DOCSLIB.ORG

L02: Case Studies: the Mars Program

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
L02: Case Studies: the Mars Program University of Toronto Department of Computer Science University of Toronto Department of Computer Science Lecture 2: NASA JPL’s Mars Program Examples of Poor Engineering Mission Launch Date Arrival Date Outcome Viking I 20 Aug 1975 Landed 20 Jul 1976 Operated until 1982 Viking II 9 Sept 1975 Landed 3 Sept 1976 Operated until 1980 ➜ “Software Forensics” Case Studies: Mars Pathfinder Mars Observer 25 Sept 1992 Last contact: Contact lost just Mars Climate Observer 22 Aug 1993 before orbit insertion Mars Polar Lander Pathfinder 4 Dec 1996 Landed Operated until 27 Sept Deep Space 2 4 July 1997 1997 Global Surveyor 7 Nov 1996 Orbit attained Still operational ➜ Some conclusions 12 Sept 1997 e.g. Reliable software has very little to do with writing good programs Climate Orbiter 11 Dec 1998 Last contact: Contact lost just 23 Sept 1999 before orbit insertion e.g. Humans make mistakes, but good engineering practice catches them! Polar Lander 3 Jan 1999 Last contact: Contact lost before 3 Dec 1999 descent Deep Space 2 3 Jan 1999 Last contact: No data was ever 3 Dec 1999 retrieved Mars Odyssey 7 Apr 2001 Expected: October 24, 2001 © 2001, Steve Easterbrook 1 © 2001, Steve Easterbrook 2 University of Toronto Department of Computer Science University of Toronto Department of Computer Science Mars Pathfinder Remember these pictures? ➜ Mission Demonstrate new landing techniques parachute and airbags Take pictures Analyze soil samples Demonstrate mobile robot technology Sojourner ➜ Major success on all fronts Returned 2.3 billion bits of information 16,500 images from the Lander 550 images from the Rover 15 chemical analyses of rocks & soil Lots of weather data Both Lander and Rover outlived their design life Broke all records for number of hits on a website!!! © 2001, Steve Easterbrook 3 © 2001, Steve Easterbrook 4 University of Toronto Department of Computer Science University of Toronto Department of Computer Science Pathfinder had Software Errors Mars Climate Orbiter ➜ Symptoms ➜ Launched Software did total system resets 11 Dec 1998 Symptoms noticed soon after Pathfinder started collecting meteorological data Some data lost each time ➜ Mission ➜ Cause interplanetary weather satellite 3 Process threads, with bus access via mutual exclusion locks (mutexs): communications relay for Mars Polar High priority: Information Bus Manager Lander Low priority: Meteorological Data Gathering Task Medium priority: Communications Task ➜ Fate: Priority Inversion: Arrived 23 Sept 1999 Low priority task gets mutex to transfer data to the bus No signal received after initial orbit High priority task blocked until mutex is released insertion Medium priority task pre-empts low priority task Eventually a watchdog timer notices Bus Manager hasn’t run for some time… ➜ Cause: ➜ Factors Faulty navigation data caused by Very hard to diagnose: failure to convert imperial to metric Hard to reproduce units Need full tracing switched on to analyze what happened Was experienced a couple of times in pre-flight testing Never reproduced or explained Hence testers assumed it was a hardware glitch © 2001, Steve Easterbrook 5 © 2001, Steve Easterbrook 6 University of Toronto Department of Computer Science University of Toronto Department of Computer Science Small Forces... MCO Navigation Error ➜ Locus of error Estimated trajectory Ground software file called “Small Forces” gives thruster performance data TCM-4 and AMD ∆V’s This data used to process telemetry from the spacecraft Spacecraft signals each Angular Momentum Desaturation (AMD) maneuver Small Forces data used to compute effect on trajectory Software underestimated effect by factor of 4.45 TCM-4 2 26 ➜ Cause of error km Small Forces Data given in Pounds-seconds (lbf-s) Actual trajectory 5 e 7k s Larger AMD ∆V’s and AMD ∆V’s m p The specification called for Newton-seconds (N-s) a ri Driving trajectory down e ➜ Result of error relative to ecliptic plane P As spacecraft approaches orbit insertion, trajectory is corrected Aimed for periapse of 226km on first orbit Mars Estimates were adjusted as the spacecraft approached orbit insertion: 1 week prior: first periapse estimated at 150-170km 1 hour prior: this was down to 110km Minimum