Showing posts with label space flight. Show all posts
Showing posts with label space flight. Show all posts

Tuesday, 9 December 2014

NASA Sucsessfuly Tests The Orion Spacecraft- But It's Not Going To Mars

A Delta IV Heavy rocket blasts off from Cape Canaveral carrying NASA's Orion Spacecraft on its first, unmanned test flight.
Image Credit: NASA/Bill Ingalls
Warning: There may be opinions ahead...

On Friday the 5th of  December the world watched as the most powerful rocket in the world blasted off from Cape Canaveral, Florida. Atop the bright orange Delta IV Heavy was NASA's new human spacecraft, Orion, making its first flight.

Although there weren't actually any people on it- that won't happen until 2021 at the earliest. This was an uncrewed test flight only, looping around the Earth then boosting out to nearly 6000 km high.

Four hours after launch Orion hit the top of Earth's atmosphere traveling at 32000 kilometers per hour, 85% of the speed it would have had if it it had come back from the Moon. Protected by its heat shield, Orion parachuted down into the Pacific Ocean in a scene reminiscent of the Apollo program.   


The mission was a complete success, testing several of Orion's key systems such as the huge heat shield,  avionics and separation systems. It also looked spectacular, with the whole flight relayed live to Earth via camera on the spacecraft. Those of you who follow me on Twitter will know I was thoroughly enjoying it.

There was one bit I didn't like though. NASA have been promoting this launch as the first step on a "Journey to Mars", part of the agency's aim to land humans onto the Red Planet in the 2030s. But I don't think Orion will ever go to Mars. In fact, at the moment it doesn't look like it's going anywhere.  

Orion drifts down on parachutes: The future of space flight, or a step into the past? Image Credit: NASA
Orion first began development as part of the Constellation program. Announced by George W. Bush after the loss of the Columbia space shuttle in 2003, the plan was to replace the space shuttle with two rockets that would land astronauts on the Moon.  The huge Ares V would do the heavy lifting, carrying the lunar lander and propulsion systems into orbit. A smaller Ares I rocket would then launch carrying Orion, The two parts would then dock in orbit and head off to the Moon.

Constellation looked very good on paper, an Apollo style return to the Moon planned for the early 2020s. Unfortunately it never received enough funding to meet its goals, and it was eventually cancelled in 2010 after just one test flight of a half-finished Ares I.

Instead of a return to the Moon, NASA was ordered to set its sights on Mars. It would turn to commercial companies, such as SpaceX and Orbital Sciences,  to replace the role of the space shuttle in supplying cargo and crew to the International Space Station. This would free NASA up to focus solely on developing the technologies needed to take humans to Mars.

Unfortunately this didn't go down well with a number of US politicians, for whom the cancellation of Constellation would mean severe job losses in the Sates that they represented. After much debate Orion was back, this time to launch on a new rocket, the Space Launch System, cobbled together out of parts left over from the Space Shuttle Program.

But the destination remained Mars, and Orion simply isn't built to do that. It's far too small, no bigger than a large car on the inside. For a journey to Mars, which could take up to a year, a much larger spacecraft will be needed.

NASA have talked about a Deep Space Habitat, a larger spacecraft that would be assembled in orbit to make the journey to Mars- although this is yet to even make it on  to the drawing board. Orion would be used to ferry astronauts up to it, and to bring them home at the end of the voyage.

But in this case it's far too large and expensive, tasked with a job that would be much better suited to the cheaper, purpose built commercial crew ships such as the SpaceX Dragon and Boeing CST100.

Orion has found itself in the worst of both worlds, too small to make the whole journey to Mars and unnecessarily big as a crew transport. And no wonder, as it's perfect for what it was designed to do: Go to the Moon. 

Worse still is its projected time table. Orion is so underfunded that the next test flight isn't until 2018, the first time that the Space Launch System will be ready. And it still wont be carrying any people- the first piloted flight is planned for no earlier than 2021.

NASA doesn't have enough money to build the life support systems yet, so the test flight last week couldn't have carried people even if they'd wanted it to. With up to two new US Presidents between it and its first crewed flight, Orion's chances of ever flying with humans on board are shaky at best.

This isn't to say that we wont go to Mars, or that we can't. I think we should, and will have the technological capability to do so within my lifetime.

