Mars Pathfinder 20th anniversary HD video

The Rocketry Forum

Help Support The Rocketry Forum:


Lorenzo von Matterhorn
Jan 31, 2009
Reaction score
On July 4, 1997, NASA's Mars Pathfinder lander and Sojourner rover successfully landed on the Red Planet utilizing a revolutionary airbag landing system. This special 20th anniversary show chronicles the stories and the people behind the groundbreaking mission that jump-started 20 years of continuous presence at Mars.

Panel discussion interspersed with documentary video:


Although the mission was planned to last from a week to a month, the rover operated successfully for almost three months. Communication failed after 7 October, with a final data transmission received from Pathfinder at 10:23 UTC on September 27, 1997. Mission managers tried to restore full communications during the following five months, but the mission was terminated on March 10, 1998. During the extended operation a high-resolution stereo panorama of the surrounding terrain was being made, and the Sojourner rover was to visit a distant ridge, but the panorama was only about one-third completed and the ridge visit had not begun when communication failed.

The on-board battery—designed to operate for one month—may have failed after repeated charging and discharging. The battery was used to heat the probe's electronics to slightly above the expected nighttime temperatures on Mars. With the failure of the battery, colder-than-normal temperatures may have caused vital parts to break, leading to loss of communications.

After the landing, Pathfinder was renamed as the Sagan Memorial Station in honor of astronomer and planetologist Carl Sagan. The mission had exceeded its goals in the first month.

After the power failure on the lander, the solar powered rover would have continued to move around the lander every day in an attempt to reestablish comm with it until the rover itself died or got stuck and died. Too bad the winds and dust will have long ago erased its path by the time someone actually visits it.

Pathfinder's Sojourner Mars microrover tech info.:



The power generated by the solar array and batteries is conditioned and distributed using a complex arrangement of Power Electronics. The electronics are fully integrated with the navigation and computer electronics to save money, space, and mass, and yet still provide more than ten different voltages to the various Rover hardware. Most of the power electronic components used are commercially available.

The 'Sojourner' rover has only a single CPU used in its operation. The computer is an 80C85 with a 2MHz clock rated at 100KIPS. It can address 64K of memory. The computer uses, in a 16Kbyte page swapping fashion, the memory provided in 4 different chip types:

16K - PROM, Harris 6617 - Boot code and 'Rover-Lite' backup code
64K - RAM, IBM 2586 - Main memory
176K - 5 each Seeq 28C256 32Kbyte rad hardened EEPROM - Programs, patches and nonvolatile data storage
512K - Micron MT1008 RAM - Temporary data storage

Rover electronics. Beautiful...:

Rover images:

Hopefully flying on the 2020 lander:

Mars Helicopter Scout


NASA Helicopter Could Fly on Mars

The U.S. House of Representatives has approved $15 million to continue development of a 2.2-pound NASA unmanned helicopter with twin contra-rotating blades designed to fly on Mars. The autonomous helicopter is slated to be included on a 2020 mission to the Red Planet and is designed to fly ahead of a surface rover for two to three minutes per day as a scout vehicle, before returning to the rover to recharge its solar batteries. Accounting for the low atmospheric pressure on Mars, the rotor disc of the proposed prototype spans 3.6 feet and supports a body that resembles a medium-sized tissue box and is hardened against solar radiation. The current design has been tested at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.

NASA says the Mars Helicopter could triple a rover’s daily range by delivering visual information that will help engineers on Earth plan the best driving route. The rover will be specially instrumented to detect scientific indications of past or present life on the planet. Images from the helicopter could also be used to look for features for the rover to study in more detail and to select samples of rocks for a cache to be collected by follow-on vehicles.

Scientists have been working on the concept of a Mars Helicopter since the 1990s; however, early efforts were set back by the large size required, available battery technology and lengthy charging times.



Lorenzo von Matterhorn
Jan 31, 2009
Reaction score
Mars Pathfinder - First Mars Rover Movies - AI interpolation, Sojourner, Mars Lander, 1997, NASA

Sojourner (rover)

Sojourner is a robotic Mars rover that landed on July 4, 1997 in the Ares Vallis region. The rover was the first wheeled vehicle to rove another planet, and was part of the Mars Pathfinder mission. It had front and rear cameras and hardware to conduct several scientific experiments. Designed for a mission lasting 7 sols, with possible extension to 30 sols, it was ultimately active for 83 sols (85 Earth days). The rover communicated with Earth through the Pathfinder base station, which had its last communication session with Earth at 3:23 a.m. PDT on September 27, 1997. This marked the end of the Sojourner mission as well. Sojourner traveled a distance of just over 100 meters (330 ft) by the time communication was lost. It was instructed to stay stationary until October 5, 1997 (sol 91) and then drive around the lander. [They fail to make it clear that that was the pre-programmed instruction for the rover to circle the lander if it lost communications in an attempt to regain comm. When the lander failed, the rover lost comm, so the rover would have continued to circle the lander every day for an unknown number of days until it failed or got stuck. Who knows how many days that was. - W]

Sojourner has solar panels and a non-rechargeable battery, which allowed limited nocturnal operations. Once the batteries were depleted, it could only operate during the day. The batteries are lithium-thionyl chloride (LiSOCl2) and could provide 150 watt-hours. The batteries also allowed the health of the rover to be checked while enclosed in the cruise stage while en route to Mars.

0.22 square meters of solar cells could produce a maximum of about 15 watts on Mars, depending on conditions. The cells were GaAs/Ge (Gallium Arsenide/Germanium) and capable of about 18 percent efficiency. They could survive down to about −140° Celsius (−220 °F).

Its central processing unit (CPU) is an 80C85 with a 2 MHz clock, addressing 64 Kbytes of memory. It has four memory stores; the previously mentioned 64 Kbytes of RAM (made by IBM) for the main processor, 16 Kbytes of radiation-hardened PROM (made by Harris), 176 Kbytes of non-volatile storage (made by Seeq Technology), and 512 Kbytes of temporary data storage (made by Micron). The electronics were housed inside the Warm Electronics Box inside the rover.

Sojourner communicated with its base station using a 9,600 baud radio modem, although error-checking protocols limited communications to a functional data rate of 2,400 baud with a theoretical range of about half a kilometer. Under normal operation, it would periodically send a "heartbeat" message to the lander. If no response was given, the rover could autonomously travel back to the location at which the last heartbeat was received. If desired, this same strategy could be used to deliberately extend the rover's operational range beyond that of its radio transceiver, although the rover rarely traveled further than 10 meters from Pathfinder during its mission.

The UHF radio modems worked similar to walkie-talkies, but sent data, not voice. It could send or receive, but not both at same time, which is known as half-duplex. The data was communicated in bursts of 2 kilobytes.

Historical Mars Pathfinder Images

The High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter took an image on Dec. 21, 2006, that provides unprecedented detail of the geology of the region and hardware on the surface.