MissionAnalysis_134.

qxd 6/5/08 1:03 PM Page 10

Artist’s impression of ESA’s Mars

Sample Return orbiter vehicle. This
mission presents many mission
analysis challenges
Mission Analysis

Johannes Schoenmaekers, Rüdiger Jehn,

Markus Landgraf & Michael Khan
Mission Analysis Section, Flight Dynamics
Division, Ground Systems Engineering
Department, Directorate of Operations and
Infrastructure, ESOC, Darmstadt, Germany

M
ission analysis forms an integral
part of every space project, and
strongly influences the mission and
element design. Once an exclusive activity of
ESA experts, mission analysis now relies on a
network of competent European industrial,
academic and ESA partners, all integrated into
the process.

Introduction
‘Mission analysis’ is the analysis of
satellite orbits to determine how best to
achieve the objectives of a space
mission. This is performed during the
entire definition, development and
preparation phases of each project.
Mission analysis support has been
provided to ESA projects by the
European Space Operations Centre
(ESOC) mission analysis team since the
early 1970s. For many years, this team
has been the focal point for mission
analysis within ESA, coordinating
activities with units at the European
Space Research and Technology
Research Centre (ESTEC), which
concentrate on Earth observation,
astrodynamic tools and research, as well
as cooperation with national agencies.

esa bulletin 133 - february 2008 11

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Artist’s impression of ESA’s Mars

Sample Return orbiter vehicle. This
mission presents many mission
analysis challenges
Mission Analysis

Johannes Schoenmaekers, Rüdiger Jehn,

Markus Landgraf & Michael Khan
Mission Analysis Section, Flight Dynamics
Division, Ground Systems Engineering
Department, Directorate of Operations and
Infrastructure, ESOC, Darmstadt, Germany

M
ission analysis forms an integral
part of every space project, and
strongly influences the mission and
element design. Once an exclusive activity of
ESA experts, mission analysis now relies on a
network of competent European industrial,
academic and ESA partners, all integrated into
the process.

Introduction
‘Mission analysis’ is the analysis of
satellite orbits to determine how best to
achieve the objectives of a space
mission. This is performed during the
entire definition, development and
preparation phases of each project.
Mission analysis support has been
provided to ESA projects by the
European Space Operations Centre
(ESOC) mission analysis team since the
early 1970s. For many years, this team
has been the focal point for mission
analysis within ESA, coordinating
activities with units at the European
Space Research and Technology
Research Centre (ESTEC), which
concentrate on Earth observation,
astrodynamic tools and research, as well
as cooperation with national agencies.

esa bulletin 133 - february 2008 11

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Operations and Infrastructure Mission Analysis

