The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
In February 1984, two shuttle-launched spacecraft, the Westar IV and Palapa B2 satellites, failed to reach orbit when their perigee kick motors (PKMs) extinguished in a few seconds, instead of burning for 86 seconds. Although the two failed PKMs could not be recovered, a television camera aboard the space shuttle Challenger had observed the premature extinction of the Palapa PKM.