But I doubt that Orion will be a part of it.

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Friday, 21 November 2014

The First Landing on a Comet

Released from the Rosetta orbiter, the fridge-sized Philae lander drifts down to become the first spacecraft to land on a comet. Image Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA 

And the second, and the third...

At 8.35 GMT last Wednesday morning, five hundred million kilometres from the Earth, a tiny lander called Philae detached from the side of the Rosetta spacecraft. 28 minutes later the signal confirming the separation arrived at ESA’s Space Operation Centre (ESOC) in Darmstadt, Germany. The first ever attempt to land a spacecraft on a comet had begun.

Unlike most spacecraft landings, Philae would not land using rocket engines or parachutes. Rosetta had pushed it away in (it was hoped) just the right direction, at just the right speed to fall gently down onto its target.

The target was Comet 67P/Churyumov–Gerasimenko, an irregular lump of dust and ice less than five kilometres across at its widest point. Separating from Rosetta 22.5 kilometres from the surface, the low gravity of Comet 67P pulled Philae into a leisurely, seven-hour descent. 


As it fell towards Comet 67P, Philae had time to spin round and take a picture of Rosetta...
Image Credit: ESA/Rosetta/Philae/CIVA 
...whilst Rosetta watched Philae disappear into the darkness.
Image Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA 
Imaged during its descent by Rosetta's OSIRIS camera in the sequence above, Philae is a 100kg box filled with ten scientific instruments, including cameras, spectrometers, a drill and two labs for analysing surface samples. And, crucially, two harpoons.

These harpoons were to fire as Philae touched down onto the surface of the comet, anchoring itself securely to 67P. The plan had been for a small thruster on the top of the lander to ignite at the same time, holding Philae down onto the surface. But that morning, the team at mission control had discovered that the thruster had stopped working. Only the harpoons could stop Philae from rebounding off the surface of Churyumov–Gerasimenko and back into space.

A picture of the first landing site from 40 meters above the surface. Image Credit: ESA/Rosetta/Philae/ROLIS/DLR
At this point I had to go to a seminar, and spent the next tow hours failing to pay attention to the speaker whilst surreptitiously checking Twitter for news. If Tom Shanks is reading this, then sorry! But I got out in time to celebrate with the rest of the world as, at 16.03 GMT, the signal arrived at ESOC: Philae had landed, the first spacecraft to touch down on a comet. There was much rejoicing.

But the celebrations were short lived. As the mission controllers studied the data relayed back by the orbiting Rosetta, they realised that the crucial harpoons had failed to deploy. Worse still, the signal from the lander was fading in and out, and the power being generated by its solar panels was varying wildly. By the evening, a tentative explanation had been found: Philae had bounced straight off the comet and gone into a spin.

In a series of incredibly detailed images, the orbiting Rosetta spacecraft tracks Philae's wild flight across the surface of Comet 67P. Image Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
By the next morning the full tale of the landing had been put together. Philae had landed at 15:34 GMT, thudding down in exactly the right place. But without the thruster or harpoons to hold it down, the tiny spacecraft had bounced back up again, heading off the comet at a leisurely 38cm/s. Thanks to the extremely low gravity of 67P, Philae flew over the surface for nearly two hours, flying almost a kilometre high. During that time the comet turned underneath it, the targeted landing site slipping away.

When Philae hit the ground again it made a second bounce, this time for only seven minutes. When it finally came to a halt, the lander was over a kilometre from the spot where it had first touched down. But exactly where Philae had ended up was a mystery.  
Panoramic view of Philae's landing site, with the spacecraft superimposed. It wasn't meant to be this dark... Image Credit: ESA/Rosetta/Philae/CIVA
The first images from the landing site showed a very different place to the flat, sunny target. Philae appeared to be at a tilt, with one leg sicking into space. Worse still, the bulk of the lander's solar panels were in the shadow of a large cliff. If Philae wasn't able to move, then it would only get around 1.5 hours of sunlight each day- nowhere near enough to recharge it's batteries.

But Philae was designed with this scenario in mind. Although the solar panels would have allowed it to carry on working for several months, it had been built with enough battery power to complete all of its initial science observations. While the mission controllers pondered a way to move away from the cliff, Philae's ten instruments swung into action.