periapse considered survivable is 80km MCO entered Mars occultation 49 seconds earlier than predicted Signal was never regained after the predicted 21 minute occultation To Earth Subsequent analysis estimates first periapse of 57km © 2001, Steve Easterbrook 7 © 2001, Steve Easterbrook 8 University of Toronto Department of Computer Science University of Toronto Department of Computer Science Contributing Factors Mars Polar Lander ➜ For 4 months, AMD data not ➜ Operations Navigation team ➜ Launched used due to file format errors unfamiliar with spacecraft 3 Jan 1999 Navigators calculated data by hand Different team from development & test File format fixed by April 1999 Did not fully understand the significance ➜ Mission Anomalies in trajectory became of the anomalies Land near South Pole apparent almost immediately Familiarity with previous mission (MGS) assumed sufficient: Dig for water ice with a robotic ➜ Limited ability to investigate: but AMD was performed 10-14 arm Thrust effects measured along line of times more often on MCO as it has ➜ sight using doppler shift asymmetric solar panels. Fate: AMD thrusts are mainly perpendicular ➜ Arrived 3 Dec 1999 to Earth-spacecraft line of sight Inadequate Testing Software Interface Spec not used No signal received after initial ➜ Poor communication between during unit testing of small forces s/w phase of descent teams: End-to-end test of ground software ➜ E.g. Issue tracking system not never completed Cause: properly used by navigation team Ground software was not considered Several candidate causes Anomalies not properly investigated “mission critical” so less rigorous V&V Most likely is premature engine ➜ ➜ shutdown due to noise on leg Inadequate staffing Inadequate Reviews sensors Operations team monitoring three Key personnel missing from critical missions simultaneously (MGS, MCO design reviews and MPL) © 2001, Steve Easterbrook 9 © 2001, Steve Easterbrook 10 University of Toronto Department of Computer Science University of Toronto Department of Computer Science What happened? Premature Shutdown Scenario ➜ ➜ Cause of error Investigation hampered by Magnetic sensor on each leg senses touchdown lack of data Legs unfold at 1500m above surface spacecraft not designed to send transient signals on touchdown sensors during unfolding telemetry during descent software accepts touchdown signals if they persist for 2 timeframes This decision severely criticized by transient signals likely to be long enough on at least one leg review boards ➜ ➜ Factors Possible causes: System requirement to ignore the transient signals Lander failed to separate from cruise But the software requirements did not describe the effect stage (plausible but unlikely) s/w designers didn’t understand the effect, so didn’t implement the requirement Landing site was too steep (plausible) Engineers present at code inspection didn’t understand the effect Heatshield failed (plausible) Not caught in testing because: Loss of control due to dynamic Unit testing didn’t include the transients effects (plausible) Sensors improperly wired during integration tests (no touchdown detected!) Loss of control due to center-of- Full test not repeated after re-wiring mass shift (plausible) Premature Shutdown of Descent ➜ Result of error Engines (most likely!) Engines shut down before spacecraft has landed Parachute drapes over lander When engine shutdown s/w enabled, flags indicated touchdown already occurred (plausible) estimated at 40m above surface, travelling at 13 m/s Backshell hits lander (plausible but estimated impact velocity 22m/s (spacecraft would not survive this) unlikely) nominal touchdown velocity 2.4m/s © 2001, Steve Easterbrook 11 © 2001, Steve Easterbrook 12 University of Toronto Department of Computer Science University of Toronto Department of Computer Science STS Ariane Path- Factor MCO MPL DS-2 Deep Space 2 51L 501 finder Didn’t test to spec ? ➜ Launched Insufficient test data 3 Jan 1999 Tested “wrong” system No regression test ➜ Mission Lack of integration testing 2 small probes piggybacked on Mars Lack of expertise at inspections Polar Lander System changed after testing ? Demonstration of new technology Reqt not implemented ? Separate from MPL 5 minutes before Lack of diagnostic data during ops atmosphere entry S/W used before ready ?? Bury themselves