Monday, June 29, 2015

CRS-7 News so Far

NASA held a morning news conference to discuss the SpaceX CRS-7 "Anomoly" or "RUD" or explosion, depending on how you want to spin the issue. So far there seems to have been an overpressure event in the second stage's LOX tank -- the exact cause isn't know -- but that seems to be where SpaceX is focusing their attention. The FAA is overseeing the investigation that SpaceX is performing, with NASA assistance as needed. The FAA considers this an "incident" rather than a full up "accident". These are terms that are probably more significant if you speak government-ese.

The other concern was whether or not the ISS was going to be in trouble with the lack of supplies. There may be a bit of a problem with water filters for the water recycler (the filters aren't worn out, but they are getting rather full of stuff), but other than that, there is enough food and supplies until the Japanese, Russian, or Cygnus supply spacecrafts can get there.

Sunday, June 28, 2015

Ouch Ouch

Looks like today's Dragon launch resulted in a "rapid unscheduled disassembly". It's possible it had gone off course, but there was a fair amount of out-gassing prior to break-up. Damn it!

Thursday, April 30, 2015

News for the Month: CRS-6 LEO, Turkmenistan/Thales GEO, Blue Origin Sub-Orbital, and a Lack of Progress

A lot has happened in the last month. The month started up with SpaceX's CRS-6 launch and attempted booster recovery. The good news is that launch and ISS station arrival were flawless, the not so good news is that the booster recovery didn't work out quite as well. Great video of the attempt, though. Elon said he was going to get himself an volcanic lair should the booster landing succeed. While he can't start on his lair just yet, I am sure SpaceX will succeed eventually. You have to admire his attitude about the whole venture. It seems he sees every flight is a chance to learn something new, and he isn't terribly attached to the success or failure of the booster landing, just as long as that effort is leading to eventual success. To booster landing, after all, is just icing on the Falcon 9 launch effort. The important measure of success is delivering product to orbit for the time being.

Meanwhile, on April 28th, Russia launched the cargo mission Progress 59 towards the International Space Station, but the ship lost attitude control soon after reaching orbit. One could hazard a guess as to what happened (a stuck attitude control jet?), but the end result is the Progress and all of it's cargo are a complete loss.

The day prior to the Progress launch, SpaceX launched another Falcon 9, this time carrying Turkmenistan's first communications satellite, TurkmenAlem52E/MonacoSAT to a geosynchronous transfer orbit. No attempt was made to land the booster on this flight. I think this was decided because the geo transfer orbit uses more fuel than the LEO orbit insertions, so the booster comes down faster and emptier than with LEO attempts. The next booster landing attempt will come up this June with the next resupply mission to the ISS.

Lastly, big news arrived this morning that Jeff Bezos' rocket company, Blue Origin, has begun their sub-orbital spacecraft testing phase with the launch and successful capsule recovery of their "New Shepard" spacecraft. The rocket, shown in the image at the top of this post, launched on April 29th, and reached an altitude of 307,000 feet. The booster of the spacecraft, called the "propulsion module" by Blue Origin, was unable to land softly as intended (it crashed) due to a hydraulic system mishap. Overall, a very successful test flight. But I have to say "New Shepard" isn't the most attractive rocket I've ever seen. The rocket's shape is more than a tad suggestive. After some research, I learned that the shape is part of the booster recovery system. That's great, but perhaps Jeff could've passed the design by marketing prior to finalizing everything.

Monday, April 13, 2015

Oh Well. Trying Again at around 4:20 PM EDT Tomorrow

Not much to say. The weather turned bad, so they decided not to launch. Just 3 minutes to go. Damn!

Still.. Getting hit by a lightning bolt on your way up isn't recommended, and I think it only happened one time before. I will post any updates on the launch time tomorrow as they come in.

