![Handout illustration of NASA's Perseverance rover deploys a supersonic parachute from its aeroshell as it slows down before landing, in this artist's illustration. Hundreds of critical events must execute perfectly and exactly Handout illustration of NASA's Perseverance rover deploys a supersonic parachute from its aeroshell as it slows down before landing, in this artist's illustration. Hundreds of critical events must execute perfectly and exactly](https://c8.alamy.com/comp/2EAD261/handout-illustration-of-nasas-perseverance-rover-deploys-a-supersonic-parachute-from-its-aeroshell-as-it-slows-down-before-landing-in-this-artists-illustration-hundreds-of-critical-events-must-execute-perfectly-and-exactly-on-time-for-the-rover-to-land-safely-on-feb-18-2021-entry-descent-and-landing-or-edl-begins-when-the-spacecraft-reaches-the-top-of-the-martian-atmosphere-travelling-nearly-12500-mph-20000-kph-edl-ends-about-seven-minutes-after-atmospheric-entry-with-perseverance-stationary-on-the-martian-surfacethe-parachute-705-feet-215-meters-in-diameter-deploys-2EAD261.jpg)
Handout illustration of NASA's Perseverance rover deploys a supersonic parachute from its aeroshell as it slows down before landing, in this artist's illustration. Hundreds of critical events must execute perfectly and exactly
![A worker stands in front of a crushing plant 500 feet (152 meters) underground in the Winsford Rock Salt mine in Winsford, northern England November 12, 2014. The mine which produces 20,000 A worker stands in front of a crushing plant 500 feet (152 meters) underground in the Winsford Rock Salt mine in Winsford, northern England November 12, 2014. The mine which produces 20,000](https://c8.alamy.com/comp/2CXNAGC/a-worker-stands-in-front-of-a-crushing-plant-500-feet-152-meters-underground-in-the-winsford-rock-salt-mine-in-winsford-northern-england-november-12-2014-the-mine-which-produces-20000-tonnes-of-salt-each-day-supplies-britains-highways-agency-with-road-salt-to-spread-across-the-road-network-during-the-winter-months-reutersphil-noble-britain-tags-environment-transport-2CXNAGC.jpg)
A worker stands in front of a crushing plant 500 feet (152 meters) underground in the Winsford Rock Salt mine in Winsford, northern England November 12, 2014. The mine which produces 20,000
National Geographic on Instagram: “Photo by @stephenwilkes | Flying in a plane at 20,000 feet (6,000 meters) over Greenland in July, I saw what looked like an abstract…”
![Analog altimeter - MD215 - Mid-Continent Instruments & Avionics, Inc. - feet or meters / 2-inch / for aircraft Analog altimeter - MD215 - Mid-Continent Instruments & Avionics, Inc. - feet or meters / 2-inch / for aircraft](https://img.aeroexpo.online/images_ar/photo-g/171403-10369972.jpg)