FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1968
1968-1 - 0060.PDF
FLIGHT International, 5 December 1968 955 This drawing of the Zond 6 mission (not to scale) shows the main events in the flight and recovery of this circumlunar probe. Zonds S and 6 are the first two space craft to be recovered from other than near- Earth orbit. The vehicle re-entered the Earth's atmosphere once to reduce its speed from 11 km/sec to 7.6 km/sec before starting its glide back to Soviet territory. Notwith standing Leonid Sedov's comments (see the Zond 6 news item below), it is possible that a manned Russian flight around the Moon could take place in the present launch win dow, December 2-8 (the corresponding dates for Apollo 8 are December 20-28) MID-COURSE CORRECTION AT 154,000 MILES LUNAR ORBIT INJECTION ORBITAL CORRECTION AT 147,000 MILES FURTHER CORRECTION AT 75,000 MILES ENTRY CORRIDOR SEPARATION OF"DESCENT APPARATUS" Spaceflight EUROPA'S THIRD STAGE FAILURE The failure of the ELDO F.7 firing, the eighth in the Europa I development programme, now leaves a fairly critical time schedule for the remaining launches if the agreed budget is not to be exceeded. Launched from Woomera at 0842hr local time (0012GMT) on November 30. this first launch of the Phase 3 trials was characterised by a successful first and second stage operation. The third stage separated successfully—a notable accomplish ment for Germany—but at the time of writing only "quick-look" information was available from the telemetry, and it was not clear whether the third stage failed to ignite or whether it did so and then cut out after about 7 sec. Failure of the third stage could be attributed to one or a number of causes (for example, inability of the attitude control system to stabilise the vehicle, or failure of the helium pressurisation system). The Italian satellite test vehicle did not therefore attain orbit, but transmission from its telemetry was received at Woomera and Gove. It seems probable that the satellite was burned up on re-entry. The implications will not be evident until the cause of the malfunction is known. If there is no fundamental problem, modification could be incorporated in the F.8 launch scheduled for next May. The real worry is that the F.9 launch, also scheduled for next year, might slip into 1970. resulting in an increase in the standing costs to ELDO. On the credit side, the fully representative Blue Streak first stage has now achieved eight consecutive successful firings; the French Coralie second stage (malfunction of which caused the failure of the F.6/1 and F.6/2 firings last year) apparently performed flawlessly; and the third stage did achieve separation, an important milestone. AERODYNAMIC RECOVERY OF ZOND 6 The re-entry and recovery of the unmanned Zond 6 spacecraft on November 17 after its flight round the Moon chalks up yet another "first" to Russia—in this case, the first application of "skip" techniques associated with aerodynamic lift to ensure safe and controlled re-entry of a vehicle travelling towards Earth at escape velocity, nearly 25,000 m.p.h. The circumlunar Zond 5 was also recovered at this speed, but a normal ballistic (non-lifting) re-entry was employed. The "skip" technique is suitable for vehicles which have appreciable L/D ratios. During re-entry the vehicle is partially slowed by atmospheric drag, and aerodynamic lift then enables the flight path to be directed out of the atmosphere, when it may re-enter for landing or for another phugoid. The purpose of the manoeuvre is to slow the vehicle down in the atmosphere and in the subsequent zoom, while allowing the heat loads to be dissipated by radiation. Aerodynamic lift also allows a wide touchdown footprint from any given identical re-entry position. The re-entry trajectory (within a 6-mile wide corridor) of Zond 6 allowed the speed at the top of the zoom to be decreased from 25,000 m.p.h. to about 17,000 m.p.h., after which the spacecraft glided down until the parachute system was deployed. The lift forces may have been generated by moveable vanes similar to those of Soyuz, and which are probably the dark rectangular areas seen around the body of the Soyuz launch vehicle (see Flight, November 28, page 917). Zonds 5 and 6 therefore become the first spacecraft to be recovered from deep space. The re-entry speed in this case is 1.4 times as great as that associated with near-Earth orbits and the achievement has been widely acclaimed, notably in Russia. At the time of the Soyuz 3 launch, Soviet scientists were hedging the question of manned flights to the Moon by saying that they still had much to learn about the problems of recovery from the "second cosmic velocity." The leading Russian scientist, Leonid Sedov, said recently that it would be "perhaps a year or more" before manned lunar flights would be attempted by his country. Photographs of the Moon were taken at a distance of 1,500 miles from the surface, and were brought back by Zond 6. They were therefore the first direct (non-television pictures) of any astronomical body other than the Earth to be secured from space. APOLLO 10 FOR MOON LANDING? The possibility that Apollo 10 may be chosen as the Moon- landing flight (see Flight for November 21, page 822) is now increasing. The flight is already scheduled as a full dress- rehearsal mission, complete with lunar module in high-Earth or lunar orbit. Officially it will be a repeat of Apollo 9. the first mission to fly the man-qualified lunar module. But if Apollo 8 and 9 enjoy the same degree of success as Apollo 7. NASA feels that no useful purpose would be served by scheduling repeat flights. The crew for Apollo 10, named on November 14. comprises Col Thomas Stafford, USAF, Cdr Eugene Cernan and Cdr John Young, both of the US Navy. The flight will take place in April or May. H. JULIAN ALLEN RETIRES Mr H. Julian Allen, director, Ames Research Centre, National Aeronautics and Space Administration, has retired. In 1952 he originated the concept of the blunt body for re-entry, with a view to overcoming the problem of destructive heating. He is also recognised as a leading authority on the design of supersonic wind tunnels. Mr John F. Parsons. Ames associate director, now becomes acting director.
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
