Fajr 1 was originally mentioned by Iran as "ready to launch" early in August 2010 when an Iranian government minister said the lift off was scheduled for the period Aug 24-30. Then, on Aug 16, came an announcement referring to launch of both Fajr 1 and Rasad (another satellite) by the "end of the current Iranian year", March 20, 2011, and mentioning delays due to testing.

At the start of February 2011, Iran said the launch of both Fajr and Rasad could come in the second week of that month, hinting at a dual launch. When the date came round, a new announcement said "early in the new (Iranian) year" - ie after March. Delays in testing Fajr were again mentioned.

At about the same time, some Iranian news sources reported that Fajr had been handed over to the launching agency to go into orbit during April.

April passed and, in May, a further pronouncement said Fajr 1 would be in orbit "by September" but nothing transpired and it simply disappeared from public view. It reappeared ten months later, in February 2012, when a planned launch attempt was again postponed for three months.

On May 13, Iranian Defence MinisterBrigadier GeneralAhmad Vahidi was simultaneously quoted by different Iranian news agencies as saying launch would occur both "between May 23 and May 30", and "during June".

Mehdi Farahi, head of Iran's Aerospace Industries Organization confirmed the May 23 date. It is possible there was some confusion converting from the Iranian calendar as the months overlap those of the conventional calendar.

Either way, the launch will not be taking place for a while. As of May 29, Iran is saying only that it will occur sometime before the end of the current Iranian year - ie March 2013.

Fajr 1 would have been Iran's fourth satellite in five launch attempts starting in 2008. It was to have used the same Safir rocket. This, together with previous references to 'testing delays' indicates that the problem is with the satellite and not the launch vehicle.

Fajr is Iran's most complex satellite to date. It has a mass of about 50 kilogrammes and is based on Iran's first satellite, Omid. An advance over Omid is its extensive use of solar cells rather than simple batteries.

It is also reported as being equipped with a cold-gas thruster to maintain the orbit but it is likely to be experimental rather than essential to the mission. Like Omid, it is equipped with a GPS receiver to help in orbit measurement.

Its purpose is imaging, though little has been said about the hoped-for resolution that will depend to a degree on how well it is stabilised. Omid was not stabilised and tumbled in orbit. There is no obvious stabilisation system in photographs of Fajr but it may use magnets to interact with the Earth's magnetic field.

Previous Iranian satellites have functioned for only short periods of time although Iran has a habit of not announcing mission-end until re-entry after 2-3 months, giving the impression of much longer operating lives.

By virtue of a 300-450 kilometre orbit, some 50-100 kilometres higher than its predecessors, it will stay up for about 18 months. Iran is saying it will operate for all of that period but this is probably in line with the way it described the lifetime of the earlier satellites.

We now wait to see how long it takes Iran to resolve the issues, that might be with stabilisation and the thruster system, and whether the next time we hear it mentioned will be as it goes into orbit.

Robert Christy has been analysing and documenting space events since the early 1960s and currently provides information via his web site.