The ten scientific instruments Philae used to study the surface of Churyumov–Gerasimenko.  Image Credit: ESA/ATG medialab

The full results from the measurements made by Philae have yet to be released, but a few preliminary discoveries have been announced. Particularly intriguing was the data collected by the Multi-Purpose Sensors for Surface and Subsurface Science, or MUPUS. This instrument deployed a small hammer, deigned to dig into the surface of Churyumov–Gerasimenko and measure the temperature at different depths.

Surprisingly, even at it's most powerful setting, the hammer couldn't make a dent in the surface of 67P. The ground beneath Philae, long expected to be a porous, loosely bound mix of dust and ice, was actually rock-solid. Although this conflicted with accepted knowledge (always a good kind measurement to make), a solid ice crust would explain why Philae bounced so high after its first touchdown. The low density of the comet suggests that, beneath this icy crust, the material of Comet 67P is much less tightly packed.

Another instrument, the Cometary Sampling and Composition Experiment or COSAC, detected signs of organic chemical compounds on the surface of Comet 67P. These carbon-rich compounds, which give the comet its deep black colour, are one of the key reasons we are interested in these icy worlds. It is thought that many of the ingredients needed for life on Earth, such as water and some amino acids, were originally delivered here by impacting comets.

With battery power running low, Philae ran through all of it's remaining scientific instruments, drilling into the surface to collect material for its onboard laboratories, receiving and transmitting radar data from Rosetta to map the insides of the comet, and taking yet more images.

By the time its batteries finally gave out, Philae had achieved all of its planned science operations. Despite the bumpy landing, the mission had been a complete success.  
At 36 minutes past midnight on Saturday morning, mission control at ESOC lost contact with Philae. But there's still hope for the little lander. Just before its batteries gave out, Philae had managed to turn itself, bringing it's largest solar panel out of the shade into the faint sunlight.

As Churyumov–Gerasimenko flies ever closer to the Sun, there's a small chance that Philae's batteries will recharge. We may yet be hearing more from the tiny lander. Even if this is the end of Philae's epic adventure, Rosetta is still in orbit of the comet, continuing to revolutionize our knowledge of these tiny, mysterious worlds.



Note: you my have noticed that I haven't commented on #shirtstorm- it's outside the scope of what I wanted (and feel qualified) to talk about, but I recommend and broadly agree with articles like these on the issue.

Another Note: I've stared writing for Astrobites! These are daily summaries  of recent scientific papers, written by astronomy postgraduate students. The style is a bit more technical than this blog, but it's worth a look if you want to to keep up to date with astronomy research. I'll be writing there once a month, and my first post is here

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Friday, 3 October 2014

Two new spacecraft join the Mars flotilla

The best view of Mars form Earth, taken with the Hubble Space Telescope. A growing number of spacecraft have been sent to study the Red Planet from close-up, including MAVEN and MOM ,which arrived this week. Image Credit: NASA/ESA and The Hubble Heritage Team STScI/AURA
On the 14th of July 1965, Mariner 4 became the first spacecraft to successfully flyby Mars, providing the first close-up images of the fourth planet from the Sun. Since then a host of spacecraft from several nations and space agencys  have flown past, orbited or even landed on Mars (along with many, many failures).

Growing interest in an eventual human mission to Mars has seen a surge in such missions over the past few years, most of them successful. Last week two new spacecraft joined the international flotilla of orbiters and rovers, including India's first interplanetary mission. So here, in order of arrival, are all of the active missions and what they're teaching us about Mars

Mars Odyssey


Artist's impression of Mars Odyssey, the oldest active spacecraft at Mars. Image Credit: NASA/JPL-Caltech
The first spacecraft to arrive at Mars in the twenty-first century was Mars Odyssey. Named after the book (and film) 2001: A Space Odyssey, this NASA orbiter reached Mars in, appropriately enough, 2001. Designed to study the chemistry of the Martian surface, its key discovery was the detection in 2002 of vast amounts of water ice lying just below the ground (click that link to be amazed by 12 year old internet...)

Whilst it has continued to make scientific observations, Odyssey has in more recent years fulfilled a vital role as a communications relay, transmitting information from the various landers and rovers on the surface to Earth and relaying commands back. I quite like this fact- we're beginning to build a space-based communications infrastructure at another planet!

