The Darkest Place

The European Space Agency has for about a decade researched the concept of a "hyper telescope," under the name Exo Earth Imager. EEI would be a fleet of 150 orbital 3-meter mirrors, spread across about 8,000 square kilometers of space, and synchronized to reflect and magnify the image of an earth-sized planet in orbit around a distant star, with high enough resolution to discern oceans, continents, forests, deserts and even major river basins. Maintaining the mirrors in their relative orbits with the level of precision needed would be challenging at least. Not insurmountably so, but certainly not trivial.

A possible solution for this is to instead mount the mirrors on a fixed surface. There have already been proposals for building large telescopes on the far side of the moon, shielded from terrestrial radio interference. NASA has even demonstrated that large astronomy-grade mirrors can be constructed in-situ from lunar regolith. A telescope of this scale would have many applications and purposes besides viewing exoplanets, but this would be its primary purpose.

I would like to propose that instead of the lunar far-side, a better location for an optical (and maybe radio as well) telescope would be inside the basin of Peary crater. I've discussed the unique properties of Peary in this blog previously, in the context of human colonization. But briefly, Peary crater, by virtue of being situated on the north pole, has the triple virtue of a basin which is constantly in darkness and protected from solar radiation, a rim that is in constant sunlight for solar power, and a substantial amount of water ice on the floor of the basin. Shackleton crater on the lunar south pole is similar in many respects, and would similarly be an excellent site for this; however Peary is about 80 km in diameter and Shackleton is only about 20 km, so Peary would afford space for a much larger telescope.

Because the basin is always "aimed" at the moon's northern sky, and the same part of the sky is always visible throughout the month and throughout the year, very detailed long-term observations could be made unhindered of this part of the sky. Yes it would be limited to only this part of the sky; however, many space-based telescopes, including NASA's Kepler Space Telescope, have similarly limited fields of view.

And yes, a small astronomical observation outpost and research facility could provide the seed of a human colony in Peary crater as well. In later posts we'll be discussing the advantages of establishing a lunar colony over either Mars, Venus or orbital stations; a moon-based space telescope (at whatever location) could be a very good beginning to a robust lunar city.

Childhood's End

There's a lot going on right now in the realm of space exploration. The Dawn mission to Ceres is getting very interesting, the New Horizons mission will reach Pluto and Charon in two weeks; this is all huge, and I haven't posted anything here at all about any of it for a couple of months, due mostly to simple writer's block. Sad about that, and hoping to do better.

So, this morning the SpaceX CRS-7 Dragon/Falcon 9 cargo mission to the International Space Station failed. Notably it was the third failure of a cargo vessel to the ISS in the past eight months, after the Orbital ATK Antares back in October and the Russian Progress 59 in April. In the scheme of such things, this really is not a big deal. The ISS crew have enough provisions until October, and there's another Progress flight scheduled for this Friday. Nobody was hurt, and out of nineteen total Falcon 9 launches since 2010, one catastrophic failure is right at the 5% failure rate which is the rough median for orbital launches.

So, why does this feel like such a monumental blow to the commercial space program, and to spaceflight in general? Rockets explode, it's one of the things they do. When the Antares exploded, spectacularly, last fall, it made the news of course, and people speculated about whether or not Orbital would survive. But nobody speculated about whether or not spaceflight itself would survive. That would have been crazy. But today I've seen that speculation in the media, in chat rooms and other online forums, in all kinds of places that are populated by people who actually understand spaceflight. In the NASA press briefing this morning you could feel that current as well, even though they did a very good job of presenting the rational analysis of this being just another rocket explosion. You could even see it in Charlie Bolden's demeanor this morning. I felt it too.

The difference is not in the scope or magnitude of the loss of the Falcon 9 rocket. We lose rockets. The difference is that this is SpaceX.

For several years now there has grown an idea that the brilliant Elon Musk was doing what no other entity had ever been able to do before. That the founder of Pay Pal was somehow smarter than all of the engineers at NASA, Roscosmos, ESA, Boeing or Lockheed, and had figured out how to make spaceflight safe and affordable when all of the others had failed. With each successful Falcon 9 flight this became easier to believe, largely because we really wanted to believe it. Even Musk's competitors watched him to see if they could emulate his success.

Underlying this was sometimes a sense that SpaceX didn't know what they didn't know, and that through trial and error they would eventually come to look more like Boeing, Lockheed and other "old space" companies. But, we wanted this to not be true. We wanted spaceflight to be as easy, safe and affordable as Musk believed it to be.