in Martian Soil Different team maintains S/W Return data on soil analysis and look Didn’t use problem reporting system ? for water Didn’t track problems properly ? ➜ Fate: Didn’t investigate anomalies Poor communication between teams ? No signals were received after launch Insufficient staffing ➜ Cause: Failure to adjust budget and schedule Inexperienced managers ? Unknown Commercial pressures took priority (System was not ready for launch) reused code w/o checking assumptions ‘Redundant’ design not redundant © 2001, Steve Easterbrook 13 © 2001, Steve Easterbrook 14 University of Toronto Department of Computer Science University of Toronto Department of Computer Science Summary Resource List ➜ ➜ Mars Observer Failures can usually be traced to a single root cause Project summary http://www.msss.com/mars/observer/project/mo_loss/moloss.html But good engineering practice should prevent these
Load more

Recommended publications
  • Deep Space 2: the Mars Microprobe Project and Beyond
    First International Conference on Mars Polar Science 3039.pdf DEEP SPACE 2: THE MARS MICROPROBE PROJECT AND BEYOND. S. E. Smrekar and S. A. Gavit, Mail Stop 183-501, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasa- dena CA 91109, USA ([email protected]). Mission Overview: The Mars Microprobe Proj- System Design, Technologies, and Instruments: ect, or Deep Space 2 (DS2), is the second of the New Telecommunications. The DS2 telecom system, Millennium Program planetary missions and is de- which is mounted on the aftbody electronics plate, signed to enable future space science network mis- relays data back to earth via the Mars Global Surveyor sions through flight validation of new technologies. A spacecraft which passes overhead approximately once secondary goal is the collection of meaningful science every 2 hours. The receiver and transmitter operate in data. Two micropenetrators will be deployed to carry the Ultraviolet Frequency Range (UHF) and data is out surface and subsurface science. returned at a rate of 7 Kbits/second. The penetrators are being carried as a piggyback Ultra-low-temperature lithium primary battery. payload on the Mars Polar Lander cruise ring and will One challenging aspect of the microprobe design is be launched in January of 1999. The Microprobe has the thermal environment. The batteries are likely to no active control, attitude determination, or propulsive stay no warmer than -78° C. A lithium-thionyl pri- systems. It is a single stage from separation until mary battery was developed to survive the extreme landing and will passively orient itself due to its aero- temperature, with a 6 to 14 V range and a 3-year shelf dynamic design (Fig.
    [Show full text]
  • Mars Exploration - a Story Fifty Years Long Giuseppe Pezzella and Antonio Viviani
    Chapter Introductory Chapter: Mars Exploration - A Story Fifty Years Long Giuseppe Pezzella and Antonio Viviani 1. Introduction Mars has been a goal of exploration programs of the most important space agencies all over the world for decades. It is, in fact, the most investigated celestial body of the Solar System. Mars robotic exploration began in the 1960s of the twentieth century by means of several space probes sent by the United States (US) and the Soviet Union (USSR). In the recent past, also European, Japanese, and Indian spacecrafts reached Mars; while other countries, such as China and the United Arab Emirates, aim to send spacecraft toward the red planet in the next future. 1.1 Exploration aims The high number of mission explorations to Mars clearly points out the impor- tance of Mars within the Solar System. Thus, the question is: “Why this great interest in Mars exploration?” The interest in Mars is due to several practical, scientific, and strategic reasons. In the practical sense, Mars is the most accessible planet in the Solar System [1]. It is the second closest planet to Earth, besides Venus, averaging about 360 million kilometers apart between the furthest and closest points in its orbit. Earth and Mars feature great similarities. For instance, both planets rotate on an axis with quite the same rotation velocity and tilt angle. The length of a day on Earth is 24 h, while slightly longer on Mars at 24 h and 37 min. The tilt of Earth axis is 23.5 deg, and Mars tilts slightly more at 25.2 deg [2].
