The Path to Manned Flight to Mars

Scientific American has a pretty fascinating article by a NASA mission architect and mission analyst discussing NASA’s future and how to, eventually, put humans on Mars. In 2009, a group of NASA scientists began brainstorming how to move forward with human space exploration, in light of the ending of the Space Shuttle program and, in 2010, the cancellation of the Constellation program that was meant to replace it. 

After some years of plotting:

We have now combined the most promising proposals with tried-and-true strategies to develop a plan to send astronauts to the near-Earth asteroid 2008 EV5 as soon as 2024 as preparation for an eventual Mars landing. This approach is designed to fit within NASA’s current budget and, crucially, breaks the overall task into a series of incremental milestones, giving the agency flexibility to speed up or slow down depending on funding. In a nutshell, the aim is to apply lessons from the robotic scientific exploration program to renew the human exploration one.

The article is rather extensive, but worth the read if you want to see what goes on in the imaginations of rocket scientists tasked with dreaming up all things awesome. It’s also a nice primer on the kinds of techniques and technologies involved in space travel, something we don’t generally think about too much. They also have a video of the authors discussing their idea, or as a shortcut to all of this, a pretty cool graphic explaining how this manned space flight is going to work.

Two things to note are that 1) instead of using space suits outside of the ship as we’re used to, with all their limited mobility, they’d instead want the astronauts to command little vehicular pods when on the asteroid surface (and presumably Mars, later). 2) is that they want to use an ion drive instead of rockets to travel through space, for weight and energy reasons. Ion thrusters basically create charged atoms (ions) and shoot them out using an opposite electric charge, creating thrust that will push the ship in the opposite direction.  

The most important point underlying these ideas, as they said above, is that progress towards landing on Mars will be incremental, involving a number of shorter trips in the meantime. In an ideal world they’d have the funding to go for broke, but they’ll have to make do for now. 

Giant Lake Discovered on Jupiter’s Moon Europa

From National Geographic:

Hidden inside the thick, icy crust of Jupiter’s moon Europa may be a giant saltwater body equal to the Great Lakes combined, NASA announced today.

Lying about 1.9 miles (3 kilometers) from the surface, the ice-trapped lake may represent the newest potentially habitable environment in the solar system—and one of the best prospects for the search for life beyond Earth.

“For decades scientists have thought Jupiter’s moon Europa was a likely place for life, but now we have specific, exciting regions on the icy moon to focus our future studies,” Don Blankenship, senior research scientist at the University of Texas at Austin’s Institute for Geophysics, told National Geographic News…

Similar in size to Earth’s moon, Europa is already thought to house a global, salty ocean beneath its 62-mile-thick (100-kilometer-thick) ice shell. NASA’s Galileo spacecraft, which orbited Jupiter and its moons from 1995 to 2003, first discovered evidence of the ocean…

There probably are many more lakes under Europa’s ice, Blankenship added.

Likewise, the prospects for searching for life on Europa could improve dramatically, as research suggests some of these icy lids covering the lakes may be much thinner than thought.

The techniques they used to infer the existence of the lake are the same that they use with satellite imagery of Earth, for example to discover subglacial lakes in Antarctica.

So when will we finally find out if there’s life on Europa? Uh… not any time soon, it seems. NASA planned a mission to specifically check out Europa using a probe called the Jupiter Icy Moons Orbiter (JIMO), but that plan was scrapped in 2005. This August, NASA launched a probe called Juno to investigate Jupiter; it will arrive around 2016. Taking more peeks at Europa does not seem to be in its job description, but who knows what it might see?

Fun facts: Juno will travel a total of 1.74 billion miles, or 2.8 billion kilometres. If that’s impossible to imagine, well, it should be. Meanwhile, the farthest probe from Earth is the Voyager 1, at 119 AU (an AU being the average distance from Earth to the sun), or almost 18 billion kilometres away. It was launched in 1977 and is still in communication with Earth. 

This news caught my attention because I was just reading about 2001: A Space Odyssey, and the sequels to that novel are based on there being life on Europa. What else did Arthur C. Clarke know that we don’t?

Reviews of Dark Matter and the Big Bang

There are two new articles today with some nice overviews of central topics in cosmology: The Status of Dark Matter from Starts With a Bang!, and The Big Bang: What Really Happened at Our Universe’s Birth from Space.com. They’re both relatively brief and easy to read, and afterwards you’ll be able to teach your friends about the nature of the universe, and how cool and smart you are.

The latter article is part 5 of an 8 day series at Space.com called The History & Future of the Cosmos; I’ll probably check out the rest of the articles soon, and you should too.