Today we learned that Tsiolkovsky doesn't play favorites. And in many ways, today SpaceX finally became a real, grown-up rocket company. And we who follow spaceflight have had to grow up a bit as well.

Ad astra.

Bespin

This is HAVOC, NASA's new proposal for utilizing lighter than air craft to explore and colonize Venus. This is an enormous paradigm shift for them. For years the common wisdom has been that Venus was utterly uninhabitable, with surface atmospheric pressures 92 times that of earth (about the equivalent of one kilometer under water on earth), and surface temperatures above 500° C. But of course, if we were to explore an earth-analog planet with oceans like ours, we would probably not begin exploring that at one kilometer down, either. By the simple physics of adiabatic lapse rate (the higher you go in the atmosphere, the colder and less dense it becomes), at some altitude above the surface of Venus the atmosphere is of terrestrial densities and temperatures. There are issues; sulfuric acid, for example, falls as rain there. But life support in this environment would be trivial compared to the Martian surface.

The transit times for a mission to the atmosphere of Venus and back to earth are much, much less than for trip to and from the surface of Mars. The Delta V budget to the Venusian atmosphere is higher than a landing on Mars (25 km/sec vs 19 km/sec), but this penalty may well be outweighed by the smaller amount of hardware needed to survive above Venus. This has very, very serious potential to be the first human exploration and colonization of another planet.

Orion Rising

Flawless launch, flight, re-entry and splash down. Nicely done, NASA. Welcome home. We've missed you.

And, a huge shout-out to United Launch Alliance as well. 

Orion Flight Test Profile

Pole Position

 

Orion EFT-1 on top of Delta IV Heavy, launch time 4:05am pst.

 

Day late and a dollar short

Last week the ESA's Rosetta mission successfully landed the Philae probe onto the surface of Comet 67P/Churyumov–Gerasimenko. Philae bounced several times before finally landing on the side of a cliff. A gentle reminder that for more critical missions which require landing, there is real virtue in having an actual human pilot at the controls.

The total number of bodies in the solar system we have successfully landed anything on intact now stands at seven; the Moon, Venus, Mars, Titan, the asteroids Eros and Itokawa, and comet Chury-Gery. We have returned samples only from the Moon, and asteroid Itokawa.

The next big robotic exploration destination will be when the Dawn spacecraft reaches Ceres next spring. I'm inclined to think that the Dawn Ceres data will be a game-changer in how we prioritize our upcoming human space exploration missions. As such, we'll be following it closely, here.

Kung Fu

If I wanted to fly to London from Seattle, it would cost me about $1300 round trip on a Boeing 747-8. On the other hand, if I needed to purchase a Boeing 747-8 for myself to get to London, that would cost me around $370,000,000. If I had to purchase my own Boeing 747-8 to fly to London, but I could only fly it one time and one way, and would need to buy a second 747-8 (which could also be used only one time) in order to get back to Seattle, now we're looking at almost 3/4 of a billion dollars just in aircraft alone, for a single round-trip flight to London. I like London, it's an amazing city, but not for that price. Divide $740,000,000 by 470 passengers and that comes down to about a million and a half dollars per person; still pricey but I personally know people who could do it, if they sold all of their stuff. If, instead of only using the aircraft for a single one-way trip we could use it over and over, in only six hundred trips at $1300 a seat we will have paid for the aircraft.

So, if I translate this for a colonization mission to Mars, in order to build any permanent colony of any size at all (on Mars, or the moon, or really anywhere) then I need my rockets to leave earth, land on Mars, leave Mars and then land back on earth, in more or less the same configuration it took off in. This is reasonable, but unfortunately this is not, to date, the way spaceflight has been able to work.

If we look at the Apollo/Saturn V moon landings as a baseline of the physics needed to send and return humans to and from another world, it is apparent that in order to reach space and return from it, a spacecraft must almost continually shed excess weight. Saturn V stood some two million kilograms on the launch pad, whereas the Apollo command module which ultimately splashed down weighed maybe a thousand kilograms. This is sloppy, expensive and wasteful, but it is the only way to get a payload of this size into space with current technology.

Tsiolkovsky's rocket equation;

in which the weight of the rocket and fuel at the beginning of the launch and at the end of the launch must not exceed the effective exhaust velocity of the rocket. With existing propellants, it is nearly impossible to lift a payload of any real size even to low earth orbit with only a single rocket stage.