    [Show full text]
  • The Evolving Launch Vehicle Market Supply and the Effect on Future NASA Missions
    Presented at the 2007 ISPA/SCEA Joint Annual International Conference and Workshop - www.iceaaonline.com The Evolving Launch Vehicle Market Supply and the Effect on Future NASA Missions Presented at the 2007 ISPA/SCEA Joint International Conference & Workshop June 12-15, New Orleans, LA Bob Bitten, Debra Emmons, Claude Freaner 1 Presented at the 2007 ISPA/SCEA Joint Annual International Conference and Workshop - www.iceaaonline.com Abstract • The upcoming retirement of the Delta II family of launch vehicles leaves a performance gap between small expendable launch vehicles, such as the Pegasus and Taurus, and large vehicles, such as the Delta IV and Atlas V families • This performance gap may lead to a variety of progressions including – large satellites that utilize the full capability of the larger launch vehicles, – medium size satellites that would require dual manifesting on the larger vehicles or – smaller satellites missions that would require a large number of smaller launch vehicles • This paper offers some comparative costs of co-manifesting single- instrument missions on a Delta IV/Atlas V, versus placing several instruments on a larger bus and using a Delta IV/Atlas V, as well as considering smaller, single instrument missions launched on a Minotaur or Taurus • This paper presents the results of a parametric study investigating the cost- effectiveness of different alternatives and their effect on future NASA missions that fall into the Small Explorer (SMEX), Medium Explorer (MIDEX), Earth System Science Pathfinder (ESSP), Discovery,
    [Show full text]
  • Report on the Loss of the Mars Polar Lander and Deep Space 2 Missions
    Report on the Loss of the Mars Polar Lander and Deep Space 2 Missions JPL Special Review Board 22 March 2000 JPL D-18709 REPORT ON THE LOSS OF MARS POLAR LANDER / DEEP SPACE 2 JPL SPECIAL REVIEW BOARD — SIGNATURE PAGE — Mars Polar Lander/Deep Space 2 Loss — JPL Special Review Board Report JPL D-18709 — page iii CONTENTS List of Tables........................................................................................................................................ vii List of Figures ...................................................................................................................................... vii Acronyms and Abbreviations.............................................................................................................. viii EXECUTIVE SUMMARY................................................................................................... xi 1INTRODUCTION .......................................................................................................................... 1 1.1 Mars Surveyor Program ......................................................................................................................... 1 1.2 Loss of the Mars Climate Orbiter Mission ........................................................................................... 1 1.2.1 Investigation of the MCO Loss .................................................................................................................. 1 1.2.2 Post-MCO Corrective Actions for Mars Polar Lander ...........................................................................
