(BEING CONTINUED FROM 24/10/12)
E)Mars Pathfinder / Sojourner Rover
This artist’s concept shows the Mars Pathfinder lander and its Sojourner rover on Mars. Image credit: NASA/JPL-Caltech
The Mars Pathfinder Sojourner Rover, a lightweight machine on wheels, accomplished a revolutionary feat on the surface of Mars. For the first time, a thinking robot equipped with sophisticated laser eyes and automated programming reacted to unplanned events on the surface of another planet.
After a few days on the Martian surface the NASA controllers turned on Sojourner’s hazard avoidance system and asked it to start making some of its own decisions. This hazard avoidance system set the rover apart from all other machines that have explored space. Sojourner made trips between designated points without the benefit of detailed information to warn it of obstacles along the way
Sojourner moved slowly at one and one half feet per minute and stopped a lot along the way to sense the terrain and process information, but there was no hurry on Mars which is not visited very often.
Sojourner was carried to Mars by Pathfinder which launched on December 4, 1996 and reached Mars on July 4, 1997, directly entering the planet’s atmosphere and bouncing on inflated airbags.
Sojourner was designed by a large NASA team lead by Jacob Matijevic and Donna Shirley.
Sojouner traveled a total of about 100 meters (328 feet) in 230 commanded maneuvers, performed more than 16 chemical analyses of rocks and soil, carried out soil mechanics and technology experiments, and explored about 250 square meters (2691 square feet) of the Martian surface. During the mission, the spacecraft relayed an unprecedented 2.3 gigabits of data, including 16,500 images from the lander’s camera, 550 images from the rover camera, 16 chemical analyses of rocks and soil, and 8.5 million measurements of atmospheric pressure, temperature and wind.
The flight team lost communication with the Sojouner September 27, after 83 days of daily commanding and data return. In all, the small 10.5 kilogram (23 lb) Sojouner operated 12 times its expected lifetime of seven days.
CT)Mars Polar Lander / Deep Space 2
Mars Polar Lander
- 01.03.99: Launch (20:21:10 UT)
- 12.03.99: Contact Lost (20:00 UT)
- Status: Crashed on Mars
- MVACS Mars volatile and climate surveyor instrument package
- SSI stereo surface imager
- RA robotic arm
- MET meteorology package
- TEGA thermal and evolved gas analyzer
- RAC robotic arm camera
- MARDI Mars descent imager
- LIDAR light detection and ranging instrument
Mars Polar Lander Mission Information:
The Mars Surveyor ’98 program is comprised of two spacecraft launched separately, the Mars Climate Orbiter (formerly the Mars Surveyor ’98 Orbiter) and the Mars Polar Lander (formerly the Mars Surveyor ’98 Lander). The two missions were designed to study the Martian weather, climate, and water and carbon dioxide budget, in order to understand the reservoirs, behavior, and atmospheric role of volatiles and to search for evidence of long-term and episodic climate changes.
The last telemetry from Mars Polar Lander was sent just prior to atmospheric entry on 3 December 1999. No further signals have been received from the lander, the cause of this loss of communication is not known.
Launched in January 1999, Mars Polar Lander was to be the first-ever landing in the polar regions of Mars, near the southern polar cap. Its primary goal was to deploy a lander and two penetrators (known as Deep Space 2) on the surface of Mars to extend our knowledge on the planet’s past and present water resources. The objective was to explore the never-before-studied carbon dioxide icecap about 1,000 kilometers from the south pole.
Two small microprobes – the Deep Space 2 technology mission – hitched a ride to Mars on the Lander, with the goal of penetrating into the Martian subsurface to detect water ice.
Mars Polar Lander and the attached Deep Space 2 probes were launched on a Delta 7425 (a Delta II Lite launch vehicle with four strap-on solid-rocket boosters and a Star 48 (PAM-D) third stage) which placed them into a low-Earth parking orbit. The third stage fired for 88 seconds at 20:57 UT 3 January 1999 to put the spacecraft into a Mars transfer trajectory and the spacecraft and third stage separated at 21:03 UT. Trajectory correction maneuvers were performed on 21 January, 15 March, 1 September, 30 October, and 30 November 1999.
After an 11 month hyperbolic transfer cruise, the Mars Polar Lander reached Mars on 3 December 1999. A final 30 minute tracking session begins at approximately 12:45 UT (7:45 a.m. EST) and was used to determine if a final thruster correction was necessary. Final contact to retrieve data on the status of the propulsion system was made from approximately 19:45 UT to 20:00 UT. At approximately 20:04, 6 minutes before atmospheric entry, an 80 second thruster firing was to turn the craft to its entry orientation. The Star 48 upper cruise stage was to be jettisoned at about 20:05 UT, and about 18 seconds later the microprobes were to be dropped from the cruise stage into the martian atmosphere (also targeted at the southern polar layered terrain). The lander was to make a direct entry into Mars’ atmosphere at 6.8 km/s at about 20:10 UT (3:10 p.m. EST). Due to lack of communication, it is not known at this time whether all these steps following final contact were executed, nor whether any of the descent plan described below took place as designed.