So, almost certainly, the first spacecraft to land humans on Mars will be of this Saturn V-type design, either SLS/Orion, or something very much like it. For exploration missions, this is fine, albeit expensive. The advantage is, we already know how to do this. For a colonization mission, the spacecraft are going to need to be much more like a 747, as far as re-useability. Elon Musk is going to want his rockets back, so he can use them again. Simply piling up hardware on the Martian surface, or at the bottom of the Atlantic, is a lousy business model.

SpaceX has already developed a vertical takeoff and landing rocket prototype, called Grasshopper. It is elegant, but burns lots and lots of heavy propellant to be able to control its landings. It is noteworthy that to date, no SpaceX cargo rocket to the ISS has actually utilized this technology, opting instead for multistage rockets and parachute descents. Adding the fuel weight for a Martian descent and surface escape launch, and still having the delta-v to reach orbit, is challenging at best. But necessary, if Martian colonization is going to be available to anybody but the very, very wealthy.

To Europa, by Bush-Pilot

In retrospect, probably the single biggest flaw in the space shuttle concept was creating a spacecraft to carry crews and cargo at the same time. No other method of transportation typically works this way. Whether you're talking about aircraft, trains, ships or whatever, passenger vessels carry passengers and cargo vessels carry cargo. Yes, a large passenger vessel might incidentally take very small amounts of cargo, and once upon a time cargo ships might take a handful of passengers, but nobody was going to mistake a passenger vessel for a cargo vessel. Except, you know, Alaskan Airlines flights inside Alaska. NASA seems to be steering its SLS rocket in the direction of alternating flights between crews and very high-dollar cargoes, rather than trying to accommodate both in a single flight. It's a subtle but important next step in mainstreaming spaceflight into the transportation industry as a whole.

According to Chris Bergin at nasaspaceflight.com (probably the best free space blog in the world, and its attendant pay site L2 is without parallel) NASA has padded its newest internal manifest for SLS with flagship robotic missions to Mars and Europa, and single-launch space stations interspersed with Orion crewed missions, in order to boost the launch rate to at least one per year. Taking advantage of SLS's enormous speed for robotic missions to the outer solar system seems a very logical extension of this, and further integrates crewed and uncrewed space exploration into a single, more unified program. For deeper space exploration, the payload capacity to carry space telescopes which could dwarf the James Webb has interesting potential as well. This program is evolving into a deep-space workhorse, analogous to what the space shuttle was supposed to be for Low Earth Orbit. Interesting times.

Orion Rising

The first Orion space capsule is complete, today. The United States of America once again is in possession of a crew-rated spacecraft, the first since the retirement of the space shuttles. In the words of Joe Biden, this is a BFD.

Russian Roulette

The malfunction and then detonation of the Antares/Cygnus cargo spacecraft at Wallops on Tuesday is now being tied to the use of refurbished 1960s Soviet vintage AJ26 rocket engines. I'm not going to speculate on whether or not this is the case; I suspect that the age of the engines had very little to to do with the accident, but I have no evidence to back this up either way.

What is more conclusive is that chemical rockets remain A) the only means we have of launching any payload into low earth orbit and beyond and b) dangerous as hell.

A little bit of sloppy number crunching, looking just at the space shuttle program. Five orbiters totaling some 130 launches, two of which failed catastrophically. That's about a 1.5% failure rate. Scaled up to commercial aircraft, that's about 20 major airline disasters every single day. At Seattle-Tacoma International Airport. By itself.

This is a serious problem for true commercial spaceflight. If the ground crew cheered every time a Boeing 737 took off or landed safely, nobody in their right mind would fly in Boeing 737s. For routine commercial spaceflight to be feasible, we need something which works reliably every time it flies. Highly volatile chemical rockets probably are not the answer.

One possible answer floating around (sorry) is lighter than air craft. The idea of riding a dirigible into space, at first glance, seems a little absurd. But John Powell of JP Aerospace has demonstrated how a hypersonic dirigible could reach the International Space Station, and beyond. Another possibility is using less volatile hybrid (HTPB/N2O "rubber and laughing-gas") rockets, but these have yet to reach the 100 km Kármán line, much less low earth orbit. But better propellants and/or oxidants may be found, which are still reasonably stable. Until then, what we have looks less like science than theology. And if part of your routine flight-plan includes "pray real hard," you're not yet ready to fly grandma to the moon.

Mars One: Bouncing the Reality Check

Today a group of engineering students from MIT published a very well-researched feasibility study about Mars One, the Dutch plan to put a human colony on Mars by 2024, for a reality TV series.