    [Show full text]
  • Phoenix Descending NASA’S Mars Strategy Goes from “Follow the Water” to “Arrive at the Ice”
    NEWS NATURE|Vol 453|8 May 2008 Phoenix descending NASA’s Mars strategy goes from “follow the water” to “arrive at the ice”. Since 2001, the slogan for from hardware and software. NASA’s Mars programme has “We may not succeed, but we NASA been “follow the water”. deserve to succeed,” he says. With Phoenix, a US$420- Engineers at the Jet Propul- million mission to the edge of sion Laboratory in Pasadena, the planet’s north ice cap, the California, which runs most of agency hopes to finally touch NASA’s planetary missions, will its quarry, in the form of dirty have their last chance to tweak water ice scraped from the the trajectory on 24 May. The subsurface and melted in the next day, Phoenix is expected probe’s on-board ovens. to use the planet’s atmosphere, If all goes as planned, Phoenix and its own heat shielding, will reach the end of its 680- parachutes and retrorockets, to million-kilometre, 10-month- slow itself down from an orbital long journey on 25 May. Its speed of 20,000 kilometres per landing site is in a region where hour to a soft, safe landing at NASA’s orbiting Mars Odyssey just 2.4 metres per second. spacecraft has detected gamma-ray and neu- Phoenix, a 350-kilogram lander, inherited Smith and his team hope that the ice and soil tron signatures suggesting a significant amount hardware from the Mars Surveyor Lander, a samples they will study with the spacecraft’s of hydrogen — thought to be a constituent of mission cancelled in 2000 after the failure of mass-spectrometer and chemical analysis sys- frozen water — near the surface.
    [Show full text]
  • Mars Program Independent Assessment Team Summary Report
    Mars Program Independent Assessment Team Summary Report March 14, 2000 Mars Climate Orbiter failed to achieve Mars orbit on September 23, 1999. On December 3, 1999, Mars Polar Lander and two Deep Space 2 microprobes failed. As a result, the NASA Administrator established the Mars Program Independent Assessment Team (MPIAT) with the following charter: Review and Analyze Successes and Failures of Recent Mars and Deep Space Missions − Mars Global Surveyor – Mars Climate Orbiter − Pathfinder – Mars Polar Lander − Deep Space 1 – Deep Space 2 Examine the Relationship Between and Among − NASA Jet Propulsion Laboratory (JPL) − California Institute of Technology (Caltech) − NASA Headquarters − Industry Partners Assess Effectiveness of Involvement of Scientists Identify Lessons Learned From Successes and Failures Review Revised Mars Surveyor Program to Assure Lessons Learned Are Utilized Oversee Mars Polar Lander and Deep Space 2 Failure Reviews Complete by March 15, 2000 In-depth reviews were conducted at NASA Headquarters, JPL, and Lockheed Martin Astronautics (LMA). Structured reviews, informal sessions with numerous Mars Program participants, and extensive debate and discussion within the MPIAT establish the basis for this report. The review process began on January 7, 2000, and concluded with a briefing to the NASA Administrator on March 14, 2000. This report represents the integrated views of the members of the MPIAT who are identified in the appendix. In total, three related reports have been produced: this report, a more detailed report titled “Mars Program Independent Assessment Team Report” (dated March 14, 2000), and the “Report on the Loss of the Mars Polar Lander and Deep Space 2 Missions” (dated March 22, 2000).
    [Show full text]
  • Solar-System-Wide Significance of Mars Polar Science
    Solar-System-Wide Significance of Mars Polar Science A White Paper submitted to the Planetary Sciences Decadal Survey 2023-2032 Point of Contact: Isaac B. Smith ([email protected]) Phone: 647-233-3374 York University and Planetary Science Institute 4700 Keele St, Toronto, Ontario, Canada Acknowledgements: A portion of the research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004). © 2020. All rights reserved. 1 This list includes many of the hundreds of current students and scientists who have made significant contributions to Mars Polar Science in the past decade. Every name listed represents a person who asked to join the white paper or agreed to be listed and provided some comments. Author List: I. B. Smith York University, PSI W. M. Calvin University of Nevada Reno D. E. Smith Massachusetts Institute of Technology C. Hansen Planetary Science Institute S. Diniega Jet Propulsion Laboratory, Caltech A. McEwen Lunar and Planetary Laboratory N. Thomas Universität Bern D. Banfield Cornell University T. N. Titus U.S. Geological Survey P. Becerra Universität Bern M. Kahre NASA Ames Research Center F. Forget Sorbonne Université M. Hecht MIT Haystack Observatory S. Byrne University of Arizona C. S. Hvidberg University of Copenhagen P. O. Hayne University of Colorado LASP J. W. Head III Brown University M. Mellon Cornell University B. Horgan Purdue University J. Mustard Brown University J. W. Holt Lunar and Planetary Laboratory A. Howard Planetary Science Institute D. McCleese Caltech C. Stoker NASA Ames Research Center P. James Space Science Institute N.
