Surveyor 1 was launched on Mission A from Cape Kennedy, Florida at 14:41:00.990 GMT on May 30, 1966, and soft landed on the moon at 06:17:37 GMT on June 2, 1966. All established goals were attained on this mission, the first in a series of unmanned spacecraft flights designed to soft land and function on the lunar surface. In addition to meeting established objectives, Surveyor 1 demonstrated a capability to operate successfully in the lunar environment over a period of time greatly in excess of that required by the mission objectives - including survival through the long lunar night and resumption of operations during the following period of daylight. At the termination of Surveyor 1 operations at the close of the second lunar day, on July 14, 1966, over 100,000 commands had been sent to the spacecraft and over 11,000 pictures had been returned.

Surveyor 1 Mission Objectives

1. To accomplish successful soft landings on the moon as demonstrated by the operations of the spacecraft subsequent to landing.

2. To provide basic data in support of Apollo.

3. To perform operations on the lunar surface which will contribute new scientific knowledge about the moon and provide further information in support of Apollo.

Primary Flight Objectives

1. To demonstrate the capability of the Surveyor spacecraft to perform successful midcourse and terminal maneuvers and a soft-landing on the moon.

2. To demonstrate the capability of the Atlas/Centaur vehicle to successfully inject the Surveyor spacecraft on a lunar intercept trajectory.

3. To demonstrate the capability of the Surveyor communications system and the Deep Space Network to maintain communications with the spacecraft during its flight and after the soft landing.

Secondary Flight Objectives

1. To obtain in-flight data on all spacecraft subsystems used in cruise flight.

2. To obtain in-flight engineering data on all spacecraft subsystems used during the midcourse maneuver, terminal maneuver, and main retro phase.

3. To obtain in-flight engineering data on the performance of the closed-loop terminal descent guidance and control system, consisting of the velocity and altitude radars, on-board analog computer, autopilot, and vernier engines.

4. To obtain engineering data on the performance of spacecraft subsystem used on the lunar surface.

Tertiary Flight Objectives

1. To obtain post-landing TV pictures of a spacecraft footpad and the immediately surrounding lunar surface material.

2. To obtain post-landing TV pictures of the lunar topography.

3. To obtain data on the radar reflectivity of the lunar surface.

4. To obtain data on the bearing strength of the lunar surface.

5. To obtain spacecraft temperature data on the lunar surface for use in the analysis of lunar surface temperatures.

Major Mission Constraints

Surveyor 1 mission design constraints were the Centaur/Surveyor separation distance what must be at least 336 km by 5 hr after injection to eliminate possible Centaur interference during Canopus acquisition.

The required separation distance was reached 2 hr and 17.5 min after launch. The Centaur passed above and behind the moon about 6 hr 20 min after Surveyor 1 touchdown.

The landing site selected prior to launch for targeting of the launch vehicle ascent trajectory was near the western end of the Apollo landing zone at -2.58 deg latitude, 316.65 deg longitude (best estimate based on post-touchdown tracking data). The followings were the additional constraints to select the landing site:

1. predicted terrain smoothness for softlanding

2. desire to land in the Apollo zone

3. desire to minimize the off-vertical incidence of the approach trajectory

4. must have availability of good postlanding lighting

5. an unbraked impact speed was selected so that the Goldsone arrival visibility constraints would be satisfied for all launch days in the launch period.

Sequence of Events

All vehicle flight events occured as programmed at near nominal times with no anomalies. The following is a brief descriptions of the vehicle flight sequence of events with all times referenced to liftoff.

(1) Atlas Booster Phase of Flight

Hypergolic ignition of all five atlas engines was initiated 2 sec before liftoff, with liftoff occuring at 14:41:00.990 GMT. The vehicle reached Mach 1 at 58 sec and maximum aerodynamic loading occured at 77 sec. The programmed pitch over of the vehicle began 15 sec after the liftoff and lasted until booster engine cutoff (BECO). At 3.1 sec after BECO, with the booster and sustainer engine centered, the booster section was jettisoned by release of pneumatically operated latches.

(2) Atlas Sustainer Phase of Flight

At BECO + 8 sec the Centaur guidance system was enabled to provide steering commands for the Atlas sustainer phase of flight. During this phase the sustainer engine was gimballed for pitch and yaw control, while the verniers were active in roll. The Centaur insulation panels were jettisoned at 175.8 sec at an altitude of approx. 49 nmi. Sustainer and vernier engine cutoff (SECO and VECO) occured at 239.4 sec. Separation of the Atlas from the Centaur occured 1.9 sec after SECO. This was followed by ignition of eight retrorockets located at the aft end of the Atlas tank section to back the Atlas, together with the interstage adapter, away from the Centaur.

(3) Centaur Phase of Flight Through Spacecraft Separation

The Centaur main engines were ignited 9.6 sec after Atlas/Centaur separation and burned for 438.4 sec, or until 689.2 sec. Main engine cutoff (MECO) was commanded by the guidance system when the desired injection conditions were reached. At main engine cutoff, the hydrogen peroxide engines were enabled for attitude stabilization. During the 67.7 sec period between MECO and spacecraft separation, the following signals were transmitted to the spacecraft from the Centaur programmer as: to extend spacecraft landing gear to unlock spacecraft omniantennas; and to turn on spacecraft transmitter high power. An arming signal also was provided by the Centaur during this period to enable the spacecraft to act on the preseparation commands.

The Centaur commanded separation of the spacecraft electrical disconnect 5.5 sec before spacecraft separation, which was initiated at 756.9 sec. The Centaur attitude control engines were disabled for 5 sec during spacecraft separation in order to minimize vehicle turning moments.

(4) Centaur Retromaneuver

At 5 sec after spacecraft separation, the Centaur began a turnaround maneuver using the attitude control engines to point the aft end of the stage in the direction of the flight path. Approximately midway in the turn and while continuing the turn, two of the 50-lb-thrust hydrogen peroxide engines were fired for a period of 20 sec to provide initial lateral separation of the Centaur from the spacecraft. At 240 sec after separation, the propellant blewdown phase of the Centaur retromaneuver was initiated by opening the hydrogen and oxygen prestart valves.

Sunday, 01-Aug-2004 00:36:47 CDT
CSR/TSGC Team Web