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.

Credits: NASA

Orbital will employ its Taurus II medium-lift launch vehicle and the Cygnus spacecraft in order to service the International Space Station (ISS) under the Commercial Resupply Services (CRS) contract.

Orbital is one of the two companies awarded CRS contracts under the Commercial Orbital Transportation Services Project (COTS).

NASA announced the COTS project on January 18, 2006. The purpose of the program is to stimulate the development of access to low Earth orbit (LEO) in the private sector. At the time, with the imminent retirement of the Space Shuttle fleet, NASA was faced with the option of buying orbital transportation services on foreign launch systems: the Russian Soyuz / Progress, the European Ariane 5 / ATV, or the Japanese H-II / HTV.

Another factor taken into consideration by NASA was that competition in the free market could lead to the development of more efficient and affordable launch systems compared to launch systems that a government agency could build and operate.

Credits: Orbital

Orbital relies on proven experience in launch vehicle technology. Taurus II is designed to provide low-cost and reliable access to space, and it uses systems from other members of Orbital’s family of successful launchers: Pegasus, Taurus, and Minotaur.

Taurus II is a two-stage launch vehicle that can use an additional third stage for achieving higher orbits. The payloads handled by Taurus II can have a mass of up to 5,400 kg.

Orbital is responsible for overall development and integration of the first stage. The two AJ26-62, designed and produced by Aerojet and Orbital, are powered by liquid oxygen and kerosene. The core design is driven by NPO Yuzhnoye, the designer of the Zenit launchers.

The AJ26-62 engines are basically the NK-33 engines designed by the Kuznetsov Design Bureau for the Russian N-1 launch vehicle, and remarketed by Aerojet under a new designation.

The second stage uses an ATK Castor-30 solid motor with thrust vectoring. This stage evolved from the Castor-120 solid stage.

The optional third stage is developed by Orbital. The stage was dubbed the Orbit Raising Kit (ORK) and it uses a helium pressure regulated bi-propellant propulsion system powered by nitrogen tetroxide and hydrazine. ORK evolved from the Orbital STAR Bus. Because it is a hypergolic stage, it allows several burns to be performed in orbit, and can be used for high-precision injections using various orbital profiles.

Credits: Orbital

Cygnus will only have cargo capability and will be able to deliver up to 2,300 kg of pressurized or un-pressurized cargo to the ISS. The spacecraft will also be able to return up to 1,200 kg of cargo from ISS to Earth.

The two components of the Cygnus spacecraft will be the service module and the cargo module.

The service module is based on the Orbital STAR bus (like the ORK stage), and will use two solar arrays for producing electrical power for the navigation systems onboard.

The pressurized cargo module is based on the Italian-built Multi-Purpose Logistics Module (MPLM). The un-pressurized cargo module is based on NASA’s ExPRESS Logistics Carrier.

Cygnus will not dock to the ISS in the same manner as the European ATV, but it will be able to maneuver close to the ISS where the Canadarm 2 robotic arm will be used to capture it and berth it to the Node 2 module, similar to the Japanese HTV or SpaceX’s Dragon spacecraft.

The Mid-Atlantic Regional Spaceport (MARS), located at NASA’s Wallops Island Flight Facility on Virginia’s Eastern shore, was chosen by Orbital to serve as the base of operations for the Taurus II launch vehicle.

MARS has two FAA licensed launch pads for LEO access. MARS also offers access to suborbital launchers, vehicle and payload storage, and processing and launch facilities.

Credits: NASA

Due to the location of the spaceport, latitude 37.8 degrees N, longitude 75.5 degrees W, optimal orbital inclinations for the launches performed at MARS are between 38 and 60 degrees. Polar and retrograde orbits can also be serviced with additional in-flight maneuvering.

The first flight of Orbital’s new Taurus II / Cygnus launch system under COTS is scheduled for late 2010.

Credits: NASA

On January 3, 2004, the MER-A rover a.k.a. Spirit landed on Mars at the Gusev Crater. The second rover, MER-B a.k.a. Opportunity, followed twenty-one days later and landed at the Meridiani Planum.

They were both designed to operate for three months on the surface of Mars. Five years later, they are still operational and NASA has planned new missions for them.

