Sojourner ( Sojourner , Alien ) is a NASA space agency rover launched as part of the Mars Pathfinder program.
| Sojorner | |
|---|---|
 Mars rover Sojorner on Mars (camera shot of the landing station) | |
| Customer |  NASA |
| Operator | |
| Tasks | Exploring mars |
| Launch pad | Cape Canaveral LC17B |
| Launch vehicle | Delta-2 7925 D240 |
| Launch | December 4, 1996 06:58:00 UTC |
| Specifications | |
| Weight | 11.5 kg (≈ 4.5 kg on Mars ) |
| Dimensions | 0.65 × 0.48 × 0.3 m |
| Power | Up to 15 watts of electricity, approximately 150 Wh / h |
| Power supplies | Gallium Arsenide Solar Battery |
| Mover | Maximum speed - 1 cm / sec |
| The term of active existence | Planned: 7 sol Total: 83 sol (unknown) |
| Landing on a celestial body | July 4, 1997 16:56:55 UTC |
| Landing coordinates | , in the Ares Valley |
| Target equipment | |
| two stereo and one single camera | The cameras provide additional data on the state and position of the rover, help to plot a route |
| MAE module | Studying the effects of dust on solar cell performance |
| Alpha Proton X-ray Spectrometer (APXS) | Analysis of the chemical composition of rocks and dust of Mars. |
| Onboard memory | 0.5 MB |
| Project site | |
Content
Title
The name of the rover Sojorner literally means "temporary resident" or "road", it was given by the winner of the vote - a 12-year-old boy from Connecticut , USA [1] . The rover is named after the female fighter against Negro slavery - Sojorner Trut . [1] .
Device
Energy Generation
The Sojorner’s power supply was carried out using one lightweight panel of the solar battery , consisting of 234 individual photovoltaic cells based on gallium / germanium arsenide (GaAs / Ge) [2] . Its power was 15 W (approximately 150 W · h / sol ) [3] . Weight - 0.340 kg. The battery area is 0.22 m². Operating temperature range from -140 to +110 ° C. The size of one cell is 2 × 4 cm. The solar battery is clearly visible in the form of a dark flat panel mounted on the upper part of the rover [2] . Solar cells are very light, thin and fragile. Created by Applied Solar Energy Corporation (ASEC).
Batteries
A hitch of 3 batteries was used as a battery, the total weight of which was 1.24 kg [2] . The battery is 40 mm in diameter and 186 mm in length. The hitch was inside the rover, under the solar panel. Each battery contained three cells based on lithium thionyl chloride (Li-SOCl 2 ). Operating voltage - 8-11 V. The capacity of one cell ranged from 8 Ah at a temperature of -20 ° C and up to 12 Ah at +25 ° C [2] . The weight of one cell is 118 g. The manufacturer is SAFT America.
The mass of the rover (see diagram ) was, together with all the equipment, about 11.5 kg, which corresponds to ≈ 4.5 kg on the surface of Mars. The size of the rover is 0.65 × 0.48 × 0.3 m.
Sojournner had 11 3.2 W 3.201 DC motors RE016DC created by Maxon Motor . Six engines rotate the wheels, one for each wheel, 4 set the direction of movement and the latter raises and lowers the spectrometer. Engines can tolerate temperatures up to −100 ° C [4] .
The rover was equipped with six wheels with a diameter of 13 cm, each of which is able to rotate independently. The device can tilt 45 ° without turning over and overcome obstacles up to 20 cm high.
Battery power was enough to operate the device for several hours a day, even in cloudy weather [3] . In addition, the rover had three radioisotope elements with several grams of plutonium-238 to maintain the required temperature in the electronic unit.
The rover maintained communication with the Earth through the landing station. The antenna of the rover was designed to transmit data at a distance of up to 0.5 km [5] .
The rover was equipped with three cameras - a front stereo system and a rear single camera. The alpha-proton X-ray spectrometer ( APXS ) was almost identical to the spectrometer installed on the Mars-96 spacecraft, the device was created by the Max Planck Society Lindau and the University of Chicago , USA [6] , equipped with a radiation source based on curium-244 manufactured by JSC “SSC RIAR” [7] [8] [9] . The spectrometer could determine the elemental composition of Mars rocks and dust, with the exception of such an element as hydrogen . Sojorner was controlled using an 8-bit Intel 80C85 processor operating at a frequency of 2 MHz (0.1 MIPS performance) [5] , the RAM was 512 KB, and there was also a solid-state flash drive with a memory capacity of 176 KB. The rover software could create 3-D terrain maps based on stereo images created using one of the front stereo cameras [10] . An automatic navigation system takes pictures of nearby areas using one of two stereo cameras. After that, the stereo images are converted into 3-D terrain maps, which are automatically created by the rover software. The software determines the degree of passability, whether the terrain, the height of obstacles, soil density and the angle of inclination of the surface are safe. Of the dozens of possible paths, the rover chooses the shortest, safest path to its target. Then, having traveled from 0.5 to 2 meters (depending on how many obstacles are in its path), the rover stopped, analyzing the obstacles that are nearby. The whole process is repeated until he reaches his goal or until he is ordered to stop from Earth. Sojorner’s security system, Rover Control Software , could capture 20 points at every turn.