Mars Express


Mars Express, the first European Mars orbiter. The long booms form the MARSIS sub-surface sounding radar, used to map the geology of the top few kilometres of the Martian crust. Image Credit: NASA  
Arriving in December 2003, Mars Express was the first European Space Agency mission to another planet. Based on the design of my current favourite mission, Rosetta, and sister craft to the near-identical Venus Express, Mars Express carries instruments to measure the chemical composition of the Martian atmosphere, surface and even subsurface. It also has a nifty spectroscopic camera allowing it to take high resolution, 3D images of Mars and, thanks to its unusually elliptical orbit, Mars' largest moon, Phobos.

In 2004 the spectrometers on Mars Express made an intriguing observation: signs of what could have been methane in the atmosphere. Methane should only last a few hundred years in an atmosphere before it reacts with the other chemicals around it, so for it to be present in detectable amounts means that something must be producing it. We know of several geological processes that could achieve this, but most methane production on Earth is biological. Could Mars Express have seen signs of life?


Mars Express also carried a lander, the British-built Beagle 2. Sadly however the landing was a failure, and contact was lost with Beagle 2 shortly after it entered the atmosphere on Christmas Day 2003. The reason for its loss is still unknown.

Opportunity

Panorama of Endurance Crater taken by the Opportunity Rover in 2004. One of the rover's solar panels can be seen in the bottom right (click to make bigger). Image Credit: NASA/JPL/Cornell 
The Mars Exploration Rover Opportunity is currently over ten years into a 90 day mission. Yep, you read that right.

January 2004 saw the arrival of two identical, six wheeled rovers on Mars. Following on from the highly successful Pathfinder mission, Spirit and Opportunity parachuted through the thin atmosphere and landed via an innovative airbag system. Original planned to last just three months and drive around a kilometre across the surface, both rovers far exceeded their targets. Spirit became stuck in sand in 2009 and didn't survive the winter (the xkcd on the topic is essential reading), but Opportunity is still going strong, having covered a distance of over 40 kilometres.

The full list of discoveries made by this stupendously successful mission would be several posts on its own, so in the interests of word count I'll talk about just one. Early in its mission Opportunity was sent to investigate the wreckage of the heat shield that had protected it during its entry into the Martian atmosphere. Near the heat shield was a strange, dark-coloured rock, out of place with the geology around it. Opportunity had discovered the first meteorite on anther planet.

The meteorite, dubbed Heat Shield Rock, was a lump of iron and nickel leas than half a metre across. Its existence was a mystery: Mars' thin atmosphere couldn't have slowed it down enough to stop it vaporising when it hit the ground. So perhaps at some point in the past Mars had a much thicker atmosphere, an atmosphere that it has since lost?

Mars Reconnaissance Orbiter
   
Over 250km above the Martian surface, the Mars Reconnaissance Orbiter easily spots the 1.6 metre long Opportunity. Image Credit: NASA
Since the before the start of the Space Age, landing people on Mars been high up the wish-list of things to do in space. A key requirement for that, as well as for larger robotic landers, is high-resolution mapping of the Martian surface. In 2006 the Mars Reconnaissance Orbiter (MRO) arrived to do just that.

Significantly larger than its predecessors, MRO's main instrument is 0.5 metre downwards-pointing telescope. The High Resolution Imaging Science Experiment, or HiRISE, is the largest telescope ever sent to another planet and can image the Martian surface at resolutions down almost 30sm/pixel.

HiRISE, together with several other instruments, has allowed us to explore huge swaths of the Martian surface in great detail. Among its many achievements has been providing evidence for brief flows of running water, as well as spotting parachuting landers heading down to the surface.

Curiosity 

The largest lander ever sent to another planet, the Mars Science Laboratory Curiosity landed via a highly complex skycrane system in 2012. Here, the nuclear-powered rover takes a selfie, next to a rock that it has drilled into  (middle left) to obtain a sample for it's onboard laboratory. Image Credit: NASA 
A common complaint about a perceived lack of technological progress is "where's my jetpack?" Whilst a person using a jetpack would actually be a really silly idea, that question does now have an answer. It's on a nuclear powered, laser equipped mobile science lab on Mars.

