OrbitalHub

Credits: NASA

Kepler is the first NASA mission capable of finding terrestrial exo-planets. Of particular interest are the planets orbiting in the so-called habitable zone, where conditions are met so that liquid water can exist on the surface of the planet.

The observations made so far have brought clear evidence that planets orbiting around other stars are a common thing, rather than the exception to the rule. Due to the limitations of present technology, only gas giants, hot-super Earths in short period orbits, and ice giants have been discovered.

The Kepler mission, part of NASA’s Discovery Program, is designed to survey a portion of our region of the Milky Way. Kepler will survey a large number of stars, and explore the structure and diversity of many planetary systems.

The scientific objectives of the mission are very ambitious: determine the fraction of terrestrial planets in or near the habitable zone, determine the distribution of sizes and the orbits of exo-planets in the surveyed planetary systems, determine reflectivity, size, and density of short-period giant planets, estimate how many planets are in multiple-star systems, and determine the characteristics of the stars that have planets orbiting around them. Scientists hope to discover additional members of the planetary systems surveyed using other indirect techniques.

Credits: NASA/Ball Aerospace

The duration of the mission must be selected to allow the detection and confirm the periodic nature of the planet transits in or near the habitable zone. Due to the characteristics of orbits of such planets, a lifetime of three and a half years (as currently envisioned) would allow a four-transit detection of most orbits up to one year in length and a three-transit detection of orbits of length up to 1.75 years.

The mission lifetime will be extendible to at least six years. The extension will permit the detection of planets smaller than Earth with two-year orbits.

Kepler will be inserted in an Earth-trailing heliocentric orbit, then the spacecraft will slowly drift away from Earth. The selected orbit offers a very stable pointing attitude, and it avoids the high radiation dosage associated with an Earth orbit. However, Kepler will be exposed occasionally to solar flares.

The communication protocol with the spacecraft includes establishing contact twice a week for commanding, health, and status, and science data downlink contact once a month.

Credits: Jon Lomberg

There are two requirements that dictated the selection of the target field. The first requirement is the ability to monitor continuously the stars surveyed because transits last only a fraction of a day. This can be achieved by having the field of view out of the ecliptic plane, so the Sun will not interfere with the observations at any time during the year. The second requirement is to have the largest possible number of stars in the field of view.

To meet both requirements, a region in the Cygnus and Lyra constellations of our galaxy has been selected as the field of view.

Kepler will use the transit method for detecting exo-planets. The sensitivity of the photometer will allow the discovery of terrestrial exo-planets (planets comparable in size and composition to Earth that are orbiting other stars).

The transit occurs when a planet passes in front of its star as viewed by an observer. Depending on the size of the planet, the change in the brightness of the star has different amplitudes. Transits of terrestrial planets cause a change in the star’s brightness of about 1/10,000, and they last from two to sixteen hours.

Credits: NASA

Changes in star brightness that are produced by a planet transit must be periodic, and all transits produced by the same planet must cause the same variation of brightness and last the same amount of time.

Of course, the case when two or more planets are in transit at the same time must be considered, and this can make the detection method a little bit more complicated.

The method allows for the calculation of the orbit, the mass, and the characteristic temperature of the exo-planet. Once we know the characteristic temperature of an exo-planet, the question of whether or not the planet is habitable (by our standards) can be answered.

The Kepler instrument is a special telescope called photometer or light meter. The telescope has a very large field of view for an astronomical telescope, 105 square degrees. The primary mirror of the telescope is 0.95 m in diameter. The telescope needs a large field of view because it has to continuously monitor the brightness of more than 100,000 stars for the duration of the mission.

Credits: Ball Aerospace

The photometer is composed of one instrument, which is an array of charge-coupled devices (CCD), 42 in total. Each CCD is 50mm x 25mm and has 2200 x 1024 pixels. Data from the individual pixels that make up each star are recorded continuously and simultaneously.

The primary mirror of the photometer was coated with enhanced silver, which allows more light to reach the telescope’s detectors.

The spacecraft provides power, attitude control, and telemetry for the photometer. The mission requirements contributed to the simple design of the spacecraft. The only moving parts are the reaction wheels used to control the attitude of the spacecraft.

The launcher selected for the mission is Delta II. Delta II is a versatile launcher, and can be configured in two or three-stage vehicles in order to accommodate a variety of requirements.

Ball Aerospace is the prime contractor for the Kepler mission, building the photometer and the spacecraft, as well as managing the system integration and testing of the spacecraft. The Jet Propulsion Laboratory is managing mission development, while NASA Ames Research Center is responsible for ground system development, mission operations, and science data analysis.

Once the first observation results are downloaded from Kepler and made available to scientists, we will be able to place our solar system within the context of planetary systems in our galaxy.

