European Space Propulsion (ESP) Limited blamed disappointing sales for going into liquidation.
Formed by Aerojet Rocketdyne in 2012, it operated from missile maker Thales UK's factory in Castlereagh.
Its offices were opened by the former First Minister Peter Robinson.
He had expressed delight the US company had selected Belfast as its European sales base.
But it never got near its projected Â£13m annual turnover.
A spokesman for the firm said: "We had high hopes, just like the Northern Ireland ministers did.
"We thank them for their support but unfortunately expected sales just never materialised."
As recently as December, then Economy Minister Jonathan Bell talked of ESP as having "brought significant benefits to Northern Ireland".
Employee numbers never got above eight.

North Wales Police had warned supporters to behave at the Racecourse and later confirmed there were no arrests at the match which ended 0-0.
Safety fears meant Chester fans had to travel on official coaches under police escort.
It is the fourth year the fixture has been marked as a "bubble match" - meaning supporters will be kept apart.
North Wales and Cheshire police forces have said restrictions could be reviewed if there was no trouble at the two games this season.
Speaking before the game, North Wales Police and Crime Commissioner Arfon Jones said: "If things go well, it looks as if this bubble business with the restrictions on travelling fans can be lifted which would be great news."
"This is now the only [current] fixture in all the tiers of English and Welsh football that is a bubble, including Premier League and Championship derby fixtures, and I think it is risk averse and disproportionate in terms of policing," he added.

Hong Kong police said a male 39-year-old foreigner alerted airline staff early on Monday, who then called the authorities.
Police said the man had lost two watches and foreign currency.
Local media said the man was a Turkish watch merchant flying in economy class from Dubai.
A spokesperson for Emirates, the airline the man took to Hong Kong, told the BBC: "Emirates is working closely with the police department and providing information to assist with their investigation." Emirates said it would not be providing further comment, citing the ongoing investigation.
There have been increasing reports of mid-air thefts around the world, some of which are said to involve organised gangs.
An American-owned aerospace firm attracted to Belfast by Invest NI and backed by the  Northern Ireland Executive is ending its local operation.
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Police have thanked Wrexham and Chester fans for their "good natured co-operation" at their derby match.
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A man has lost HK$2m ($257,730; £175,530) in cash and valuables from his hand luggage, during a flight into Hong Kong, police said.