Apollo Mission Vehicles

Six such vehicles carried astronauts from and to the Moon as part of the Apollo program for scientific investigation, collapsing into an adapter on the back of S-IVB third stage rocket.

After visual inspection of its landing gear, the LM’s descent engine conducted a 30-second Descent Orbit Insertion burn to reduce speed and gradually approach lunar surface.

The LM

The Lunar Roving Vehicle or LRV provided astronauts with shelter and essential life support systems while on lunar excursions, providing water, oxygen, and nitrogen supplies for up to five days on either trip. Composed of two parts–descent stage (landing gear/engine/equipment for lunar trips) and ascent stage (living quarters/command and control systems/flight deck) it allowed docking back onto Earth orbit and back.

To untie the CSM and SLA, astronauts pressed a button that activated detonating cords at various joints between SLA panels – blowing them apart – using dual redundant pyrotechnic thrusters at their lower ends, rotating 30-60 degrees per second. As soon as the LM reached lunar parking orbit, astronauts pressed another button that retract three-foot probes from footpads of descent stage before firing ascent stage engines back to life and sparking its engines for ascent stage ascent engine firings before docking with CSM before course correction burns launched it into lunar orbital orbit after course correction burns had taken place.

Once in orbit, astronauts would power up and test systems as they prepared for lunar rendezvous. Wally Schirra captured this footage during Apollo 8 to show the Lunar Module’s docking sequence.

As part of their rendezvous procedure, astronauts opened and transferred from the LM’s docking hatch and moved to its ascent and landing systems. Its docking system consisted of four 21-foot (6.4 m) panels that opened like flower petals to move at speeds up to 25 miles per hour (37 kilometers per hour). When reaching lunar parking orbit, commander and pilot replaced hatches and docking equipment as well as unfolded landing legs before unfolding their legs again.

Once on the surface, astronauts used an LRV to move from place to place on the lunar surface. As it was the first wheeled vehicle designed specifically to traverse lunar terrain, its introduction allowed astronauts to cover much more area during EVAs than with previous vehicles. For the Apollo 15 and 17 missions specifically, an LRV designed specifically to fit two astronauts along with their equipment, supplies, and lunar samples was utilized.


The Command/Service Module was the primary element of Apollo system. It contained the crew cabin, pressurized environment for living, overhead hatch/docking port, forward hatch, forward landing radar antenna and solar power array as well as its rocket engine – Command/Service Module Ascent (SMA). SMA powered both return to lunar orbit and ascent to Moon.

The SMA was powered by a hypergolic fuel engine using liquid hydrogen and oxygen reactants as fuel for thrust creation in space, discharging its waste heat via a radiator system, providing propellant for landing on the Moon and returning back home, as well as serving as main propulsion system that maneuvered Apollo spacecraft into and out of lunar orbit, reaction control system, instrument unit and fuel cells with drinking water and oxygen reactants for environmental control and high gain antenna capabilities.

SMA had several cargo compartments which were used to carry both the Lunar Roving Vehicle (LRV) for Apollo 15, 16 and 17 missions and the Particles and Fields Subsatellite on later missions to the Moon. The LRV was a battery-powered “dune buggy” used to traverse lunar surface during extravehicular activities (EVA); on Apollo 15 alone it covered 27.8 kilometers within three hours 26 minutes driving time!

At launch time, the SMA was connected to the Instrument Unit of the Lunar Module by four points along its lower panels. When docking occurred, astronauts activated Lockheed’s Launch Escape System (LES). If fire broke out during launch or an onboard fire occurred or guidance system failure, this would pull away from Saturn V Third Stage and pull CM away using canard system and jettison recovery system from spacecraft’s path and propel its decompression chute back to earth safely.


The Lunar Roving Vehicle, commonly referred to as a “Moon buggy”, played an essential part in Apollo missions 15-17. It allowed astronauts to cover more terrain during moon walks compared to wearing bulky spacesuits during previous missions.

The four-wheeled rover was powered by two battery packs that could operate at full capacity for 57 miles in normal operation, as determined by NASA planners. As a precaution against possible battery failures, astronauts were not permitted to drive further from Lunar Module than they could walk; NASA planners set the safe range at six miles. Furthermore, astronauts used various tools on board including lunar rake which resembled a cat litter box scoop for collecting rocks and dust samples that they’d bring back home for analysis before returning them home for return home.

Astronauts used a joystick-like hand controller between two seats to navigate their rover, pushing any direction to steer while pulling back activated the brakes. Furthermore, astronauts monitored speed, heading, power levels and temperature levels on a display panel.

When the Lunar Module wasn’t in use, the LRV would be folded up and stored in quad 1 for reentry to Earth. Deploying it was often the hardest part of an EVA; astronauts needed to climb its egress ladder before using pulleys and reels to lower it into quad 1.

On their inaugural lunar trek during Apollo 16’s EVA on the third day, astronauts drove the lunar rover for over three hours and covered 17.3 miles (27.8 kilometers). This far outdistanced the previous lunar landings and allowed for key scientific discoveries to take place.

As the trip continued, however, its batteries reached dangerously hot temperatures and were approaching failure by the end of their excursion. Mission Control instructed them to switch between batteries while driving and park under shaded areas–which would radiate less heat into them–in an attempt to keep them working longer. Ultimately though, a combination of careful driving and parking in shade kept working them.

The Rover

On this mission, a single Mars Exploration Rover was employed. This device was designed to travel from place to place looking for signs that Mars once supported life; equipped with front and rear cameras to capture images as well as hardware for conducting scientific experiments.

The rover is powered by a Multi-Mission Radioisotope Thermoelectric Generator, providing approximately 110 watts of electrical power. To meet peak power demand, two Li-Ion rechargeable 42 amp-hour batteries are installed. Furthermore, as a backup measure it has an additional battery system and redundant UHF subsystem with two Electra-Lite radios in case there’s any problems with its primary system.

Before entering Mars’ atmosphere, the spacecraft performed a series of translational propulsive maneuvers to fine-tune its trajectory. This sequence typically lasted seven minutes and became known as “seven minutes of terror”, since any errors could potentially destroy years of hard work and the mission altogether.

Once in Mars’ orbit, another set of maneuvers to further refine its trajectory are performed over 45 days prior to entering its Approach phase and performing a controlled crash landing on Mars.

The Rover enters the atmosphere from a low altitude in order to reduce friction and optimize aerodynamic performance before beginning its final descent for an assisted parachute landing.

Once on board, the Rover began searching for signs of water in rocks immediately. Utilizing its Planetary Instrument for X-ray Lithochemistry (PIXL), which measures chemical signatures of various elements in rocks samples using laser beams, PIXL was able to reveal much about their mineral makeup as well as whether any organic molecules — the building blocks of life — existed within.

Engineers provide the rover with a list of regions it should explore, but once on the surface it takes over making decisions on its own about where and when it will operate. Subha Comandur, lead for CADRE at JPL explains that its software lets it choose among multiple routes or even change direction if something goes awry.

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