The study is good, and solid. It basically comes down to "they don't know what they don't know" (the news.com.au headline about the study was "Humans on Mars One mission would start dying in 68 days" which sums it up pretty well). You can read all of the MIT feasibility study here, it's a pretty interesting read.

http://web.mit.edu/sydneydo/Public/Mars%20One%20Feasibility%20Analysis%20IAC14.pdf

The elephant in the ballroom here is that Mars One, to date, has raised a grand total of about $600,000 worldwide. With that, they can buy one pretty nice brand-new single engine Cessna, and maybe fuel, a bag of donuts and a thermos of coffee for the flight to wherever a Cessna 172 can get to from Amsterdam.

Cargo to Crew

This is the ULA Delta IV Heavy that will launch the Orion spacecraft on its uncrewed maiden voyage this December.

This raises the issue of the difference between rockets for cargo flights into low earth orbit versus crewed flights to the same destinations, and specifically why we can't just use the same rockets for what is nearly the same job. It turns out that modifying an existing cargo rocket for crewed flight is a fairly involved exercise.

The reason is safety, mostly. Rockets have an unhappy propensity for exploding, so any crewed vehicle must be able to safely escape an explosion. Part of the solution is a Launch Escape System, which is simply a small rocket on top of the spacecraft to pull it away from the main engines and fuel tanks in the event of a catastrophic failure. Here is an example, with an Apollo space capsule.

Cargo rockets take the shortest, fastest and simplest (hence closest to vertical) route to orbit that their engines allow, with little consideration for the massive changes in g-forces that the cargo is subjected to. Humans need a slower and gentler ascent. Also, cargo rockets maximize the distance they coast upward unpowered between stages, and by launching essentially vertically the exhaust remains below them. Neither of these are problematical so long as the launch proceeds normally. However, if the LES needed to deploy at certain parts of the launch trajectory (such as at the top of one stage's coasting before the stage above it ignited, or the first few seconds of a launch when the huge exhaust fireball is below the rocket), the LES would be unable to safely extract the spacecraft. These time intervals in which the LES cannot launch the crew safely away from an exploding rocket are called "black zones." Every crewed rocket has some, but the goal is to minimize both the amount and duration of these. One method for accomplishing this, for example, is to launch the rocket in a lower parabola so that for most of its flight to orbit, the spacecraft does not have its own exhaust gasses below it.

The currently used Delta IV, Atlas V and SpaceX Falcon rockets are all presently being modified for commercial crewed flights. Each of these rockets will be discussed here in greater detail, as this series progresses.

Orion Promo #7

Just two months to go before the maiden flight of the Orion spacecraft, on 4 December 2014. Yes, I'm shamelessly reposting NASA propaganda videos here. Because, you know, rockets!

Churchill Downs

Ok, so, if we're going to have a "Space Race," we need to define the racetrack.

There are two really important things to understand about the immediate future (next couple of decades, say) of human spaceflight. One, space flight is really difficult. Two, the main reason space flight is really difficult is that the places we want to go are really far away.

There are only a few destinations worth realistic consideration between now and 2040, and hence part of what I would consider the current Space Race; Near Earth Orbit, the moon and lunar orbit (and the earth/moon Langrangian orbits), near-earth asteroids and comets, and Mars and its moons. That's it, that's as far as humans will possibly get in the next quarter century, if we're very ambitious and very lucky. The one possible addition to this is that if the Dawn spacecraft proves that Ceres is a helluva lot more interesting than currently assumed, it could be prioritized into the mix, but I consider that highly unlikely. The moons of Jupiter and Saturn, tantalizing though they are, are going to have to wait for later generations. Hopefully we will land robot probes there much sooner.

I'm going to talk a bit about linear, point-to-point distances, as a vacuum-packed crow might fly. Spacecraft don't fly in straight lines, a fact I'll be discussing in greater detail at a later point, but the distance ratios for comparison are relatively the same regardless.

Low Earth Orbit, meaning the altitude of the International Space Station, is about 425 km above the earth. That's about the driving distance from Seattle to Spokane, or Chicago to St Louis. To date, only NASA, Roscosmos and China's single Shenzhou 5 mission have successfully put humans here. Only NASA has ever put humans any higher than this.

The moon (and environs) are about 400,000 km away, some 940 times the distance to the ISS. Which is why nobody has been back there in almost 43 years.

At the very closest point in its orbit, Mars is about 100,000,000 km away from earth. That's 250 times the distance to the moon, or about 235,000 times the distance to the ISS. Which, again, is the farthest distance humans have traveled since 1972.

