OrbitalHub

Wikipedia dixit:

“Ceres is the largest object in the asteroid belt, which lies between the orbits of Mars and Jupiter. Its diameter is approximately 945 kilometers (587 miles), making it the largest of the minor planets within the orbit of Neptune. The thirty-third largest known body in the Solar System, it is the only one within the orbit of Neptune that is designated a dwarf planet by the International Astronomical Union (IAU). Composed of rock and ice, Ceres is estimated to comprise approximately one third of the mass of the entire asteroid belt. Ceres is the only object in the asteroid belt known to be unambiguously rounded by its own gravity. From Earth, the apparent magnitude of Ceres ranges from 6.7 to 9.3, and hence even at its brightest, it is too dim to be seen with the naked eye, except under extremely dark skies.

Ceres was the first asteroid discovered, by Giuseppe Piazzi at Palermo on 1 January 1801. It was originally considered a planet, but was reclassified as an asteroid in the 1850s when many other objects in similar orbits were discovered.

Ceres appears to be differentiated into a rocky core and icy mantle, and may harbor a remnant internal ocean of liquid water under the layer of ice. The surface is probably a mixture of water ice and various hydrated minerals such as carbonates and clay. In January 2014, emissions of water vapor were detected from several regions of Ceres. This was unexpected, because large bodies in the asteroid belt do not typically emit vapor, a hallmark of comets.

The robotic NASA spacecraft Dawn entered orbit around Ceres on 6 March 2015. Pictures with a resolution previously unattained were taken during imaging sessions starting in January 2015 as Dawn approached Ceres, showing a cratered surface. Two distinct bright spots (or high-albedo features) inside a crater, incorrectly reported as observed in earlier Hubble images, were seen in a 19 February 2015 image, leading to speculation about a possible cryovolcanic origin or outgassing. On 3 March 2015, a NASA spokesperson said the spots are consistent with highly reflective materials containing ice or salts, but that cryovolcanism is unlikely. On 11 May 2015, NASA released a higher resolution image showing that, instead of one or two spots, there are actually several.”

Video credit: NASA JPL

Credits: NASA/JPL

Juno is a NASA spacecraft scheduled to start its journey to Jupiter in a few days. Juno will help scientists understand the origin and evolution of Jupiter. While the dense cover of clouds helps Jupiter keep its secrets away from Earth observers, Juno will get close enough to Jupiter so that fundamental processes and conditions characteristic to the early solar system will be revealed.

First, Juno will try to determine if Jupiter has a solid planetary core. While this is an important piece of the puzzle, it might also help determine how Jupiter’s magnetic field is generated (by the way, scientists are still unclear how Earth’s magnetic field is generated, and there are several theories trying to explain it). Juno will also map Jupiter’s magnetic field, study the auroras, and determine the amount of water and ammonia in the atmosphere.

The launch vehicle to lift off with Juno is the most powerful Atlas rocket ever built, the United Launch Alliance Atlas V 551. In this configuration, an Atlas V launch vehicle can lift 18,810 kg to Low Earth Orbit (LEO) and 8,900 kg to Geosynchronous Transfer Orbit (GTO). However, the Atlas V 551 is not powerful enough to put Juno on a direct trajectory to Jupiter. In order to get as far as Jupiter’s orbit, Juno has to perform a gravity assist maneuver.

Juno will orbit Jupiter in a polar orbit and get as close as 5,000 km above the planet’s top clouds. This will allow the spacecraft to do science below the radiation belt of the planet and allow for a complete coverage of the planet. The low altitude will allow for a detailed analysis of the planet’s atmosphere. The orbit will also allow Juno to take a very close look at the auroras that are forming at the north and south Jovian poles.

The scientific payload carried by Juno includes a gravity/radio science system, a microwave radiometer, a vector magnetometer, particle detectors, ultraviolet and infrared spectrometers, and a color camera to capture images of the Jovian poles.

One interesting feature of the spacecraft is the electronics vault. Even if Juno’s highly elliptical orbit avoids the deadly radiation belts by approaching the planet at the north pole, skimming the clouds below the radiation belts, and exiting over the south pole, as an additional protection measure the onboard electronics are protected by a radiation shielded vault. This will ensure that the computers will not malfunction due to single events, and that the electronics will meet the requirements for the mission lifespan.