In recent years, the network has been mission analysts to adjust their work to The navigational analysis has to show
enlarged to include European industrial evolving mission requirements and that the stochastic disturbances affecting
and academic partners. The European design and ensuring that the informa- the trajectory can be sufficiently
workshops on space mission analysis, tion provided is properly interpreted. measured and corrected in order to
the first of which was held at ESOC on A generalist, familiar with all mission guarantee spacecraft safety and achieve
10–12 December 2007, acknowledge this analysis aspects, is preferable at this the accuracy needed for payload
evolution and provide a unique platform stage to ensure that the best solutions operations. The fuel needed to correct
for technical exchange between the are chosen. In this context, a close link these errors is also computed. Typical
experts involved. With 87 participants to operations or, even better, operational disturbances are launcher injection
and 40 presentations, the first workshop experience is of high value. errors, orbit correction manoeuvre
covered the entire spectrum of mission Later on in a project, the baseline errors, uncertainties in the solar
analysis subjects. solution is studied in more detail in radiation pressure and atmospheric
Several joint presentations on major order to demonstrate feasibility and drag, as well as velocity increments
projects such as BepiColombo, LISA further optimise performance, in associated with attitude control.
Pathfinder and Mars Sample Return addition to generating all the informa- The contingency analysis quantifies
showed the high degree of harmoni- tion needed for platform, payload, the consequences of spacecraft failures,
sation. They are used here to illustrate ground segment, launcher service and such as a missed orbit manoeuvre or a
the mission analysis process and the way operations design. spacecraft safe mode, proposes risk
in which the cooperation with industry The orbit analysis includes the deter- mitigation or recovery strategies, and
and universities is implemented, while at mination of the frequency of mano- quantifies the fuel and time penalty to
the same time guaranteeing continuity euvres to maintain the operational orbit implement them.
and completeness of the mission analysis and the fuel needed for these, bearing in The launch window analysis
support, system optimality and mind payload operations and spacecraft determines the days during which the
industrial competition. safety. Usually the manoeuvres com- spacecraft can be launched and the time
pensate for known orbital perturbations, slots when lift-off can occur, as well as
Mission Analysis Process such as third-body gravitational effects, the target injection orbit. It has to be
At the start of a project, the mission and those caused by the asymmetries of proved that the mission objectives can be
requirements are evaluated in order to the planet’s gravitational field. achieved in each of these windows. The
provide an overview of the available
trajectory options. For each option, the The BepiColombo interplanetary cruise to Mercury, ecliptic projection showing swingbys
mission analyst computes the Artist’s impression of BepiColombo in cruise configuration (exploded view). From top to bottom, the Mercury Magnetospheric Orbiter (MMO), the sunshield, the Mercury Planet Orbiter (MPO) and the
information needed by the project to BepiColombo transfer module
perform a proper trade-off between the
different options and to define one or
more baseline and back-up solutions for extra fuel required to compensate for the of the project guarantees a continuing cornerstone mission of the ESA
further detailed analysis, definition and non-optimal injection time and orbit awareness of the possible alternatives Horizons 2000 scientific programme,
optimisation. also has to be quantified. This task that were assessed in the early phase of BepiColombo consists of two scientific
This information usually includes: the requires interaction, via the project, with the project. Typical examples are the spacecraft, the Mercury Planetary
timeline of major events; launcher the launcher authorities. redesign of the Cassini-Huygens Orbiter (MPO) and the Mercury
injection orbit and mass; delta-V The results of the in-depth analysis mission after the identification of a Magnetospheric Orbiter (MMO). The
budget; power and thermal aspects, such for the baseline solution are compiled in transponder design problem and the latter spacecraft will be built and
as eclipses and distance from the Sun; the Consolidated Report on Mission redefinition of the Rosetta mission after operated by the Japan Aerospace
Earth distance; Sun-spacecraft-Earth Analysis (CREMA). losing the option to fly to Comet Exploration Agency (JAXA) and
and Sun-Earth-spacecraft angles and Launch delays, spacecraft mass Wirtanen in January 2003. passively attached to the MPO during
their influence on communications; overruns, technology development the cruise to Mercury. The two
coverage of science targets; and a problems or other difficulties often BepiColombo spacecraft will study the origin and
qualitative assessment of complexity prevent the baseline mission from being The first assessment studies for an ESA evolution of Mercury, its interior
and operational risk. At this stage the flown as planned. During mission mission to Mercury started in dynamics and the origin of its magnetic
emphasis is on a good overview, rather operations, contingencies may also November 1993. Since then, the mission field.
than on accuracy and optimality. require a mission redesign within the design evolved from a single Mercury Going to Mercury is not simple: if no
The information is usually compiled constraints of the existing spacecraft, orbiter that used chemical propulsion planetary flybys are used, it would cost
in a Mission Analysis Guidelines payload and ground segment. and gravity assists to reach the planet, to even more fuel than a journey to Pluto!
(MAG) document. A frequent inter- Continuity in the mission analysis a system with two orbiters, based on So, before starting the competitive
action with the project team allows the support throughout the entire lifecycle electrical propulsion. Now, as the fifth definition study with Alenia Spazio and

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Operations and Infrastructure Mission Analysis