    [Show full text]
  • + Mars Reconnaissance Orbiter Launch Press
    NATIONAL AERONAUTICS AND SPACE ADMINISTRATION Mars Reconnaissance Orbiter Launch Press Kit August 2005 Media Contacts Dolores Beasley Policy/Program Management 202/358-1753 Headquarters [email protected] Washington, D.C. Guy Webster Mars Reconnaissance Orbiter Mission 818/354-5011 Jet Propulsion Laboratory, [email protected] Pasadena, Calif. George Diller Launch 321/867-2468 Kennedy Space Center, Fla. [email protected] Joan Underwood Spacecraft & Launch Vehicle 303/971-7398 Lockheed Martin Space Systems [email protected] Denver, Colo. Contents General Release ..................................………………………..........................................…..... 3 Media Services Information ………………………………………..........................................…..... 5 Quick Facts ………………………………………………………................................….………… 6 Mars at a Glance ………………………………………………………..................................………. 7 Where We've Been and Where We're Going ……………………................…………................... 8 Science Investigations ............................................................................................................... 12 Technology Objectives .............................................................................................................. 21 Mission Overview ……………...………………………………………...............................………. 22 Spacecraft ................................................................................................................................. 33 Mars: The Water Trail …………………………………………………………………...............……
    [Show full text]
  • Dreaming of Mars Sample Return
    National Aeronautics and Space Administration Dreaming of Mars Sample Return Jet Propulsion Laboratory California Institute of Technology Pasadena, California Erik M. Conway October 2012 Solar System @ 50 2 – 11/13/2012 3 – 11/13/2012 4 – 11/13/2012 5 – 11/13/2012 Threads of this Story • Design and Engineering in support of science • Competition for funds within NASA • NASA’s dual self-image as – A scientific agency – The enabler of human expansion into the solar system 6 – 11/13/2012 Act I: Scientists and Sample Return, 1977-1989 7 – 11/13/2012 Act II: Sample Return in the Faster, Better, Cheaper Era 8 – 11/13/2012 9 – 11/13/2012 10 – 11/13/2012 11 – 11/13/2012 12 – 11/13/2012 13 – 11/13/2012 LANDED CONFIGURATION HGA MAV/MAV INSULATION UHF ANTENNA SSI LGA 2 REC & 2 TRANS SSOHOWN ROVER Y SOLAR ARRAY Z 2 PLCS X DRILL ENVELOPE INSTRUMENT DECK UPPER SURFACE RAMPS Report on the Loss of the Mars Polar Lander and Deep Space 2 Missions JPL Special Review Board 22 March 2000 JPL D-18709 15 – 11/13/2012 Ac t III The Bubble Team and Large Lander Studies 16 – 11/13/2012 Evolution from MSR Large Lander to Mars Smart Lander (circa early 2000) Mars Science Laboratory Mars 98 & MSR Mars Smart Lander Mars Expl. Rover Mars Science Lab. •EDL architecture given one last “fresh” look, focused on: •The failure of the M98 •Extensive evaluation of •MSL mission was delayed Cost Reduction lander mission during MSR’s many different EDL and to 2007 and then 2009, Performance Increase phase A, led to a change in Landing architectures resulting in more time to risk posture on landing suitable for MSR were develop technologies.
