There is no GPS on the Moon – so to see where thing land and go , we have to trust on orbital observations . To make this work easy , NASA has developed an cunning object that does n’t ask power to make its mien known : You put it on top of your lander and you are quick to be found , then you wait for NASA’sLunar Reconnaissance Orbiter(LRO ) to fritter a laser at you . It worked for theVikram scouter , and has now worked for Smart Lander for Investigating Moon ( SLIM ) too .

SLIMis a Japanese Aerospace Exploration Agency lander , and Vikram is a foreign mission from the Indian Space Research Organisation . With these lander , the Asian nations became the fourth and 5th nation to set down on the Moon . NASA Laser Retroreflector Arrays have hitch a ride on both of them so they can be tested out .

The twist on SLIM is the size of a cookie , 5 cm ( 2 column inch ) across . It has eight quartz corner - cube prisms set into a dome - shaped aluminum material body . Thanks to those , it can excogitate light issue forth from multiple directions . LRO can apply its laser altimeter to hit it and tape the Christ Within that bounces back .

“ LRO ’s altimeter was n’t work up for this case of lotion , so the hazard of pinpointing a tiny retroreflector on the Moon ’s aerofoil are already small , ” Xiaoli Sun , who led the team that built SLIM ’s retroreflector at NASA ’s Goddard Space Flight Center as part of a partnership between NASA and JAXA , enjoin in astatement .

But there was a knottiness : SLIM landed on its side , so it was n’t easy to in reality get a ping from the retroreflector . The first eight attempts lead to nothing . It was only the 9th and tenth endeavor that result in a signal back . It look at multiple attempts for Vikram as well , but there , the team did n’t have to make indisputable they cognise exactly where the location of the lander was . To confirm the signal was from SLIM , that was necessary .

Still , it shows that the system works – even in unexpected conditions . A future system of positioning involving the retroreflectors would have an orbital partner really designed to do such a job . LRO ’s altimeter is not bespoken . So the fact that the system work even at an slant is great .

“ For the LRO team to have attain a retroreflector that faces sideways , alternatively of the sky , shows that these minuscule devices are incredibly resilient , ” Sun added .

The scheme could be used in future crewed and uncrewed missions to bring closer to other spacecraft or objects already on the surface of the Moon .