The lander would have touched down at approximately 20:15 UT Earth received time (3:15 p.m. EST) in the late southern spring season, during which the Sun will always be above the horizon at the landing site. The other times listed above are also Earth received times, light travel time from Mars at that point was approximately 14 minutes.
Immediately after landing the solar panels were to be deployed. The first signal from the lander was to reach Earth at 20:39 UT (3:39 p.m. EST), but was never received.
An independent investigation into the failure, whose results were released publicly on 28 March 2000, indicated that the most probable cause of the failure was the generation of spurious signals when the lander’s legs deployed during the descent. These signals falsely indicated that the spacecraft had touched down on Mars when in fact it was still descending. The main engines prematurely shut down, and the lander fell to the Martian landscape.
Just two weeks after landing its Curiosity rover on Mars, the US space agency has announced it will send another robot to the planet in 2016.
The InSight spacecraft will be a static lander that will carry instruments to investigate Mars’ deep interior.
Scientists say this will give them a clearer idea of how the rocky planets formed – the Earth included.
InSight beat two other proposals in a competition to find Nasa’s next relatively low-cost mission.
This so-called Discovery class of endeavour is cost-capped at $425m (£270m; 345m euros), although that figure does not include the rocket to launch the spacecraft.
InSight stands for Interior Exploration using Seismic Investigations, Geodesy and Heat Transport.
InSight – Mission to Mars’ interior
- Launch window: 8-27 March 2016
- Landing: 20 September 2016
- Destination: Flat equatorial plain
- Mission length: Two Earth years
- Cost: $425m cap (without rocket)
It will be led from the Jet Propulsion Laboratory (JPL) in Pasadena, California.
The design of the lander leans heavily on the successful Phoenix probe put on the Red Planet in 2008. But although the 2016 venture will look very similar, it will carry very different instrumentation.
A seismic experiment will listen for “marsquakes” and use this information to map the boundaries between the rock layers inside Earth’s neighbour.
It will determine if the planet has a liquid or solid core, and provide some clues as to why its surface is not divided up into tectonic plates as on Earth.
Key components of this package will come from France and the UK.
InSight will also push a German-built thermal probe into the surface to gauge Mars’ temperature profile. This will reveal how the planet is cooling.
The giant shield volcano Olympus Mons is evidence of Mars’ geologically much more active past
JPL will provide the two cameras on InSight and a robotic arm.
It will also deliver another sensor that will very accurately determine the degree to which the planet wobbles on its axis.
All the data combined will inform researchers about the internal state of Mars today and how it has changed through the eons.
“This is science that has been compelling for many years,” said John Grunsfeld, who heads up Nasa’s science division.
“Seismology, for instance, is the standard method by which we’ve learned to understand the interior of the Earth – and we have no such knowledge for Mars.
“This has been something the principal investigator (JPL’s Bruce Banerdt) of this mission has been trying to get to Mars for nearly three decades, and so I’m really thrilled that this is now at a mature stage where he has been able to propose something that fits within the cost and schedule constraints of the Discovery programme.”
It is clear from surface features that the Red Planet was much more geologically active in the past. The remains of the largest volcano in the Solar System – Olympus Mons – can be seen on Mars.
When and why this activity waned remains to be established, but it is an issue that plays directly to the question of life on the planet.
The 1970s Viking landers carried seismometers but did not return the information hoped for
Earth retains an atmosphere and water at its surface because of the protective magnetic field generated in its liquid iron/nickel core.
At some point, Mars lost its global magnetic shield and that allowed the stream of particles billowing away from the Sun – the “solar wind” – to strip away the planet’s atmosphere, leading to the loss also of its surface water. This change may have stifled any chance for life to establish itself on Mars.
Tom Pike from Imperial College London, UK, will be working on the mission.
He told BBC News: “This is not going to be a mission of pretty pictures like Curiosity, but when we get the first marsquakes I think that is going to be a really cool data set.
“We’ll be doing comparative planetology. We know the internal structure of the Earth, but we have nothing to compare it with.
“We don’t know if Earth is a special case or a more general case. A lot of science is based on it being a more general case because that allows you to develop theories about how the core formed, the mantle around it and then the crust on top. But we’d really like to test this out on another planet.
“InSight will enable us to do that Mars.”
Curiosity 360 panorama
Nasa is currently basking in the success of its Curiosity rover, which landed on the planet two weeks ago. That mission, by comparison, is costing $2.5bn (£1.6bn; 2bn euros).
The space agency says the InSight selection was made before the six-wheeled vehicle touched down and so was not influenced in any way by recent events.
The outlook for American Mars scientists now looks considerably brighter than it did at the beginning of the year.
Back in February, they were told Nasa’s budget for Red Planet exploration would be cut back sharply; and many feared that if Curiosity was lost during its risky landing, they might not see another US-led Martian lander for perhaps 10 years.
The two missions that missed out in the final Discovery selection were:
- Titan Mare Explorer – Billed as the first direct exploration of an ocean environment beyond Earth. This would put a “boat” on a large methane-ethane sea on Saturn’s moon Titan.
- Comet Hopper – This would study cometary evolution by landing on a comet multiple times and observing its changes as it interacted with the Sun.
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