| Curiosity | Opportunity / Spirit | Sojorner | |
|---|---|---|---|
| Launch | 2011 | 2003 | 1996 |
| Weight (kg) | 899 | 174 [11] | 10.6 [12] |
| Dimensions (In meters, L × W × H) | 3.1 × 2.7 × 2.1 | 1.6 × 2.3 × 1.5 [11] | 0.7 × 0.5 × 0.3 [12] |
| Energy (kW / sol) | 2.5-2.7 | 0.3-0.9 [13] | <0.1 [14] |
| Scientific instruments | 10 [15] | five | 4 [12] |
| Maximum speed (cm / sec) | four | 5 [16] | 1 [17] |
| Data Transfer (MB / day) | 19-31 | 6-25 [18] | <3.5 [19] |
| Performance ( MIPS ) | 400 | 20 [20] | 0.1 [21] |
| Memory (MB) | 256 [22] | 128 | 0.5 |
| Estimated landing area (km) | 20x7 | 80x12 | 200x100 |
Mission Progress
Mars descended to the surface on July 4, 1997 as part of a lander. The rover was designed for a 7-solo (Sol - Martian day) mission, with the possibility of expanding to 30 sol [5] . Despite this, he worked for 83 sols until the “Pathfinder” descent station, acting as a repeater, failed (after which Rover lost the ability to communicate directly with the Earth); the last contact with her took place at 10:23 UTC on September 27, 1997 [23] , along with this, the connection was also lost with the rover, despite the fact that it was in working condition [23] . The place of the last stop of the rover is still unknown, the future Mars Geoscience Imaging at Centimeter-Scale (MAGIC) camera, whose resolution will be 5 centimeters per pixel, will help to eliminate this gap [24] .
In total, Sojorner covered a distance of about 100 meters [25] before losing communication.
See also
- Mars pathfinder
- Ares Valley
- List of stones on Mars
Notes
- ↑ 1 2 NASA Names First Rover to Explore the Surface of Mars - NASA
- ↑ 1 2 3 4 Mars Microrover Power Subsystem . Jet Propulsion Laboratory (24 July 1997).
- ↑ 1 2 A Description of the Rover Sojourner
- ↑ “Cosmonautics News” No. 18/19, 1997. Article “Mars Pathfinder”
- ↑ 1 2 3 NASA - Mars Pathfinder FAQ
- ↑ NASA - Mars Pathfinder Instrument Descriptions
- ↑ The United States required Russian Curium-244 isotopes To fly to Mars . Lenta.ru (November 28, 2014). Date of treatment February 14, 2019.
- ↑ Sources of curium-244 produced by SSC RIAR will be used by India for flights to the moon . NIIAR (February 14, 2017). Date of treatment February 14, 2019.
- ↑ Rosatom will help India study the moon with radiation . RIA Novosti (February 13, 2017). Date of treatment February 14, 2019.
- ↑ B. Cooper - MFEX: Microrover Flight Experiment - NASA
- ↑ 1 2 Mars Exploration Rover Landings (German) . JPL Date of treatment July 30, 2012.
- ↑ 1 2 3 Mars Pathfinder / Sojourner (German) . NASA Date of treatment July 30, 2012. Archived on February 25, 2014.
- ↑ NASA's 2009 Mars Science Laboratory (German) . JPL Date of treatment June 5, 2011.
- ↑ Pathfinder Mars Mission - Sojourner mini-rover (German) . Date of treatment June 5, 2011.
- ↑ Mars Science Laboratory: NASA Hosts Teleconference About Curiosity Rover Progess
- ↑ Spacecraft: Surface Operations: Rover (German) . JPL Date of treatment July 30, 2012.
- ↑ Introduction to the Mars Microrover (German) . JPL Date of treatment July 30, 2012.
- ↑ Mars Exploration Rover Telecommunications (German) . JPL Date of treatment June 5, 2011.
- ↑ The Robot Hall of Fame: Mars Pathfinder Sojourner Rover (German) . robothalloffame.org . Date of treatment June 5, 2011. Archived on October 7, 2007.
- ↑ Avionics Innovations for the Mars Exploration Rover Mission: Increasing Brain Power (German) . JPL Date of treatment July 30, 2012.
- ↑ Institut für Planetenforschung Berlin-Adlershof (German) . Date of treatment July 27, 2012. Archived March 4, 2016.
- ↑ Mars Science Laboratory , Brains
- ↑ 1 2 Mars Pathfinder - Welcome to Mars - Sol 86
- ↑ A. Ravine, et al. - GEOSCIENCE IMAGING AT CENTIMETER-SCALE (MAGIC) FROM ORBIT. (2012)
- ↑ Sojourner ( inaccessible link) . Archived on March 20, 2015.
Research spacecraft landing locations on Mars map
Spirit
Opportunity
Sojorner
Viking 1
Viking 2
Phoenix
Mars 3
Curiosity
Schiaparelli