In recent years, the network has been mission analysts to adjust their work to The navigational analysis has to show
enlarged to include European industrial evolving mission requirements and that the stochastic disturbances affecting
and academic partners. The European design and ensuring that the informa- the trajectory can be sufficiently
workshops on space mission analysis, tion provided is properly interpreted. measured and corrected in order to
the first of which was held at ESOC on A generalist, familiar with all mission guarantee spacecraft safety and achieve
10–12 December 2007, acknowledge this analysis aspects, is preferable at this the accuracy needed for payload
evolution and provide a unique platform stage to ensure that the best solutions operations. The fuel needed to correct
for technical exchange between the are chosen. In this context, a close link these errors is also computed. Typical
experts involved. With 87 participants to operations or, even better, operational disturbances are launcher injection
and 40 presentations, the first workshop experience is of high value. errors, orbit correction manoeuvre
covered the entire spectrum of mission Later on in a project, the baseline errors, uncertainties in the solar
analysis subjects. solution is studied in more detail in radiation pressure and atmospheric
Several joint presentations on major order to demonstrate feasibility and drag, as well as velocity increments
projects such as BepiColombo, LISA further optimise performance, in associated with attitude control.
Pathfinder and Mars Sample Return addition to generating all the informa- The contingency analysis quantifies
showed the high degree of harmoni- tion needed for platform, payload, the consequences of spacecraft failures,
sation. They are used here to illustrate ground segment, launcher service and such as a missed orbit manoeuvre or a
the mission analysis process and the way operations design. spacecraft safe mode, proposes risk
in which the cooperation with industry The orbit analysis includes the deter- mitigation or recovery strategies, and
and universities is implemented, while at mination of the frequency of mano- quantifies the fuel and time penalty to
the same time guaranteeing continuity euvres to maintain the operational orbit implement them.
and completeness of the mission analysis and the fuel needed for these, bearing in The launch window analysis
support, system optimality and mind payload operations and spacecraft determines the days during which the
industrial competition. safety. Usually the manoeuvres com- spacecraft can be launched and the time
pensate for known orbital perturbations, slots when lift-off can occur, as well as
Mission Analysis Process such as third-body gravitational effects, the target injection orbit. It has to be
At the start of a project, the mission and those caused by the asymmetries of proved that the mission objectives can be
requirements are evaluated in order to the planet’s gravitational field. achieved in each of these windows. The
provide an overview of the available
trajectory options. For each option, the The BepiColombo interplanetary cruise to Mercury, ecliptic projection showing swingbys
mission analyst computes the Artist’s impression of BepiColombo in cruise configuration (exploded view). From top to bottom, the Mercury Magnetospheric Orbiter (MMO), the sunshield, the Mercury Planet Orbiter (MPO) and the
information needed by the project to BepiColombo transfer module
perform a proper trade-off between the
different options and to define one or
more baseline and back-up solutions for extra fuel required to compensate for the of the project guarantees a continuing cornerstone mission of the ESA
further detailed analysis, definition and non-optimal injection time and orbit awareness of the possible alternatives Horizons 2000 scientific programme,
optimisation. also has to be quantified. This task that were assessed in the early phase of BepiColombo consists of two scientific
This information usually includes: the requires interaction, via the project, with the project. Typical examples are the spacecraft, the Mercury Planetary
timeline of major events; launcher the launcher authorities. redesign of the Cassini-Huygens Orbiter (MPO) and the Mercury
injection orbit and mass; delta-V The results of the in-depth analysis mission after the identification of a Magnetospheric Orbiter (MMO). The
budget; power and thermal aspects, such for the baseline solution are compiled in transponder design problem and the latter spacecraft will be built and
as eclipses and distance from the Sun; the Consolidated Report on Mission redefinition of the Rosetta mission after operated by the Japan Aerospace
Earth distance; Sun-spacecraft-Earth Analysis (CREMA). losing the option to fly to Comet Exploration Agency (JAXA) and
and Sun-Earth-spacecraft angles and Launch delays, spacecraft mass Wirtanen in January 2003. passively attached to the MPO during
their influence on communications; overruns, technology development the cruise to Mercury. The two
coverage of science targets; and a problems or other difficulties often BepiColombo spacecraft will study the origin and
qualitative assessment of complexity prevent the baseline mission from being The first assessment studies for an ESA evolution of Mercury, its interior
and operational risk. At this stage the flown as planned. During mission mission to Mercury started in dynamics and the origin of its magnetic
emphasis is on a good overview, rather operations, contingencies may also November 1993. Since then, the mission field.
than on accuracy and optimality. require a mission redesign within the design evolved from a single Mercury Going to Mercury is not simple: if no
The information is usually compiled constraints of the existing spacecraft, orbiter that used chemical propulsion planetary flybys are used, it would cost
in a Mission Analysis Guidelines payload and ground segment. and gravity assists to reach the planet, to even more fuel than a journey to Pluto!
(MAG) document. A frequent inter- Continuity in the mission analysis a system with two orbiters, based on So, before starting the competitive
action with the project team allows the support throughout the entire lifecycle electrical propulsion. Now, as the fifth definition study with Alenia Spazio and

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Operations and Infrastructure Mission Analysis

