¿ Astronomy Picture of the Day [1]Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2021 February 16 IFRAME: [2]https://www.youtube.com/embed/M4tdMR5HLtg?rel=0 Perseverance: Seven Minutes to Mars Video Credit: [3]NASA, [4]JPL Explanation: How hard is it to land safely on Mars? So hard that many [5]more attempts have failed than succeeded. The next attempt will be on Thursday. The main problem is that the [6]Martian atmosphere is too thick to ignore -- or it will [7]melt your spacecraft. On the other hand, the atmosphere is too thin to rely on [8]parachutes -- or your spacecraft will crash land. Therefore, as outlined in the [9]featured video, the Perseverance lander will lose much of its high speed by deploying a huge parachute, but then switch to rockets, and finally, assuming everything goes right, culminate with a hovering [10]Sky Crane that will slowly lower the [11]car-sized Perseverance rover to the surface with ropes. It may sound crazy, but the [12]Curiosity rover was [13]placed on Mars using a similar method in 2012. From atmospheric entry to surface touch-down takes about seven minutes, all coordinated by an onboard computer because [14]Mars is too far away for rapid interactive communication. During this time, [15]humans on [16]Earth will [17]simply wait to hear if the landing was successful. Last week, [18]UAE's [19]Hope spacecraft successfully began orbiting Mars, followed a day later by the [20]Chinese [21]Tianwen-1 mission, which will likely schedule a landing of its own rover sometime in the next few months. News: [22]NASA Perseverance Coverage Tomorrow's picture: light pillar with flare __________________________________________________________________ [23]< | [24]Archive | [25]Submissions | [26]Index | [27]Search | [28]Calendar | [29]RSS | [30]Education | [31]About APOD | [32]Discuss | [33]> __________________________________________________________________ Authors & editors: [34]Robert Nemiroff ([35]MTU) & [36]Jerry Bonnell ([37]UMCP) NASA Official: Phillip Newman [38]Specific rights apply. [39]NASA Web Privacy Policy and Important Notices A service of: [40]ASD at [41]NASA / [42]GSFC & [43]Michigan Tech. U. References 1. https://apod.nasa.gov/apod/archivepix.html 2. https://www.youtube.com/embed/M4tdMR5HLtg?rel=0 3. https://www.nasa.gov/ 4. http://www.jpl.nasa.gov/ 5. https://mars.nasa.gov/mars-exploration/missions/historical-log/ 6. https://en.wikipedia.org/wiki/Atmosphere_of_Mars 7. https://youtu.be/lSoWxG30rb0 8. https://youtu.be/Qg6xxRZWnI4 9. https://youtu.be/M4tdMR5HLtg 10. https://www.planetary.org/space-images/curiositys-skycrane-maneuver 11. https://mars.nasa.gov/mars2020/spacecraft/rover/ 12. https://apod.nasa.gov/apod/ap191029.html 13. https://apod.nasa.gov/apod/ap120731.html 14. https://solarsystem.nasa.gov/planets/mars/in-depth/ 15. https://apod.nasa.gov/apod/ap190818.html 16. https://apod.nasa.gov/apod/ap190825.html 17. https://www.pdsa.org.uk/media/7845/kitten-hiding-page-image.jpg 18. https://en.wikipedia.org/wiki/United_Arab_Emirates 19. https://en.wikipedia.org/wiki/Emirates_Mars_Mission 20. https://en.wikipedia.org/wiki/China 21. https://en.wikipedia.org/wiki/Tianwen-1 22. https://mars.nasa.gov/mars2020/timeline/landing/watch-online/ 23. https://apod.nasa.gov/apod/ap210215.html 24. https://apod.nasa.gov/apod/archivepix.html 25. https://apod.nasa.gov/apod/lib/apsubmit2015.html 26. https://apod.nasa.gov/apod/lib/aptree.html 27. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search 28. https://apod.nasa.gov/apod/calendar/allyears.html 29. https://apod.nasa.gov/apod.rss 30. https://apod.nasa.gov/apod/lib/edlinks.html 31. https://apod.nasa.gov/apod/lib/about_apod.html 32. http://asterisk.apod.com/discuss_apod.php?date=210216 33. https://apod.nasa.gov/apod/ap210217.html 34. http://www.phy.mtu.edu/faculty/Nemiroff.html 35. http://www.phy.mtu.edu/ 36. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html 37. http://www.astro.umd.edu/ 38. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 39. https://www.nasa.gov/about/highlights/HP_Privacy.html 40. https://astrophysics.gsfc.nasa.gov/ 41. https://www.nasa.gov/ 42. https://www.nasa.gov/centers/goddard/ 43. http://www.mtu.edu/