Tim Peake completing a spacewalk

The case for and against human spaceflight

Should we just call the shots from home? Read through our background information and then decide for yourself

Ever wondered why Britain has never launched its own astronauts into space? British people who have been to space before have gone on other countries’ spacecraft. Tim Peake, who spent six months in space in 2016, went on behalf of the European Space Agency rather than the UK Space Agency.


The furthest humans have travelled from Earth, in kilometres (Apollo 13, 1970)

Many well-known figures in the field have argued against human spaceflight. They say it is more expensive and riskier than sending robots. If a robot crash-landed into Mars there would be disappointment and the loss of years of work, for sure, but that doesn’t compare to the loss of human life. And, they say, robots can do many of the jobs that humans can do plus many that they can’t.

19.5 billion

The furthest an unmanned spacecraft has travelled, in kilometres. (Voyager, 1977–present)

The history books certainly show that space travel is dangerous: the Challenger and Columbia space shuttle disasters together claimed the lives of 14 astronauts. There have been other fatalities and close calls too, with Apollo 13 perhaps the most famous narrow escape. No one has ever died in space – the deaths have all occurred during launch and re-entry. 

Land covered on selected missions
  Date of Mission With or without humans Distance covered (km) Time (days)
Spirit rover 2004–10 without 7.73 2,695
Opportunity rover 2004–present (2015) without 42.2 4,082
Apollo 15 rover 1971 with 27.8 12
Apollo 17 rover 1972 with 35.74 12

Is risk a good enough argument for not pushing the boundaries of what is possible? What if Columbus, Cook and Cabot had decided sailing out into uncharted waters was too much of a risk? What if we had never ventured out of our caves in the first place? Or out of Africa?

Sending humans into space has led to many technological developments. Would the same innovations have been made if we restricted ourselves to robots? Then there is the inspiration factor: many of the scientists of today were inspired by the daring accomplishments of the Apollo astronauts. Imagine the impact of seeing a fellow human set foot on Mars for the first time.


  • Humans can make on-the-spot decisions – a robot can only follow its (admittedly sophisticated) programming or wait for significantly delayed instructions from Earth.
  • Astronauts can currently cover a lot more ground on the surface of a planet or moon and can use more advanced equipment to explore.
  • Some healthcare advancements have come directly from preparing the astronauts.


  • Humans need to be kept alive. This means bigger, more expensive missions carrying everything needed to sustain life. 
  • It is risky. The consequences of a mission going wrong are much more serious.
  • It’s too expensive – missions would cost less without humans.

Lead image:

ESA (European Space Agency) astronaut Tim Peake during his first spacewalk.

NASA Johnson/Flickr


Downloadable resources

About this resource

This resource was first published in ‘Space Biology’ in June 2015 and reviewed and updated in April 2017.

Statistics and maths, Ecology and environment, Biotechnology and engineering
Space Biology
Education levels:
16–19, Continuing professional development