At 900kg, the Mars Science Laboratory, better known as Curiosity, was far too large for it to land using air bags like Spirit and Opportunity. Instead they used a skycrane, a rocket powered aircraft that slowed the rover down from 200 mph to zero before lowering it down on cables. This video has the full details of an operation that surely ranks among  the most difficult and technologically impressive achievements of humankind.

Curiosity's primary mission on Mars was to determine if the conditions on Mars could at some point in its past have been suitable for life. By the end of its first (Earth) year on the Red Planet Curiosity had met its scientific objectives, showing that the rocks around it had once formed part of a lake bed, with water and all of the chemical ingredients needed for life.

The Mars of several billion years ago was evidently very different to the barren planet we see today. However, Curiosity found no trace of the methane in the atmosphere that had been detected years earlier by Mars Express.      

Completing its primary mission in August, it has not all been smooth driving for Curiosity. NASA's recent Senior Review of its planetary exploration missions found that the rover was not being used to its full scientific potential, and that a better balance between  driving and taking data needs to be found. Whatever its troubles, Curiosity will certainly make more exciting discoveries over the next few years, as it begins to climb a 6km high mountain.

MAVEN


Arriving at Mars last week, MAVEN has been sent to find out what happened to Mars' atmosphere. Image Credit: NASA
Finally we come to last week's new arrivals. First to arrive was the  Mars Atmosphere and Volatile Evolution (MAVEN), a NASA mission. As a wide range of general scientific capabilities is already present at Mars, MAVEN's mission is somewhat more specialized than previous spacecraft. Its primary objective is to find out what happened to Mars atmosphere.

To support, for example, the prehistoric running water and intact meteorites found by previous missions, Mars must have had a thick atmosphere similar to the Earth's. Yet all that remains now is thin shell of carbon dioxide. Where did the atmosphere go?

In an attempt to answer these questions MAVEN will be sent on a daring mission into the upper reaches of Mars' atmosphere. The bent shape of its solar panels, seen in the artists impression above, will help with this, allowing it to remain stable as it becomes in effect our first interplanetary aircraft.

There, its advanced suite of spectrometers along with a magnetometer, will measure in detail the composition of the atmosphere and, crucially, its interaction with the solar wind. As Mars has no global magnetic field to protect it, the force of the solar wind has become the prime suspect in the case of the missing atmosphere.

MOM


MOM is the only Mars orbiter capable of taking images of the whole of Mars in one go. Compare with the HST image at the start! Image Credit: ISRO
Arriving into Martian orbit on Friday 24th September, The Indian Space Research Organisation's Mars Orbiter Mission (MOM) has one notable difference with all the spacecraft to have come before it: The price tag.

Although the quote value of $74 million probably doesn't take all of its costs into account, MOM still cost many times less than MAVEN. Despite this, it has a small yet advanced suite of instruments, These include the first camera capable of taking full-disc images of Mars, as well as a dedicated methane detector which will try and finally nail down the story of this elusive gas in Mars' atmosphere. Although MOM only has a six-month mission planned, plans made this week to share science data with NASA suggest that it many well keep going for some time.

India's success in pacing a spacecraft into Martin orbit may be the start of a new stage in space exploration, showing that exploring the solar system isn't limited to a few select countries and can be done without spending billions. India, and the countries that follow it, will reap the technological benefits from these missions just as the "traditional" spacefarers have done before.

And that's it! With seven working spacecraft now on or orbiting Mars, as well as more missions launching soon, we are learning more about the fourth planet from the Sun than ever before. Within our lifetimes we may finally find out whether Mars once supported life, or even if it has any now. And the more we study the Red Planet and how to get there, the closer humankind gets to finally voyaging from Earth to join our robotic explorers.

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Thursday, 7 August 2014

Rosetta Enters orbit around Comet 67P/Churyumov-Gerasimenko

A strange new world: Comet 67P/Churyumov-Gerasimenko as seen by the Rosetta spacecraft, which became the first spacecraft to orbit a comet on 6th August. Image Credit: ESA.
After a 10 year voyage through the the solar system, the European Space Agency's robotic explorer Rosetta has become the first spacecraft to enter orbit around a comet. Since waking up in January from a two-and-a-half year hibernation, Rosetta has been steadily gaining on on comet Churyumov-Gerasimenko, also known as 67P. On Wednesday morning it finally arrived, burning its main engine for 6 minutes and 26 seconds to reach a relative speed with Comet 67P of just one meter per second.