not end when a good trajectory is found. propulsion or have to be done using
In the case of BepiColombo, the Ariane chemical propulsion. Mission analysts
rocket became unaffordable and from the University of Glasgow and
solutions with the smaller Soyuz rocket Politecnico di Milano have been called
had to be found. upon to write software for trajectory
To compensate for the missing thrust optimisation and graphical user
from the powerful Ariane-5 rocket, one interfaces to make the very complex
lunar flyby and an Earth flyby were trajectories easier to present and to
introduced. The solar arrays had to be understand. Finally, the Spanish
reduced in size, cutting the available ion technological business group GMV has
engine thrust in half. As a consequence, delivered the ‘ASTRO’ toolbox to
the transfer duration increased to five visualise the complex navigational
years. aspects and simplify many day-to-day
The current interplanetary trajectory astrodynamic calculations.
is shown on the previous page. It
includes single flybys at the Moon, LISA Pathfinder
Earth, two at Venus and two at Mercury, As a precursor for the Laser
as well as several long thrust arcs Interferometer Space Antenna (LISA)
provided by solar-electric propulsion. gravity wave hunter, the LISA
However, the mission analysts already Pathfinder mission is required to
Artist’s impression of LISA Pathfinder, showing the science spacecraft and propulsion module after separation have back-up options available, with up perform its experiments in an extremely
to six Mercury flybys giving even more low-force, low-disturbance environment.
fuel savings. For example, any force differences of
EADS Astrium, the framework of the powerful Ariane-5 rocket was to be used, One way to compensate for a potential more than one billionth of a g (1g =
mission had to be defined. A complex just two flybys at Venus and two at mass crisis in the mission is a ‘gravity 9.81 ms–2, the gravity acceleration on
interplanetary trajectory was designed, Mercury were required, in combination capture’ on arrival at Mercury. In Earth’s surface) between the proof
working together with mission experts at with solar-electric propulsion. The collaboration with EADS Astrium, a masses of the payload is to be avoided,
the Institut d’Astrophysique Spatiale in target could then be reached in less than sophisticated arrival strategy was ruling out Earth’s vicinity up to
Orsay, France. Originally, when the three years. But mission analysis does designed in which the Sun’s gravity is distances of 120 000 km. Lagrange (libration) points L1 to L5 on the ‘Jacobi surface’ (green) in the Sun-Earth system (not to scale)
used in such a way that the spacecraft is Given these requirements, the dayside
BepiColombo cruise from lunar swingby to capture at Mercury decelerated enough to be temporarily L1 Lagrange point of the Sun-Earth There are industrial and academic assign this task to the prime contractor
captured in a high orbit around system was chosen as the target players who work with ESA’s experts, and have it reviewed by ESA experts.
Mercury. If the orbit insertion fails, location for LISA Pathfinder. There, at sometimes in parallel, sometimes by One important trade-off in this
there are multiple opportunities to 1.5 million kilometres from Earth, the providing tools, and sometimes by optimisation was the total number of
attempt another capture burn before the forces of Earth’s gravity, Sun’s gravity, reviewing each other’s results. manoeuvres, with an increase in
spacecraft eventually drifts away and the and the centrifugal force of Earth’s The possibility of putting LISA manoeuvres reducing the propellant
mission is lost. motion around the Sun cancel each Pathfinder as a co-passenger on a expenditure, but at the same time
For such a demanding ESA other, so that the spacecraft moves about commercial Ariane-5 launch was increasing the LEOP duration and
cornerstone mission, the ESOC mission like a three-dimensional pendulum with excluded in phase A. This means that, complexity. Mission designs with up to
analysis team relies on industrial support a period of roughly 180 days. The instead of being injected into a 25 manoeuvres were considered by the
to analyse all aspects of the mission in pendulum motion in the plane of Earth’s geostationary transfer orbit, a dedicated prime contractor in order to achieve the
the required detail. One example is orbit has a slightly different period than small Russian Rockot launcher will place minimum change in velocity (delta-V, or
navigation, a key issue for the safety of the motion perpendicular to it, causing the spacecraft in a slightly elliptical low ΔV). Concerns about the operability of
the mission. When six flybys may need to non-repeating orbits about the Lagrange Earth orbit below an altitude of this approach were evaluated, eventually
be performed with high precision, a point. The size of the free pendulum, or 1000 km. The most efficient way to resulting in a reduction to 15
detailed simulation of the orbit libration, motion is of the same order as transfer the vehicle from this initial low- manoeuvres. This number allowed a
determination and trajectory correction the distance of the Lagrange point from energy orbit and send it towards the credible approach for the nominal
is required. This resulted in dedicated Earth, so that the spacecraft appears to Lagrange point was sought. The operations in the Earth-orbiting phase,
software being written by Deimos Space, be circling the Sun on an annulus strategic approach to use a number of while also catering for simple
building on ESA’s long-standing between 10° and 45° when viewed from perigee burns was regarded as the only contingency situations during that
expertise and prototype software. Earth. possible solution. Since this transfer phase. In addition, the radiation
As a consequence, we now know LISA Pathfinder is not an unusual strategy could only be optimised under exposure could be kept within the
which trajectory correction manoeuvres case when it comes to the coordination the constraints given by the spacecraft constraints given by the spacecraft and
can be made with solar electric of mission analysis activities in Europe. capabilities, it was a logical decision to payload requirements.

