Radio Link With Lunar Mission

Press, Volume CVIII, Issue 31865, 18 December 1968, Page 26

Radio Link With Lunar Mission

On their flight to and j from the moon, radio com- ; munications with Apollo 8 ■ astronauts will he continu- [ ous. in contrast to earth [ orbital flights. Spacecraft in earth orbit ex-' perience communications “blackouts” sometimes for more than an hour while the craft is passing over areas far from any ground communications station. For space-to-ground radio contact, a craft and ground station must be in a “line of sight.” On the Apollo 8 round-the-moon mission, once the craft reaches a distance from earth of about 4000 miles, the craft I is “visible’ ’to such a large' area on earth that it will be[ in line of sight of at least one: (station at all times. However, the Apollo 8 craft’ will experience communications blackouts during each!

orbit of the moon whenever [its orbital path takes it be[hind the moon. Such interruptions will last about 45 [minutes during each two[hour moon orbit During earth orbital flights. [ a spacecraft’s movement around the globe requires it . to switch to different ground stations along the route. As . the Apollo 8 heads towards ’ the moon, the need for switcht ing stations will be because of i the earth rotation, not the craft’s movement. ; Rainfall at Amberley.— Last month’s rainfall at Amberley 1 was only' a quarter as much as I during November of last year. >; according to readings taken by [I Mr H. H. Foster.. The monthly [totals were 1.28 in and 6.06 in ! 1 respectively. Rain fell on eight [days last ’month, the heaviest H fall being O.SSin on November |5. The llmonth tnfaLs are ’ 22.80 in this year and 26.19 in illast year.