I had intended to create a drawing which accurately depicted these scales, and figured out that I couldn't. The disparity of scale is simply too great. And maybe that illustrates the point as well as any drawing could.

From Russia, With Love

So, there's really no better place to begin a series about the current race for human spaceflight, exploration and colonization than to discuss the realities of human spaceflight right now. As of this morning, our total presence off of planet earth right now is five men and one woman on board the International Space Station. I'll talk lots about the ISS in a later post, but I wanted to start with the rocket which got the crew to the ISS today, the venerable Soyuz.

Soyuz is like the Volkswagen Beetle of the world's space programs; small, simple, reliable, and basically unchanged since 1967. 121 crewed launches as of today; I think that's more than all of the rest of the world's crewed space launches combined. Soyuz exemplifies the Russian model of "low-tech solutions to high-tech problems," the spacecraft has always had the look and feel of something that could have been built as a weekend project in someone's garage. I kind of love this spacecraft.

Space Race 2020, Introduction

This is the first new post of a new series I'm calling "Space Race 2020," although I will very likely go back and reflag some earlier posts with it. This is what really inspired me to start blogging regularly again, after a bit of a hiatus. We are entering a very exciting time in space exploration, and I really enjoy geeking about it online. Why 2020? Partly because it is the nominal end-of-mission date for the International Space Station (although I won't be terribly surprised if it continues flying crewed missions for another decade beyond that), partly because it is a target launch date for a number of upcoming programs, but mostly because it sounded better than "The New Space Race," and I'm lazy and won't have to change it for another six years or so.

In the series I intend to talk about both the challenges ahead and the hardware being developed to meet those challenges, and focus on both big players like NASA and much smaller independent players as well. I'm specifically going to look at the immediate future of this decade and the next, meaning realistically probably no further afield than Mars. Well, maybe Ceres or Europa, if someone gets really ambitious.

So, quick disclaimers. I do not presently work in any part of the aerospace industry, and I do not own shares in any part of the aerospace industry, nor am I in any way affiliated with any particular part of the aerospace industry. I do live in Seattle, which is the home of Boeing, and also Blue Origin. I previously served aboard submarines which carried and launched both Poseidon C3 and Trident C4 missiles, and spent a fair amount of time at Port Canaveral for ballistic missile testing and telemetry (and incidentally got to see a number of space shuttle and satellite launches in the process), but my specialty was navigation, not weapons. The last time I was directly or even indirectly involved with the design, development or deployment of any rocket that did not have the word "Estes" on it somewhere, Ronald Reagan was president. I am a US citizen and a veteran of the US Navy, so naturally I have some bias toward American space programs, but my main thrust is to see successful human spaceflight under all and any flag. Russia, China, Japan, India, the European Union and other governmental agencies, and also the various commercial and otherwise independent space ventures, all are contributing to our exploration and eventual colonization of the solar system, and will be covered here in various detail. Also, my age informs my biases. I was barely old enough to watch (and be enthralled by) the Apollo moon landings, and it is my great hope to be able to watch the first humans land on Mars as well. Also, selfishly, I would very much like for the cost of commercial spaceflight to become affordable to the point of experiencing it personally, while I am still young enough to do so. Nothing too extravagant; if I can get over the Kármán line before I'm 75 or so, I'll call that a win.

The race is on.

Space Launch System, a reality check

In the past few days I've seen several discussions (based, so far as I can tell, much more on politics than any real science) about how the new NASA Space Launch System (crewed spaceflight to the moon, Mars, asteroids and beyond) should be abandoned, either in favor of the old Constellation/Ares program or Elon Musk's SpaceX program. Some of the arguments put forward have been patently absurd, so I made a quick graphic here to illustrate why.

So, the Ares I (Bush administration) program was abandoned because Ares I was grossly over budget, years behind schedule and had absolutely nothing to show for any of this. The very large R&D budget had all been spent on the R, with nothing left over for D. The later-to-be-developed Ares IV and Ares V rockets showed more promise, but were scrubbed along with the Ares I.

The SLS (Obama administration) Block I, like Ares IV and V, is based partly on "legacy" Space Shuttle hardware. But in order to meet the congressional mandate of having this off the launchpad by 2017, NASA heavily relied also on legacy hardware from the Saturn V. No new hardware means no R&D; SLS Block I is, amazingly, actually a bit ahead of schedule. The SLS Block II spacecraft, which rely in turn on SLS Block I technology, are essentially the Ares IV and Ares V. See illustration for comparison.