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Operations and Infrastructure Mission Analysis

not end when a good trajectory is found. propulsion or have to be done using
In the case of BepiColombo, the Ariane chemical propulsion. Mission analysts
rocket became unaffordable and from the University of Glasgow and
solutions with the smaller Soyuz rocket Politecnico di Milano have been called
had to be found. upon to write software for trajectory
To compensate for the missing thrust optimisation and graphical user
from the powerful Ariane-5 rocket, one interfaces to make the very complex
lunar flyby and an Earth flyby were trajectories easier to present and to
introduced. The solar arrays had to be understand. Finally, the Spanish
reduced in size, cutting the available ion technological business group GMV has
engine thrust in half. As a consequence, delivered the ‘ASTRO’ toolbox to
the transfer duration increased to five visualise the complex navigational
years. aspects and simplify many day-to-day
The current interplanetary trajectory astrodynamic calculations.
is shown on the previous page. It
includes single flybys at the Moon, LISA Pathfinder
Earth, two at Venus and two at Mercury, As a precursor for the Laser
as well as several long thrust arcs Interferometer Space Antenna (LISA)
provided by solar-electric propulsion. gravity wave hunter, the LISA
However, the mission analysts already Pathfinder mission is required to
Artist’s impression of LISA Pathfinder, showing the science spacecraft and propulsion module after separation have back-up options available, with up perform its experiments in an extremely
to six Mercury flybys giving even more low-force, low-disturbance environment.
fuel savings. For example, any force differences of
EADS Astrium, the framework of the powerful Ariane-5 rocket was to be used, One way to compensate for a potential more than one billionth of a g (1g =
mission had to be defined. A complex just two flybys at Venus and two at mass crisis in the mission is a ‘gravity 9.81 ms–2, the gravity acceleration on
interplanetary trajectory was designed, Mercury were required, in combination capture’ on arrival at Mercury. In Earth’s surface) between the proof
working together with mission experts at with solar-electric propulsion. The collaboration with EADS Astrium, a masses of the payload is to be avoided,
the Institut d’Astrophysique Spatiale in target could then be reached in less than sophisticated arrival strategy was ruling out Earth’s vicinity up to
Orsay, France. Originally, when the three years. But mission analysis does designed in which the Sun’s gravity is distances of 120 000 km. Lagrange (libration) points L1 to L5 on the ‘Jacobi surface’ (green) in the Sun-Earth system (not to scale)
used in such a way that the spacecraft is Given these requirements, the dayside
BepiColombo cruise from lunar swingby to capture at Mercury decelerated enough to be temporarily L1 Lagrange point of the Sun-Earth There are industrial and academic assign this task to the prime contractor
captured in a high orbit around system was chosen as the target players who work with ESA’s experts, and have it reviewed by ESA experts.
Mercury. If the orbit insertion fails, location for LISA Pathfinder. There, at sometimes in parallel, sometimes by One important trade-off in this
there are multiple opportunities to 1.5 million kilometres from Earth, the providing tools, and sometimes by optimisation was the total number of
attempt another capture burn before the forces of Earth’s gravity, Sun’s gravity, reviewing each other’s results. manoeuvres, with an increase in
spacecraft eventually drifts away and the and the centrifugal force of Earth’s The possibility of putting LISA manoeuvres reducing the propellant
mission is lost. motion around the Sun cancel each Pathfinder as a co-passenger on a expenditure, but at the same time
For such a demanding ESA other, so that the spacecraft moves about commercial Ariane-5 launch was increasing the LEOP duration and
cornerstone mission, the ESOC mission like a three-dimensional pendulum with excluded in phase A. This means that, complexity. Mission designs with up to
analysis team relies on industrial support a period of roughly 180 days. The instead of being injected into a 25 manoeuvres were considered by the
to analyse all aspects of the mission in pendulum motion in the plane of Earth’s geostationary transfer orbit, a dedicated prime contractor in order to achieve the
the required detail. One example is orbit has a slightly different period than small Russian Rockot launcher will place minimum change in velocity (delta-V, or
navigation, a key issue for the safety of the motion perpendicular to it, causing the spacecraft in a slightly elliptical low ΔV). Concerns about the operability of
the mission. When six flybys may need to non-repeating orbits about the Lagrange Earth orbit below an altitude of this approach were evaluated, eventually
be performed with high precision, a point. The size of the free pendulum, or 1000 km. The most efficient way to resulting in a reduction to 15
detailed simulation of the orbit libration, motion is of the same order as transfer the vehicle from this initial low- manoeuvres. This number allowed a
determination and trajectory correction the distance of the Lagrange point from energy orbit and send it towards the credible approach for the nominal
is required. This resulted in dedicated Earth, so that the spacecraft appears to Lagrange point was sought. The operations in the Earth-orbiting phase,
software being written by Deimos Space, be circling the Sun on an annulus strategic approach to use a number of while also catering for simple
building on ESA’s long-standing between 10° and 45° when viewed from perigee burns was regarded as the only contingency situations during that
expertise and prototype software. Earth. possible solution. Since this transfer phase. In addition, the radiation
As a consequence, we now know LISA Pathfinder is not an unusual strategy could only be optimised under exposure could be kept within the
which trajectory correction manoeuvres case when it comes to the coordination the constraints given by the spacecraft constraints given by the spacecraft and
can be made with solar electric of mission analysis activities in Europe. capabilities, it was a logical decision to payload requirements.

