Space-based exploration and astronomy has progressed in leaps and bounds over the last few decades, with space observatories and planetary probes delivering a treasure-trove of stunning images of features far beyond our imagination, including my favourites, the Hubble Telesope's iconic 'Pillars of Creation' and the Cassini probe's images of geysers spewing into space on Saturn's moon Enceladus.
New missions continue to offer ever more enticing peeks into the unknown - to name just a few: the Kepler telescope has discovered thousands of planets orbiting other stars; in summer 2015 the New Horizons spacecraft reached Pluto on the outer edge of the solar system, sending back pictures of a unique and fascinating icy world, and just recently, in July 2016 NASA announced the successful arrival of the Juno space probe at Jupiter, where it will orbit the giant planet for over a year, collecting a huge amount of data including photos of its swirling atmosphere, and its never-before imaged polar regions.
But with such a plethora of amazing images from these missions, I wonder if perhaps we are becoming a bit blasé about the difficulty of actually achieving such success.
When things don't go as planned...
Earlier this year we had a rude reminder of just how easy it is for things to go wrong, with the loss of the Japanese Space Agency's Hitomi space telescope just a month after it was launched. This was planned as a crucial mission for observations at gamma ray and X-ray wavelengths.....but it was not to be. For reasons still not fully understood, errors occurred in routine manoeuvring, causing the spacecraft to start spinning uncontrollably, losing communications and damaging it beyond repair.
Space service call-out?
Of course, there is a steep learning curve involved in developing and realising a space mission, and as projects become increasingly ambitious, its normal to expect some hitches, as in any ground-breaking engineering project. But the crucial difference is that once a spacecraft leaves Earth, repairing it becomes exponentially more difficult – it's a little tricky to just send a service engineer out to fix it! Nevertheless, the space science community is creative and inventive , and space engineers have had some remarkable successes in turning around potential catastrophes.
Perhaps the best known is the Hubble Space Telescope – soon after its launch in 1990, astronomers realised that there was a fault in its primary mirror, resulting in images of much poorer quality. Fortunately, the telescope is in low earth orbit, 570 km up, and was designed from the outset to be serviceable by Space Shuttle astronauts; and in 1993 the problem was resolved when astronauts installed a corrective mirror. Since then, Hubble has received four more servicing visits – the repairs, replacement parts, and updates that have been carried out have enabled it to carry on functioning, producing its astounding images of the universe, for an incredible 26 years, and counting!
Servicing more distant telescopes and probes is more problematic though. NASA's next big space telescope mission, the James Webb Space Telescope, due to be launched in 2018, will be located 1.5 million km from earth, much too far for manned service missions. What if a technical problem occurs after launch?
It depends on the nature of the problem of course, but space project managers can be very inventive – for example, technical failures on the Kepler telescope in 2013 meant that the instrument could no longer be pointed exactly enough to carry out its original mission. But rather than abandoning, engineers figured out how to stabilise it using solar radiation pressure, and modified the mission to suit – and it just keeps on discovering new exoplanets!
Glittering telescope
And how about a totally different approach to space telescope design, to minimise cost and risks? Some rather off-beat ideas are being seriously explored for possible future missions, such as NASA's 'Orbiting Rainbows' project, which proposes using a cloud of tiny reflective particles, manipulated by several lasers, to act as a mirror. What a beautiful concept!
https://www.nasa.gov/mission_pages/juno/main/index.html
http://www.skyandtelescope.com/astronomy-news/recovery-for-hitomi-observatory-now-unlikely/
http://www.universetoday.com/13267/the-mars-curse-why-have-so-many-missions-failed/
http://www.nasa.gov/mission_pages/hubble/servicing/index.html
http://jwst.nasa.gov/index.html (James Webb Telescope)
http://time.com/3643896/kepler-planets-repair/
http://www.jpl.nasa.gov/news/news.php?feature=4553 'Glitter cloud may serve as space mirror'
1. NASA/JPL-Caltech
2. http://hubblesite.org/the_telescope/team_hubble/graphics/telescope_team_sm3a_2_lg.jpg
3. G. Swartzlander/Rochester Institute of Technology