On April 24th, 1980 the US tried to free 52 diplomates held hostage in Iran by force - and failed. In 2020 smart Australian diplomacy succeeded in freeing Kylie Moore-Gilbert from Iran's worst jail after 800 days behind bars.

This is how it went down:

In the relatively empty pandemic skies, a jet plane snaking its way from Canberra to Tehran, via Darwin and Bangkok, is definitely one of them.

So when a nondescript long-range Airbus A319 taxied out of Fairbairn Airport early on Monday, curiosity was aroused. Then again, plane spotters always are excitable.

But no-one could have guessed its secret mission: to rescue Melbourne academic Kylie Moore-Gilbert from Iran.

Secret Mission : A particularly high-risk task

Skytraders is a Melbourne-based aviation company well versed in tackling difficult government tasks.

It's done all manner of dangerous tasks under "dark ops" protocols for Home Affairs and Foreign Affairs.

But this job was particularly hairy and high risk.

The plane landed in Bangkok 11 hours later and after refuelling, flew to Iran, landing at Tehran's Mehrabad Airport, Tehran, at 9:05pm local time, 22 hours after leaving Canberra.

It is not clear if cargo was unloaded or personnel disembarked.

But just 75 minutes after touchdown, the plane departed Tehran for Doha, Qatar, where it was parked for a day.

Iran sees an opportunity

Then came a flurry of activity involving officials from several countries. This had been months in the making.

Behind the scenes, Australia had been scrambling for opportunities to free Dr Moore-Gilbert, who was sentenced to 10 years' imprisonment for espionage — charges the Melbourne University Middle East specialist has vehemently denied.

More than once, the Government thought it was on the brink of success before seeing delicately poised negotiations crumble.

But Iran, a shrewd expert in hostage diplomacy, saw a great opportunity of its own.

Which might have been the whole point of her arrest in the first place.

Tehran wanted to repatriate three of its shady operatives from a Thai jail, locked up for their involvement in a botched 2012 plot to assassinate Israeli diplomats in Bangkok.

'What's in it for Thailand?'

How Australia convinced Thailand to surrender three of its prized prisoners for Australia's benefit is not known. But it was done.

As one senior Canberra-based diplomat from another country mused when the news broke — "I wonder what's in it for Thailand?"

And on Wednesday (2:50pm Canberra time), VH-VCJ flew out of Bangkok for Tehran, for the second time in two days, arriving just over nine hours later.

On board were three Iranians: Saeid Moradi, Mohammad Kharzei and Masoud Sedaghat Zadeh, the trio linked to the Bangkok bomb plot.

Despite their face masks, one of them was unmistakable in footage released by Iranian broadcaster IRIB: Moradi is missing both his legs.

Moradi attempted to throw a bomb at Thai police in February 2012, only to have the bomb detonate at his feet.

All three men were greeted on arrival by Iran's Deputy Foreign Minister Abbas Araghchi.

Just one hour and 40 minutes after landing, the Skytraders Airbus departed Tehran, Kylie Moore-Gilbert on board, having been escorted on to the plane by Lyndall Sachs, the ambassador to Iran.

Ms Sachs's team has a story that might never be fully told.

Australian officials can't remember anything like it

An extraordinary extraction that had so many moving parts and a couple of false starts had been pulled off when few dared believe it might be achieved.

"These types of transfers aren't unusual," Thailand's deputy Attorney-General Chatchom Akapin told Associated Press with admirable nonchalance.

"We transfer prisoners to other countries and at the same time receive Thais back under this type of agreement all the time."

This is, of course, nonsense. Rubbish.

What happened this week doesn't happen all the time.

Australian officials can't remember anything like it, in fact.

But it happened.

Yet the full repercussions are not yet known.

Thailand's cooperation has been substantial. Israel's too, most probably.

But in Australia finding a neat solution to Iran's hostage diplomacy, what is the precedent set?

If a citizen of one country can be used to extract leverage over another nation, what next?

As one senior Australian official said: "What was the alternative?"

Story By | Andrew Probyn, foreign affairs reporter Stephen Dziedzic and political reporter Matthew Doran