NASAs Mars Polar Lander

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					                  Project History
• 1994 Mars Surveyor
  Program

• 1995 Mars Climate Orbiter
  and Mars Polar Lander
  identified

• 1996 Success of Mars
  global surveyor

• 1998 Launch of Mars
  Climate orbiter and Mars
  Polar Lander
               Mars Climate Orbiter

• Launched 11th December     • Root Cause failure to use metric
  1998                         units in navigation software

• Mars Arrival 23rd          • In addition 12 other areas
  September 1999               problematic

• Phase I report published   • 11 of which had direct
  10th November 1999           relevance to Mars Polar Lander
               Mars Polar Lander

• Launched 3rd January 1999   • Lack of evidence makes
• Mars Arrival 3rd December     correct evaluation of cause
  1999                          or causes of failure
• Communications ended as       impossible at this time
  scheduled
• Never resumed
• Probable root cause
  premature shutdown of
  descent engines, due to
  software vulnerability
                  Mission Brief
• Land near Martian South
  Pole
• Carry out research for 3
  months
• Search for signs that
  Mars was, or is, a
  suitable place to sustain
  life
• Detailed climate changes
  on the surface of mars
                     Signs of Life

• Drill down and search for
  frozen water
• Take soil samples and test
• Study weather conditions
• Take photographs
• Record Martian sounds
• Send back information via
  Mars Global Surveyor
                     Specification
• Total cost of project = $120   • Max temp = 1650 °C
  million, $29.6 million +       • Normal temp = -58°C
  launch vehicle about           • Weight = 576 kg total
  $195million in total (MCO        including 64kg propellant,
  = $85 million)                   82kg cruise stage and 140kg
• Primarily solar power with       aero-stage and heat shield.
  internal battery for landing
• Distance travelled = 470
  million miles
• Landing site = 500 miles
  from south pole
Technical Evaluation of
  Mars Polar Lander
          Pre-Entry Events
  Preparations for entry into atmosphere
     will begin 14 hours in advance




Final four-hour tracking session of the cruise
7 hours before entry, a 30 minute tracking session will
begin. If manoeuvre is required, computer commands
  could be sent to the spacecraft during this session.




                                A one-hour tracking
                                session will begin five
                                hours before entry.
10 minutes before entry, the spacecraft will be commanded
to switch to internal navigation, computing its position,
course and speed from gyroscopes and accelerometers.
                               5 minutes before entry and
                               10 minutes before landing,
                               the cruise stage separates
                               from the aero-shell encased
                               lander



6 minutes before entry, the
spacecraft will fire it’s
thrusters for 80 seconds to
turn it to it’s entry orientation
      Entry, Descent and Landing

Travelling at about 6.8
km per second the
spacecraft will enter
the upper fringes of the
Martian atmosphere


                           The Lander will begin
                           using its thrusters to
                           keep the entry capsule
                           aligned with it’s
                           direction of travel
Two minutes before
landing, the Lander’s
parachute will be fired
when the spacecraft is
7.3km above the
Martian surface


                          10 seconds after the
                          parachute opens, the
                          Mars Descent Imager
                          will be powered on and
                          the spacecraft’s heat
                          shield will be jettisoned.
                                  100 seconds before
                                  landing, the Lander
                                  legs will be
                                  deployed; 1.5
                                  seconds after that,
                                  the landing radar
                                  will be activated.


The radar will be able to
gauge the spacecraft’s altitude
about 44 seconds after it is
turned on, at an altitude of
about 2.5km above the surface
Shortly after radar
ground acquisition the
thrusters will be turned
off, and the back shell
will separate from the
lander

                           The descent engines will
                           be turned on half a
                           second later, turning the
                           Lander so it’s flight path
                           gradually becomes
                           vertical
                            Descent engines will
                            maintain the spacecraft’s
                            orientation as it descends




The radar will be
turned off at an altitude
of about 40 metres
above the surface and
the spacecraft will fall
back on it’s inertial
guidance as it lands
At 12 metres the Lander will drop straight down at a
constant speed
                        The descent engines will be
                        turned off when touchdown
                        is detected by sensors in the
                        footpads




The Lander will use the
solar panels to generate
power from the Sun
           What Really Happened?
•   Space craft enters the atmosphere
•   Legs deploy and “jolt” the craft
•   “Jolt” detected by sensors
•   Automatic shut-off of engines


                     Problem?
• Space craft still miles above the surface of the Mars
                        Other Possibilities

•   MPL heat shield is jettisoned early, therefore MPL couldn’t put up with the heat

•   Possible landing but with the DTE antenna pointing downwards

•   It may have landed at the wrong location

•   It may have landed on a gradient of more than 20°
                 What Could Have Been
                  Done to Prevent it?
•   If the team testing the deployment of the legs had conducted the test while also
    testing flight software, the “bug” may have been detected



•   Unfortunately, with the “faster, better, cheaper”, philosophy of NASA at the time,
    integration testing was deemed too expensive and was not completely conducted.
     JPL Special Review Board Report
    on the Failure of Deep Space Probes
•   Probe impact on an ice surface was not a design requirement and was not tested
    during development because this possibility was believed unlikely. This condition
    still seems unlikely but can not ruled out.