The surface of Comet 67P/Churyumov-Gerasimenko taken from a distance of 100km with Rosetta's OSIRIS science camera. Image Credit: ESA
A few hours later Rosetta returned the first close up images from the comet, our first good look at a completely new world since the Dawn spacecraft orbited Vesta in 2011. The image above, with a scale of around 2.5 meters per pixel, reveals a varied topography strewn with boulders.

Previous missions and telescope observations have revealed that comets like Churyumov-Gerasimenko are "dirty snowballs", irregular mixes of ice and dust. Working out how that chemical composition and the varying geological activity of the comet has produced such a landscape is one of the questions that Rosetta will try and answer.       


Video: ESA

Unlike most space missions, Rosetta's initial orbit around Comet 67P doesn't follow the standard circle or ellipse. Until the mass of the comet can be measured by observing its gravitational pull on Rosetta, the ground controllers at ESA don't know exactly what manoeuvres will be needed to reach a stable orbit.

Instead, as the video shows, Rosetta will fly around the comet in a strange triangular orbit, flying in hyperbolic arcs with thruster burns at each corner. From there the orbit will be slowly lowered, until the spacecraft is in an ellipse just 10km above the surface of Comet 67P.


An overexposed image of Comet 67P taken on 2nd August, revealing jets of material streaming from the surface. Image Credit: ESA 
The seeming tranquillity of the first close-up images is deceptive. I've already written about how Rosetta has seen the activity of Churyumov-Gerasimenko increase as it gets closer to the Sun, and this overexposed image shows two distinct plumes of material streaming out of the surface of the comet.

This activity will continue to increase during Rosetta's time at the comet. By the time Churyumov-Gerasimenko reaches perihelion, the closest point in its orbit to the Sun in a year's time,  the plumes will have grown into a characteristic tail, or coma.


Video: DLR

Arguably the most exciting phase of the mission is still to come. In November Rosetta will deploy the Philae lander, a fridge-sized box that will attempt to become the first man-made object to land on a comet. Rosetta has already made an initial search of Churyumov-Gerasimenko for possible landing sites, shown as green cricles in the video. Over the next few months this will be narrowed down  to one area for Philae to target, guiding itself in with a pair of harpoons.

With a successful orbital insertion, the Rosetta mission is shaping up to be one of the most exciting space missions ever carried out. The pictures and data that it is returning are already fantastic, and I'm sure I'll write about it again as the mission continues.

P.S. Last time a wrote about Rosetta, I was contacted by a group working on a website where you can see a visualisation of the whole mission, charting the entire ten-year voyage up until now. I recommend a look.

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Wednesday, 2 July 2014

Nasa's Orbiting Carbon Observartory 2 Launches into Space in a Dramatic Liftoff




This morning NASA's Orbiting Carbon Observatory 2 (OCO2) launched into Earth orbit on a Delta 2 rocket. I've posted the video of the launch here, as it was one of the most dramatic rocket launches I've ever seen (and I watch most of them).

When the engines ignited there was a huge flash, which for a moment made me think the rocket had exploded.  Fortunately, a second later the Delta 2 soared into the sky, completing a flawless launch and orbital insertion within the hour.

Losing this rocket would have been incredibly sad, as the first Orbiting Carbon Observatory was lost during launch in 2009. The protective faring (the pointy bit on the front of the rocket) on its Taurus XL launcher failed to open, resulting in the rocket being too heavy to reach orbit.

NASA quickly ordered a replacement, OCO2 to be built, a process complicated by the fact that many components were no longer being produced. When a second Taurus XL rocket failed due to problems with the fairing, the OCO2 was switched to the ultra-reliable Delta 2. Today, five years later, that Delta 2 delivered OCO2 to it's place in the "A-train", a large formation of Earth-observing satellites.