While the previous missions to the Jovian system have been powered by Radio Thermal Generators (RTGs), Juno will benefit from advances in solar power cell design. The cells used for Juno’s solar panels are far more efficient and radiation tolerant than the cells available to space systems engineers decades ago. Three solar panels that extend more than 10 meters from the hexagonal body of the spacecraft will provide the power required by the scientific instruments.

The mission is scheduled for launch on August 5, 2011. After coasting for more than two years, in October 2013, Juno will swing by Earth. The gravity assist maneuver will provide the delta V necessary for the spacecraft to reach Jupiter’s orbit. Juno will arrive at Jupiter in July 2016. After performing the Jupiter Orbital Insertion (JOI) maneuver, the spacecraft will start to collect and send back home scientific data.

Juno will send back science and telemetry data through the Deep Space Network (DSN), a network of powerful antennas located in Madrid, Spain; Barstow, California; and Canberra, Australia.

At the end of the mission, planned for October 2017, and after 33 complete revolutions around Jupiter, Juno will fire up its thrusters and decrease its velocity, enter the upper atmosphere of Jupiter, and get incinerated. Why such a tragic end to the Juno mission? Remember the Prime Directive? While the Prime Directive is known only to Star Trek fans… and it might get serious consideration only from Star Fleet officers, the possibility of having Juno crashing on one of the Jovian satellites (especially Europa) has to be eliminated. NASA scientists take contamination of other worlds very seriously.

You can find out more about the Juno mission on NASA’s dedicated web site. The Juno mission is managed by NASA’s Jet Propulsion Laboratory in Pasadena, California. The Principal Investigator for the Juno mission is Dr. Scott Bolton of Southwest Research Institute in San Antonio, Texas. The spacecraft was designed and built by Lockheed Martin of Denver, Colorado.

Credits: NASA

ARES (or the Aerial Regional-scale Environment Survey) is an autonomous powered airplane. ARES will bridge the gap between remote sensing and surface exploration on Mars.

This new class of science will allow magnetic surveys with an improved resolution, geologic diversity coverage, and in-situ atmospheric science.

ARES method of deployment is unique because the robotic aircraft has to travel to Mars folded inside a protective shell. After the atmospheric entry and the parachute deployment, the heat shield that protects the aircraft during entry is released. Once the heat shield is out of the way, the folded aircraft leaves the protective shell. The unfolded tail will stabilize the tumbling aircraft. Finally, the wings will unfold and the aircraft will pull up from the dive.

It is needless to say that reliability is essential. All the mechanical systems of the aircraft that are involved in this maneuver must perform without any flaws, and that has to happen after spending six to eight months in vacuum at (more than) freezing temperatures. It is hard to imagine that ARES would be able to fly with a folded wing.

Credits: NASA

The ARES design is the result of five years of extensive analysis and testing. Testing has included wind tunnel tests, ejection tests, and flight tests. In order to simulate the Mars environment, the flight tests had to be performed at certain Mach and Reynolds numbers. A 50% scale prototype was released from a high-altitude research balloon. The robust design that resulted will handle the uncertainties in the Mars environment.

ARES could be selected as the next Mars Scout Mission. For more details about ARES you can visit NASA’s website. ARES Principal Investigator, Dr. Joel S. Levine, presented ARES at a TEDxNASA event. If you want to build your own paper-made scale model of the ARES Mars Airplane, you can find the model here.

Credits: Mark Dowman

Airships are making a big comeback now as the energy consumption for all modes of transportation is being re-analyzed. Missions with special requirements like surveillance and reconnaissance missions and transportation of heavy payloads to remote outposts are the main driver for the reinvention of the airship.

But Earth is not the only place where airships can be deployed. There are a number of destinations in the solar system that would make a perfect environment for deployment and operation of airships, like Mars, Venus, and Titan – Saturn’s largest moon.

The presence of an atmosphere makes possible the use of vehicles that can fly within atmosphere for planetary exploration. Also, planetary exploration with low-powered vehicles like airships really makes sense considering the fact that energy is always at a premium.