Space-X CRS-6 Launch and Recovery Today

Space-X is launching CRS-6 today with another attempt at landing the booster stage on the self-guided barge "Just Read the Instructions". Yes, that's the barge's name, and is a nod to British Sci-Fi author Iain M Banks, who passed in 2013. As of 12:45 PST, the Falcon is about 45 minutes away from launch, which will take place at around 4:30 PM EDT or 1:30 PM PDT. You can watch the launch here, now or here starting at 4:15 PM EDT/1:15 PM PDT. Go check it out.

Thursday, March 12, 2015

The Importance of Dog Bones and Doughnuts: Revisiting the Freeluna Space Program

Given the success of SpaceX and Elon Musk's and Mars One's intent to colonize Mars, I think it's high time to revisit the notion of a rotating space station in low earth orbit, and eventually using said station (or something like it) to transport people to Mars. Before we go colonizing other planets, we really need to find out if humans can stay healthy in a partial gravity (less than 1 g but more than 0 g) environment, such as what humans will encounter on Mars (0.377 g) or the Moon (0.165 g). To the best of my knowledge, there has been absolutely no research done in these two gravity regimes. Our knowledge of zero gravity (microgravity) is extensive, and we have known for decades that exposure to it causes substantial physiological decay. What we need to find out is how badly or if Mars colonists will suffer decay within the gravity field of Mars.

To this end, let me introduce you to the concepts used to design a rotating space station created for the purpose of testing partial gravity fields on the human body. In the old 50's sci-fi movies, we saw plenty of examples of spinning wheels in space that represented space stations. In the movie 2001: a Space Odyssey, Dr. Heywood R. Floyd first finds himself heading for a double wheeled space station spinning in Low Earth Orbit, before he heads to the moon. The principle of artificial gravity used in these films is just an application of conservation of angular momentum, commonly called centrifugal force. Spinning a person around in circles can cause problems such as dizziness for some people, but almost all people can tolerate a spin rate of 2 rpm and some people can tolerate a spin rate as fast as 7 rpm. Depending on the RPM and the gravitational pull one is trying to induce, the radius of the spinning space station varies. The formula for calculating the radius for earth-like gravity is as follows:

Where 9.8 is acceleration of gravity at Earth's surface in meters/second^2 (use 3.7 for Mars and 1.6 for the moon), 'pi' is 3.14159.., and so on. With this calculation in hand, you can derive various habitat radii for different RPM.

If one so desired, a apparatus could be set-up on earth to simulate these spin rates and radii to test for human spin tolerance, such as with a vehicle connected to a central pivot via appropriate length cables and forced to drive around in circles to simulate station spin. The induced gravitational pull would be somewhat over 1 g, but should allow observation of inner ear phenomena, nonetheless. A graph below shows the various speeds of such a system...

Building a complete space station ring could get quite expensive, but building just a pole with small habitats on either end of it would be far less of a challenge. For a Mars equivalent gravity in a station spinning at 2 RPM, the length of the pole would need to be about twice the radius shown in the first table, or about 169 meters long. This could be reduced by offsetting the center of mass of the station towards one end of the pole. By placing most of the mass of the station at one end of the pole, the pole length to the Mars habitat would still need to be 84.4 meters from the center of mass of the station, but the pole length extending the opposite direction could be much shorter. The extra mass could consist of the station's batteries, rocket engines, fuel, water, solar, panels, radiators, etc. It might also contain a lunar habitat, using the shorter radius of 36.5 meters, thus allowing testing of both Martian and Lunar gravity effects in one station. A crude layout of such a station, which I am calling "the Dog Bone", is shown below:

The martian habitat would be on the left end of the station's central boom, and the lunar habitat would be on the right end of that boom. The extra pod to the right of the lunar habitat represents the extra weight of various station components which offsets the station's Center of Mass or Center of Gravity (I'm using the terms interchangeably here. Sorry, sue me if you must.). If it can be shown that subjects can tolerate a higher RPM, then the central boom of the station shrinks significantly.

