THE YE-6M LUNAR LANDER SERIES: 1966

Campaign objectives:

Throughout 1965 there was a high level of frustration in the Soviet robotic lunar and planetary programs. In the period 1963-65, three of six Venus-type spacecraft were successfully dispatched, two of three Mars-type, and live of eleven soft landers for the Moon. Nevertheless, all of these spacecraft failed either in transit or at the target. Only one, Zond 3, a test launch to Mars distance, returned anything of scientific or propaganda value, and that was from its flyby of the Moon. On the plus side things were improving, because three missions in late 1965 reached their targets and failed only at the last minute, Venera 2 and Luna 7 and 8.

Spacecraft launched
First spacecraft:	Luna 9 (Ye-6M No.202/13)
Mission Type:	Lunar Lander
Country j Builder:	X JSSR/NPO-Lavoch ki n
launch Vehicle:	Molniva-M
Launch Date: Time:	January 31, 1966 at 11:41:37 UT (Baikonur)
Landing Date: Time:	February 3, 1966 at 18:44:54 UT
Mission End:	February 6, 1966 at 22:55 UT
Outcome:	Success.
Second spacecraft:	Luna 13 (Ye-6M No.205/14)
Mission Type:	Lunar Lander
Country j Builder:	lJSSR/NPO-Lavoch ki n
launch Vehicle:	Molniva-M
Launch Date/ Time:	December 2L 1966 at 10:17:00 UT (Baikonur)
Landing Date; Time:	December 24. 1966 at 18:01:00 UT
Mission End:	December 28. 1966 at 06:13 UT
Outcome:	Success.

When responsibility for robotic lunar and planetary missions was transferred from ОКБ-1 to NPO-Lavochkin at the end of 1965, a dozen failed missions made Georgi Babakin decide to modify the Ye-6 lander as the Ye-6Mi. His changes produced an immediate success, with Luna 9 making the desired soft landing on February 3, 1966, and sending back the first pictures from the surface of another world. Once again the Soviets had beaten the US to a space exploration milestone. Western headlines proclaimed a new space lead for the LTSSR. Although several years behind schedule, largely owing to the difficulty in developing the upper stage for its launcher, the US succeeded at its first attempt at a lunar landing. Surveyor 1 touched down on June 2, 1966, and returned imagery of a far superior quality. In December 1966 the second and final lander in the Ye-6M scries, Luna 13, was successful as well.

Spacecraft:

The Ye-6M spacecraft was identical to ihe Ye-6 with modifications to the landing shock absorbers and a new independent guidance system. The airbags that enclosed the lander were inflated after the retro-rocket had ignited, requiring relocation of the tank of the nitrogen with which to inflate the bags from one of the side modules onto the cruise stage itself, because the side modules were jettisoned prior to braking. No additional redundancy was introduced.

Luna 9 launch mass: 1,538 kg (lander 105 kgj

Luna 13 launch mass: 1,620 kg (lander 113 kg)

Automatic Lunar station (ALS)

Guidance system module (MOO)

Detachable module *2 with radio equipment

Radio altimeter

Engine installation

Figure 10.2 Luna 9 spacecraft diagram (courtesy Energtya Corp).

Two-edged mirror

Figure 10.3 Luna 9 lander.

Figure 10.4 Luna 13 lander (from Space Travel Encyclopedia)-. 1. Transmitter antennae; 2. Receiver antennae; 3. Deployment arm; 4. Penetrometer; 5. Gamma-ray densit­ometer; 6. Panoramic stereo cameras; 7. Infra-red radiometers; 8. Stabilizing petals.

The Luna 9 lander had a mass of 105 kg. including 5 kg of scientific instruments. At 112 kg. the Luna 13 lander carried an increased scientific payload including two panoramic cameras for stereoscopic imaging and a pair of spring-loaded deployable

1.5 meter long bootns for testing soil mechanics.

Figure 10.5 Luna 9 lander with single camera, and Luna 13 lander with dual-camera (inset).