So far, the only extraterrestrial deployment of an airship was performed during the Vega mission to Venus, in 1984. Two balloons were released and they floated 54 km above the planet’s surface for nearly two days.

Lighter-Than-Air (LTA) AERial ROBOTS (AEROBOTS) would present some advantages over their Heavier-Than-Air (HTA) siblings and the traditional planetary scouts, the exploration rovers: they would have long-duration mission and long-distance capabilities, they would not have to deal with obstacle avoidance problems, and they have low-power consumption. However, the environment in which the airship will operate will impose some restrictions on the capabilities of the airship (consider things like atmospheric composition and density, temperature, and the amount of solar radiation available). More on the planetary environments in the solar system and airship evaluations for each one of them can be found here.

NASA has funded a number of projects for solar system exploration that make use of aerobots. The Jet Propulsion Laboratory’s Planetary Aerobot Program is developing balloons to support scientific payloads in the atmosphere of other planets in our solar system. You can find more details about JPL’s Planetary Aerobot Program here.

Credits: ESA

On July 10, 2010, the European comet chaser Rosetta will perform the second asteroid flyby of its mission. The first flyby was performed on September 6, 2008, when Rosetta had a close encounter with the asteroid 2867 Steins. Rosetta will skim by the asteroid 21 Lutetia at approximately 3,000 km. The speed of the spacecraft relative to the asteroid will be around 54,000 km/h.

The asteroid Lutetia was discovered on November 15, 1852, by the German astronomer Hermann Goldschmidt. Besides the characteristics of its trajectory, few things are known about the asteroid. From the preliminary observations made by Rosetta, scientists were able to estimate the diameter of the asteroid to 134 km, but the actual shape and composition still remain to be determined.

During the flyby, the spacecraft will operate in a special Asteroid Flyby Mode. This will allow the spacecraft to control its attitude and keep the asteroid in the field of view of the imaging instruments carried onboard.

Rosetta has to follow a complicated trajectory that includes three Earth gravity assists and one at Mars, in order to accelerate to the speed needed for reaching its final destination. The last gravity assist maneuver occurred on November 13, 2009, when Rosetta swung by Earth.

After 6 years into the mission, the systems on the spacecraft are doing very well, and the best is yet to come: the rendezvous with the comet 67/P Churyumov-Gerasimenko in 2014. Rosetta will deploy a small lander on the surface of the comet, and it will continue to fly alongside the nucleus of the comet for more than one year.

OrbitalHub will re-cast the live webstream from ESOC, ESA’s European Space Operations Center, in Darmstadt, Germany. The program starts July 10, 2010, at 20:00 GMT. The closest approach will occur at 20:10:07 GMT. Come back and watch the events unfold!

Credits: JAXA

While solar sail projects around the world are starving for funding, in Japan things are different. The Japan Aerospace Exploration Agency (JAXA) is developing a small solar power sail demonstrator, IKAROS (Interplanetary Kite-craft Accelerated by Radiation Of the Sun). IKAROS is equipped with a square sail made of polyimide resin and 0.0075 mm thick. Long-term plans of the agency include a medium-sized solar power sail with a diameter of 50 m and ion-propulsion engines that will explore the Trojan asteroids and Jupiter.

The solar power sail is a slightly different concept than the traditional solar sail. In addition to the solar sail, the solar power sail has a thin film of solar cells deployed on the membrane. The solar cells generate electricity that can be used to power ion-propulsion engines onboard the spacecraft. Fuel-effective mission profiles are made possible by such hybrids.

IKAROS will be launched from the Tanegashima Space Center on top of a H-II launch vehicle. It will share the ride with the Venus Climate Orbiter “AKATSUKI”.

JAXA is committed to leading the research and the development of solar sails:
“JAXA will lead future solar system exploration using solar power sails. Our missions will lead to lower cost in the solar cells market, whose growth is a key factor for global warming prevention. Those low-cost solar cells are also the foundation of future solar power satellite systems.”

Centauri Dreams presents the comments of Osamu Mori, the project leader for the sail mission, on the solar-powered attitude control system of the spacecraft and the deployment method of the sail. You can find more information about IKAROS on JAXA’s web site.