Considering the harsh conditions on Mars, NASA’s twin rovers have accomplished remarkable things: they have returned a quarter-million images, driven more than thirteen miles, climbed a mountain, descended into impact craters, and survived dust storms. Using the Mars Odyssey orbiter as a communication relay, the rovers have sent more than 36 GB of scientific data back to Earth.

“These rovers are incredibly resilient considering the extreme environment the hardware experiences every day,” said John Callas, JPL project manager for Spirit and Opportunity. “We realize that a major rover component on either vehicle could fail at any time and end a mission with no advance notice, but on the other hand, we could accomplish the equivalent duration of four more prime missions on each rover in the year ahead.”

Credits: NASA

Digging into the MER mission archive, one detail caught my eye. The rovers carry plaques commemorating the crews of Columbia and Challenger, and some of the landmarks surrounding the landing sites of the rovers are dedicated to the astronauts of Apollo 1, Columbia, and Challenger.

Spirit is carrying a plaque commemorating the STS-107 Space Shuttle Columbia crew, which has been mounted on the high-gain antenna of the rover.

The names of the STS-107 crew are inscribed on the plaque: Rick D. Husband, William C. McCool, Michael P. Anderson, Kalpana Chawla, David M. Brown, Laurel B. Clark, and Ilan Ramon. Their names are now looking over the Martian landscapes.

To further honor their memory, the landing site of the MER Spirit is called the Columbia Memorial Station.

Credits: NASA

Three of the hills surrounding the Columbia Memorial Station are dedicated to the Apollo 1 crew: Gus Grissom, Ed White, and Roger Chafee. Grissom Hill is located 7.5 km to the southwest of Columbia Memorial Station, White Hill is 11.2 km northwest of the landing site, and Chafee Hill is located 14.3 km south-southwest of the landing site.

The area where Opportunity landed in the Meridiani Planum is called Challenger Memorial Station, in memory of the last crew of the Space Shuttle Challenger: Francis R. Scobee, Michael J. Smith, Judith A. Resnik, Ellison S. Onizuka, Ronald E. McNair, Gregory B. Jarvis, and Sharon Christa McAuliffe. I remember that Sharon Christa McAuliffe was NASA’s first teacher in space.

“The journeys have been motivated by science, but have led to something else important,” said Steve Squyres of Cornell University, in Ithaca, N.Y. Squyres is principal investigator for the rover science instruments. “This has turned into humanity’s first overland expedition on another planet. When people look back on this period of Mars exploration decades from now, Spirit and Opportunity may be considered most significant not for the science they accomplished, but for the first time we truly went exploring across the surface of Mars.”

Credits: NASA

If you want free lecture notes, exams, and videos from MIT, without any registration required, you can find them at MIT Open Courseware.

MIT Open Courseware reflects most of the undergraduate and graduate subjects taught at MIT. One of the courses that caught my eye was an engineering course called Aircraft Systems Engineering.

Even if the formal title of the course is Aircraft Systems Engineering, the lectures are focused on Space Shuttle design. If you are a space enthusiast and have a technical background, you will probably enjoy these lectures.

The course was taught by Professor Jeff Hoffman and Professor Aaron Cohen.

Jeff Hoffman is a former Space Shuttle astronaut. He was a NASA astronaut from 1978 to 1997, having made five space flights and becoming the first astronaut to log 1,000 hours of flight time aboard the Space Shuttle. In 2001, Jeff Hoffman joined the MIT faculty, where he teaches courses on space operations and design and space policy. His principal areas of research are advanced EVA systems, space radiation protection, management of space science projects, and space systems architecture.

Aaron Cohen served as Director of NASA’s Lyndon B. Johnson Space Center in Houston, Texas. He was Manager of the Command and Service Module in the Apollo Spacecraft Program Office. In 1972, he was appointed Space Shuttle Orbiter Project Manager, responsible for design, development, production, and test flights. He also served for a year as the Acting Deputy Administrator for NASA.

