Astronomy Picture of the Day

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.

2004 March 29
See Explanation.  Clicking on the picture will download
 the highest resolution version available.

NASA's X-43A Scramjet Sets Air Speed Record
Illustration Credit: X-43A Development Team, DFRC, NASA

Explanation: Using oxygen from the air itself, a NASA experimental jet propelled itself past Mach 7 in the atmosphere above the Pacific Ocean this weekend. The small automated X-43A Hyper-X craft was dropped from a huge converted B-52 bomber and then accelerated by a standard Pegasus rocket. At Mach 7, seven times the speed of sound, the X-43A separated and the novel scramjet kicked in. Atmospheric oxygen was then scooped up, combined with onboard hydrogen, and combusted in flight to propel the X-43A to record air speeds during maneuvers over the next 10 seconds. Engines of ramjet design have been suggested as a satellite launch method without heavy fuel tanks and even romanticized for interstellar space travel. The previously acknowledged air-speed record for jet-powered flight was Mach 3.3 for the decommissioned SR-71. Re-entering space rockets can start as high as Mach 36 before the atmosphere decelerates them. The X-43A, depicted in the artist's illustration above, might well propel itself past Mach 10 in future tests.

Tomorrow's picture: sun deck

< | Archive | Index | Search | Calendar | Glossary | Education | About APOD | >

Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
NASA Web Site Statements, Warnings, and Disclaimers
NASA Official: Jay Norris. Specific rights apply.
A service of: LHEA at NASA / GSFC
& Michigan Tech. U.