Artist's impression of NASA's Orbiting Carbon Observatory 2 (OCO2), which launched this morning on a mission to precisely measure the amount of carbon dioxide in Earth's atmosphere. Image Credit: NASA.
The OCO2's mission is to precisely measure the amount of carbon dioxide in the atmosphere below it, It has a high enough resolution to distinguish both regional  variation, identifying areas which produce or remove CO2, and seasonal variation, investigating how the CO2 levels change with time.

OCO2's only instrument is a spectrometer, designed to split the light coming through the atmosphere to distinguish the particular colours emitted from CO2. It is so precise that it will be able to measure changes in CO2 levels of less than 2 parts in a million.

Hopefully over the next few years the OCO2 will provide a new and important insight into this vital component of the atmosphere. But for now, enjoy the video of its incredible launch!

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Friday, 30 May 2014

SpaceX reveal the Dragon V2 Manned Spacecraft.

SpaceX's new Dragon V2 Spacecraft, a seven person capsule that may soon be taking astronauts to the International Space Station. It was revealed to the public on the 29th of June. Photo Credit: SpaceX

On Thursday evening (well, Friday morning here)  SpaceX founder Elon Musk took to the stage to reveal the Dragon Version 2, SpaceX's entry to the race to build the next manned spacecraft for Nasa.

In my not so humble opinion, it looks amazing.

The design is very different from the current, cargo carrying version of the Dragon. Instead of the blunt-nosed capsule based on traditional spacecraft designs, the Dragon V2 is a sleek cone, flanked by pairs of SuperDraco rocket engines.

It's these (3D printed!) engines that are the Dragon V2's key innovation. They are powerful enough to act as a launch escape system, blasting the capsule away from an exploding rocket in the event of an accident. But their primary purpose is to allow the Dragon V2 to do what no space craft has done before: Land propulsively, coming down onto a landing pad using rockets, without the use of a parachute.

 This will hopefully allow it, along with its Falcon 9 launch rocket, to be rapidly reused, massively reducing the prohibitive cost of spaceflight. SpaceX have released an animation showing just how this would work:



The video shows my favourite bit of the new spacecraft: The trunk, the disposable rear section holding cargo and the Dragon's solar panels, has rocket fins! Combined with the propulsive landing, this makes the spacecraft remind me of old-school, 1930s Flash Gorden-esque sci-fi.


The interior of the Dragon V2, with seats for seven astronauts, is incredibly futuristic.Photo credit: SpaceX
The interior, however, is anything but old fashioned. With it's spacious, seven seat design and touch screen controls, the Dragon's insides are radically different from anything thats gone before. My first reaction to it was "that can't be real"- it's just nothing like the cluttered, button heavy Soyuz or Space Shuttle cockpits. But this is the first time we've seen a new manned spacecraft for decades, so we really should expect not to recognize it. It will be interesting to see what the interiors of spacecraft built by SpaceX's competetors look like. Indeed, the glimpses Boeing have released into their CST 100 craft look similarly futuristic.

The Dragon V2 certainly looks beautiful, but will it work? Only time will tell. Pending Nasa funding, SpaceX plan to start flying it into orbit next year, with its first manned flight penciled in for 2016. If all goes well, we could soon finally have a true twenty-first century spacecraft.








Monday, 19 May 2014

Rosetta's Destination Comet Grows a Tail


Comet 67P/Churyumov–Gerasimenko (centre), target for ESA's Rosetta space probe, begins to develop a tail.
Image credit: ESA

Just a short post today, as I'm writing a lot of other stuff at the moment (more on that to follow...).

Back in January I wrote about the European Space Agency's exciting Rosetta mission as it reactivated from a three year hibernation. Last week the mission reached another major milestone, although not one it had any control over.

Rosetta's target, the comet 67P/Churyumov–Gerasimenko, has begun to wake up.

The comet, seen as a fast moving white dot in this series of images taken with Rosetta's main camera, has suddenly exploded into life, beginning to form the huge tail that comets are famous for. As Rosetta closes into orbit with 67P/Churyumov–Gerasimenko in August, we will be able to see this fascinating process unfold up-close for the first time.

Comets actually spend most of their time without tails, orbiting for millions if not billions of years in the far reaches of the Solar System. Occasionally a chance encounter with another object will give them just enough of a gravitational nudge to send them tumbling into towards the Sun.