The World’s First Commercial Spaceport

Spaceport America opened on Tuesday with a snazzy dedication. Its sole tenant at the moment is Virgin Galactic, which has already sold hundreds of future trips to the edge of space for $200,000 a pop. It’s unclear when they’ll actually be in a position to start sending up customers, but it seems that it will be within the next couple of years. I think I’ll hold off until the price comes down a bit though…

From New Scientist:

 Over 100 of those in attendance for Virgin’s “dedication” of the hangar have already put deposits down to fly on Virgin’s SpaceShipTwo. They watch in awe at a test flight of WhiteKnightTwo, the plane that will help the spaceship on its way. Slung between WhiteKnightTwo’s two fuselages, SpaceShipTwo will be transported to 15 kilometres above Earth, before it breaks away and fires its engine to reach the edge of space. Six passengers and two pilots will then experience a few minutes of weightlessness on flights that will last a couple of hours.

“I think the first moment when I see the curvature of the Earth will be the really exciting part,” says David Whitcomb, co-founder of Revolutionary Tennis Innovations, who was the 186th person to sign up for the trips. “Even if the first one crashes, I’m still going.”

There are still technical hurdles to overcome before commercial trips begin. So far, Virgin Galactic has only tested SpaceShipTwo without rocket power. The rocket motor has been undergoing separate tests, and the firm hopes powered flights will begin next year.

The spaceport’s construction is funded by taxpayers in New Mexico. Promised that it will bring 2000 jobs to the area in the next five years, they have paid $209 million, via bonds. “We think it will help New Mexico,” says Judy Wallin, a local cattle rancher. After December 2013, these bonds expire and rent from Virgin Galactic is expected to pay for operations.

Christine Anderson, executive director of the New Mexico Spaceport Authority, says New Mexico is the ideal place for a spaceport. As it is at an altitude of about 1400 metres, rockets need less fuel to take off than if they were starting out at sea level. The 330 clear days per year also help, as does the area’s sparse population, which means there is less chance that a crash would endanger large numbers of people.

Perhaps best of all is its location next to the 890,000 hectare White Sands Missile Range – the site of the first space flight by a rocket launched on US soil. This means the spaceport’s airspace is restricted, so no commercial aircraft fly overhead.

I find it interesting that New Mexico paid for the spaceport – that’s a big investment into a very novel and expensive industry. I can’t help but feel that $200,000 a flight is just too expensive to attract a large base of people, but if there is interest then I trust that competition and innovation will emerge to drive that cost down. In the meantime I’ll keep my eyes peeled for the first YouTube video from a Virgin Galactic flight.

If you’d like more info, here’s another article on the opening of Spaceport America: I didn’t think either article was great, so maybe in combination they suffice. 

New Global Navigation Satellite Systems Rising

The first two operational satellites in a new European Union global navigation satellite system are set to launch this Thursday. They’ll form part of a 27-satellite system called Galileo as a European alternative to GPS, which is run by the U.S. Little did I know that Russia also has its own system called GLONASS, which this month achieved worldwide coverage, and that China has launched 9 out of the 35 satellites that will comprise its own system, called Compass.

I’m guessing that when these are all in full use, they’ll be able to be coordinated for unprecedented accuracy, even though the signals made available to civilians are less accurate than those for the military. It could also bring new space tension to international relations; I could only imagine what it was like as an EU representative explaining to your American allies that you wanted your own independent satellite system, just in case. 

This was brought to my attention by an article at GPS Daily with facts on the Galileo system. Here are just a few points from the article:

Galileo will consist of 30 satellites, six more than the US Global Positioning System (GPS). The system will offer several services from 2014, becoming fully operational in 2020 when a constellation of 27 satellites, supported by three spares, is deployed…

HOW IT WORKS: Like GPS, Galileo works by the geometrical process called triangulation. The satellites emit synchronised signals in the 1.1-Gigahertz (GHz) band. Ground receivers capture the signals and compute the time it takes for each signal to arrive from their brief journey across space. Minute differences in time, caused by the varying distances, enable a calculation of the receiver’s position on the Earth’s surface.

ATOMIC TIME-KEEPING: Galileo depends on atomic clocks to ensure that location data is precise. One billionth of a second too fast or too slow translates into an positioning error of about 30 centimetres (12 inches).

The satellites will each contain four timepieces accurate to one second in three million years.

In two hydrogen clocks, hydrogen atoms oscillate between two energy states to generate a signal in the form of an electromagnetic wave. Two compact rubidium clocks use the transition of the rubidium-87 atom between two hyperfine energy states.

ROLLOUT: Two test satellites were launched in 2005 and 2008. The first two operational satellites are scheduled to be hoisted on October 20 by Soyuz, making the Russian rocket’s maiden launch from Europe’s spacebase.

