The south of England was bless with a really clear night sky yesterday evening (Saturday 26 February 2011), which was just perfect for the International Space Station pass over Southampton at about 18.35 GMT.   The other fortuitous feature was that Discovery was due to dock with ISS at 19.16 GMT, so there was the prospect of a unique, and never to be seen again, event of seeing the two vehicles as separate objects during the pass.   As is happens, the two objects were indistinguishable with the ‘naked eye’, but just discernable with binoculars!   I don’t know how close they would have been from each other 40 minutes prior to docking but from the observed evidence, they would have been less than 100 m apart.

And talking of unique views, how about this for being in right place at the right time?  The link shows the view of Discovery’s launch on Thursday from a passing passenger jet.   I suspect the trim of the aircraft might have been disturbed for a few minutes while everyone rushed over to one side to watch this very unusual spectacle!

http://news.discovery.com/space/extraordinary-discovery-launch-from-a-passenger-jet-110226.html

I had the opportunity to see the ISS  over Southampton yesterday evening (Thursday 24 February 2011) – brilliant (literally)!  This evening (Friday) there is a similarly good pass over Southern England, but unfortunately the forecast is cloud and rain. This is especially galling as it’s likely that the shuttle Discovery and the Station will be in formation prior to their docking manoeuvre tomorrow (Saturday).  The live online HD coverage of Discovery’s final launch yesterday evening was excellent, courtesy of NASA TV.  At the peak time there were about 42,000 viewers sharing the transmission, which makes the quality of the coverage even more amazing.   The tension as the launch window approached was very well conveyed, particularly as there was a ‘launch hold’ situation with the range safety computer systems about 20 minutes before the normal launch time of 21.50 GMT.   The problem was solved only moments before launch, with Discovery having only 2 minutes of launch window left when it finally left the launch complex.   Couldn’t have scripted it better!  However, I can imagine the pressure on those engineers responsible for solving the problem during those frantic few pre-launch minutes!

Russian scientists have recently raised the spectre of global disaster once again in the form of an impact of the asteroid Apophis, which is about 270 m across, with the Earth.   The asteroid was christened Apophis, after an ancient Egyptian spirit of evil and destruction, when it was thought that it might impact the Earth on Friday the 13th April 2029.  Refinement of Apophis’s trajectory now suggests that it will pass the Earth harmlessly at a distance of around 5 Earth radii on that date.  Perhaps the recent concern surrounds the idea that the object may pass through a so-called ‘gravitational keyhole’, and then return to impact the Earth many years later.  So what’s this all about?  I don’t know how good you are at thinking in 3D, but give this a go.   Imagine a plane passing through the Earth’s centre, which is perpendicular to Apophis’s trajectory at its point of closest approach in 2029.  You might refer to this as the ‘impact plane’, as it allows the miss-distance to be easily measured.   Now, there are small elliptical areas on this plane of the order of a few 10s of metres in size referred to as keyholes.   If Apophis passes through one of these, it’s perturbed trajectory will take it into an orbit around the Sun which is resonant with the Earth’s orbit.   This means that after an exact number of orbits the asteroid can return to impact the Earth in the future.   The main concern with the Russian research is the keyhole that will cause an Earth impact exactly 7 years later on Friday 13th April 2036.  I thought this had already been investigated and the risk found to be negligible, so I’m not sure why the prospect of impact with Apophis has been resurrected?  Anyway, one good thing is that the Russian scientists were kind enough to give our research at Southampton a plug – our work looked at the cost of such an impact in terms of human life and infrastructure damage – so thank you for that !

The second Automated Transfer Vehicle, christened Kepler, was launched on the 200th Ariane flight yesterday from the Ariane space port in French Guiana.  Weighing in at around 20 tonnes, this was also the biggest payload yet launched by Ariane.  The vehicle is destined to rendezvous and dock with the International Space Station (ISS) within the next few days.  It will be a busy time, with the shuttle due to launch to ISS next Friday (25 February).  However, the main reason for this entry is the accompanying cool photo, taken by the crew aboard ISS, of the Ariane launch seen from ISS.  A window of visibility of the ISS is opening up in the UK on 24 February, so I will be out under the night sky then in the hope of seeing ATV or shuttle flying in formation with the station!  If you want predictions of when ISS can be seen over your location, I can recommend a really ace website www.heavens-above.com.

The UK Daily Telegraph recently ran a story about a collaboration between Japan’s space agency (JAXA), and a traditional manufacturer of fishing nets.  Believe it or not the idea is to build a huge net, spanning several kilometers in size, comprised of a lattice of thin metal strands to capture debris in Earth orbit.  I think I must be missing something here, or the article has omitted some important detail.  But the fact that the average speed of debris with respect to the net will be of the order of 10 km/sec does pose one or two problems!  Given the size of the net, the probability of debris impacts upon it is essentially 1, within a short period of time.  The consequence of the resulting numerous high energy impacts will cause the net to gradually erode into many thousands of tiny fragments,  so significantly worsening the problem it is intended to solve.  There is also the effect that the net would have upon an orbiting object with which it collides.  Such an event is likely to cause fragmentation of the object, and the consequences for operational, or even crewed, spacecraft would be disastrous.   The article does say that the net is ‘super-strong’, but nothing is going to stop and capture an object travelling with such high relative speeds.  I repeat – what am I missing here?

A US company ATK has combined with European space company Astrium to propose a launch vehicle, tagged ‘Liberty’, that will lift US astronauts to orbit (see also blog entry about Alan Bond’s Skylon on 8 January 2011).  The consortium offers a vehicle which uses Shuttle and Ariane 5 components to lift a payload of the order of 20 tonnes to low Earth orbit.  The configuration is a Ares-1 look-alike, with a first stage comprised of a shuttle-derived solid propellant booster, and a second stage based on the liquid propellant core stage of the European Ariane 5 launcher (see accompanying diagram).  The proposal suggests that manned flights could take place as early as 2015, despite the status of the Ariane as a non manned-rated vehicle.

Clearly the European end of the team don’t have experience of crewed missions, and you could ask if a US/Europe lineup is doomed to failure under the current ITAR restrictions?  Aside from these issues, Liberty is capable of lifting the Orion command module (at 9 tonnes), but not the combined Orion command and service module configuration with a mass in excess of 21 tonnes.

Perhaps the political dimension of an international programme will save the day, but unfortunately my guess is that the days of Liberty are numbered.