I don't think such a station need be incredibly expensive to build. The central boom is the most awkward piece of the station, and I believe it could be assembled in orbit. The boom is, after all, not much more than a big aluminum pipe. Assuming 3 boom sections could be put in orbit per flight, with each boom being approximately 13 meters long, it would take about 3 flights just for the boom sections, potentially two more flights for habitat sections, and two more flights for the "counterweight" and docking interface, so somewhere around $480 million for launch costs for the station. Assuming my numbers are off by a factor of three, this is still a very inexpensive space project, and the payoff for having such a station is huge.

Friday, March 06, 2015

Dawn Spacecraft is Ceres-ly Orbiting a Dwarf Planet

It has been announced that the Dawn Spacecraft has successfully transitioned to orbiting around the dwarf planet Ceres. Someone thought it amusing to label this accomplishment as a first, as Dawn is now orbiting a dwarf planet, rather than orbiting some other type of celestial rock, which we have orbited before. But seriously, it wasn't until 2006 that Ceres was even referred to as a dwarf planet. Before then, it was called an asteroid, and an orbit of an asteroid was already achieved on February 14th, 2000 (Mission was NEAR, the asteroid was 433 Eros). With any luck, the IAU will redefine Ceres as something like a dormant, mega-comet at some point, and a new NASA mission can be sent there to claim yet another astronomical first.

The real first is that Dawn has accomplished is to achieve orbit at two separate celestial destinations during one mission (Vesta and now Ceres), and this is due to its use of ion propulsion. Ion engines are about ten times more efficient than conventional bi-propellant engines, when it comes to using fuel. As a result, they allow spacecraft a greater wander range than a conventional engine would allow. In this case, increased engine performance results in much smaller fuel tanks, which results in a smaller spacecraft with more range.

Ion engines put out a miniscule amount of thrust -- it takes the Dawn spacecraft 4 days to accelerate from 0 to 60 miles per hour, but unlike chemical propulsion, Dawn can maintain that thrust continuously for months at a time. The Ion engines are remarkably simple and sturdy, and can run for upwards of five years at full thrust without breaking.

Now that Dawn has arrived at Ceres, we will get the chance to investigate this peculiar planetoid. So far, scientists have speculated that Ceres has a thick crust of ice surrounding a rocky core. It appears as though Ceres' surface is coated with a fairly thick layer of dust, and there appears to be some activity that has revealed the underlying ice layer. We should be in for an exciting several months of science ahead.

Friday, February 27, 2015

Spock: End of an Era 2015

My son called me with the saddest news this morning. Leonard Nimoy, directory, artist, and actor indelibly linked to the character Spock, from Star Trek the original series, has died. He was 83 and suffering from end-stage Chronic Obstructive Pulmonary Disease (emphysema) when he was taken to the hospital on the 19th of February with chest pains. On the 23rd, he tweeted, "A life is like a garden. Perfect moments can be had, but not preserved, except in memory. LLAP" Leonard was born in Boston, Massachusetts in 1931 to Russian Jewish parents. He started acting at the age of 8 in children's and neighborhood theater. His parents encouraged him to take up a more stable career than acting. His father even encouraged him to learn to play the accordian, rather than act. Fortunately, his grandfather intervened at that point and steered young Leonard towards the acting life. Thus the world owes Leonard's grandfather a huge debt of gratitude on at least two counts.

Leonard served in the Army from 1953 to 1955. He took on various parts in TV shows and movies starting in 1951, often in westerns, police dramas, and similar action roles. In 1964, Leonard acted in a pilot for a futuristic, space-age action/drama TV show that was to become Star Trek in 1966. Although the original Star Trek series only lasted for three seasons, it left an indelible mark on the American psyche, as well as on the careers of all of the actors who were involved with it, most especially for Leonard Nimoy and William Shatner. Leonard wasn't entirely keen on being type-cast and had somewhat of a love/hate relationship with Spock over the years. It should be noted that some of his other works, such as this, this, and this, were mercifully overshadowed by the character Spock.

He was a great man though, and will be greatly missed. For more insight into Leonard Nimoy, here are links to an interview he did back in 2012..

Hero Complex Part 1
Hero Complex Part 2