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Operations and Infrastructure Mission Analysis

LISA Pathfinder orbits before departure from Earth

This example shows nicely that the capabilities to expand and maintain the
system overview provided by ESA software to the latest standards.
experts, including spacecraft, mission,
operations, and ground segment, is Mars Sample Return
invaluable when it comes to the Following ExoMars, the first Mars
realisation of solutions that are often mission of ESA’s Aurora Programme,
driven by a desire to improve the which is due for launch in 2013, and a
propellant budget situation. technology demonstration mission due
For the everyday work on Lagrange in the 2016 timeframe, the Mars Sample
point missions, ESA specialists use the Return (MSR) mission is planned to
LODATO software package that has its take place towards the end of the
roots in the rapid prototype develop- coming decade.
ment undertaken by them in the past. The most complex unmanned ESA
LODATO was improved by Deimos mission ever, MSR will require two
Space under contract with ESA, using Ariane-5 launches. One will launch a Artist’s impression of the Mars Sample Return Mission, showing
software design guidelines. Mars orbiter and an Earth Return lift-off of the Mars Ascent Vehicle (MAV) from the descent module – aerobraking to the target orbit Class V mission involving return of features a series of bottlenecks for which
The results from educational Vehicle, the second will launch the around Mars; samples to Earth; there is no workaround. Mars entry and
partnerships with academia have been Surface Element and Mars Ascent – rendezvous and capture of the – long duration: 5–7 years between first landing, sample collection, sample
included in LODATO, so that the Vehicle (MAV). The Surface Element back to Earth and place it on an launched sample container; launch and sample return. launch, rendezvous and capture, sample
rendezvous problem at the Lagrange will probably involve a rover and atmospheric entry trajectory. – safe Earth return and precise Since the sheer magnitude and container sealing, and Earth return and
points can be treated, as well as lunar possibly a drill for sample extraction. Among the numerous technical insertion into a narrow re-entry complexity will result in a mission cost targeting all involve single points of
flybys and navigation aspects. From an After collecting about 500 grams of soil, challenges inherent to MSR are: corridor; that is too high for a single agency to failure with no chance for a second try.
insider’s point of view, it pays to have rock and atmosphere samples, the MAV – targeted soft-landing of a large – compliance with stringent planetary shoulder, MSR is likely to be a Failure to execute any of these steps
the competence for new developments in will launch into a low Mars orbit where module on the Mars surface; protection requirements to avoid multiagency endeavour. Current studies exactly as planned will result in a total
mission design software within ESA, the orbiter will gather the sample – automatic, accurate launch from the forward and backward conta- focus on a NASA/ESA cooperation. loss of the mission.
while also using industrial and academic container, seal it hermetically, carry it Martian surface into low Mars orbit; mination – MSR is by definition a More than most missions, MSR The challenges also extend to mission

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Operations and Infrastructure Mission Analysis

LISA Pathfinder orbits before departure from Earth

This example shows nicely that the capabilities to expand and maintain the
system overview provided by ESA software to the latest standards.
experts, including spacecraft, mission,
operations, and ground segment, is Mars Sample Return
invaluable when it comes to the Following ExoMars, the first Mars
realisation of solutions that are often mission of ESA’s Aurora Programme,
driven by a desire to improve the which is due for launch in 2013, and a
propellant budget situation. technology demonstration mission due
For the everyday work on Lagrange in the 2016 timeframe, the Mars Sample
point missions, ESA specialists use the Return (MSR) mission is planned to
LODATO software package that has its take place towards the end of the
roots in the rapid prototype develop- coming decade.
ment undertaken by them in the past. The most complex unmanned ESA
LODATO was improved by Deimos mission ever, MSR will require two
Space under contract with ESA, using Ariane-5 launches. One will launch a Artist’s impression of the Mars Sample Return Mission, showing
software design guidelines. Mars orbiter and an Earth Return lift-off of the Mars Ascent Vehicle (MAV) from the descent module – aerobraking to the target orbit Class V mission involving return of features a series of bottlenecks for which
The results from educational Vehicle, the second will launch the around Mars; samples to Earth; there is no workaround. Mars entry and
partnerships with academia have been Surface Element and Mars Ascent – rendezvous and capture of the – long duration: 5–7 years between first landing, sample collection, sample
included in LODATO, so that the Vehicle (MAV). The Surface Element back to Earth and place it on an launched sample container; launch and sample return. launch, rendezvous and capture, sample
rendezvous problem at the Lagrange will probably involve a rover and atmospheric entry trajectory. – safe Earth return and precise Since the sheer magnitude and container sealing, and Earth return and
points can be treated, as well as lunar possibly a drill for sample extraction. Among the numerous technical insertion into a narrow re-entry complexity will result in a mission cost targeting all involve single points of
flybys and navigation aspects. From an After collecting about 500 grams of soil, challenges inherent to MSR are: corridor; that is too high for a single agency to failure with no chance for a second try.
insider’s point of view, it pays to have rock and atmosphere samples, the MAV – targeted soft-landing of a large – compliance with stringent planetary shoulder, MSR is likely to be a Failure to execute any of these steps
the competence for new developments in will launch into a low Mars orbit where module on the Mars surface; protection requirements to avoid multiagency endeavour. Current studies exactly as planned will result in a total
mission design software within ESA, the orbiter will gather the sample – automatic, accurate launch from the forward and backward conta- focus on a NASA/ESA cooperation. loss of the mission.
while also using industrial and academic container, seal it hermetically, carry it Martian surface into low Mars orbit; mination – MSR is by definition a More than most missions, MSR The challenges also extend to mission