Arguing that Ares is a better platform than SLS is akin to arguing that Muhammed Ali was a better boxer than Cassius Clay.

SpaceX, meanwhile, has been fantastically successful so far at launching uncrewed cargo vessels to the International Space Station in low earth orbit, and by 2017 the Dragon Rider spacecraft will be taking crews to the ISS as well. But the Dragon program is basically a redux of the old NASA Gemini program. Which is excellent, and inspired even, but the transition from Gemini to Apollo was one of the most expensive undertakings in human history. Musk could sell a thousand Teslas a day and not be able to build something capable of taking humans to Mars. It is not possible to simply "scale-up" from an earth-orbital spacecraft to an interplanetary (or even translunar) one; the Soviets tried this with disastrous results. Musk has discussed the possibility of developing a rocket to Mars, and I believe he has the know-how to do it. But it's not on the drawing boards yet, it doesn't even exist as a power-point presentation, and I have yet to hear a plausible answer to the question of how he would pay for it.

So, for better or worse, SLS and the Orion spacecraft are America's space program right now, and there isn't a credible replacement for them in the foreseeable future.

Race to the Rocks

Now there are two companies competing to mine the asteroids. The race is on!

Ice Hockey

The European Space Agency is planning a mission to try to actually deflect an asteroid from its trajectory. This could be really important to us if we ever found a large asteroid to be on a collision course with earth. Good on them.

Asteroid deflection mission seeks smashing ideas

15 January 2013

A space rock several hundred metres across is heading towards our planet and the last-ditch attempt to avert a disaster – an untested mission to deflect it – fails. This fictional scene of films and novels could well be a reality one day. But what can space agencies do to ensure it works?

ESA is appealing for research ideas to help guide the development of a US–European asteroid deflection mission now under study.

Concepts are being sought for both ground- and space-based investigations, seeking improved understanding of the physics of very high-speed collisions involving both man-made and natural objects in space.

ESA’s call will help to guide future studies linked to the Asteroid Impact and Deflection mission – AIDA.

This innovative but low-budget transatlantic partnership involves the joint operations of two small spacecraft sent to intercept a binary asteroid.

The first Double Asteroid Redirection Test (DART) spacecraft, designed by the US Johns Hopkins Applied Physics Laboratory will collide with the smaller of the two asteroids.

Meanwhile, ESA’s Asteroid Impact Monitor (AIM) craft will survey these bodies in detail, before and after the collision.

The impact should change the pace at which the objects spin around each other, observable from Earth. But AIM’s close-up view will ‘ground-truth’ such observations.

“The advantage is that the spacecraft are simple and independent,” says Andy Cheng of Johns Hopkins, leading the AIDA project on the US side. “They can both complete their primary investigation without the other one.”

But by working in tandem, the quality and quantity of results will increase greatly, explains Andrés Gálvez, ESA AIDA study manager: “Both missions become better when put together – getting much more out of the overall investment.

“And the vast amounts of data coming from the joint mission should help to validate various theories, such as our impact modelling.”

Last week the 325 m Apophis asteroid passed close to Earth, and in mid-February the recently discovered 2012 DA14 space rock will pass closer than many satellites.

ESA is seeking to assess the impact hazard from Near-Earth Objects (NEOs) through its Space Situational Awareness (SSA) programme.

“AIDA offers a promising platform for the test and demonstration of different deflection methods,” adds Detlef Koschny, managing SSA’s NEO effort. “It is therefore important to ask the users early on what they’d like to do with a mission like this.”

For some time, ESA and its international partners have been studying missions to investigate asteroid deflection techniques.

The most popular concept involves a ‘hypervelocity impact’ – a collision at multiple kilometres per second, at such high speed that materials do not just shatter car-crash-style but are vaporised, turning even metal and solid rock into the hot soup of charged particles called plasma.

Such impact testing would help assess if asteroid deflection could be accomplished.

Increased knowledge of hypervelocity impacts would also have wider uses. Planetary scientists would gain fresh insight into our Solar System’s violent early history, including clues to the origin of life and the magnitude of extinction events.

And in practical terms, growing levels of orbital debris increases the risk of highly destructive hypervelocity impacts with critical satellite infrastructure or humans working in orbit. Studying this kind of impact will help to quantify the hazard and inspire protection techniques.

The AIDA Call for Experiment Ideas is being released on 1 February at http://www.esa.int/neo. For further information, see http://www.esa.int/Our_Activities/Technology/NEO/High_impact_factor_space_R_D_AIDA_Call_For_Experiment