo orbit around the asteroid, and fire the thrusters due backwards.This shifts the orbit from orbiting around the equator of the asteroid to an offset halo (that looks like a spiral from a sun-centered perspective).
I prefer the halo approach, both because you can probably make it passively safe (where a thruster failure doesn’t involve the spacecraft colliding with the asteroid), because you can probably have your spacecraft a lot closer to the asteroid thus increasing the gravitational acceleration (and thus peak thrust you can impart), because you avoid the cosine losses from canted thrusters, and because it’s a lot easier to add multiple gravity tractors flying in formation with the halo/spiral approach.The equation governing the thrust you can impart into an asteroid in such a halo orbit is:Where rho is the radius of the halo orbit, and z is the axial offset distance of the halo orbit, G is the universal gravitational constant, Mast is the mass of the asteroid, and Msc is the mass of the spacecraft. As you can see, the closer you are in, and the heavier your spacecraft, the more force you can transmit into the asteroid, hence the idea of augmenting the spacecraft mass with locally harvested regolith, rock, and boulder materials. It is pretty easy to increase the effective towing mass by >10x using locally harvested materials. While traditional gravity tractor methods required more than a decade of advanced notice, enhanced gravity tractoring might only take a year or two of advanced notice if you already have the infrastructure in place to deal with a threat.
As an interesting aside, I noticed the other night that it looks like my coblogger John Hare might have actually beat the NASA guys to coming to this conclusion by at least a few months, based on this Selenian Boondocks blog post from February 2013, which describes a concept almost identical to the one shown in Figure 20 from the paper.
NGC 6240 offers a rare, nearby glimpse of a cosmic catastrophe in its final throes. The titanic galaxy-galaxy collision takes place a mere 400 million light-years away in the constellation Ophiuchus. The merging galaxies spew distorted tidal tails of stars, gas, and dust and undergo fast and furious bursts of star formation.
The two supermassive black holes in the original galactic cores will also coalesce into a single, even more massive black hole and soon, only one large galaxy will remai [...]
Cape Canaveral Air Force Station, Fla. – A United Launch Alliance (ULA) Atlas V rocket successfully launched the Air Force Space Command 5 (AFSPC-5) satellite for the U.S. Air Force at 11:05 a.m. EDT today from Space Launch Complex-41. The rocket carried the X-37B Orbital Test Vehicle or OTV, a reliable, reusable, unmanned space test platform for the U.S. Air Force.
“ULA is honored to launch this unique spacecraft for the U.S Air Force. Congratulations to the Air Force and all of our mis [...]