The launch of Kepler is planned for March 5, 2009. For more information about the Kepler mission, you can visit the Kepler mission web page.

On January 28, 1986, the Space Shuttle Challenger broke apart seventy-three seconds into its flight. The disintegration of the space shuttle occurred after an O-ring seal in one of its solid rocket boosters (SRB) failed. The O-ring failure caused a breach in the SRB, and a flare from within the solid rocket motor reached outside. This led to the separation of the SRB aft attachment and the structural failure of the external tank.

The Space Shuttle program was halted for 32 months. A special commission was appointed by President Ronald Reagan to investigate the accident. The commission offered NASA nine recommendations that were to be implemented as a condition to have the space shuttle flights resumed.

The crew of Space Shuttle Challenger was composed of Francis R. Scobee, Michael J. Smith, Judith A. Resnik, Ellison S. Onizuka, Ronald E. McNair, Gregory B. Jarvis, and Sharon Christa McAuliffe.

The area where M.E.R. Opportunity landed in the Meridiani Planum on Mars is called Challenger Memorial Station, in memory of the last crew of the Space Shuttle Challenger.

Credits: JAXA

After a launch postponement due to a bad weather forecast, IBUKI was finally launched on January 23, 2009.

IBUKI was launched aboard H-IIA Launch Vehicle No. 15 from the Tanegashima Space Center. Sixteen minutes after liftoff, the separation of IBUKI was confirmed. The satellite was injected into the scheduled orbit: 684.8 km x 667.4 km, with an orbit inclination of 98 degrees.

IBUKI was not the only satellite launched by flight 15. The payload included several piggyback payloads. It is common practice to include small satellites in the payload that are made by private companies or universities, in the case of an excessive launch capability.

Seven micro-satellites, six selected through public tender and one JAXA satellite, were launched by the H-IIA launch vehicle with IBUKI: KAGAYAKI / SORUN CORPORATION (debris detection and Aurora electric current observation mission), STARS / Kagawa University (tether space robot demonstration), KKS-1 / Tokyo Metropolitan College of Industrial Technology (demonstration of the micro cluster and three axis attitude control functions), PRISM / The University of Tokyo (earth image acquisition by using an expandable refracting telescope), SOHLA-1 / ASTRO TECHNOLOGY SOHLA (measurements of thunder and lightning), SPRITE-SAT / Tohoku University (observations of the sprite phenomenon and gamma radiation of the Earth’s origin), and Small Demonstration Satellite-1 (SDS-1) / JAXA (on-orbit verification of the space wire demonstration).

Credits: JAXA

For more details on the additional payloads of H-IIA F15, you can check out the piggyback payload web page on the JAXA web site. Some of the links on the page require knowledge of Japanese or hands-on experience with the Google translation tool.

IBUKI will undergo a check of the onboard equipment function for about three months before becoming operational.

On January 27, 1967, during a test and training exercise at Launch Complex 34, Cape Canaveral, the command module of the Apollo/Saturn 204 mission was destroyed by fire.

The crew training at that time was composed of the astronauts selected for the first manned Apollo Program mission: Command Pilot Virgil I. Gus Grissom, Senior Pilot Ed White, and Pilot Roger B. Chaffee. All three astronauts died in the fire.

Credits: CNES

In 2005, ESA’s Advanced Concepts Team held its first Global Trajectory Optimization Competition (GTOC). The purpose of the competition is to stimulate research of techniques for finding the optimal trajectory for different space missions.

What is interesting about this competition is how it has been taken up by the community after its first edition. The winners of the competition become the hosts for the next edition.

The first edition of the competition was won by the Outer Planets Mission Analysis Group of JPL. The second edition was won by the Department of Energetic in the Polytechnic of Turin, and the third edition was won by CNES (Centre National d’Etudes Spatiales).

CNES has announced the 4^th Edition of the GTOC. We quote this year’s announcers of the competition, Regis Bertrand, Richard Epenoy, and Benoit Meyssignac:

“Mission designers generally solve trajectory optimisation problems by means of local optimisation methods together with their own experience of the problem. Even if this way is known to provide good results, it never guarantees to yield the global optimum. On the other hand, global optimisation techniques can offer significant assistance in finding an acceptable solution to a given problem, even though convergence to the global optimum is still not guaranteed. By focusing on a problem with a very large number of locally optimal solutions, the Global Trajectory Optimisation Competition promotes the development of methods that most thoroughly and most quickly search through a large and unconventional design space for optima.”

The deadline for registration is February 27, 2009. On March 2, 2009, the competition problem will be disclosed, and March 30, 2009, is the deadline for return of solutions. In September 2009, during a one-day workshop held in Toulouse, France, the teams selected will present their methods and solutions.