One of the guest lecturers is Dale D. Myers. He was NASA Deputy Administrator between October 6, 1986 and May 13, 1989. In the first lecture of the course, Dale D. Myers gives a presentation on the beginning of the Space Shuttle program and describes how the external environment generated the requirements that forced the configuration of the Space Shuttle. This is a must-see, like any other lecture given by someone who has many years of experience under his/her belt. Watching this lecture reminded me of one of my professors back in university, who used to say that the must-have organ for a good engineer is the nose.

The course covers the subsystems of the Space Shuttle, including the requirements that shaped the design, the testing of each subsystem, and how they were operated. The structure of the orbiter, the thermal protection subsystem, the Space Shuttle main engines, landing and mechanical systems, the power systems, accident investigation, etc. are all covered by guest lecturers that were directly involved in the design and construction of the Space Shuttle.

I hope you enjoy the videos as much as I have. Happy New Year and all the best for 2009!

The awarded contracts are fixed-price indefinite delivery, indefinite quantity contracts. They will begin January 1, 2009, and are effective through December 31, 2016. SpaceX and Orbital each will have to deliver a minimum of twenty metric tons of cargo to the space station, and they will also have to deliver non-standard services in support of the cargo resupply, including analysis and special tasks as the government deems necessary.

SpaceX will service the ISS with its Falcon9/Dragon system.

“The SpaceX team is honored to have been selected by NASA as the winner of the Cargo Resupply Services contract,” said Elon Musk, CEO and CTO, SpaceX. “This is a tremendous responsibility, given the swiftly approaching retirement of the Space Shuttle and the significant future needs of the Space Station. This also demonstrates the success of the NASA COTS program, which has opened a new era for NASA in US Commercial spaceflight.”

Orbital will employ the Taurus II^TM medium-lift launch vehicle and the Cygnus^TM maneuvering space vehicle.

“We are very appreciative of the trust NASA has placed with us to provide commercial cargo transportation services to and from the International Space Station, beginning with our demonstration flight scheduled in late 2010,” said Mr. David W. Thompson, Orbital’s Chairman and Chief Executive Officer. “The CRS program will serve as a showcase for the types of commercial services U.S. space companies can offer NASA, allowing the space agency to devote a greater proportion of its resources for the challenges of human spaceflight, deep space exploration and scientific investigations of our planet and the universe in which we live.”

Both Orbital and SpaceX have issued press releases with more details about the CRS contracts.

Credits: SpaceX

Another critical milestone has been reached by SpaceX with the arrival of Falcon 9 hardware at Cape Canaveral.

After the full mission-length firing test of the Falcon 9 first stage engines and the firing test of the Dragon maneuvering thruster, the arrival of the Falcon 9 first stage fuel tank fulfills SpaceX’s commitment to having Falcon 9 hardware at Cape Canaveral by year-end.

“Christmas has arrived a few days early for our team at the Cape,” said Brian Mosdell, Director of Florida Launch Operations for SpaceX. “The packages measure extra large this year, and they will keep everyone busy in the coming weeks.”

All of the Falcon 9 elements and the ground support hardware have already left the SpaceX manufacturing facility in Hawthorne, California. The hardware will make its way to the launch site at Cape Canaveral over the next two weeks. The Falcon 9 will then be assembled on horizontal and raised to vertical on the custom built erector.

Credits: SpaceX

There are four Falcon 9 launches scheduled for 2009. Two of these launches are demonstration flights with the Dragon spacecraft as part of the NASA Commercial Orbital Transportation Services (COTS) competition. A total of three flights of the Falcon 9/Dragon launch system will be conducted under the agreement, in order to demonstrate cargo delivery capability to the International Space Station (ISS).

NASA’s agreement with SpaceX can be extended to include demonstrating transport of crew to and from the ISS.

“2008 has been a year of rapid progress for SpaceX,” said Elon Musk, CEO and CTO of SpaceX. “The delivery of the Falcon 9 to the Cape is a major milestone in designing and deploying the most reliable, cost-efficient fleet of launch vehicles in the world. I applaud our SpaceX team who has worked 24/7 to make this happen.”

SpaceX has made available a video of Elon Musk giving a tour of the SpaceX Falcon 9 launch site at Space Launch Complex 40, Cape Canaveral AFS, Florida.