Image copyright NASA Image caption Planet satellites launch from the space station: The firm has some 150 operational spacecraft

One of the UK's most successful space entrepreneurs has launched a withering attack on Brexit, labelling it "galactic scale stupidity".

Will Marshall's Planet company operates the world's largest satellite imaging network, with 150 spacecraft able to fully picture Earth on a daily basis.

He warns EU withdrawal will do immense harm to Britain's space industry. The UK will be "lost in space", he says.

The UK Space Agency responded by saying home businesses had a positive outlook.

The most recent survey of confidence across the sector found that three-quarters of organisations expected growth over the next three years, it added.

Dr Marshall, a Nasa employee before founding Planet, airs his concerns in a blog posting.

"Post Brexit, no CEO would locate a space company [in the UK]," he argues.

"Why put your European base outside the single market of the largest trading block in the world?! Or likely without access to the main government programmes? Company after company will avoid it," he adds.

Image copyright Getty Images Image caption Dr Marshall says the idea of a UK sat-nav system is "pie in the sky"

Dr Marshall holds particular scorn for the UK government's actions on Galileo, the EU version of the Global Positioning System (GPS).

Ministers have decided to walk away from the project because Brussels says a future Britain, as a "third country" outside the EU, cannot be involved in the system's most secure elements - this despite the UK having already invested £1.5bn in Galileo.

London says it will build its own sat-nav system instead, but Dr Marshall calls this a "pie in the sky" plan that has significant economic and security implications.

"The costs would dwarf the entire UK space budget," he writes, and all for a redundant system that is "likely years behind and second tier to that of its close allies!"

Image copyright PLANET LABS INC Image caption Planet's view of Brussels: The EU is an ever more dominant force in European space activity

Dr Marshall's enterprise is headquartered in California, with a European base in Germany.

Founded along with Robbie Schingler and Chris Boshuizen in 2010 - Planet has led a revolution in Earth observation that's based on the use of low-cost, shoe-box-sized satellites.

Europe as a whole is racing to catch up, although the UK - it has to be said - has been better placed than most. Companies like Surrey Satellite Technology Ltd pioneered the use of commercial off-the-shelf components to reduce the cost of spacecraft manufacturing, and Clyde Space of Glasgow is now one of the go-to producers of just the type of satellites used by Planet.

But the former Oxford and Leicester physicist worries that his home country is pulling itself out of a space ecosystem in which it has become embedded and on which so much of its capability depends.

The UK puts about three-quarters of its civil space budget through the European Space Agency (Esa) and has become a significant player in the EU's growing space activities - not just in Galileo but in Brussels' other big project: the Copernicus/Sentinel Earth observation system.

Esa is a separate legal entity to the EU and ministers say Britain will stay in it even as the country leaves the wider union.

But Esa and the EU are becoming ever more aligned, with Brussels now the single biggest contributor to the agency's budget - €1.25bn out of a total of €5.72bn per annum. The EU uses Esa as its technical and procurement agent.

Many commentators believe the growing influence of Brussels within Esa is leading to tension, and that this unease will only heighten when a big agency member-state like Britain exits the EU.

Dr Marshall shares this concern and warns the UK's voice within Esa will become diminished as a result.

Image copyright PLANET LABS INC Image caption Sulawesi tsunami aftermath: Planet's satellites picture the entire Earth once a day

"Furthermore, in conversations with senior officials at the UK government during my recent trip there, it became terrifyingly clear that space is an afterthought to the larger political issues of Brexit: there is no plan to mitigate these impacts," he writes.

A spokesperson for the UK Space Agency (UKSA) said Dr Marshall's pessimism was not shared across industry and pointed to the recent "Size and Health" survey of British space businesses.

This found that 73% of organisations expected income to grow over the next three years and 48% of those expected that growth to be more than 10% higher than in the previous three years.

"Space is a truly global endeavour and a key part of the government's modern Industrial Strategy, with over £100m committed for new space infrastructure and a further £92m to develop options for a UK global satellite navigation system," the spokesperson told BBC News.

"We have an excellent track record of working closely with the sector to drive growth, create jobs and collaborate with partners in Europe and the rest of the world.

"This will continue once we leave the EU. We are committed to close international partnerships on space and science programmes, and will remain a leading member of the European Space Agency, which is independent of the EU."

Last week, OneWeb, an international start-up that has chosen to base itself in London, launched the first six satellites in what it hopes will become a near-2,000-spacecraft constellation to deliver internet broadband to every corner of the globe.

Jonathan.Amos-INTERNET@bbc.co.uk and follow me on Twitter: @BBCAmos