Once there, the increasing heat from the Sun begins to melt the ice that makes up most of the comet. The ice is embedded and mixed in with rock and dust, so as it sublimates (turns directly from solid to gas) it beings to blast that dust out in volcano-like eruptions. The escaping gas and dust flows out into a huge cloud, or coma, out of which forms the tail. And it really is big: Whilst the nucleus of a comet may only be few kilometers across, the tail can grow to lengths of hundreds of millions of kilometers. That's significantly larger than the Sun, although the coma is much less dense.

Comets actually have two tails, seen clearly in the image of comet Hale-Bopp below (One of my earliest memories is of being taken outside at night to watch this comet as it flew past Earth in 1997). The blue tail is formed of charged particles, or ions, individual charged particles released from the comet. These interact with the magnetic field carried in the solar wind, so stream out from the comet in a straight line directly away from the Sun.

The white tail is formed out of the dust liberated by the escaping water, pushed away from the comet by sunlight. As they fall back from the comet each dust particle moves into a separate orbit, slightly slower than the orbit of the comet thanks to the increased distance from the Sun. This causes the tail stretch out into a curve, as each successive particle out from the comet gets slightly further behind on its orbit.

Thanks to this behavior comet tails are a key tool in our attempts to understand the solar wind, which has a big affect on the satellites and other space technology that modern civilization depends on. One of Rosetta's targets as it closes in on 67P/Churyumov–Gerasimenko is to investigate this relationship between the comet and the solar wind from the inside.
Comet Hale-Bopp, which flew past Earth in 1997. The separate ion (blue) and dust (white) tails can be clearly seen.
Image credit: Nasa. 

Rosetta is closing in on its target, aiming to reach orbit in August. As I hope I've shown you, the show has only just begun...

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Wednesday, 30 April 2014

Spaceflight via Russian Trampolines


You can't get off Earth using a trampoline, but you might just be able to escape Mars biggest moon, Phobos. Image: NASA
Since the Space Shuttle was retired in 2011, NASA has had to rely on Russian Soyuz rockets to get its astronauts into space. This hasn't come cheap, costing $70million a seat. But they've had to grin and bear it, as the next American spacecraft capable of carrying humans (probably the SpaceX Dragon) wont be ready until at least 2017.

As you may have noticed in the news, US-Russian relationships are rather strained at the moment, and the Ukraine sanctions are beginning to affect the Russian space industry. Yesterday Dmitry Rogozin, the Russian deputy prime minister, tweeted that:

“After analysing the sanctions against our space industry, I suggest to the USA to bring their astronauts to the International Space Station using a trampoline,”

Now this could have lead to a very interesting long blog post about the politics of space exploration, but there's a far more important question the ask: Could you actually get into space using a trampoline?

The key factor in getting off a planet is the escape velocity, how fast you need to go to escape a given object's gravity. For Earth this value is about 11.2 kilometres per second, which is fairly fast.

How fast can you go using a trampoline?

The Guinness Book of World Records lists the highest height achieved by a team on a trampoline as 6.73 meters, using two people to provide the bounce for a third. With a bit of maths, that means that the speed they were going as they left the trampoline was about 11.5 meters per second.

Not fast enough for Earth, but the Solar System is full of smaller objects. Which is the largest with an escape velocity of less than 11.5 meters per second?

It turns out to be Phobos, one of the moons of Mars, which comes in with an escape velocity of 11.4 metres per second. Its a small world, a lumpy rock with an average diameter of eleven kilometres and a mass nearly two billion times smaller than that of the Earth.

This might be a practical question, as Phobos has been mentioned as a possible destination for Mars-bound astronauts. It takes much less fuel to get there than to land on Mars, and could be used as a base to remotely control Mars rovers without the annoying time delay caused by the signals having to go from Mars to Earth and back.  

So if in 20 years time you're an adventurer stranded on a desolate Martian moon, make sure you've got a trampoline.

Note: Discussions over lunch resulted in the decision that the speed you could jump on the trampoline wouldn't be affected by the lower gravity, as the key factor is the energy you're  producing in your legs. You'd jump higher, but accelerate less slowly down towards the trampoline, affects which would cancel out. If you can do some maths showing this is wrong, please let me know. 

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