•   Both probes suffer electronic or battery failure at impact. (battery test wasn’t
    adequate)

•   Probes failed due to ionization breakdown in Mars atmosphere


•   Probe lands on its side interfering with antenna performance
A Managerial Evaluation of

The Mars Climate Orbiter
         and the
Mars Polar Lander Mishaps
   Measures to be adopted by NASA from
      Project Inception to Completion
• Project should be cheaper, faster and better

• Use of off-the-shelf materials to achieve the same result

• A board to be set up to oversee and communicate with Lockheed Martin Astronautics



                                                 •Use of analysis and modelling as an
                                                 acceptable lower cost approach to system
                                                 testing and validation

                                                 •Limit changes required to correct a known
                                                 problem that is thought not to contribute to
                                                 mission success
Failure of the Mars Climate Orbiter
and the Mars Polar Lander Projects
              Failure was found to be due to one root cause
                  and several other contributing factors


          Root cause for Mars Climate Orbiter failure:
               Use of two different units of measurement;
          Lockheed Martin Astronautics (LMA): Imperial Units
             Jet Propulsion Laboratory (JPL): Metric Units


           Root cause for Mars Polar Lander failure:
Premature shut-off of it’s engines whilst descending to the surface of Mars
            Other Contributing Factors
•   Departure from previous management approaches
•   Lack of a Review Plan
•   Absence of clear communication between subsidiary groups involved
•   Multiple key areas controlled by a single individuals
•   Leadership deficiencies
•   ‘Faster, Cheaper’ mind-set led to a difficult working environment
                           Observations
          • Absence of mission systems engineer during operations phase

     • Inadequate independent verification, validation and testing of software

   • Lack of identification of acceptable risks by operation team in the context of
                         ‘Faster, Cheaper, Better’ philosophy

• Absence of fault tree analysis for determining what could go wrong during mission

   • Project management was too focused on meeting mission costs and schedule
                        objectives, than on mission risk

 • Critical flight decisions did not involve the mission scientists who had the most
      knowledge of Mars, the instruments, and the mission science objectives
      Lessons Learned by Project Team
• Continuously perform system analysis necessary to explicitly identify mission
  risk and communicate these risks to all segments of the project team

• Establish and fully staff a comprehensive systems engineering team

• Engage operations personnel early in project, preferably during mission
  formulation stage

• Systems engineers must work with project managers and other teams to
  mitigate and identify mission risks

• To institutionalise management team to make trade-off decisions
    Lessons Learned (Continued)
• Roles and responsibilities must be made clear

• Strong cohesive force must be developed in the project from
inception to completion

• Acceptable risk must be defined and quantified and
wherever possible communicated throughout the team

• Regular and frequent meetings must be open to all levels of
the program
Final Decision By Board
        Mission Success First

           Philosophy
     Test, Test and Test Some More

               Motto
        Know What You Build
         Test What You Build
          Test What You Fly
          Test Like You Fly
Factors Promoting Project Success

   • Effective and efficient communication

   • Availability of required resources

   • Availability of experienced/professional manpower

   • Good monitoring practices

   • Good project strategic management

   • Un-ambiguity of roles
               Technical Lessons Learnt
                  On top of managerial errors, which obviously had a
                 knock on effect on the technical aspects of the project:

•   Correct testing methods used for all aspects of the mission

•   The technical and design processes should be integrated

•   Each new piece of technology or ideology increases the risk of failure and this
    increased risk should be accounted for
       Evaluation of Plan and Approach
•   No Matter how well you plan, it is   •   Without meeting with NASA
    impossible to plan for every             employees or examining what is left
    eventuality                              of the spacecraft, it will be
                                             impossible to ever get an exact
                                             answer as to what went wrong
•   Overall plan worked well

•   Large amount of slack time useful    •   Information from a significant
                                             amount of sources guaranteed that
                                             the overall picture was complete as
•   Combined view points and
                                             possible
    exchange of ideas
                              Conclusion
•   Faster and Cheaper does not       • European Polar Lander
    automatically equal better

•   Project might not be a complete   • Political issues
    failure

                                      •Only one chance for project to be a success
•   Possible sightings

•   Polar Lander 2000 cancelled       • With failure of Mars Climate Orbiter, project
                                      should have been delayed
                                        Links
•   http://mars.jpl.nasa.gov/msp98/mvacs/overview/timeline.html

•   http://www.spaceref.com/news/viewnews.html?id=105

•   http://www.savethemarslander.org/

•   http://www.space.com/scienceastronomy/solarsystem/mpl_crash_000106.html

•   http://abcnews.go.com/ABC2000/abc2000science/marspolar_speculation991208.html

•   http://www.chron.com/content/interactive/space/astronomy/marspolarlander/000322.html

•   http://www.fas.org/mars/marspolar000328.html

				
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