Two more will follow in 2012, forming the constellation’s operational nucleus. Fourteen satellites should be in place by 2015 and able to offer three services, and the rest by 2020. The network will be managed by two control centres in Europe and sensor and uplink stations around the world. The system is designed to be compatible with GPS and Russia’s GLONASS.

This is a pretty interesting time. I don’t know what new advances are going to result from these new navigation systems, but I’m sure it’ll be cool and unexpected.

Edit: It looks like the future is now: the new iPhone 4S is using GLONASS along with GPS for positioning information. 

 

 

Three Years in the Eyes of a Mars Rover

Here’s a video made up of photos of the Martian horizon, one photo taken each day over the course of a 3-year journey by the Mars Rover Opportunity. If you wanted to see what it would look like taking a field trip on Mars, here’s the closest you’ll get for a while.

Opportunity is the 3rd successful Mars Rover (all sent by NASA), and the only one still in communication with NASA. It’s been going strong for 7 and a half years. It’s solar-powered and, interestingly, incorporates metal from the World Trade Center. A nuclear-powered Mars Rover named Curiosity is set to launch at the end of the year. 

Lunar Mining for Titanium

Researchers have found that there may be plenty of titanium on the moon, up to ten times as large a proportion in a certain type of ore as in the same ore on Earth.

From Moon Daily:

The discovery was made thanks to a camera aboard the US Lunar Reconnaissance Orbiter, which swept the surface of the Moon, scrutinising it in seven different light wavelengths…

They established this signature thanks to rock samples brought back to Earth by Apollo 17 astronauts in 1972 and images of the area around the mission’s landing site by the Hubble space telescope.

“Looking up at the Moon, its surface appears painted with shades of grey, at least to the human eye,” explained Robinson.

“But with the right instruments, the Moon can appear colourful.

“The maria [lunar plains] appear reddish in some places and blue in others.

“Although subtle, these colour variations tell us important things about the chemistry and evolution of the lunar surface. They indicate the titanium and iron abundance, as well as the maturity of a lunar soil.”

Titanium is as strong as steel but nearly half as light, which makes it a highly desired — and also very expensive — metal.

On Earth, titanium is found, at the very most, in around one percent of similar types of ore. But the new map found abundances in the lunar maria that range from about one percent to 10 percent, the conference organisers said in a press release. In the lunar highlands, abundance was around one percent…

“Lunar titanium is mostly found in the mineral ilmenite, a compound containing iron, titanium and oxygen,” they said.

“Future miners living and working on the Moon could break down ilmenite to liberate these elements.

“In addition, Apollo data shows that titanium-rich minerals are more efficient at retaining particles from the solar wind, such as helium and hydrogen. These gases would also provide a vital resource for future human inhabitants of lunar colonies.”

They use British spelling! My favourite. This is cool, mostly because it shows that we still have lots to learn about the moon; there might be a lot more value there than we know now, making it worthwhile to go visit (again).

 

 

“Scientists Release Most Accurate Simulation of the Universe to Date”

A new computer simulation out of New Mexico State University, running on NASA’s Pleiades supercomputer, has become the new hotness in universe simulation. Called the Bolshoi, it’s based off of data from NASA’s Wilkinson Microwave Anisotropy Probe (WMAP), which measures variation in cosmic microwave radiation remaining from the Big Bang. The Bolshoi’s predecessor, the Millennium Run, used an older version of WMAP data that has since been shown to be inaccurate. 

From ScienceDaily:

The simulation traces the evolution of the large-scale structure of the universe, including the evolution and distribution of the dark matter halos in which galaxies coalesced and grew. Initial studies show good agreement between the simulation’s predictions and astronomers’ observations.

The standard explanation for how the universe evolved after the Big Bang is known as the Lambda Cold Dark Matter model, and it is the theoretical basis for the Bolshoi simulation. According to this model, gravity acted initially on slight density fluctuations present shortly after the Big Bang to pull together the first clumps of dark matter. These grew into larger and larger clumps through the hierarchical merging of smaller progenitors. Although the nature of dark matter remains a mystery, it accounts for about 82 percent of the matter in the universe. As a result, the evolution of structure in the universe has been driven by the gravitational interactions of dark matter. The ordinary matter that forms stars and planets has fallen into the “gravitational wells” created by clumps of dark matter, giving rise to galaxies in the centers of dark matter halos.

A principal purpose of the Bolshoi simulation is to compute and model the evolution of dark matter halos…

The Bolshoi simulation focused on a representative section of the universe, computing the evolution of a cubic volume measuring about one billion light-years on a side and following the interactions of 8.6 billion particles of dark matter. It took 6 million CPU-hours to run the full computation on the Pleiades supercomputer, recently ranked as the seventh fastest supercomputer in the world.