    [Show full text]
  • Mars Exploration Camp Is to Excite Young Minds and Inspire Student Trainees Toward Future Science, Technology, Engineering, and Mathematics (STEM) Pursuits
    National Aeronautics and Space Administration Summer of Innovation Mars Exploration 4th – 9th grade www.nasa.gov Introduction The goal of the NASA Summer of Innovation Mars Exploration camp is to excite young minds and inspire student trainees toward future science, technology, engineering, and mathematics (STEM) pursuits. Raising trainee achievement in STEM pursuits begins by leading trainees on a journey of understanding through these highly engaging activities. The activities and experiences in this guide come from across NASAʼs vast collection of educational materials. This themed camp outline provides examples of one-day, two-day, and weeklong science and engineering programs. Each day contains 6-8 hours of activities totaling more than 35 hours of instructional time. The camp template will assist you in developing an appropriate learning progression focusing on the concepts necessary to engage in learning about Mars. The Mars Exploration camp provides an interactive set of learning experiences that center on the past, present, and future exploration of Mars. The activities scaffold to include cooperative learning, problem solving, critical thinking, and hands-on experiences. As each activity progresses, the conceptual challenges increase, offering trainees full immersion in the topics. Intended Learning Experiences Through the participation in these camps future scientists and engineers will have the opportunity to explore Mars. Student trainees gain learning experiences that help make scientific careers something they can envision
    [Show full text]
  • Mars Polar Lander JPL Report Part 5 (Pdf)
    8 SUMMARY OF POTENTIAL DS2 FAILURE MODES This section provides a summary description of the DS2 potential failure modes considered by the Board. It also provides a high-level assessment of the plausibility of each of the failure modes based on the Board’s review of the relevant design, implementation, and test history, and what may be inferred from data obtained throughout the mission operations. References are made to Sections 9, which contains detailed descriptions of the failure modes summarized in this section, along with findings and Lessons Learned. Failure modes are divided into two groups: ! Failure Modes Affecting Both Probes ! Failure Modes Affecting a Single Probe The four DS2 potential failure modes identified by the Board as plausible are highlighted as FLAG 1, FLAG 2, FLAG 3, and FLAG 4. Figure 8-1 illustrates the DS2 entry, descent, and impact (EDI) sequence and shows potential failure modes. Mars Polar Lander/Deep Space 2 Loss — JPL Special Review Board Report JPL D-18709 — page 124 • Probes experience battery drain prior to entry, descent, and impact sequence • Probes separate prematurely • Probes fail to separate from cruise stage (flaw in separation system) • Aeroshells fail (design flaw) • MPL fails to separate from cruise stage • MPL overheating, skip-out, excessive down-track entry points • Probes skip out or land too far down track; can’t • Random part failure communicate with MGS • Undetected aeroshell handling damage • Probes bounce on impact • Probes encounter surface conditions that exceed design capabilities • Structural failure on impact • Electronic or battery failure on impact • Ionization breakdown in Mars atmosphere • DS2 UHF link fails • Probes land on their sides, interfering with antenna performance Figure 8-1.
    [Show full text]
  • Mer Landing.Qxd
    NATIONAL AERONAUTICS AND SPACE ADMINISTRATION Mars Exploration Rover Landings Press Kit January 2004 Media Contacts Donald Savage Policy/Program Management 202/358-1547 Headquarters [email protected] Washington, D.C. Guy Webster Mars Exploration Rover Mission 818/354-5011 Jet Propulsion Laboratory, [email protected] Pasadena, Calif. David Brand Science Payload 607/255-3651 Cornell University, [email protected] Ithaca, N.Y. Contents General Release …………………………………………………………..................................…… 3 Media Services Information ……………………………………….........................................…..... 5 Quick Facts ………………………………………………………................................……………… 6 Mars at a Glance ……………………………………………………….................................………. 7 Historical Mars Missions ………………………………………………….....................................… 8 Mars: The Water Trail ………………………………………………………………….................…… 9 Where We've Been and Where We're Going …………………………………................ 14 Science Investigations .............................................................................................................. 17 Landing Sites ............................................................................................................................. 23 Mission Overview ……………...………………………………………..............................………. 28 Spacecraft ................................................................................................................................. 38 Program/Project Management …………………………………………….................................…
    [Show full text]