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Operations and Infrastructure Mission Analysis

need to be addressed at a fundamental extensively to optimise spacecraft design.

level. Early identification and proactive This valuable contribution is coordinated
mitigation of any mission risk are the with ESA’s work and integrated in the
keys to meeting the challenging schedule. Consolidated Report on Mission
Conversely, failure to address a technical Analysis (CREMA). The responsibility
issue in a timely fashion is likely to raise for the CREMA remains with the ESOC
the likelihood of delays or cost overruns mission analysis group in order to
and expose the project to political risk. maintain coverage and optimality of the
MSR is not a standalone mission; it entire system, including platform,
will enable Europe to act as an equal payload, ground segment, launcher
partner in even more challenging future service and operations.
projects, such as manned planetary Direct industrial support is used for
missions. As stated, mission analysis well-defined, specialised, offline study
should be seen and conducted as an tasks which do not need frequent
integral part of global mission design. In interaction with the projects. Study
view of the complexity, optimising the contracts are also used to develop new
involvement of all available mission methods and tools, when universities
analysis capabilities is essential. The long focus on the conceptual work and Timeline chart showing possible outbound and return transfers and environmental conditions
preparation phase and mission duration industry focuses on the implementation.
and the need for a global, long-term view Working groups are a useful platform after losing the Comet Wirtanen present their work for feedback, to get an
mandate that ultimately ESA retains full to harmonise the work of several ESA opportunity and, recently, the mission overview on the ongoing activities, to
control of the key aspects, of which and non-ESA experts in the case of definition for the Cosmic Vision create awareness of the available
mission analysis is one. complex, urgent or critical problems, missions to Jupiter and Saturn. expertise and, last but not least, establish
such as the Rosetta lander mission Recurring workshops dedicated to good personal contacts, which are crucial
Summary analysis, the Rosetta mission redesign mission analysis enable the partners to for our cooperation to function. e
While remaining responsible for the
mission analysis of ESA’s projects, the
ESOC mission analysis team shares the
work with industrial partners, academic
researchers, other groups in ESA and,
Artist’s impression of the latest concept for the ExoMars rover, now ready for the next phase of development, Phase-B2 occasionally, other agencies. The
industrial contribution is either indirect,
in the frame of a system design study or
analysis. The design of the interplanetary analysis of the effect of natural orbit spacecraft procurement contracts, or
transfers and the Mars operational phase perturbations and identification of direct, in the form of a study contract.
is driven by compliance with the possible mission risks and problems. For Usually a Mission Analysis Guidelines
numerous technical requirements. These each of these tasks, considerable know- document is produced as input to
include arrival at Mars at least six how is present within ESA and industry. industrial system design studies, to avoid
months before the start of the dust storm The key to success, especially in view of a complete mission analysis being
season, a minimum stay time of six the fairly tight schedule, is to make the performed by the contractor. This is cost
months and no superior conjunctions at best possible use of the available efficient, in particular for parallel studies.
Mars approach or during surface expertise. As only a limited number of companies
operations. MSR stands out from ‘usual’ missions can afford to maintain a sufficiently
A typical mission analysis product is in several ways. Firstly, to a deeper extent broad mission analysis expertise, this
the timeline shown on the next page, than with other projects, MSR mission allows a much larger number of
which presents the possible transfers in analysis is linked with programmatic and companies to make an offer, thus
correlation with these mission systems aspects. Furthermore, it requires improving competition. Benefit is taken
requirements and allows the project to profound knowledge of the Martian from the contractor’s available expertise
make a proper selection. The individual environment, the scientific goals and the by inviting the company to review and
mission analysis tasks comprise launch political situation. The extraordinary list enhance the mission analysis guidelines.
window optimisation, interplanetary of technical challenges has already been Often, the prime contractor of a
navigation, Entry, Descent and Landing mentioned. In combination with the spacecraft procurement or one of its
(EDL) optimisation, aerobraking, maxi- unprecedented mission cost, the mission major subcontractors has significant
misation of the data relay capabilities, also faces significant political risks. Both mission analysis expertise and uses it