A note about that last sentence: keep in mind that supercomputers progress in leaps and bounds. The Pleiades is the seventh fastest supercomputer in the world, but it’s about 1/8 as fast as the fastest supercomputer (which is still in production, in Japan), and less than 1/2 as fast as the fastest supercomputer that’s actually completed (in China). 

About dark matter: it’s matter that does not interact with electromagnetic radiation (like light, radio waves or infrared), which means as yet we haven’t been able to actually detect it. The reason scientists think it exists is because it’s the most likely explanation for cosmological gravitational effects they’ve observed; the matter we can detect doesn’t explain all the gravity we detect. 

Finally… I don’t know what’s up with the astronomy world, but one individual wrote the code for this simulation, which I find odd. Did he have some kind of monopoly on the data? It takes teams of programmers to make a video game world, but only one to simulate a universe, apparently. 

Gravitational Redshift On a Cosmological Scale Verifies General Theory of Relativity

For the first time, gravitational redshift has been measured outside of the solar system, on a cosmological scale. This effect of gravity on light is predicted by the general theory of relativity, and these measurements from the Dark Cosmology Centre at the Niels Bohr Institute, published in Nature, match the predictions. If you’re familiar with redshift, feel free to skip ahead to the second quote block.

Redshift is the result of the Doppler effect on light. Wikipedia has a pretty solid explanation of the Doppler effect, which is when wave frequencies increase (and thus wavelengths decrease) as the source of the wave moves towards the observer, and vice versa for a source moving away:

When the source of the waves is moving toward the observer, each successive wave crest is emitted from a position closer to the observer than the previous wave. Therefore each wave takes slightly less time to reach the observer than the previous wave. Therefore the time between the arrival of successive wave crests at the observer is reduced, causing an increase in the frequency. While they are traveling, the distance between successive wave fronts is reduced; so the waves “bunch together”. Conversely, if the source of waves is moving away from the observer, each wave is emitted from a position farther from the observer than the previous wave, so the arrival time between successive waves is increased, reducing the frequency. The distance between successive wave fronts is increased, so the waves “spread out”.

Light can be described as a wave, with different wavelengths for different colours. Blue has the smallest wavelength and highest frequency, red has the largest wavelength and smallest frequency. That means that, as described by the Doppler effect, when a source of light (or more generally, electromagnetic radiation) is moving away from an observer it will shift towards the red end of the spectrum. Since the universe is expanding, light from distant galaxies is redshifted, and the degree of redshift can tell you their distance: this is cosmological redshift, or Hubble’s Law.

Meanwhile there is gravitational redshift: light moving from a place of stronger to weaker gravity will be redshifted. To the best of my understanding, this is because time moves slower near stronger sources of gravity, which intuitively seems to make sense as an explanation for wavelength expanding as it moves away from the gravity source. Light also has to travel further when it goes near a large source of gravity, since gravity curves space as well as time.

Gravitational redshift is what’s explained and predicted by general relativity, and what these researchers observed. From Science Daily:

Radek Wojtak, together with colleagues Steen Hansen and Jens Hjorth, has analysed measurements of light from galaxies in approximately 8,000 galaxy clusters. Galaxy clusters are accumulations of thousands of galaxies, held together by their own gravity. This gravity affects the light being sent out into space from the galaxies.

The researchers have studied the galaxies lying in the middle of the galaxy clusters and those lying on the periphery and measured the wavelengths of the light.

“We could measure small differences in the redshift of the galaxies and see that the light from galaxies in the middle of a cluster had to ‘crawl’ out through the gravitational field, while it was easier for the light from the outlying galaxies to emerge,” explains Radek Wojtak.

They also calculated the mass of the galaxy cluster and from that its gravitational potential, and armed with this could reliably predict the redshift from different regions of the cluster. Einstein emerges victorious, yet again – so you can see why everyone is very skeptical about the now famous CERN neutrino experiment. 

In trying to wrap my head around this I discovered this site explaining relativity, time dilation and quantum theory in a pretty digestible form; you should check it out if you have any interest.

Least Reflective Object in the Known Universe

From PhysOrg: “Recent analysis on a planet dubbed TrES-2b has found that it probably absorbs 99.9 percent of the light that strikes it, more than any other known cosmic entity.” Apparently coal reflects about 5% of the light that hits it, whereas this planet reflects 0.1%; this thing reflects 50 times less light than friggin’ coal. Interestingly enough though,

TrES-2b orbits so close to its star that it is extremely hot and glows thermally — despite its “darkness,” if the planet was in Earth’s solar system it would appear 3,000 times brighter than Venus, the solar system’s brightest planet.

The astronomers responsible currently have no clue what it is about this planet’s atmosphere (and other planets’ like it) that makes it so light-absorbant. It’s probably just an evil planet – that is my educated guess.