



"But particular challenges on a spacecraft are the logistics; you need to be able to take a stable sighting through a window. We're asking the crew to evaluate some ideas we have on how to accomplish that and to give us feedback and perhaps new ideas for how to get a stable, clean sight. That's something we just can't test on the ground."The investigation tests specific techniques, focusing on stability, for possibly using a sextant for emergency navigation on space vehicles such as Orion. With the right techniques, crews can use the tool to navigate their way home based on angles between the moon or planets and stars, even if communications and computers become compromised."No need to reinvent the wheel when it comes to celestial navigation," Holt says."We want a robust, mechanical back-up with as few parts and as little need for power as possible to get you back home safely. Now that we plan to go farther into space than ever before, crews need the capability to navigate autonomously in the event of lost communication with the ground."Early explorers put a lot of effort into refining sextants to be compact and relatively easy to use. The tool's operational simplicity and spaceflight heritage make it a good candidate for further investigation as backup navigation.