18 esa bulletin 134 - may 2008 www.esa.int www.esa.int esa bulletin 134 - may 2008 19
MissionAnalysis_134.qxd 6/5/08 1:03 PM Page 18

Operations and Infrastructure Mission Analysis

need to be addressed at a fundamental extensively to optimise spacecraft design.

level. Early identification and proactive This valuable contribution is coordinated
mitigation of any mission risk are the with ESA’s work and integrated in the
keys to meeting the challenging schedule. Consolidated Report on Mission
Conversely, failure to address a technical Analysis (CREMA). The responsibility
issue in a timely fashion is likely to raise for the CREMA remains with the ESOC
the likelihood of delays or cost overruns mission analysis group in order to
and expose the project to political risk. maintain coverage and optimality of the
MSR is not a standalone mission; it entire system, including platform,
will enable Europe to act as an equal payload, ground segment, launcher
partner in even more challenging future service and operations.
projects, such as manned planetary Direct industrial support is used for
missions. As stated, mission analysis well-defined, specialised, offline study
should be seen and conducted as an tasks which do not need frequent
integral part of global mission design. In interaction with the projects. Study
view of the complexity, optimising the contracts are also used to develop new
involvement of all available mission methods and tools, when universities
analysis capabilities is essential. The long focus on the conceptual work and Timeline chart showing possible outbound and return transfers and environmental conditions
preparation phase and mission duration industry focuses on the implementation.
and the need for a global, long-term view Working groups are a useful platform after losing the Comet Wirtanen present their work for feedback, to get an
mandate that ultimately ESA retains full to harmonise the work of several ESA opportunity and, recently, the mission overview on the ongoing activities, to
control of the key aspects, of which and non-ESA experts in the case of definition for the Cosmic Vision create awareness of the available
mission analysis is one. complex, urgent or critical problems, missions to Jupiter and Saturn. expertise and, last but not least, establish
such as the Rosetta lander mission Recurring workshops dedicated to good personal contacts, which are crucial
Summary analysis, the Rosetta mission redesign mission analysis enable the partners to for our cooperation to function. e
While remaining responsible for the
mission analysis of ESA’s projects, the
ESOC mission analysis team shares the
work with industrial partners, academic
researchers, other groups in ESA and,
Artist’s impression of the latest concept for the ExoMars rover, now ready for the next phase of development, Phase-B2 occasionally, other agencies. The
industrial contribution is either indirect,
in the frame of a system design study or
analysis. The design of the interplanetary analysis of the effect of natural orbit spacecraft procurement contracts, or
transfers and the Mars operational phase perturbations and identification of direct, in the form of a study contract.
is driven by compliance with the possible mission risks and problems. For Usually a Mission Analysis Guidelines
numerous technical requirements. These each of these tasks, considerable know- document is produced as input to
include arrival at Mars at least six how is present within ESA and industry. industrial system design studies, to avoid
months before the start of the dust storm The key to success, especially in view of a complete mission analysis being
season, a minimum stay time of six the fairly tight schedule, is to make the performed by the contractor. This is cost
months and no superior conjunctions at best possible use of the available efficient, in particular for parallel studies.
Mars approach or during surface expertise. As only a limited number of companies
operations. MSR stands out from ‘usual’ missions can afford to maintain a sufficiently
A typical mission analysis product is in several ways. Firstly, to a deeper extent broad mission analysis expertise, this
the timeline shown on the next page, than with other projects, MSR mission allows a much larger number of
which presents the possible transfers in analysis is linked with programmatic and companies to make an offer, thus
correlation with these mission systems aspects. Furthermore, it requires improving competition. Benefit is taken
requirements and allows the project to profound knowledge of the Martian from the contractor’s available expertise
make a proper selection. The individual environment, the scientific goals and the by inviting the company to review and
mission analysis tasks comprise launch political situation. The extraordinary list enhance the mission analysis guidelines.
window optimisation, interplanetary of technical challenges has already been Often, the prime contractor of a
navigation, Entry, Descent and Landing mentioned. In combination with the spacecraft procurement or one of its
(EDL) optimisation, aerobraking, maxi- unprecedented mission cost, the mission major subcontractors has significant
misation of the data relay capabilities, also faces significant political risks. Both mission analysis expertise and uses it

18 esa bulletin 134 - may 2008 www.esa.int www.esa.int esa bulletin 134 - may 2008 19