Payload:

Luna 9:

1. Panoramic camera

2. Radiation detector

The scanning photometer camera system of Luna 4 to 8 was improved. It weighed only 1.5 kg, drew only 2.5 W, and had higher resolution. It used a lilting mirror in a revolving turret to produce a 29 x 360 degree panorama of 6,000 lines. The sensitivity could be adjusted by command, and it could operate from 80 to 150,000 lux. A panorama required approximately 100 minutes to transmit as 250 Hz analog video on the 183.538 lVIFTz channel. Optical calibration and tilt-indication targets were suspended from the pop-up antennas, and three short poles carried dihedral mirrors to provide stereo images for small areas of the surface, to measure distances, and to locate the horizon and tilt more precisely. The radiation detector measured solar corpuscular radiation both in flight and on the lunar surface.

Luna 13:

1. Dual panoramic cameras for stereo

2. Radiation detector

3. Infrared radiometer for soil temperature

4. Penetrometer for soil strength and bearing capacity

5. Gamma – г а у га dia ti on/ backsca tter densi tometer

6. Three axis accelerometer for surface mechanics on landing

The penetrometer, which had a 5 cm long cone, was mounted at the end of one of the deployable booms and a 65 N explosive charge drove it into the ground in order to measure the mechanical soil properties. The gamma-ray backsca tter densitometer was mounted at the end of the other boom to measure soil density.

Mission description:

Launched on January 31. 1966, the Luna 9 spacecraft flew flawlessly across cislunar space, made its braking maneuver and ejected its capsule, which bounced and rolled to a halt at 18:45:04 IJT on February 3 at 7.08°N 295.63 H in the Ocean of Storms. After the four petals opened outward and stabilized the capsule, the spring-loaded antennas were commanded to deploy, with one evidently failing. Five minutes after touchdown the television camera was activated to show the first ground-level view of the lunar surface. At that time the Sun was just 3.5 degrees above the horizon and much of the ground was in shadow. In one of the ironies of the Cold War. the British using the Jodrell Bank radio telescope were the first to publish pictures from Luna 9. after intercepting and readily recognizing the transmission as a fax machine signal. Although the Soviets had published their frequencies and had enlisted the assistance of Jodrell Bank to track previous missions, they were understandably upset to have their accomplishment ‘scooped* in the world’s press, particularly as the aspect ratio was incorrectly set. The US intelligence station at Asmara, Ethiopia, also intercepted the images but this was not made known at the time.

Luna 9 came to rest near the rim of a 25 meter diameter crater and w as lilted at 15 degrees. Over the next few hours it settled to a tilt of 22.5 degrees, enabling stereo images to be made of nearby features. Over seven communications sessions lasting a total of 8 hours and 5 minutes four panoramas were transmitted, the final one with the Sun approaching an elevation of 40 degrees. The last contact w as at 22:55 UT on February 6, as the battery depleted.

The second Ye-6M spacecraft, Luna 13. landed at 18:01:00 UT on December 24. 1966, at 18.87 N 297.95"E between the craters Seleucus and Krafft in the Ocean of Storms. In the act of bouncing and rolling, the accelerometer recorded data on soil density to depths of about 20 cm. It deployed tw o booms to measure soil density and surface radioactivity. The television system provided imagery at various times over

the next 2 days, but the failure of one of the two cameras precluded stereo imagery. The depletion of the battery terminated operations at 06:13 IJT on December 28.

Results:

Luna 9:

Nine images were returned by Luna 9, including five that were assembled to provide a panoramic view of the surface in the vicinity of the lander. The radiation detector measured a daily dosage of 30 millirads, which would not be hazardous to humans. The successful landing was clear evidence that the lunar surface was sufficiently dense to support a future manned spacecraft.

Figure 10.6 Portion of a Luna 9 panorama.

Figure 10.7 Portion of a Luna 13 panorama.

Luna 13:

Only one camera worked on Luna 13, returning five 220-degree panoramas in which the Sun was at increasing elevations. The soil density was found to be approximately

0. 8 g/cc, much less than lunar bulk density and terrestrial analogs, but sufficient to support heavy landers. The radiation detector confirmed the 30 n і Hi rads day reading by Luna 9. The infrared radiometer recorded surface temperature as a function of solar elevation, measuring a temperature of 117°C at local noon. It was decided that the first cosmonauts to land on the Moon would do so in the Ocean of Storms.